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TM 11-6625-2735-14-1

1. STARTS AFTER DELAY Li LI KOTE DOT RECOMMENDED TEST EQUIPMENT SWITCH CLOSED SEE PARTS LIST FOR EARLIER SPECIFICATIONS che ECOMMENDED TYPE ExT L O 4 Fej OR DEPICTED IN BLUE Test oscilloscope Frequency response DC to 75 MHz lektrorix 7603 equipped with 7A13 L i Deflection tactor 1mvto5 ViDiv Amplifier and 7850 Time base units cr Tr TED EXTA 522342 5 laput impedance 1 20 pF equivalent P 8 2v 3 5704 5 Sweep rate 50 ns TE 5 TRIGGER ETZA 15 iso SHOWN IN 1 44 T os Sees e POSITION ard 7 Probe Fast rise 10X attenuation com Tektronix P6053B or equivalent MRNA ME F patible with vertical amplifier of test de T a oscilloscope tt 4 87 k Voltmeter iNon laading Input Impedance 10 MO Tektronix DM 501 Digital Multimeter or Digital Multimeter Hange 0 500 V equivalent 870 MW 4225 LT 475 Control Settings Sweep Controls CHI Display Controls TIME DIV 0 1 ms EROM CHII am INTENSITY Midrange VAR TIME DIV Gal brated detent e ETE 5 FOCUS Midrange DELAY TIME Pe To Reser S METRY 40 2 1 2 SCALE ILLUM Midrange P
2. j LOGIC MULT 3 i LOGIC MULTI 4 0588 TO 9696 7 AXIS INTEN esy L 9 3 AMFLIFIEA hem ped 1 ai FF SWITCH 01212 QUTPUT 01308 01316 i B TRIGGER BY AMPLIFIER 21310 01318 SEXY AMP amp TUNNEL DELAYED GATE DELAYED GaTE 01022 TRIG INPUT 712 d742 TD DRIVERS DIODES COMPARATOR 4j AMPLIFIER 01026 Y Q714 Q744 9729 0752 CR776 9802 0996 0716 Q746 DELAY TIME POSITION DELAY START STOP q COMPARATOR 0926 0928 AMPLIFIER 9930 4772 0782 CR786 0804 1957 160 V ka 0v EN 50 Y DELAYING TAIGGER 2 OMM i TD RESET LOW VOLTAGE 715 Y UNREG 21690 2790 POWER SUPPLY IT 0788 0792 Q1424 thru IS Q796 01498 UNAEG U1418 11454 FROM SWEEP END 4 171484 ss DIFFERENCE AMP p av 01034 Q1044 DELAY FROM SWEEP 61V GENERATOR TO GRATICULE LAMPS MORTON 5 EL6UGO47 9920 2922 91492 01498 Q938 FO 1 Biock diagram VOLTAGES AND WAVEFORMS The voltages and waveforms shown on this diagram were obtained by using the recommended test equipment and test set ups listed below RECOMMENDED TEST EQUIPMENT SPECIFICATIONS RECOMMENDED TYPE Tektronix 7603 eq
3. 2 Lass cas Mak 77 7 d tbc PLC DC PLA VERTICAL 5 7 MODE 1 s300 TM 11 5625 2735 14 1 icti a i NORM 22 W k NRD i VOLTAGE amp WAVEFORM DO CENTER od anu Qaia s f CONDITIONS 2e 8355 125 a e 939 S 4 7 CH I VEAT am FROM 3188 gt SIG FROM 927182 COUPLED VERT FROM 998 722 frase 9 24 RAST E md R354 534 2 ako 439 E iwi ourer CR30 megri AM BASES R355 RM TE 34 lt 41 w NNER 2 amp 102 mm a BASES 220 RA 5 BV 33 FOUT Lt re dl av ELT Loans 8358 NNER f Ceca 25 5374 Ri BASES 2 Ouf meni 9444 R3G3 CH d amp _ ta a ANGEL En L Suena d J385 Mass ve 9319 uct Eae 50 E M chi MOUOLITMIC TRO CENTER CHANNEL SUSAR I SWITCH nen Yon i R421 l Mr 232 a 2 aao REAR PANEL 475 VERT MODE CR336 TO CHOP AND TEST INTERNAL TRIGGER 8322 0324 7 OO cx
4. j EROM AG gal p 79990 v CRISS ap 6 6V NOT Lom w SA WITH DMAA ear ke RIB p SEES 3 2k k x po 2969 i 8v i pm lt gt CH7 T 5v 2 14 6 90 ad 510504 L 781 291 Whee 59 co A 9922 RILI sav BEN um 2 EN COUPLED 41039 ek gt TPOS G 1222 3 viene L 7 2 OC COUPLED cRIOZ od 1025 ga Tm 911 emos VRIDRR eeu ET T ng Biv zo Cs 4 1 LRG ee Ty 1999 acc OPTION Bit a ed mann n 15 BC PLI DCPL2 COC PLAS 79 47 Rayi RCPS 6965 C ins 18 ja quer 10 Mee a vi COUPLED HSY Lev Ren 106 aoia WA un HT gal an aA uua y AY MT Man e atenn pu ELGUGOSS 7 7 T 7 SWEEP GENERATORS Wy A San hate vcio a FO 9 Sweep generators schematic diagram 4 CR que VOLTAGES AND WAVEFORMS The voltages and waveforms shown on this diagram were obtained by usirg the recommended t
5. REAR PANEL EL6UGO27 Fig 2 2 Front panel and rear panel controls and connectors TM 11 6625 2735 14 1 CH 2 OR Y GAIN 2 and 5 mV VOLTS DIV VAR UNCAL Input coupling AC GND DC 100 OR 20 MHz BW TRIG VIEW Input connector for Channel 2 deflection signals or Y axis deflection in the X Y mode of operation Screwdriver adjustments to set the gain of the Vertical Preamp Selects vertical deflection fac tor in a 1 2 5 sequence VAR control must be in the calibrated detent for the in dicated deflection factor Provides continuously variable uncalibrated deflection factors between the calibrated settings of the VOLTS DIV switch Light indicates that the VAR control is not in the calibrated position Selects the method of coupling signal to the input of the Vertical Amplifier AC Signal is capacitively coupled to the Vertical Amplifier DC component of signal is blocked Low frequency limit lower 3 dB point is about 10 Hertz GND Input signal is removed and the input circuit is ground ed Does not ground the input signal DC All components of the in put signal are passed to the Vertical Amplifier Multi purpose switch that limits vertical bandwidth or displays an external triggering signal Full bandwidth of 200 MHz is provided in the switch position obtained when the TRIG VIEW is pushed in then released The full bandwidth position serves as the reference for the foll
6. RET AS PART OF INVERTER BOARD BY THE LEAD MAY TURN THE INVERTER 11 6625 2735 14 1 Start circuit When 1601 is closed the external dc source is applied to C1614 VR1641 and R1645 The initial surge is coupled to Q1642 through C1614 VR1639 and R1641 Transistor Q1642 saturates until Q1614 charges through R1639 to the value determined by VR1639 and the base emitter junc tion of Q1642 about 5 7 volts then Q1642 is cut off R1641 limits the base current in Q1642 Zener diode VR1639 once C1614 is charged makes Q1642 insensitive to input variations R1642 limits Q1642 collector current Q1644 R1645 and VR1641 provide a constant current during the time Q1642 is saturated regardless of the dc source voltage CR1643 is reverse biased by this starting current The starting current is applied to the inverter transistors through T1631 Inverter Circuit The starting surge is applied to the bases of Q1652 Q1662 Q1654 and Q1664 trough T1631 R1652 R1662 R1654 and R1664 Since the transistors do not have identical parameters one pair will conduct before the other and start the inverter Operating base current is provided through CR1643 R1626 R1631 and T1631 primary and secondary are the main frequency determining components for the inverter Four base resistors R1652 R1662 R1654 and SEE PARTS LIST FOR EARLIER VALUES AND SERIAL NUMBER RANGES OF PARTS OUTLINED OR DEPICTED IN GRE Y
7. teri els VAR i MW 44 E v C 157 QUIZ 9145 tr T cri o5 R23 EUH 3 2 2 JR Go ze ES Am 92497 Jwenn EARS 49 ko i Sav fca l S5 Li K me 70 PIN il i w TE IET Set a ca a a RISA 20 4 ese B SE MAN SE fee Book IK Te 00 Se Ci33 5 1170 FROM R42 BCALE 2 15 RI2G 16 205 Ww CRI82 L 2 ax H S GANJ i g BT YERT POS 8 pco 255779 CH gt LIBO Ciaz LIB PUES 6 3 died EL mu cH VERT SIGNAL TO PIN 10 03 70 gt a 5 25 a A e SEL LIT RIA 5 ee pi 30 522 56 HYBEID cero j LI DUAL FET INPUT MOART OF ETCHED CIRCUIT BOARD L AMPLIFIER ELGUGOAB CH VERTICAL PREAMP FO 2 Channel 1 vertical preamplitler schematic diagram VOLTAGES AND WAVEFORMS The voltages and waveforms shown on this diagram were obtained by using the recommended test equipment and test set ups listed below RECOMMENDED TEST EQUIPMENT SPECIFICATIONS RECOMMENDED TYPE Test oscilloscope Frequency response DC to 75 MHz Tektronix 7603 equipped with A13
8. INTENSITY Midrange VAH TIME DiV Calibrated detent FOCUS Midrange DELAY TIME SCALE ILLUM Midrange POSITION Futl counterclockwise HORIZ DISPLAY A X10 MAG Off button out POSITION Midrange FINE Midrange Verticai Controls CH 1 and CH 2 POSITION Center trace on graticule VOLTS DIV 2 mV for dc voltages Voltage Measurements 100 mV for waveforms Voltage measurements are taken with no signal applied VAR VOLTS DIV Calibrated detent and the trace positioned to the center horizontal graticule AC GND DC DC iinc The voltmeter common is connected to chassis INVERT Off button out ground VERT MODE CH 1 100 or 20 MHz BW Full bandwidth Pus Waveform Conditions then reizase Apply the 4 5 calibrator signal to CH 1 input through a P6075 10X probe supplied with 475 Connect 475 A GATE irear panel tr rough a 42 inch 5G ohm cable to test oscilloscope exte nal trigger input Set test os cilloscope trigger source to external and set vertical input far ac coupling For waveforms which have the horizontal i Trigger Controls A and B centerline iabe ed D V set the test oscilloscope vertical COUPLING AC input for dc coupling LEVEL 9 SLOPE Set test oscilloscope VOL TS DIV and TIME DIV con SOURCE NORM trois as indicated on readout symbols on each wavsform TRIG MODE AUTO A TRIGGER NORM Tolerance of voltages and waveforms shown are 20 ALT TRACE d e PULSE FROM RSI 5V d FROM
9. Within 596 over any 2 division interval Within 396 Continuously variable between cali brated settings Extends the slowest A sweep rate to at least 1 25 sec onds per division Increases sweep holdoff time to at least 9 times the TIME DIV switch setting Accuracy specification applies over the ful 10 divisions of deflection unless otherwise specified For all sweeps exclude the first 25 ns when checking 0 01 and 0 02 us div un magnified sweep rates For all sweeps except B exclude the first 25 ns or 2 unblanked div whichever is greater and all beyond the 100th divi sion of the sweep when checking magnified sweep rates For B sweep exclude the first 25 ns or 5 unblanked div whichever is greater and all beyond the 100th division of the sweep when check ing B magnified sweep rates Accuracy applies over 8 divisions of deflection B sweep must be at least 1 TIME DIV setting faster than A Sweep on all ranges When checking A TIME DIV accuracy exclude the first 0 5 division after the display start when checking B TIME DIV accuracy exclude the first 0 2 division or 0 1 4S whichever is greater after the transition of A to B At least 2 5 1 At least 10 1 divisions Characteristics Magnified Registration POSITION Control Range Delay Time and Differential Time Measurement Accuracy simplified Over One or More Major Dial Divisions Over Less Than One Major Dial Division
10. OS 261B V 1 U and O8 261C V 1 U Sheet 2 of 3 Change 1 B 3 TM 11 6625 2735 14 1 SECTION Il INTEGRAL COMPONENTS OF END ITEM PROBE P6106 B 4 Change 1 TM 11 6625 2735 14 1 SECTION Il INTEGRAL COMPONENTS OF END ITEM 1 ILLUSTRATION 2 3 QUANTITY NATIONAL DESCRIPTION 4 STOCK LOCATION NUMBER RCVD DATE PART NUMBER 6625 00 127 0079 OSCILLOSCOPE 1 OS 261B V 1 U and 0S 261C V 1 U 80008 Consisting of POUCH Top of 1 016 0535 02 80009 oscilloscope ACCESSORY PACKAGE pouch 020 0580 00 80009 Consisting of ACCESSORY BAG In pouch 1 016 0537 00 HOOK TIP In pouch 1 013 0071 00 80009 CONNECTOR UG274C U BNC T In pouch 1 103 0030 00 80008 CONNECTOR UG1035 U dual banana to male BNC n pouch 1 103 0035 00 80009 BANANA TIP In pouch 1 134 0013 00 80009 ADAPTER Plug tip In pouch 1 134 0016 01 80009 FUSE In pouch 1 AGC3 4 71400 FUSE In pouch 2 AGC 1 1 2 71400 206 0105 00 80009 PEN TIP In pouch 1 206 0134 03 80009 206 0168 00 80009 337 1674 01 80009 Change 1 B 5 TM 11 6625 2735 14 1 1 B 6 SECTION Il INTEGRAL COMPONENTS OF END ITEM 3 DESCRIPTION PART NUMBER PROBE WITH ACCESSORIES 010 61 1 01 80009 Consisting of PROBE 010 6101 00 80009 Consisting of PROBE HEAD 206 0223 00 80009 Consisting of PROBE TIP 208 0191 01 80009 PROBE TIP 0150201 01 80009 CABLE ASSEMBLY 175 1661 01 80009
11. 11 Remove the solder from the holes in the circuit board wire terminal pads where wires were removed in this procedure to facilitate installation To install a new Power Transformer reverse this removal procedure Cathode ray Tube Removal Use care when handling a crt Projective clothing and safety glasses should be worn Avoid striking it on any object which might cause if to crack or implode When storing a crt place it in a protective carton or set it face down on a smooth surface in a protected location with a soft mat under the faceplate to prefect it from scratches 1 475 DM 43 and DM 40 only Disconnect three ribbon cables from the DM 43 or DM 40 main circuit board Remove two screws from the rear of the main circuit board chassis and separate the board and chassis assembly from the instrument chassis 2 Remove the Vertical Output circuit board shield if installed 3 Remove two flat head screws from the blue plastic cover at the rear of the instrument Carefully position the blue plastic cover to allow access to the screws holding the crt rear cover then remove the crt rear cover 4 Disconnect the crt anode plug from the high voltage jack and touch the lead to the chassis to remove any stored charge 5 Disconnect the crt base socket from the rear of the crt 6 Disconnect the four vertical deflection plate leads from the Vertical Output board at the crt neck pins 7 Disconnect the two horizontal d
12. WASHER FLAT 0 195 ID X 0 367 INCH OD BRS 42 l SPRING HLCPS 0 20 INCH LONG 43 1 ACTUATOR CAM SW ATTEN 4 1 SHAFT CAM SW REAR 45 4 NUT PLAIN HEX 4 40 X 0 188 INCH BRS 46 l SPRING FLAT GREEN COLORED 1 SPRING FLAT RED COLORED 47 2 ROLLER DETENT 48 l 5 BEARING CAM SW FRONT 49 5 CKT BOARD ASSY GAIN SWITCH 50 6 TERM PIN 0 46 L X 0 025 SQ PH BRZ GL 51 29 TERMINAL PIN 0 365 L X 0 25 PH BRZ GOLD PL 52 10 CONTACT ASSY EL CAM SWITCH TOP ATTACHING PARTS FOR EACH 53 l RIVET TUBULAR 0 051 OD X 0 115 INCH LONG m a 54 SOCKET PIN TERM 0 188 INCH LONG SOCKET PLUG IN 3 PIN SQUARE SOCKET PLUG IN 3 PIN LOW PROFILE 55 2 CPLG SHAFT FLEX FOR 0 125 INCH DIA SHAFTS SETSCREW 4 40 X 0 188 INCH HEX SOC STL 56 1 RES VAR NONWIR 128 5128 57 1 SPACER SWITCH PLASTIC 58 l RES VAR NONWIR R228 S228 59 1 SPACER SWITCH PLASTIC 60 2 SHIELD ELEC CIRCUIT BOARD ATTACHING PARTS FOR EACH 61 3 SCR TPG THD FOR 2 56 X 0 312 INCH PNH STL 62 3 WASHER LOCK INTL 0 092 ID X 0 175 0D STL 63 3 WASHER FLAT 0 09 ID X 0 25 INCH OD BRS m wm E w 64 1 SW PUSH BUTTON VERT 5300 65 4 SPACER PUSH SW 0 13 W X 0 375 INCH L PLSTC 66 2 LAMPHOLDER 67 2 EXTENSION SHAFT 0 123 OD S 5 7 INCH LONG 68 1 EXTENSION SHAFT 0 13 SQ X 6 215 LONG PLSTC 5 EXTENSION SHAFT 5 607 LONG 69 2 CPLG SHAFT RGD 0 12
13. gt FROM DLIBC e freee SCO CONDITIONS Hess POPS AROMA E RR Carver I ote VOLTAGE amp WAVEFORM 15 5447 2 26K TM 11 6625 2735 14 1 KECHL 15 TW wm an MC E Sires ZRT paso n eat Amel lu 1 PLAT S 2 43 5v gt Puy paqa n SEL P ques VRAGZ baggy AW Pu js a VERTICAL zave H OUTPUT BIAS prd RAI 2 5 gt geir pn 9470 Es 829 HY BED M VERT OUTPUT cate i 150 c2 Max SEL i d 25 2 8v R461 SEL 5 av 5 san 421 R 5 m 3 ace 452 a 243 3 By DU iUe im 3 5 PART ETCHED CIRCUIT BOARD H fDSPLI H 3 1 L casa cass i gt 5 L458 R4s LA99 R499 M BOT 41 3 5 P450 2450 3 Bohr meet ont o sa x a Yo ABRE AP n S AHS GESTS Rte iu tent egets ord Y 15 SN 35 VERTICAL OUTPUT AMPLIFIER lt gt 1616051 FO 5 Yerilcal output amplifier schematic diagram VOLTAGES AND WAVEFORMS The voltages and wavef
14. 6 Clean the area around the solder connection with a flux remover solvent Be careful not to remove informa tion printed on the board When soldering to the ceramic strips in the Instruments slightly larger soldering iron can be used It is recommended that a solder containing about 3 silver be used when soldering to these strips to avoid destroying the bond to the ceramic material This bond can be broken by repeated use of ordinary tin lead solder or by the application of too much heat however occasional use of ordinary solder will not break the bond if excessive heat is not applied Observe the following precautions when soldering to a ceramic terminal strip 1 Use a hot iron for a short time Apply only enough heat to make the solder flow freely 2 Maintain a clean properly tinned tip 3 Avoid putting pressure on the ceramic terminal strip 4 Do not attempt to fill the terminal strip notch with solder use only enough solder to cover the wires ade quately 5 Clean the flux from the terminal strip with a flux remover solvent 4 20 If it becomes necessary to solder in the general area of any of the high frequency contacts in the instrument clean the contacts immediately upon completion of the soldering Refer to Cleanlng Switch Contacts under PREVENTIVE MAINTENANCE for recommended cleaners and procedures Small Component Replacement WARNING Always disconnect the instrument from the power source be
15. ADAPTER 103 0189 00 80009 POUCH OBD 05006 TIP 013 0107 03 80009 SLEEVE 166 0404 01 80009 CLIP 344 0046 00 80009 HOLDER 352 0351 00 80009 TIP 206 0191 01 80009 LEAD 175 0125 01 80009 LEAD 175 0124 01 80009 4 LOCATION In pouch In pouch On probe On probe On probe On probe On probe In pouch In pouch In pouch In pouch In pouch In pouch In pouch In pouch 7 QUANTITY RCVD DATE SECTION Il INTEGRAL COMPONENTS OF END ITEM ILLUSTRATION 3 DESCRIPTION 2 NATIONAL gt UJ STOCK FIG ITEM NUMBER NO NO PART NUMBER PROBE WITH ACCESSORIES 010 6106 01 80009 Consisting of PROBE 010 6106 00 80009 Consisting of PROBE HEAD 206 0216 00 80009 Consisting of PROBE TIP 206 0191 01 80009 PROBE TIP 015 0201 01 80009 CABLE ASSEMBLY 175 1661 00 80009 COMPENSATION BOX 206 0237 00 80009 RETAINER 343 0570 00 80009 POUCH OBD 05006 TIP 013 0107 03 80009 SLEEVE 166 0404 01 80009 CLIP 344 0046 00 80009 HOLDER 352 0351 00 80009 TIP 206 0191 01 80009 LEAD 175 0263 01 80009 LEAD 175 0124 01 80009 TIP 015 0201 01 80009 FSCM 4 LOCATION In pouch In pouch On probe On probe On probe On probe On probe On probe In pouch In pouch In pouch In pouch In pouch In pouch In pouch In pouch In pouch
16. CHECK Signal should be flat See A PROPERLY ADJUSTED B IMPROPERLY ADJUSTED 1600066 Figure 6 8 inverter Balance Change 1 6 2 7 TM 11 6625 2735 14 1 OPTION 7 EK EQUIP DC INVERTER ATTACHING PARTS SCREW MACHINE 4 40 X 0 25 INCH PNH STL WASHER FLAT 0 109 ID X 0 25 INCH OD STL ATTACHING PARTS SCREW MACHINE 4 40 X 0 25 100 DEG FLH STL m m CIRCUIT BOARD ASSY INVERTER SOCKET PIN TERM 0 188 INCH LONG XFMR TOROID SEE T1601 EPL ATTACHING PARTS RETAINER XFMR SCREW MACHINE 8 32 X 0 750 INCH FLH STL ACTUATOR SWITCH SWITCH SENS 10A 250V SPDT SNAP ACTION ATTACHING PARTS SCREW MACHINE 2 56 X 1 75 INCH PNH STL 9 4 aa wwes f NUT PLAIN 2 56 X 0 188 INCH BRS m a PLATE ACT GUIDE INVERTER SPRING SW ACT POWER SOURCE SWITCH TOGGLE DPDT SA 125VAC 0 25 40 THD ATTACHING PARTS NUT PLAIN HEX 0 25 40 X 0 312 INCH BBS WASHER LOCK INTL 0 26 ID X 0 40 OD STL 0 WIRING HARNESS GROMMET RUBBER 0 50 INCH DIA COVER SCOPE REAR TERMINAL LUG 0 146 INCH DIA DE 45 DEG BEND MARKER IDENT CONNECTOR RCPT POWER ATTACHING PARTS SCREW MACHINE 4 4C X 0 25 100 DEG PLH STL FOOT CABINET PLASTIC W LATCH GROOVE ACCESSORIES 3 e 5 la B B P ATTACHING PARTS SCR ASSEM WSHR 4 40 X 0 312 INCH PNH BRS 27 1 2 28 TRANSISTOR SEE Q1
17. FRONT ATTACHING PARTS SCR TPG THD FOR 6 20 X 0 5 TYPE B PNH STL SHLD ELECTRICAL HIGH VOLTAGE ATTACHING PARTS SCREW MACHINE 4 40 X 0 188 INCH PNH STL am GROMMET PLASTIC U SHP 0 548 0 462 INCH CKT BOAD ASSY FAN MOTOR SEE A6 EPL ATTACHING PARTS SCR TPG THD 4 24 X 0 25 INCH PNH STL CKT BOARD ASSY INCLUDES SOCKET PLUC IN 14 CONTACT LOW CLEARANCE TERMINAL PIN 0 365 L X 0 25 PH BRZ GOL SOCKET PIN TERM 0 188 INCH LONG SOCKET PLUG IN 20 LEAD DIP CKT BD MTG SOCKET PLUG IN 3 PIN SQUARE SOCKET PLUG IN 3 PIN LOW PROFILE MOTOR DC Bl690 MOUNT MOTOR SHLD ELECTRICAL FAN MOTOR MOUNT MOTOR om PL ATTACHING PARTS SCREW MACHINE 4 40 X 0 25 INCH PNH STL FO amp Index No 15 82 83 84 85 90 91 92 93 94 95 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 l 14 Qty l AJ NO AY TM 11 6625 2735 14 1 12345 TRANSISTOR CHAS MTG Q1318 ATTACHING PARTS SCREW MACHINE 4 40 X 0 375 INCH PNH STL TERMINAL LUG SE 8 INSULATOR BSHG 0 25 DIA X 0 188 INCH L HEAT SINK ELEC TRANSISTOR BRACKET XSTR ALUMINUM ATTACHING PARTS 4 Name 4 Description n 5 NCH STL ALA 791 1 4 9 UL LD
18. REAR PANEL Ss V n Cres 2 4829 4 TI REAR PANEL 5065 D 0 589 sx e sevo DC COUPLED BIL pu RGIS TO QI338 5 Ev 4634 Raid B 1 1 1 Y DISABLE FROM 51050 A A TD RESET 02N i HOLDOFF 0 R556 s Resa efikas MED DC COUPLED 5 FREM 940A RG29 5 aw 1 334 P LINE Ridge lt 1497 051492 EIN 100K LaF v LI a vw EN Ri493 ISN 1498 i FROM vVRSTO 4 2192 2154 SON 27292 8 06 E T 2 19 rS 2 50V FREM FO 8 Sweep and Z axis logic schematic dlagram EL6UGOS4 The voltages and waveforms shown on this diagram were obtained by using tne recommended test equipment and test set ups listed below ITEM Test oscilloscope Probe Voltmeter Non loading Digital Multimeter 475 Control Settings Display Controls INTENSIT Y FOCUS SCALE ILLUM VOLTAGES AND WAVEFORMS RECOMMENDED TEST EQUIPMENT SPECIFICATIONS RECOMMENDED TYPE Frequency response DC to 75 MHz Tektrorix 7603 equippec with 7A13 Deflection factor 1 mv to 5 Amplifier and 7050 Time base units or Input impedance 1 20 pF equ valent Sweep rate 50 ns Fast rise 10X attenuation probe com Tektranix 5 or equivalent patible with vertical
19. _ FOOT CABINET W CORD WRAP ATTACHING PARTS FOR EACH SCREW MACHINE 8 32 X 1 0 INCH PNH STL em SHLD GSKT ELEC 0 187 INCH DIA 2 75 FT L SECT CAB REAR ATTACHING PARTS SCREW MACHINE 6 32 X 0 875 INCH PNH STL ve NE mc e FILTER ELEM AIR 2 5 X 2 5 X 0 25 CONNECTOR RCPT BNC FEMALE W HARDWARE ATTACHING PARTS FOR EACH TERMINAL LUG 0 391 ID INT TOOTH M Rm CONN RCPT ELEC 4 CONT QUICK DISCONNECT ATTACHING PARTS FOR EACH NUT PLAIN HEX 9 MM X 0 437 INCH WASHER LOCK INTL 0 375 ID X 0 50 OD STL o PLATE CONN MTG ALUMINUM COVER SCOPE REAR ATTACHING PARTS SCREW MACHINE 4 40 X 0 25 100 DEG FLH STL me a COMES ee my COVER INCLUDES COVER FAN IMPLR STOP FAN IMPLR FAN SCREEN FAN 2 5 X 2 5 X O O32 AL COV ASSY LINE V FUSEHOLDER 0 262 ID TUBE FOR CRTG FUSE ATTACHING PARTS SCREW TPG TF 4 20 X 0 312 PNH STL CD PL m m m BODY ASSY LINE ATTACHING PAR NUT PLAIN HEX 6 32 X 0 25 1 WASHER LOCK 6 0 018 5 CD PL T i BODY LINE VOLTGE INCLUDES BUS CONDUCTOR CONT ASSY ELEC LINE V SEL LOW MED HI RIVET TUBULAR 0 188 L X 0 125 OD BRS CLIP ELECTRICAL FUSE CU BE ALBALOY PL CABLE ASSY PWR 3 WIRE 92 INCH LONG ATTACHING PARTS BSHG STRAIN RLF 90 DEG 0 25 INCH DIA HOLE CABLE NIP ELEC 0 265 ID X 0 38 0D W FLG BSHG STRAIN RLF 180 DEG 0 156 DIA HOLE 7 21 TM 11 6625 2735
20. c Set the sine wave generator for a 6 division display of reference frequency It may be necessary to insert more attenuation to reduce display amplitude NOTE If generator has no reference frequency setting set for 5 megahertz d Without changing the generator output amplitude increase the output frequency until the display is reduced to 4 2 divisions e CHECK For a generator frequency reading of 200 megahertz or more 15 to 40 f Set VERT MODE to CH 2 and move test signal setup to CH 2 input g CHECK Repeat the bandwidth check procedure parts c d and e 5 8 9 Check Bandwidth Limit Operation a Set 100 OR 20 MHz BW control to 100 NOTE If may be necessary to change sine wave generators See test equipment required Table 5 1 for selection of generator with an output of 100 megahertz and below b Set the sine wave generator for a 6 division display of reference frequency c Without changing the generator output amplitude increase the output frequency until the display is reduced to 4 2 divisions d CHECK For a generator reading of approximately 100 megahertz e Set 100 OR 20 MHz BW control to 20 f Set the sine wave generator for a 6 division display of reference frequency g Without changing the generator output amplitude increase the output frequency until the display is reduced to 4 2 divisions h CHECK For a generator reading of approximately 20 megahertz
21. w LAMPHOLDER ACTUATOR SWITCH COUPLING ACTUATOR SWITCH COUPLING e SPRING FLAT RED COLORED ROLLER DETENT 0 125 DIA X 0 125 INCH L GUIDE SLIDE SW ADPT SHAFT CPLG SLIDE TO SHAFT SETSCREW 4 40 X 0 125 INCH HEX SOC STL ACTUATOR SWITCH A SOURCE ACTUATOR SWITCH A SOURCE SPRING FLAT GREEN COLORED ROLLER DETENT 0 125 DIA X 0 125 INCH L GUIDE SLIDE Sw ADPT SHAFT CPLG SLIDE TO SHAFT SETSCREW 4 40 X 0 125 INCH HEX SOC STL ACTUATOR SWITCH B SOURCE ACTUATOR SWITCH B SOURCE SPRING FLAT GREEN COLORED ROLLER DETENT 0 125 DIA X 0 125 INCH L GUIDE SLIDE SW ADPT SHAFT CPLG SLIDE TO SHAFT FO 16 Located in Back of Manual 7 25 TM 11 6625 2735 14 1 7 26 50 51 52 53 54 55 56 57 58 59 62 63 64 65 66 67 69 70 71 72 73 74 75 76 1 4 4 KI 23 17 AJ AJ e e Lnd ou NO ta Doe D iR SW ATTACHING PARTS RING RETAINING O ii FREE IDX we CONTACT ASSY EL CAM SWITCH TOP ATTACHING PARTS RIVET TUBULAR 0 051 OD X 0 115 INCH LONG am Kw e e AJ va 2 a PLATE LEVER MTG SLIDE SWITCH ATTACHING PARTS EYELET METALLIC 0 089 OD X 0 218 INCH LONG m Eka BRACKET ELEC SW ALUMINUM BOARD ASSY TIMING ATTACHING PARTS SCR ASSEM WSHR 4 40 X 0 312 INCH PNH BRS POS
22. 3 8 volts Check TP996 for approximately 1 7 volts Check the collector of 0984 for approximately 0 2 volt Install Q572 and check the collector of Q984 for a repetitive sweep waveform MIX Sweep and Logic The A Sweep A INTEN Sweep and B DLY D Sweep should be working properly before starting this procedure Remove all external signals to the Instrument set ATIME DIVto 1 ms unlock knobs and set BTIME DIV to 0 1 ms set HORIZ DISPLAY to MIX set TRIG MODE to AUTO and set B TRIGGER SOURCE to STARTS AFTER DELAY Compare the waveform obtained at pin 10 of J5 against the waveform at the collector of Q922 and check for similarity Check TP996 for a delayed gate with an amplitude of appoimately 1 7 volts that occurs during the run down ramp on the collector of Q922 The time position of the delayed gate can decontrolled with DELAY TIME POSITION Check the collector of Q984 for a fast ramp waveform that occurs during a slow ramp waveform The fast ramp waveform runs down at a rate set by the B TIME DIV control and is positioned in time by the DELAY TIME POSITION control TM 11 6625 2735 14 1 Troubleshooting the Horizontal Amplifier The Horizontal Amplifier contains push pull circuitry that can be checked in the following manner Set TIME DIV to 1 ms lock knobs and set TRIG MODE to SINGL SWP Remove Q1114 Q956 and Q1026 from their sockets Connect a voltmeter between the base of Q1152 and the base of Q1162 adjust R1130 for O
23. BNC cable to test ascilloscope external trigger input Set test os Trigger Controls A and B cilloscope trigger source to external and set vertical input COUPLING AC for ac coupling LEVEL 0 SLOPE Set test oscilloscope VOI TS DIV and TiME DIV con SOURCE NORM trols as indicated on readcut symbois on each waveform TRIG MODE AUTO A TRIGGER HOLDOFF NORM Tolerance of voltages and wavefarms shown are 2096 TM 11 6625 2735 14 1 Il a Duca BEL x TT SEL Rm 3 Cso C37 JIO ATTEN Gwo a4 57 si l 1 m 4 TO 104 Re CRIO4 470K SWITCH AC 2 20 1 n SHOWN Li z IN POSITION 20 NU AC GNO DC 59 6 8204 ta Uo RAS ISHING oy E I5V 5 LI 1 lo 1 Hi 2 _ 20 Piva 5 P300 2 5 50 SwITCH SADWN iN la 2 3 NOTE DOT INDICATES SWITCH 4 2 POSITION i T CLOSES CONTACT Y 1 LI 1 WHEN TWO ARE PRESENT i tHOV IBY asyo av i VOLTAGE amp WAVEFORM gt ping 1 v apt 1 CONDITIONS 5125 2 2 1 d R 5 Bl gl bo EA 869 d E Piwo EY Y Map 8 Ry CHI
24. Determines the operating mode for the A Trigger Circuit AUTO With the proper trigger control settings A Sweep can be initiated by signals that have repetition rates above about 20 Hertz and are within the fre quency range selected by the COUPLING switch In the absence of an adequate trigger signal or when the trigger con trols are misadjusted the sweep free runs to produce a reference trace TRIG Indicator A TRIG HOLDOFF External Trigger Input not labeled A and B Sweep DELAY TIME POSITION NORM With the proper trigger control settings A Sweep can be initiated by signals that are within the frequency range selected by the COUPLING switch In the absence of an adequate trigger signal or when the trigger controls are misad justed there is no trace SINGL SWP After a sweep is displayed further sweeps can not be presented until the SINGL SWP pushbutton is pressed again The display is triggered as for NORM opera tion using the A Triggering con trols A light on condition indicates that A Sweep Generator is triggered and will produce a stable display Provides control of holdoff time between sweeps to obtain stable displays when triggering in aperiodic signals such as complex digital words Variable can increase hold off time up to at least 9 times the setting of the TIME DIV switch In the B ENDS A position fully clockwise the A Sweep is reset at the end of the B Sweep to provide the
25. EL6UG007 PREFIX ALL REF DES WITH A6 Fig 7 5 A6 board component locations TM 11 6625 2735 14 1 C1082 ON BACK C1072 ON BACK NN C1062 ON BACK 1090 ON BACK PREFIX ALL REF DES WITH A7 EL6UGOO8 Fig 7 6 A7 boerd component locations 7 8 TM 11 6625 2735 14 1 5 Mun ETD 5 5 m ci Sp 8 8 a Bi 888 SELI 2 5152 5 I E Sp S 4149 mE at AD ont ga asi 9t B 1 8 eg mE ca tah Y w q a ma 5 am 5 Ras 5 EPIS arza 53 E J Ce m S lt X g S50 C610 444 c 0 1492 7 9 Fig 7 7 board component locations Sheet 1 of 3 TM 11 6625 2735 14 1 PREFIX ALL REF DES WITH 8 8 84 15 8118 S ge sois v 8 2 2 4 YO i e WII LJ 5 796 Ja 9720 e NIX Se od ELI N S B 50 a 8759 5 50 R534 R547 R565 RO S 5 Ps E R804 5 21559 Cla IS 1546 e IRIS 8807 88 95985 GAS 6 562 2119 0556 SA LA N a 27 3 2 MENTRE 8578 R588 R799 80 2 EL6UGO10 Fig 7 7 A8 board component locations Sheet 2 of 3 7 10 TM 11 6625 2735 14
26. EL6UGO62 Change 1 6 2 3 TO PAN 11 T1400 TO 514018 TM 11 6625 2735 14 1 R1664 distribute the drive evenly between the four transistors C1652 C1662 C1654 and C1664 degenerate the high frequency response and reduce transients Feedback to maintain inverter operation is provided from T1400 primary to T1631 primary through R1626 R1631 1633 1632 and CR1634 Resistors R1626 and R1631 provide frequency stability and current limiting R1633 CR1632 and CR1634 compensate for differences in transistors and components CR1632 and CH1634 conduct during different inverter half cycles and permit R1633 to balance the drive to T1400 C1681 C1682 C1683 C1684 C1685 and C1686 are added to the secondary of T1400 with Option 7 to provide optimum reduction of transients during inverter opera tion DC Input External power is applied through P1601 CR1601 is normally reverse biased If the wrong polarity external power is applied CR1601 becomes forward biased and blows fuse F1601 Low pass network T1601 C1601 C1603 and C1609 is a filter to reduce transients to the dc source OC WVERTER BOARD P1401 NSARION 6018 1 i 1401 D BY _ J 4 GAMGEO RANGE Put WITH GREY POWER 00 SWITCH 1665 2 NOTE 140 SHOWN iN OFF POSTION 14V POSITION SEL PARTS LIST FOR EARLIER AND San Start Stop Switch
27. REASON This is the output line of the 5 VDC power supply 24 VDC is the input voltage PRINTED NAME GRADE OR TITLE AND TELEPHONE NUMBER 556 I M DeSpiritof 999 1776 SIGN HERE 7 7 LGU id DA FORM 2028 2 PREVIOUS EDITIONS P S IF YOUR OUTFIT WANTS KNOW ABOUT YOUR VJ OBSOLETE RECOMMENDATION MAKE A CARBON COPY OF THIS AND GIVE IT TO YOUR HEADQUARTERS oe gan anan gt TEAR ALONG PERFORA TED LINE Gan Ce eee eee JO1 LA WV IN 1111 DOPE ABOUT IT ON THIS I1 OUT FOLD IT 4 DROP IT IN THE MAIL _ n a ee ine on oo n e Re enn pen PRINTED NAME GRADE OR TITLE AND TELEPHONE NUMBER SIGN HERE DA FORM 2028 2 PREVIOUS EDITIONS P S IF YOUR OUTFIT WANTS TO KNOW ABOUT YOUR I JUL 79 ARE OBSOLETE RECOMMENDATION MAKE A CARBON COPY OF THIS Ue ALAN SA TA VEEP NINE 1257 NAT AND GIVE IT TO YOUR HEADQUARTERS REVERSE OF DA FONW 2028 2 pw YOUR UNIT ADDRESS n den lM lt DEPARTMENT OF THE ARMY OFFICIAL BUSINESS PENALTY FOR PRIVATE USE 300 Commander US Army Communications Electronics Command ATTN DRSEL ME MQ E ro aaam a aa MONT MOU POSTAGE ANO FEES PAIO OEPARTMENT OF THE ARMY DOD 314 ak Ain io men men ATIAN JIJ INGBW
28. e 5556 ST 25101956 MAK BE LAlR ABELEO ON Ea E 2 ETT fan gases 5 EN a ty 5 x i gt 3 3 1 n A 1 B H 1 H o surg i gt i Ay g emasa E i SEE i 2 1 Gv Wow 3 o 257453 i 1 ERE 1 NE 4 5130 OOD 3 23d POLE lt lt fi E Baer A tian 9 ap o b poi spe nama 1 H IDE t E M 19 oe gt ER Los i i WE 6 i d m TC nALOA WS fF AT 4 t a Suse pe Nee ee ki 5 1 d iag 3 5 Mev FICS i d iue 551469 e are 15 ES 27457 Dy i SOREN e TCRIGES Rt ani in pas ev D QD A Lm i ov 4 OUV CWE SUPPLY gt MER eae E T o c i Mene taut 24 Haba Potius 4 FO 12 Low voltage power supply schematic diagram EL6UGOSA The voltages and waveforms shown this diagram were obtainec by using the recommended test equipment and test set ups listed below ITEM Test oscilloscope VOLTAGES AND WAVEFORMS RECOMMENDED TEST EQUIPMENT SPECIFICATIONS RECOM
29. i Return 100 OR 20 MHz BW control to full bandwidth 10 Check Cascaded Bandwidth a Set VERT MODE to CH 1 b Connect CH 2 VERT SIGNAL OUT output connec tor on rear panel through a 42 inch 50 ohrn BNC cable to a 50 ohm termination and connect to CH 1 input c Set the sine wave generator for a 6 division display of reference frequency d Without changing the generator output amplitude increase the output frequency until the display is reduced to 4 2 divisions e CHECK For a reading of 50 megahertz or more f Disconnect all test equipment TM 11 6625 2735 14 1 TRIGGER SYSTEM CHECK Equipment Required GR To BNC Male Adapter 1 Sine Wave Generator BNC Female To BNC Female Adapter Low Frequency Generator BNC Elbow Amplitude Calibrator BNC T Connector 50 Ohm Signal Pickoff 42 inch 50 Ohm BNC Cable 10X BNC Attenuator 18 inch 50 Ohm BNC Cable 2 required BNG ANENUATOT 7 GR To BNC Female Adapter 14 50 Ohm BNC Termination 2 required Control Settings Sweep POWER ON A TIME DIV 50 us new setting B TIME DIV 50 us new setting VAR TIME DIV Calibrated detent Display DELAY TIME POSITION Fully counterclockwise INTENSITY Midrange HORIZ DISPLAY A FOCUS Midrange X10 MAG Off button out POSITION Horiz Midrange Midrange SO eno 9 Midrange Xertica en bang CEA 11 Check A Low Frequency Triggering POSITION Midrange a Connect the low frequency generator output to a V
30. 103 5 to 126 5 V 207 to 253 V 108 to 132 volts 216 to 264 volts 1 5 A 3AG Fast blow 6 75 A 3AG Fast blow Fuse Rating Change 1 2 1 TM 11 6625 2735 14 1 SELECTOR SWITCH SHOWN IN MEDIUM POSITION LINE FUSE ELEVGOOJ Fig 2 1 Reguiating Range Selector and Line Fuse 5 Check Table 211 for the recommended range posi tion of the Range Selector Switch Bar see Figure 2 1 Select a range which is centered about the average line voltage to which the instrument is to be connected The middle position M is a typical setting 6 If necessary gently pull out the Range Selector Switch Bar slide the bar to the desired position and plug it back in 7 Install the cover on the Regulating Range Selector assembly and gently tighten the 2 captive screws 8 Connect the instrument to the recommended power source pull the instrument POWER switch to ON and begin usage of the 475 Oscilloscope Options Options are available to alter oscilloscope performance to meet particular applications A number in either MOD slot see instrument rear panel indicates that the instru ment contains an option Refer to the Option section in this manual to find any change in operating instructions as a result of the option 2 2 CONTROLS AND CONNECTORS General The major controls and connectors for operation of the 475 are located on the front panel of the instrument A few auxiliary functions are provid
31. 3 Remove two screws from the inverter chassis one screw at the front and one at the rear of the inverter chassis near the top of the instrument main chassis Remove one remaining screw from the main chassis to the inverter chassis accessible through the space along the bottom of the power transformer A long Phillips screw driver is necessary to remove all three screws 4 Remove the Inverter chassis from the instrument using care to prevent damage to interconnecting wires that pass through the hole in the main chassis 5 Remove the screws holding the Inverter circuit board to the Inverter chassis To install the Inverter circuit board reverse the removal procedure Power Supply Board Removal 475 DM 43 and DM 40 only Remove the board as follows 1 Remove the Vertical Output circuit board shield if installed TM 11 6625 2735 14 1 2 Disconnect one ribbon cable from the rear of the 475 DM 43 or DM 40 Main circuit board and guide the plug through a slotted opening in the main circuit board chassis 3 Unsolder five wires from the power transformer and confirm each wire color with its location in the following list a Wire to terminal 10 is white with a brown stripe b Wire to terminal 10A is white with a red stripe c Wire to terminal 11 is white with an orange stripe d Wire to terminal 12A is white with a yellow stripe e Wire to terminal 12 is white with a green stripe 4 Remove two screws from
32. 5 4 256 g 2 AMA Fig 6 1 Option 04 schemetic diagram FO s 1 through 14 are located in Back of Manual 6 2 TM 11 6625 2735 14 1 OPTION 7 Option 7 is a dc to ac inverter that permits Tektronix Oscilloscopes to operate on 12 or 24V dc with no performance deterioration Circuitry is provided to protect against damage due to connection of 24 V when in the 12 V mode of operation The 24 volt external input permits use with conven tional dc power marine and aircraft Option 7 is an integral part of the oscilloscope The modified oscilloscope has a three position voltage input selection slide switch visible through the right hand side panel at the rear of the line voltage selector switch A dc input connector is located below the fan cover on the rear panel SPECIFICATIONS AC Requirements No increase in ac requirements over those of os cilloscopes not having Option 7 DC Requirements 11 5 to 14 volts or 22 to 28 volts 11 5 volt operation excludes graticule light operation and Option 5 Operating range may be extended to 15 volts or 30 volts with a series dropping resistor Maximum elevation for or power lead is 60 V with respect to oscilloscope chassis ground Temperature The same operating and nonoperating range as the oscilloscope without Option 7 SAFETY CONSIDERATIONS Option 7 becomes a part of the modified instrument
33. 51601 Section A in the off stop position discharges the capacitors in the turn off and start circuits This ensures the correct time constants when 51601 is chang ed to the on start position In the start position the dc input is applied to the inverter circutiry by 51601 Section A At the same time 1601 section B is closed completing the feedback loop for the inverter transistors 51601 section B stops the inverter in the off position by opening the feedback loop between T1400 and T1631 Power Mode Switch 51665 See Figure 6 4 Sections A and F connect filter C1671 and R1671 to T1400 during 12 or 24 V operation to reduce converter transients Sections C and D select either trans former terminals 10A and 12A or 10 and 12 to provide the same secondary output when operating on 12 or 24 V Sections Band E connect transformer terminals 10 and 12 to 51665 C and D and to the inverter feedback circuit during both 12 and 24 V operation Snow 4v POSITION PARTIAL AB INTERFACE BOARD EL6UGO63 Figure 6 4 Option 07 primary winding 6 2 4 Change 1 ized waveforms in Circuit Board Chassis Removal The circuit board is mounted on a small chassis located between the power transformer and the crt shield To remove the chassis remove three screws Two thread forming screws are located at the top of the chassis One screw is at the bottom of the chassis and is removed from the right hand side by going just below
34. 69 70 71 72 73 74 75 76 77 78 79 80 81 Qty 4 p Qus a n N mi on ge gt er O N 12345 8 Description LENS LIGHT WHITE EXTENSION SHAFT 11 487 INCH LONG W KNOB RES VAR NONWIR A TRIGGER R530 5530 RES VAR NONWIR B TRIGGER R750 S750 RES VAR NONWIR TRIG HOLDOFF R644 644 nec n ROP VAN RILIAIZA ATTACHING PARTS FOR EACH NUT PLAIN HEX 0 25 32 X 0 312 INCH BRS WASHER FLAT 0 25 ID X 0 375 INCH OD STL m wa Wea PANEL FRONT CONNECTOR RCPT BNC FEMALE W HARDWARE ATTACHING PARTS FOR EACH TERMINAL 000 0 391 ID INT TOOTH a m fee COIL CAL ATTACHING PARTS NUT PLAIN HEX 3 48 X 0 187 INCH CD PL BRS WASHER FLAT 0 119 ID X 0 375 INCH OD STL WSHR SHOULDERED 0 125 ID X 0 50 INCH OD ar A4 4 4 T SPACER CUR LOOP 1 094 X 0 344 X 0 125 INCH NUT FINISHING 0 25 HEX X 0 312 LONG BRS m tw LAMPHOLDER SCALE FACTOR ATTACHING PARTS FOR EACH SCREW MACHINE 2 56 X 0 25 INCH PNH STL SHLD GSKT ELEC 0 026 OD NPRNW WIRE NET CO BOARD ASSY CRT SCALE ILLIUM 10 REFLECTOR LIGHT SCALE ILLUMINATION LAMPHOLDER SCALE ILLUMINATION WIRE ELECTRICAL 2 WIRE RIBBON CONNECTOR TERM 22 26 AWG BRS amp CU BE GOLD CONN BODY PL EL 2 WIRE RED SUPPORT CRT FRONT FRAME SECT CAB
35. 9 R365 R364 R363 R367 D R36 U350 1961252 TEED 6968222 896425 698225 teta ca 1968255 6664 E M o a 8 B 346 USED WITH OPTION 07 E Fig 7 2 A3 board component locations Sheet 1 of 2 Change 1 7 3 TM 11 6625 2735 14 1 A NATEN OCATED F BOARD N BACK O ES LS a tn ee q 0132 Dou by A 2025 S m 2 gen D B Tu Ze w 6225 a 5 a T 5 k m 2 S gt 8 5 2 ia x cd E lt S 9 Os 5 3 144 gt RIO7 Be AV E 5227 5 8 891 R185 CR290 R285 Tk T N a szia amp 8 Lr i v a a 7 ew Dm B G 24 G a 5 9 on in im Pr Mn 35e Ki com 33 id a lt wa J gs 3 AS 7 EN MA A AN EL6UGOO4 Fig 7 2 A3 board component locations Sheet 2 of 2 7 4 00 6 CR312 VL yo NM DU ZZ EL6UGOO5 Fig 7 3 A4 board component locations TM 11 6625 2735 14 1 s ve pa ra LS C485 VR462 R487 n CR480 FRONT BACK PREFIX ALL REF DES WITH A5 Fig 7 4 AS board component locations 7 6 TM 11 6625 2735 14 1
36. A TRIGGER DEFLECTION SYS SET TIME DIV 0 5 ms CHECK FOR ABOUT ____ SOUHCE TO CH FIVE COMPLETE CYCLES 10 DIVISIONS CHECK FOR STABLE _ DISPLAY 1 YES SET TIME DIV TO 5 ms AND PRESS X10 MAG CIRCUIT Q390 soe TO ON CHECK FOR ABOUT FIVE COMPLETE f 5 10 DIVISIONS CHECK VERTICAL CHANNEL SWITCHING CHECK A TRIGGER GENERATOR ER GENERATOR Q3 m YES CHECK F VAR TIME DIV M mS CONTROL IS SET TO CALIBRATED DETENT NO CHECK CALIBRATOR CIRCUIT CHECK FOR A 1 KILOHERTZ SQUAREWAVE AT CALIBRATOR CURRENT LOOP WITH TEST OSCILLOSCOPE NORMAL SQUAREWAVE OPERATION CHECK Z AXIS AMPLIFIER SET TIME DIV 1 ms AND X10 _ _ _ SET HORIZ DISPLAY INTEN SET B a TRIGGER SOURCE STARTS AFTER DELAY PULL AND UNLOCK DL Y D SWP KNOB AND SET IT TO 0 5 ms CHECK FOR AN INTENSIFIED PORTION ON THE DISPLAY a NO INTENSIFIED PORTION YES NO TORGE YES __ 4 CHECK INTENSIFIED TURN THE DELAY TIME POSITION SWEEP AND LOGIC CONTROL THROUGH ITS RANGE CHECK HORIZONTAL AMPLIFIER FOR PROPER 40 GAIN INTENSIFIED PORTION DOES MOVE PROPER INTENSIFIED PORTION ON DISPLAY CHECK DELAY TIME POSITION CIRCUIT DELAY HORIZONTAL MOVES ON DISPLAY PICKOFF COMPARATOR CHECK SWEE
37. Deflection factor 1mVvto5 Amplifier and 7850 Time base units Input impedance 1 20 pF equivalent Sweep rate 50 ns Probe Fast rise 10X attenuation probe com patible with vertical amplifier of test oscilloscope Tektronix P6053B or equivalent Voltmeter Non loading Input Impedance 10 Digital Multimeter Range 0 to 500 a Tektronix DM 501 Digital Multimeter or equivalent 475 Control Settings Sweep Controls Display Controls TIME DIV 0 1 ms INTENSITY Midrange Calibrated detent FOCUS Midrange SCALE ILLUM Midrange RUE counterclockwise X10 MAG Off button out POSITION Horiz Midrange FINE Midrange Vertical Controls CH 1 and CH 2 POSITION Center trace on graticule VOLTS DIV 2 mV for dc voltages Voltage Measurements 100 mV for waveforms A Voltage measurements are taken with no signa applied ALONE EY n detent and the trace positioned to the center horizontal graticule line The voltmeter common is connected to chassis INVERT Off button out ground VERT MODE CH 1 100 or 20 MHz BW Full bandwidth Push in Waveform Conditions h le then release Apply the 475 calibrator signal to CH 1 tnput through P6075 10X probe supplied with 475 Connect 475 A GATE rear panel through a 42 inch 50 ohm BNC cable to test oscilloscope external trigger input Set test os Trigger Controls A and B cilloscopo trigger source to external and Set vertic
38. POSITION control for a display that remains in the display area horizontally Magnified Sweep Display 1 Preset the instrument controls and follow steps 1 through 6 for obtaining a Normal Sweep Display 2 Adjust the horizontal POSITION control to move the area to be magnified to within the center graticule division of the crt If necessary change the TIME DIV switch setting so the complete area to be magnified is within the center division 3 Set the X10 MAG switch to the on position button in and adjust the horizontal POSITION control for precise positioning of the magnified display Divide the TIME DIV setting by 10 to determine the magnified sweep rate Delayed Sweep Displays 1 Preset the instrument controls and follow steps 1 through 6 for obtaining a Normal Sweep Display 2 Set the HORIZ DISPLAY switch to A INTEN and the B Trigger SOURCE switch to STARTS AFTER DELAY 3 Pull out the B TIME DIV switch knob and turn clockwise so the intensified zone on the display is the desired length Adjust the INTENSITY control to achieve the desired display brightness 4 Adjust the DELAY TIME POSITION dial to position the intensified zone to the portion of the display to be delayed TM 11 6625 2735 14 1 5 Set the HORIZ DISPLAY switch to B DLYD The intensified zone on the display noted in step 3 is now being displayed in delay form The delayed sweep rate is indicated by the line on the B TIME DIV switch knob 6 For a de
39. R1464 8 V SERIES REGULATOR g Q1464 Q1466 91465 01468 115 230 NOMINAL LINE INPUT 15V RECTIFIER CR1472 50 FEEDBACK 1 15 V SERIES REGULATOR Q1474 Q1478 EL6UG036 Fig 3 9 Detailed block diagram of the Power Supply circuit 3 22 Power Input Power is applied to the primary of transformer T1400 through Line Fuse F1401 POWER switch 1401 Thermal Cutout 51402 Line Voltage Selector switch 51403 and the Regulating Range Selector Line Voltage Selector switch 51403 connects the split primaries of T1400 in parallel for 115 volt nominal operation or in series for 230 volt nominal operation Line Fuse F1401 should be changed for each nominal line voltage current rating of fuse for 230 volt operation must be 0 754 fast for 115 volt operation current rating of fuse must be 1 5A fast Thermal cutout S1402 provides thermal protection for this instrument If the internal temperature of the instru ment exceeds a safe operating level 51402 opens to interrupt the applied power When the temperature returns to a safe level 51402 automatically closes to reapply the power The vacant windings between pins 10 10A 11 12 and 12A or T1400 are intended for use with the optional Inverter Circuit Board Option 7 or for use with a 475 Oscilloscope modification a Power Supply Board 475 DM43 and 40 Secondary Circuit The 8 volt 15 volt 5 volt 15 volt 50 volt and 110 volt supplies a
40. SWITCHING CIRCUIT EL6UG035 Fig 3 8 Detailed block diagram of the Horizontal Amplifier circuit 3 20 Input Paraphase Amplifier Q1124 and Q1134 form the Input Paraphase Amplifier This is an emitter coupled amplifier stage that converts the single ended input signal to a push pull output signal The X10 Magnifier circuitry is in this stage and consists of a divide by ten attenuator R1106 R1107 R1108 When the X10 Magnifier is on the input signal is applied un attenuated to the Input Paraphase Amplifier When the X10 Magnifier is off the input signal is applied to the Input Paraphase Amplifier through the attenuator X10 MAG indicator DS1110 lights when the X10 Magnifier is being used CR1121 and CR1122 limit signal amplitudes at the input to the amplifier to prevent amplifier overdrive Q1140 is a relatively constant current source for Q1124 and Q1134 CR1140 provides temperature compensation for the base emitter junction of Q1140 Magnifier Registra tion adjustment R1130 balances quiescent DC current in Q1124 and Q1134 so that a center screen display does not change position when the X10 Magnifier is turned on Q1112 and Q1114 together form a temperature com pensated current source that is an interruptable path for the horizontal positioning currents When the TIME DIV switch is in any position other than X Y the anodes of CR1103 CR1104 and CR1111 are connected to 8 volts through R1104 which reverse biases them In the X Y
41. TM 11 6625 2735 14 1 5 USED ON CODE 6 QTY REQD 7 QUANTITY RCVD DATE B 7 TM 11 6625 2735 14 1 B 8 1 Illus number SECTION Ill BASIC ISSUE ITEMS 2 Description 9 Usable a z Danone n Gen FSCM and Part number On Code y number U M rqr TECHNICAL MANUAL TM 11 6025 2735 14 1 EA 1 TM 11 6625 2735 14 1 APPENDIX D MAINTENANCE ALLOCATION Section I INTRODUCTION D 1 General This appendix provides a summary of the maintenance operations for the OS 261B V I U and OS 261C V I U It authorizes categories of maintenance for specific mainte nance functions on repairable items and components and the tools and equipment required to perform each function This appendix may be used as an aid in planning mainte nance operations D 2 Maintenance Function Maintenance functions will be limited to and defined as follows a Inspect To determine the serviceability of an item by comparing its physical mechanical and or electrical characteristics with established standards through exami nation b Test To verify serviceability and to detect incipient failure by measuring the mechanical or electrical charac teristics of an item and comparing those characteristics with prescribed standards c Service Operations required periodically to keep an item in proper operating conditions 1 e to clean decon taminate to preserve to drain to paint or to replenish fuel lubricants hydraulic
42. The calibration procedure given in Section 6 if performed completely will ensure the instru ment meets the electrical characteristics listed in this section 1 1 TM 11 6625 2735 14 1 TABLE 1 1 ELECTRICAL Characteristics Performance Requirements Supplemental Information VERTICAL DEFLECTION SYSTEM CH 1 and CH 2 Deflection Factor Calibrated 2 mV to 5 V DIV in 11 steps 1 2 5 Range sequence Cascaded Operation CH 2 VERT Deflection Factor to Approximately SIGNAL OUT Connected to CH 1 400 Bandwidth DC to gt 50 MHz Uncalibrated VAR VOLTS DIV Provides continuously variable de Range flection factors between the cali brated steps Extends maximum un calibrated deflection factor to at least 12 5 volts per division in the 5 V DIV position Low Frequency Linearity Deflection Factor Accuracy 3 of indicated deflection Bandwidth 15 C to 40 DC to 200 MHz 40 to 55 DC to 175 MHZ Risetime 15 C to 40 1 75 ns or less Calculated 40 to 55 2 0 ns or less Calculated AC Coupled Lower 3 dB point 10 Hz or less with 1X probe Bandwidth with 100 or 20 MHz Approximately 20 MHz BW Switch in 20 MHz Position Bandwidth with 100 or 20 MHz Approximately 100 MHz BW Switch in 100 MHz Position Input Resistance and Capaci 1 within 2 paralleled by ap 0 35 Risetime is calculated from the formula BW in megahertz 1 2 CH 2 VERT SIGNAL OUT into
43. The safety considerations for the unmodified instrument apply FUNCTION OF CONTROLS AND CONNECTORS Mode Switch AC Applies ac power to the oscilloscope power switch Be sure that the 1106 Line Selector switch is set to the correct line voltage for proper battery charging DC 12 Permits 12 V operation of the instrument from an external 12 V source DC 24 Permits 24 V operation of the instrument from either an external 24 V power source or from the 1106 Power Supply which may be mechanically attached to the oscilloscope Dc Input Connector Option 7 mode switch and dc input connector are located on the modified oscilloscope OPERATION AND INSPECTION Set the oscilloscope and Option 7 for the power source available as listed below Oscilloscope Option 7 Power Source Line Selector Mode Switch 115 V AC 115 AC 230 V AC 230 AC 12 V DC 12 24 V DC 24 1106 24 the oscilloscope on Check that the oscilloscope operates properly on any of the listed power sources that may be available Connect the oscilloscope frame to a ground earth reference before using CIRCUIT DESCRIPTION Option 7 is a dc to ac inverter It operates on 12 or 24 V dc The circuit description is for 24 V operation unless noted otherwise Refer to the schematic diagrams 6 2 and 6 3 throughout the detailed circuit description The operating frequency of the inverter is approximate ly 400 Hz Change 1 6 2 1 TM 11 6325 2735 1
44. Trigger View Deflection Factor Approximately 50 mV DIV Hisetime Delay Difference Centering of Trigger Point Horizontal Calibrated Sweep Range A Sweep or B DLY D Sweep 0 5 s DIV to 0 01 ws DIV in 24 steps 1 2 5 sequence X10 MAG extends max imum sweep rate to 1 ns DIV A Delaying Sweep or A INTEN 0 5 s DIV to 0 05 us DIV in 22 steps 1 2 5 sequence DEFLECTION SYSTEM TM 11 6625 2735 14 1 Supplemental Information 20 Exclude LF REJ and HF REJ trigger coupling modes 4 0 ns over the 10 to 90 part of the fast rise portion 2 5 ns with a 5 division signal having 1 ns or less risetime from a 25 0 source centered vertically with equal cable length from signal source to vertical channel and ex ternal trigger inputs each termin ated in 50 0 Adjustable to within 1 0 division of center screen 1 5 TM 11 6625 2735 14 1 Characteristics Calibrated Sweep Accuracy 20 C to 30 A or B DLY D Sweep 5 ms DIV to 0 01 us DIV 5 S DIV to 10 ms DIV A INTEN Sweeps or A Delaying 0 5 s DIV to 0 05 us DIV 15 C to 55 C All Sweeps X10 Magnified Sweep Accuracy Mixed Sweep Accuracy VAR TIME DIV Control Range Sweep Length A Only A Trigger Holdoff 1 6 TABLE 1 1 cont ELECTRICAL Performance Requirements Supplemental Information HORIZONTAL DEFLECTION SYSTEM cont UNMAGNIFIED MAGNIFIED 1 3
45. is applied to the bases of Q1018 and Q968 through CR1017 and CR987 respec tively This sets the quiescent current flow through Q988 and Q1018 to establish the dc level starting points for the sweeps as previously explained However when the HORIZ DISPLAY switch is in the MIX position the fixed level at the base of Q1086 is replaced by the sawtooth voltage waveform being generated by the Delaying Sweep Generator Now the dc level starting point of the Non Delaying Generator that is running is constantly being changed by the Delaying Sweep sawtooth until the Delaying Sweep runs down to a voltage determined by the setting of the DELAY TIME POSITION control At this time one of the disconnect transistors Q974 in the slow Non Delaying Generator or Q1004 in the fast Non Delaying Generator depending on the settings of the TIME DIV controls is turned off allowing the appropriate Non Delaying Generator to begin a ramp waveform determined by the setting of B DLY D control The output waveform from the Non Delaying Sweep Generator that is running will be a composite sawtooth waveform with the first and last parts occurring at a rate determined by the Delaying Sweep Generator last part blanked out of CRT display and the middle part occurring at a rate deter mined by one of the Non Delaying Sweep Generators Non Delaying Sweep End Difference Amplifier Q1044 and Q1034 are connected as a voltage com parator and generate the same sort
46. note the recommended test equip ment front panel control settings voltage and waveform conditions and test equipment cable connection Instructions Voltages and waveforms given on the schematics should be checked against each instrument while it is operating properly Deviations should be noted on the schematics for later reference 9 Check Individual Components The following procedures describe methods of checking individual components Components which are soldered in place should be checked after disconnecting one end from the circuit This isolates the measurement from the effects of Surrounding circuitry a SEMICONDUCTORS Power switch must be turned off before removing or replacing components A good check of transistor operation is actual in circuit performance under operating conditions and most tran sistors in the 475 can be checked this way A transistor can be most effectively checked by substituting a new compo nent for it or one which has been checked previously However be sure that circuit conditions are not such that a replacement transistor might also be damaged If sub stitute transistors are not available use a dynamic tester Static type testers are not recommended since they do not check operation under simulated operating con ditions When troubleshooting transistors with a voltmeter measure emitter to base and emitter to collector voltages to determine if the voltages are consistent with no
47. o loi I iai jo xix lt wo lt lt gt 1 221 215 pela HS E ERSTES LESER EI EH SES LR EI ST EI EI S 5 lt zirir urizioi9 ixioiziuj 19 xix alrlol lo lolo IN gt 51515 gt 51211 2 0 2 LOW VOLTAGE POWER SUPPLY HIGH VOLTAGE POWER SUPPLY zaxis ameen einc A TRACE ROTATION CRT Y AXIS ALIGN een anan ANE m VERTICAL OUTPUT AMPLIFIER CIRCUIT NEBEREEEN CH 1 OR CH 2 VAR VOLTS DIV BALANCE E CH 1 OR CH 2 VOLTS DIV BALANCE CH 1 OR CH 2 GAIN VJCOTIC At TOAAICICA DA YEN TRANSIEN rw TRIGGER GEN TU e p TRIGGER sens svum andere 17 III A AA AFEKILITEDINA A VI CHINU rat A C oT tt ats ato tte X GAIN X Y PHASE DIFFERENCE AUF me CRT CHANGE 4 33 4 34 blank TM 11 6625 2735 14 1 Section 5 475 Service PERFORMANCE CHECK IMPORTANT PLEASE READ BEFORE USING THIS PROCEDURE Introduction The following procedure is intended to be used for incoming inspection to determine the acceptability of newly purchased or recent
48. temperature As temperature increases the value of HT170 decreases This results a decrease in voltage across CR170 and CR174 CR170 and CR174 are voltage variable capacitance semiconductors whose capacitance increases with a decrease in reverse voltage across them Thus CR170 and CR174 will provide more peaking higher temperatures T178 is a toroid inductor that cancels high frequency common mode signals generated by the previous stages The Channel 1 Vertical Position Centering adjustment centers the range of control of the Channel 1 POSITION control CHANNEL 2 PREAMP gt General The Channel 2 Preamp circuit is virtually the same as the Channel 1 Preamp circuit Only the differences between the two circuits are described here Portions of this circuit not described in the following description operate in the same manner as for the Channel 1 Preamp circuit shows a detailed block diagram of the Channel 2 Preamp circuit A schematic of this circuit is shown on Diagram 2 at the rear of this manual TM 11 6625 2735 14 1 VOLTS DIV BAL CH 2 R235 vOLTS DIv 4 bup 5 S208 ST 2ND 3RD R22 CASCODE CASCODE CASCODE AMPL AMPL AMPL 0240 0272 0278 ue P CH 2 41 CH20 w x2 epi 13 CH 2 VERTICAL SIGNAL TO J10 AAA al an R295 VERTICAL CHANNEL we ape R210 Q SWITCHING CIRCUIT i VAR LY e R24 1 BAL 4 1 en i INPUT
49. the A Sweep holdoff should be at a high voltage level Check TP588 for approximately 2 volts Check the emitter of Q644 for approximately 4 3 volts Pin 3 of U600 should now have a low auto gate voltage Check TP572 for approximately 0 volt Check pin 16 of U600 for approximately 0 volt Check pin 17 of U600 for approximately 0 7 volt Check pin 6 of U600 for ap proximately 4 8 volts Check pin 3 of U600 for ap proximately 0 2 volt Install 0574 and check the collector of Q922 for a repetitive sweep waveform TM 11 6625 2735 14 1 B DLY D Sweep and Logic The A Sweep and A INTEN sweep should be working properly before starting this procedure Remove all exter nal signals to the instrument set TIME DIV to 1 ms lock knobs set HORIZ DISPLAY to B DLY D and set TRIG MODE to AUTO 1 Remove Q574 from its socket Check the collector of 0922 for approximately 14 5 volts Check the base of Q792 for approximately 5 volts Check the collector of Q792 for approximately 41 2 volts Check TP802 for approximately O volt Check TP826 for approximately 1 8 volts Check TP996 for approximately 3 7 volts Check the collector of Q984 for approximately 14 volts 2 Install Q574 and remove Q572 Check the collector of Q922 for approximately 0 2 volt Check the base of Q792 for approximately 2 volts Check the collector of Q792 for approximately 0 7 volt Check TP802 for ap proximately 0 volt Check TP826 for approximately
50. verted At least 100 1 at 50 MHz At least 12 and 12 divisions from graticule center 0 25 ns or less at 5 mV DIV 20 30 1 3 TM 11 6625 2735 14 1 Characteristics Sensitivity DC Coupled AC Coupled HF REJ Coupled LF REJ Coupled Trigger Jitter External Trigger Input Maximum Input Voltage Input Resistance and Capa citance 1 4 TABLE 1 1 cont ELECTRICAL Performance Requirements TRIGGER SYSTEM upplemental Information 0 3 div internal or 50 mV external from DC to 40 MHz increasing to 1 5 div internal or 250 mV external at 200 MHz 0 3 div internal or 50 mV external from 60 Hz to 40 MHz increasing to 1 5 div internal or 250 mV external at 200 MHz Attenuates signals below about 60 Hz 0 5 div internal or 100 mV external from 60 Hz to 50 kHz Attenuates signals below about 60 Hz and above about 50 kHz 0 5 div internal or 100 mV external from 50 kHz to 40 MHz increasing to 1 5 div internal or 500 mV ex ternal at 200 MHz Attenuates sig nals below about 50 kHz 0 2 ns or less at 200 MHz at 1 ns DIV sweep rate X10 MAG on 250 V DC peak AC or 250 V P P AC 1 kHz or less 1 MQ within 10 paralleled by ap proximately 20 pF TABLE 1 1 cont ELECTRICAL Performance Requirements TRIGGER SYSTEM cont Characteristics LEVEL Control Range EXT At least and 2 V 4 V P P EXT 10 At least and 20 V 40 V P P Exclude LF REJ coupling mode
51. zen bsan 55352 55324 1 Eoss tov P fia T CARA CM 2 VERT 1 SIGNAL OUT 4 IS NOTE COUDECT CALIBRATOR SIGNAL Y igi a VERT MOBE TO CH2 DET x 5341 U330 IK 1406 9350 402 3 ie enn 2 R437 r C431 D t 9 DCCOUFLEG OTE DC LEVEL 15 DEPENDENT Du SETTIVA CF VERTICAL POSITION CONTRALS 13 NOTE SET 475 VERT MODE TG CHCP AND TEST DSC LLOSCQAPE HHTERKAL TRIGGER z 35 14 chop BLANKING 93400 l EL6UGOSO VERTICAL CHANNEL SWITCHING lt FO 4 Vertical channel switching schematic diagram The voltages and waveforms shown on this dia test set ups listed below ITEM Test oscilioscope Probe Voltmeter Non loading Digital Multimeter VOLTAGES AND WAVEFORMS RECOMMENDED TEST EQUIPMENT SPECIFICATIONS _ Frequency response DC to 75 MHz Deflection factor 1 mV to 5 Input impedance 1 MQ 20 pF Sweep rate 50 ns Fast rise 10X attenuation probe com patible with vertica amplifier of test oscilloscope Input Impedance 10 MA Range 0 to 500 V gram were obtained by using the recommended test equipment and RECOMMENDED TYPE Tektronix 7603 cquipped with 7A13 Amplifier and 7B50 Time base units or equivalent Tektronix P6053B or equiva
52. 1 1 1 SES i i Aw in i i Bay i 1 1 oy ay neyi ct Se E ev 32 7 3 1 ve dwe 2244 4 org 4 4 a pru TO 1 Im L jo 5 1 oe Yo s E RU sica 4 J i c2 5 1 RA Riv as c gt E ye 5 ME 30 ud ee RINSE PE AT S G lcg E LE E Pies ER Cacat g d ki gt veh pike pou Rica x ROS 2 7 ite i psu 453 Si r 4950 gt i Au ay p 07254 n EZ 1992 pA KRISS MISS RUS J110 VSO LY loj Le 7 o FOR DM SERES JUMPER A x zem gb L crae 0 Cloe4 REMOVED WHEN DM 15 USED 07052 L Giza a a 4 x qose Ga em ERE nM 2m 3 2 ot PLA kaas CROSS E 1 2 2984 2964 2 685 X sol IT BL 708 586 5 x 4 01054 a espe LA x Ross xt E i loose l 5 i 584 T 216 PUE d GOES tr N close ie 8 y d ji 5 6 65 4 N re e on ya ROST AN 1090 cago 52 55 i Ripe An d a
53. 10 and 11 Channel 1 of U370 The logic levels connected to pins 1 12 13 and 16 determine what signals are presented at output pins 14 and 15 The following logic truth table defines the switching function of U370 TABLE 3 1 Input Output Logic for U370 Output Signal Pins 14 15 Channel 2 Channel 1 Add Algebraic sum of Channel 1 and 2 U370 also makes available samples of the Channel 1 signal at pins 8 and 9 and samples of the Channel 2 signal at pins 4 and 5 The output signals at pins 4 5 8 and 9 are always present when signals are applied to the channel inputs regardless of the switching logic levels applied to U370 The Channel 1 signal present at pin 9 provides drive to the Horizontal Amplifier in the X Y mode of horizontal operation The Channel 1 signal at pin 8 and the Channel 2 signal at pin 4 are used by the Trigger Generator circuits in the appropriate positions of the Trigger SOURCE switches The Channel 2 signal at pin 5 connects to the Channel 2 Vertical Signal Out Amplifier Switching Logic Flip Flops U350A and U350B are edge triggered flip flops that derive the switching logic for the Channel Switch IC U370 In the CH 1 CH 2 and ADD positions of the VERT MODE switch the output logic from U350A and U350B is determined by the voltage levels applied to the clear pins 1 and 13 and preset pins 4 and 10 inputs In the ALT mode of operation the flip flops are switched by the alternate trace sync pulse
54. 1318 Change 1 A 1 A 2 blank TM 11 6625 2735 14 1 APPENDIX B COMPONENTS OF END ITEM LIST AND BASIC ISSUE ITEMS LISTS Section l B 1 SCOPE This appendix lists integral components of and basic issue items for Oscilloscope 0S 261B V 1 U and 03 261C V 1 U to help you inventory items required for safe and efficient operation B 2 GENERAL This Components of End Item List is divided into the following sections a Section II Integral Components of the End Item These items when assembled comprise the oscilloscope and must accompany it whenever it is transferred or turned in The illustrations will help you identify these items b Section III Basic Issue Items These are the minimum essential items required to place the oscilloscope in opera tion to operate it and to perform emergency repairs Although shipped separately packaged BII must be with the oscilloscope during operation and whenever it is trans ferred between property accounts The illustrations will assist you with hard to identify items This manual is your authority to request requisition replacement BII based on TOE MTOE authorization of the end item B 3 EXPLANATION OF COLUMNS a Illustration This column is divided as follows 1 Figure Number Indicates the figure number of the illustration on which the item is shown INTRODUCTION 2 Item Number The number used to identify item called out in the illustration b National Stock Numb
55. 14 1 FO amp Index No Qty 12345 Name amp Description 15 115 1 PANEL REAR LINE VOLT ATTACHING PARTS 116 1 SCREW MACHINE 4 40 X 0 188100 DEG FLH STL 117 SCREW MACHINE 4 40 X 0 312 100 DEG FLH STL 1 SCREW MACHINE 4 40 X 0 438 INCH FLH STL OPTION 7 ONLY NUT PLAIN HEX 4 40 X 0 25 INCH STL OPTION 7 ONLY 118 TERMINAL LUG SE 4 119 1 NUT PLAIN EXT W 4 40 X 0 25 INCH STL TERMINAL LUG 0 146 ID LOCKING BRZ TINNED ATTACHING PARTS 1 NUT PLAIN EXT W 6 32 X 0 312 INCH STL w a wa MARKER IDENT MARKED GROUNDSYMBOL 120 COVER REAR ATTACHING PARTS 121 2 SCREW MACHINE 4 40 X 0 25 INCH PNH STL gt lt OR oo 122 SUPPORT CRT REAR 123 1 GROMMET PLASTIC U SHP 1 0 X 0 42 INCH 124 l BRKT CRT SHIELD REAR NYLON ATTACHING PARTS 125 3 SCREW MACHINE 6 32 X 0 312 INCH PNH STL 126 WASHER FLAT 0 15 ID X 0 032 THK STL CD PL 127 1 TERMINAL LUG 0 146 ID LOCKING BRZ TINNED 128 2 NUT PLAIN SQ 6 32 X 0 312 INCH STL 129 l NUT PLAIN EXT W 6 32 X 0 312 INCH STI Vo cm 130 1 CLAMP LOOP 0 062 INCH DIA 131 l COIL TUBE DEFLE Y AXIS L1385 ATTACHING PARTS 132 1 CLAMP COIL Y AXIS 133 2 SCREW MACHINE 4 40 X 0 25 INCH PNH STL 134 2 WASHER FLAT 0 125 ID X 0 25 OD STL 135 TERMINAL LUG SE 4 am o 136 1 SHIELD ELEC CRT 1 SOCKET PLUG IN CRT 137 1 SOCKET PLUG IN 14 PIN 138 4 CONNECTOR TERM 22 26 AWG BRS amp CU BE GOLD 139 HLD
56. 5 Unit of Measure U M Indicates the measure used in performing the actual maintenance function This measure is expressed by a two character alphabetical abbreviation e g ea in pr If the unit of measure differs from the unit of issue requisition the lowest unit of issue that will satisfy your requirements E 1 TM 11 6625 2735 14 1 SECTION EXPENDABLE SUPPLIES AND MATERIALS 1 2 3 NATIONAL ITEM STOCK NUMBER LEVEL NUMBER 8020 00 721 9657 7920 00 862 6710 6850 00 105 3084 E 2 4 DESCRIPTION Brush paint Cloth lint free Paint Sandpaper Detergent Trichlorotrifluoroethane cri CALIBRATOR a15a2 01504 Q1512 TM 11 6625 2735 14 1 475 BLOCK DIAGRAM ALTERNATE AMP MOTE indici nugiosr of signal lings berawan blocks SWITCHING LOGIC 0330 4550 as CHOP EY BLANKING 2 AMP ee 9340 0348 Jen PO r CH 1 PREAMP U120 TRIG Goss ensite Q172 Q182 VIEW 0179 0194 Q188 CHANNEL h SWITCH Qy Ic DELAY 2 VERTICAL LINE Satoh sein es OUTPUT RE w AMPLIFIER CH 2 PREAMP DL380 U4JO CR U220 2 0272 0282 gt Y Q273 0284 2288 8 CH 2 VERT
57. Allen wrench to loosen the front setscrew in each coupling 3 Remove the TRIG VIEW 100 OR 20 MHz BW control shaft Loosen the coupling setscrew with a 0 050 inch Allen wrench 4 Remove the INVERT control extension shaft Insert a scribe or small screwdriver between the end of the white plastic switch shaft and the inside end of the black plastic extension shaft and pry gently 5 Disconnect eight coaxial cables from the front and back sides of the board and confirm color coding of each cable with its jack number in the following list Record any exceptions to this procedure for reference when reassembling a Cable to J380 is white with black and brown stripes b Cable to J385 is white with black and red stripes c Cable to J399 is white with a yellow stripe d Cable to J430 is white with a violet stripe e Cable to J405 is white with a blue stripe f Cable to J410 is white with a green stripe g Cable to J400 back of board is white with a brown stripe h Cable to J349 bottom back of board rear of INVERT switch is white with a red stripe 6 Disconnect the delay line connection on the Ver tical Preamp board This requires the use of a soldering iron a 40 to 60 Watt iron works best to unsolder the delay line ground connection 4 24 7 Unsolder the capacitor lead at the Vertical Preamp board bottom back of board between the rear of the INVERT switch and J349 using a 15 Watt soldering iron 8
58. Cabinet Installation 2 Test Oscilloscope Page 4 10 Rack Adapter Removal 3 Multimeter age 0 Rack Adapter Installation 4 Variable Autotransformer Page 4 10 Preventive Maintenance Troubleshooting Techniques Page 4 10 Introduction Page 4 4 1 Check Control Settings Page 4 10 Cleanin 2 Check Associated Equipment Switch Contacts Page 4 5 3 Check Instrument Calibration General Interior 4 5 4 Visual Check Page 4 10 Exterior 5 Isolate Trouble to a Circuit CRT Face Filter and Shields 6 Circuit Troubleshooting Sequence age D Air Filter wa 7 Check Circuit Board Interconnection Visual Inspection Page 4 6 ji 8 Check Voltages and Waveforms Lubricati Page 4 6 9 Check Individual Components Page 4 6 10 Repair and Readjust the Circuit Recalibration Special Troubleshooting Information Troubleshooting General Introduction age 4 6 Troubleshooting the L V Power Supplies Page 4 15 Troubleshooting Aids Page 4 6 Troubleshooting the High Voltage Circuit Page 4 16 Diagrams Troubleshooting the Sweep Circuits Page 4 16 4 1 TM 11 6625 2735 14 1 Troubleshooting the Horizontal Amplifier age 4 Cathode ray Tube Installation age Troubleshooting the Vertical System High Voltage Multiplier Removal Troubleshooting the Z Axis Circuit Delay Line Removal Recalibration After Repair Corrective Maintenance Instrument Repackaging Introduction Obtaining Replacement Parts Page 4
59. Center A and B trigger coupling and source switches then remove the Trigger Generator and Z Axis Logic circuit board from the instrument To install the Trigger Generator and Z Axis Logic board reverse the removal procedure Timing Board Removal Remove the board as follows 1 Remove the Trigger Generator and Z Axis Logic circuit board as outlined previously 2 Remove the X10 MAG and UNCAL light lenses Pry them away from the front panel with a fingernail and pull them straight out 3 Remove the VAR and TIME DIV knobs Set these knobs fully clockwise and loosen their setscrews A 1 16 inch Allen wrench is required 4 Remove the hexagonal post and the board mounting screws 4 26 5 Remove the Timing circuit board from the instru ment Use caution to prevent damage to the connecting pins on bottom of the board To install the Timing circuit board reverse the removal procedure Vertical Output Board Removal Remove the board as follows 1 Remove the Vertical Output circuit board shield if installed 2 Disconnect the three wire cable from the top front of the Vertical Output board 3 Disconnect two wires from the board at the crt neck pins 4 Unsolder the delay line ground terminal at the delay line connection with the board a 40 to 60 Watt soldering iron works best Disconnect and dress the delay line away from the board 5 Unsolder the flexible grounding braid from the case of integrated circuit
60. D SWP at least 1 sweep setting faster than A sweep setting on all ranges Set time mark generator to maintain appropriate time marks f Disconnect all test equipment 29 Check X Gain a Set TRIG MODE to AUTO set DLY D SWP to lock knobs set TIME DIV to X Y set VERT MODE to CH 2 and set X CH 1 VOLTS DIV to 5 mV b Set amplitude calibrator to 20 millivolts and con nect to X CH 1 input through a 42 inch 50 ohm BNC cable c Set X CH 1 and Y CH 2 POSITION controls to set the 2 dot display at graticule center d CHECK The deflection between the 2 displayed dots for 4 divisions within 396 e Disconnect all test equipment TM 11 6625 2735 14 1 30 Check X Bandwidth NOTE See test equipment required Table 5 1 for selection of sine wave generator with an output of 100 megahertz and below a Connect the sine wave generator output cable to a 50 ohm termination to X input b Set the sine wave generator for a 4 division horizon tal display of reference frequency c Increase the frequency of the sine wave generator until the display is reduced to 2 8 divisions d CHECK The sine wave generator for a reading of 3 megahertz or higher e Disconnect all test equipment GATE OUTPUTS EXTERNAL Z AXIS AND CALIBRATOR CHECKS Equipment Required 1 Amplitude Calibrator 2 42 inch 50 ohm BNC Cable 2 required 3 50 Ohm BNC Termination 4 10X Probe sed Table 5 1 10X Probe examples Contr
61. FL Filter R Resistor fixed or variable The following special symbols are used on the diagrams NOTE DOT INDICATES SWITCH CLOSED PIS a nerima VUTOU 42V BAL Str ink PIE ug to E C 2 SOK Panel A e Plug Index Modified Component See Parts List o Sel Selected Components n v LT Connector nnector ovr ee Refer to Waveform g opi Voltage an ao Screwdriver Adjustment EN Ne M CO Assembly Number Name Etched Circuit Board Outlined te in Blue mad Schematic Name and Number 874 VERTICAL AMPLIFIER Ra Change 1 6 1 TM 11 6625 2735 14 1 OPTION 04 This section describes the features of Option 04 as it f 2 on e pertains to the 475 Oacilloscope This circuitry modifies a Todes the instrument to meet conducted and radiated in terference requirements over the frequency range of 150 kHz to 25 MHz conducted and 150 kHz to 1 GHz elated Four signal output bnc connectors on the rear plenum chamber changed to a type that improves shielding of the connected signal leads The following additions and changes were made to the standard circuitry to meet the specification requirements EMI filter FL1401 added in series with the input _ Capacitor added across the transformer secondary power cord windings DA 6 F am an aa m a d t ti EI 1
62. J240 ven MONOLITHIC c ron HYBRID VERTICAL AMPLIFVER A 12 1 DUAL FET PUT gt Noag 25 24 PER E FAMPLI FIER 3 2 5 IOK 269 V ES 2 si 5 1 8114 R208 Es FART OF ETCHE y Nd W i 159 510 Ba 5Y CIRCUIT BOARD a 2 ONE RTO DR OAK Acc IRE Mri a IU trae MO one 46 Nae V rn e MADI an ais An rode cn IM dae ses Zo pt ERK qot 2 VERTICAL PREAMP lt gt ELeuao s FO 3 Channel 2 vertical preamplitier schematic diagram VOLTAGES AND WAVEFORMS The voltages and waveforms shown on this diagram were obtained by using the recommended tesl equipment and test set ups listed below RECOMMENDED TEST EQUIPMENT SPECIFICATIONS Frequency response OC to 75 MHz Deflection factor 1 mV to 5 ViDiv input impedance 1 20 pF Sweep rate 50 ns RECOMMENDED TYPE Test oscilloscope Tektronix 7603 equipped with 7A13 Amplifier and 7850 Time base units or equivalent Probe Fast rise 1CX attenuation probe com Tektronix P6053B or equivalent patible with vertical amolifier of test oscilloscope MA 0 to 500 V Input Impedance Range Voltmeter Non loading Digital Multimeter Tektronix DM 501 Digital Multimeter or equivalent 475 Control Setlings Sweep Controls Display Controts TIME DIV
63. JUIIGY virw can a 524 Quins eR ee DE 0317005034 SNOW Uv31 a RECOMMENDED CHANGES TO EQUIPMEN THEN JOT DOWN THE DOPE ABOUT IT ON THIS Syr ou CAREFULLY TEAR ka ITIN THE MAIL 11 6625 2735 14 17 Jun 182 Oscilloscope 0S 261B V 1 U IN THIS SPACE TELL WHAT WRONG AND WHAT SHOULD BE DONE ABOUT IT PRINTED GRADE OR TITLE AND TELEPHONE NUMBER SIGN HERE D A den 2028 2 PREVIOUS EDITIONS 5 YOUR OUTFIT WANTS TO KNOW ABOUT YOUR JUL ARE OBSOLETE RECOMMENDATION MAKE A CARBON COPY OF THIS 71 127 IT PA MAN MA m AND Gi VE IT TO YOUR HEADQUARTERS REVERSE OF DA FONW 2020 2 PILL IN YOUR UNIT 3 ADORESS FOLD BACK ese es Jay aww an ew es am OT up n ewes eww aw gt en DEPARTMENT OF THE ARMY POSTAGE AND FEES PAID DEPARTMENT OF THE ARMY DOD 314 OFFICIAL BUSINESS PENALTY FOR PRIVATE USE 300 Commander US Army Communications Electronics Command ATTN DRSEL ME MQ Fort Monmouth New Jersey 07703 MI VUOdU4 RECOMMENDED CHANGES TO EQUIPMENT TECHNICAt PUBLICATIONS Se Dad WRONG WITH THis PUBLICATION FROM PRINT YOUR UNIT S COMPLETE ADDRESS THEN JOT DOWN THE DOPE ABOUT IT ON THIS FORM CAREFULLY TEAR Ce AND bef BAN IT OUT FOLD IT AND PUBLI
64. Locations lllustrations To aid in locating test points and components the Component Locations pages permit very rapid location of test points and com ponents Resistor Color Code In addition to the brown com position resistors some metal film resistors and some wire wound resistors are used in the 475 The resistance values of wire wound resistors are usually printed on the body of the component The resistance values of composi tion resistors and metal film resistors are color coded on the components with EIA color code some metal film resistors may have the value printed on the body The color code is read starting with the stripe nearest the end of the resistor Composition resistors have four stripes which consist of two significant figures a multiplier and a tolerance value Fig 4 2 Metal film resistors have five stripes consisting of three significant figures a multiplier and a tolerance value Capacitor Color Code The capacitance values of common disc capacitors and small electrolytics are marked on the side of the component body The white ceramic and epoxy coated tantalum capacitors used in the 475 are color coded using a modied EIA code see TM 11 6625 2735 14 1 TABLE 4 1 Circuit Number to Diagram Locator Circuit Number Diagram Series Name of Circuit Number 10 49 CH 1 ATTENUATORS 100 199 CH 1 VERTICAL PREAMP 10 69 CH 2 ATTENUATORS 200 299 CH 2 VERTICAL PREAMP 300 439 VE
65. Main Interface board 8 Unsolder one wire from a post on the High Voltage Multiplier 9 Unsolder the flexible grounding braid from the case of integrated circuit U470 on the Vertical Output board using a 40 to 60 Watt soldering iron 10 Remove one screw that holds the crt neck shield to the black plastic rear bracket 4 31 TM 11 6625 2735 14 1 11 Hold the crt base socket away from the neck shield and slide the shield to the rear of the instrument about 2 inches 12 Pry the Multiplier jack from its mounting clip on the main chassis 13 Remove the High Voltage Multiplier If necessary carefully pry the Main Interface board away for easier removal and guide the Multiplier jack through the main chassis 14 To install the High Voltage Multiplier reverse the removal procedure Use the Cathode ray Tube installa tion procedure for installing the crt Delay Line Removal 1 Remove the cathode ray tube as outlined previous ly 2 Disconnect a two wire cable near the rear of the INTENSITY control cable from y axis alignment coil 3 Remove a screw connecting a solder lug and heavy braid from the Vertical Output board at the crt neck shield 4 Remove one screw that holds the crt neck shield to the black plastic rear bracket 5 Hold the crt base socket away from the neck shield and remove the crt neck shield through the main chassis rear opening using care to guide the y axis coil cable through the board and
66. Mixed Mode Operation overall relationship between all of the circuits Complete Non Delaying Sweep End Difference schematics of each circuit are also given in the Diagrams Amplifier Section Refer to these diagrams throughout the following TIME DIV Functions Knobs Unlocked 3 20 circuit description for electrical values waveforms and relationships of the front panel controls to the individual stages HORIZONTAL AMPLIFIER lt gt General Page 3 2 Input Paraphase Amplifier Page 3 2 Signals to be displayed on the CRT are applied to the Gain Setting Amplifier Page 3 2 CH 1 OR X or CH 2 OR Y connectors The input signals are then amplified by the Preamplifier circuits Each Preamplifier circuit includes separate vertical deflection factor input coupling balance gain and variable attenua tion controls The Channel 2 Preamplifier circuit also contains an INVERT feature to invert the Channel 2 signal Output Amplifier LOW VOLTAGE POWER SUPPLY lt gt General age Power Input Page 3 2 as displayed on the CRT Secondary Circuit Page 3 2 50 Volt Supply Page 3 2 The output of each Vertical Preamplifier circuit con 110 Volt Suppl se nects to the Vertical Channel Switching circuit This 15 Volt Supply 0212142 Jo 5 Volt Supply circuit selects the channel s to be displayed An output 8 Volt Supply signal from this circuit connects to the Z Axis Amplifier 15 Volt Supply circuit to
67. Q e EL6UGO16 Fig 7 8 A9 board component locations Sheet 5 of 6 7 16 TM 11 6625 2735 14 1 2 E 9 m m T go mh oai 16 Q 6 jd gg O gp eum opi B ME ou Or A i 2 1 0642 3 d 5 E 5 5 J 5 E s p 52 i 5 5015 A mo 20 i ae 1 e 9 e o E 5 iB Fe jam JE zione Change 1 7 17 7 18 blank TM 11 6625 2735 14 1 FO amp Index w No Qty 12345 Name amp Description 15 1 l RTNR IMPLOSION 5 6422 X 4 743X 0 441 GRAY 2 6 THUMBSCREW 4 40 X 0 45 INCH KNURLED 3 1 SHLD ELCTRN TUB CRT 2 KNOB GRAY WITH SETSCREW SETSCREW 5 40 X 0 125 STL BK OXD HEX 5 2 KNOB RED VAR 1 SETSCREW 5 40 X 0 125 STL OXD HEX 6 2 KNOB GRAY VOLTS DI 2 SETSCREW 5 40 X 0 125 STL BK OXD HEX 7 2 KNOB LEVER SWITCH B 1 PUSH BUTTON GRAY INVERT 9 1 PUSH BUTTON BEAM FINDER 10 1 PUSH BUTTON GRAY CH2 11 PUSH BUTTON GRAY CHOP 12 1 PUSH BUTTON GRAY ADD 13 1 PUSH BUTTON GRAY ALT 14 1 PUSH BUTTON GRAY CHI 15 3 KNOB GRAY 1 SETSCREW 5 40 X 0 125 STL BK OXD HEX 16 1 PUSH BUTTON GRAY X10 17 1 KNOB GRAY SETSCREW 5 40 X 0 125 STL BK OXD HEX 18 1 KNOB GRAY 1 SETSCREW 5 40 X 0 125 STL BK OXD HEX 19 1 KNOB GRAY WITH SETSCREW 1 SETSCREW 5 40 X 0 125 STL BK 20 1 KNOB
68. R264 2 L a COUPLING P 270 S20A A265 gt TO SCALE FACTOR 1 SWITCHING CIRCUIT INVERT 5 mV 2258 _ POSITION 6 R280 R215 CH 2 A INVERT BAL i a omen 2mV GAIN VOLTS DIV EL6UG030 Fig 3 3 Detailed block diagram of the Channel 2 Vertical Preamplifier circuit First Cascode Amplifier Basically the First Cascode Amplifier stage in Channel 2 operates as described for the First Cascode Amplifier stage in Channel 1 However the Channel 2 First Cascode Amplifier also contains the INVERT switching function This allows the Channel 2 signal to be inverted as displayed on the CRT The INVERT switch when pushed changes the biasing on the output transistors of U220 so that the normally inactive transistors are now carrying the signal Since their outputs are cross coupled from side to side the output signal is of opposite polarity to that available in the normal button out position of the INVERT switch The Channel 2 Invert Balance adjustment R215 adjusts the DC balance of the stage to eliminate baseline shift in the display when switching from a normal to an inverted display VERTICAL CHANNEL SWITCHING gt General The Vertical Channel Switching circuit determines whether the Channel 1 or the Channel 2 Preamp signal or both will be connected to the Vertical Output Amplifier circuit In the ALT and CHOP modes of operation both channels are alterna
69. SCALE ILLUM R1480 l SPACER SWITCH PLASTIC 7 32 FO amp Index No 2173 TM 11 6625 2735 14 1 Qty 12345 Name amp Description 0D f jou po gwos gwos gwo RES VAR NONWIR ASTIG 1397 SPACER SWITCH PLASTIC RES VAR NONWIR TRACE ROT R1386 SPACER SWITCH PLASTIC WIRING HARNESS TRIGGER EYELET METALLIC 0 152 OD X 0 245 INCH L BRS EYELET METALLIC 0 126 OD X 0 23 INCH L BRS WIRING HARNESS MAIN CONNECTOR TERM 22 26 AWG BRS amp CU BE GOLD HLDR TERM CONN 1 WIRE BLACK EYELET METALLIC 0 152 OD X 0 245 INCH L BRS EYELET METALLIC 0 126 OD X 0 23 INCH L BRS WIRING HARNESS PROBE POWER CONNECTOR TERM 22 26 AWG BRS amp CU BE GOLD HLDR TERM CONN 2 WIRE BLACK 7 33 TM 11 6625 2735 14 1 CABINET EL6UGO24 Fig amp Fig 3 Index No Qty 12345 Name 8 Description 7 9 1 CABINET SCOPE 2 4 FOOT CABINET BOTTOM 3 HLDR POUCH ASSY 4 COVER SCOPE FRONT 5 COVER HDL LATCH 2 12 DIA X 0 7 ACETAL 6 1 HANDLE CARRYING ATTACHING PARTS 4 SCR TPG THD FOR 6 32 X 0 50 DEG FLH ST a 8 PLATE IDENT 9 2 SPRING HLCPS 0 959 DIA X 1 250 INCH LONG 10 2 INDEX HDL RING 11 2 HUB HDL INDEX 1 42 DIA X 0 565 THK AL CD ATTACHING PARTS FOR EACH 12 SCR CAP HEX HD 10 24 X 0 375 INCH LONG 13 WSHR SPR TNSN 0 218 ID X 0 69 INCH OD 7 34 TM 11 6625 2735 14 1 APPENDIX A RE
70. Set test oscilloscope VOLTS DIV and TIME DIV con trols as indicated on readout syrnbols each waveform Tolerance of voltages and waveforms shown are 20 OTE sre PARTS LIST 1 WHEN DH US USED i G ouz IURE GATE or S R04 x 9 i 543 3 Dil S905 Bv PL m T Ae aY DO AE A AWAY W MAIN GATE ja teso Annan veins Bii AN ere vn mwe tig H 15Y ioc PL FRO E THAING CAPACITORS 21971 101 R16 3 SEE SARS ERASERS RR EI e ANS Ki Fay APT die pnr de 7 D 6 2 15k 07 3 1 FROM 4 m VOLTAGE amp WAVEFORM CONDITIONS 2 4 0 3 DELAY SITION c 5 T e Te TIME TM 11 6625 2735 14 1 A ak P410 LISED FOR SERIES CONNECTIONS CONNECT JUMPER DM I NOT 5 ALAN SAA pote seen nere elit n 22207 1090 i eee U3 HCRIZ DISPLAY 1 i EE 5 SOU br 22 RIG INTEN PED 1 IR T PRIN RE TO ai courtes _ 5 1 7 ga wav LOW MN Pa ART 0 7 y HONY sb s ___ moram 1
71. U470 using a 40 to 60 Watt soldering iron 6 Remove the integrated circuit mounting nut from the main chassis A 1 4 inch open end wrench may be necessary to remove the nut 7 Remove the two circuit board screws along the top edge of the board and remove the Vertical Output circuit board To install the Vertical Output circuit board reverse the removal procedure Fan Motor Board Removal Remove the board as follows 1 Remove the Virtical Preamp circuit board as outlin ed previously 2 Disconnect a two wire ribbon cable at the Fan Motor board 3 Loosen the setscrew in the fan impeller coupling with a 0 050 inch Allen wrench 4 Remove two thread forming screws nearest the Fan Motor circuit board that hold the fan motor mount to the main chassis 5 Remove the fan motor and Fan Motor circuit board as a unit To install the Fan Motor circuit board reverse the removal procedure Inverter Board Removal Option 7 only Remove the board as follows 1 Remove the Vertical Output circuit board shield if installed 2 Unsolder five wires from the power transformer terminals and confirm each wire color with its location in the following list a Wire to terminal 10 is white with a brown stripe b Wire to terminal 10A is white with a red stripe c Wire to terminal 11 is white with a gray stripe d Wire to terminal 12A is white with an orange stripe e Wire to terminal 12 is white with a yellow stripe
72. Vertical Preamp circuit board reverse the removal procedure Vertical Mode Gain Switch Board Removal The Ver tical Mode Gain Switch board and the Channel 1 and Channel 2 attenuators are removed as a unit 1 Remove the Vertical Preamp circuit board as outlin ed previously 2 Remove the two UNCAL light lenses VAR VOLTS DIV UNCAL Pry them away from front panel with a fingernail and pull them straight out 3 Remove the VAR and VOLTS DIV knobs Set these knobs fully clockwise and loosen their setscrews This requires a 1 16 inch Allen wrench 4 Remove the AC G ND DC switch knobs by pulling the knobs away from the switch using a tight finger grip 5 Remove both attenuator shields using a small Phillips screwdriver each is held with five screws and washers 6 Disconnect four ribbon cables from the Vertical Mode Gain Switch board and confirm the number of wires in each cable with its plug number in the following list Note the locations of cables to facilitate correct reinstalla tion a Disconnect a five wire cable from the Main Interface board at P300 b Disconnect a one wire cable from the Main inter face board at P128 c Disconnect two three wire cables from the VOLTS DIV sensitivity indicator lights at P310 and P320 7 Unsolder the braid connecting the CH 2 attenuator to the Main Interface at the Main Interface board 8 Remove the four nuts that secure the attenuators to the front casting and remove
73. Vertical Preamp circuit board as outlin ed previously 2 Remove the Trigger Generator and Z Axis Logic board as outlined previously 3 Remove the high voltage shield and remove the Vertical Output circuit board shield if installed 4 Remove the BEAM FINDER and X10 MAG pushbut ton extension shafts Insert a scribe or small screwdriver between the end of the white plastic switch shaft and the inside end of the black plastic extension shaft and pry gently 5 Remove the INTENSITY FOCUS SCALE ILLUM ASTIG and TRACE ROTATION control extension shafts Loosen the front setscrew in each coupling with a 0 050 inch Allen wrench 6 Disconnnect twelve ribbon or wire cable connectors from the Main Interface circuit board and confirm the number and color of wires for each plug and its location in the following list a Disconnect one wire from pin E at the top left of the board b Disconnect a two wire cable from pins B and C at the top left of the board c Disconnect a two wire cable near the rear of the intensity control cable from the y axis alignment coil d Disconnect a two wire cable near Q1482 cable from the graticule lamps e Disconnect a four wire cable at the right center of the board cable from POSITION and FINE controls 4 28 f Disconnect a four wire cable at the rear of the A TRIG HOLDOFF control cable from the DELAY TIME POSITION control g Disconnect a two wire cable from the Calibrator cu
74. calibration fixture Vertical centering bandwidth a Tektronix SG 503 Leveled and isolation checks Trigger Sine Wave Generator Use checks X bandwidth check for all frequencies b Tektronix Type 191 Constant Amplitude Signal Generator Use at fre quencies of 100 megahertz and below AND Wavetek Model 10014 use only for checking 200 mega hertz bandwidth and trig gering Horizontal timing checks a Tektronix TG 501 Time Mark Generator b Tektronix 2901 Time Mark Generator Low frequency trigger checks a Tektronix SG 502 Oscil lator b General Radio 1310 B Os cillator with a binding post to BNC adapter Used throughout procedure Tektronix Part Number for signal interconnection 012 0057 01 6 Cable 2 required Impedance 50 ohms length Used throughout procedure Tektronix Part Number 18 inches connectors BNC for signal interconnection 012 0076 00 7 50 Ohm Signal Pickoff 8 Adapter Frequency response 50 kilo hertz to 875 megahertz im pedance 50 ohms for signal input signal output and trig ger output Connectors BNC Female to BNC Female Requires a TM 500 Series Power Module 5 2 Trigger checks a Tektronix CT 3 Signal Plckoff Part Number 017 0061 00 Used throughout procedure a Tektronix Part Number for signal interconnection 103 0028 00 Description 9 Adapter 10 Adapter 11 Elbow Adapter 12 T Connector 13 10X Attenuato
75. carton and remove styrofoam packing case and accessory box 2 Open styrofoam packing case and remove the oscilloscope 3 Open accessory box and remove accessories 4 Remove oscilloscope from polyethylene bag 5 Place styrofoam packing case and accessory box inside carton Store carton in dry place Checking Unpacked Equipment Check the oscillo scope after unpacking 1 Inspect the equipment for damage incurred during shipment If the equipment has been damaged report the eamagc on SF 364 2 Check the equipment against the component listing in the operator s manual and on the packing slip to see if the shipment is complete Report all discrepancies in TM 11 6625 2735 14 1 The oscilloscope can be operated where the ambient air temperature is in the range of 28 C to 65 C and can be stored where the temperature range is 62 C to 475 C After storage at temperatures outside of the operating ranges allow the chassis temperature to stabilize within the operating limits before applying power Oscilloscope cooling is provided by a fan drawing air through the cabinet Components that require the most cooling are either mounted externally at the rear of the cabinet on a heat radiator or are provided with individual heatsinks Clearance must be provided on all sides for air flow Do not block or restrict air flow through any holes in the cabinet by placing objects on or against the oscilloscope A thermal cutout in the
76. chassis holes 6 Remove the Keps nut and delay line bracket holding the Delay Line to the main chassis 7 Disconnect the Delay Line ends at the Vertical Preamp and Vertical Output boards This may require the use of a soldering iron a 40 to 60 Watt iron works best 8 Remove the Delay Line using care to guide the Delay Line ends through the main chassis holes without causing sharp bends in the line 4 32 To install the Delay Line reverse the removal procedure Use the Cathode ray Tube Installation procedure for installing the crt Recalibration After Repair After any electrical component has been replaced the calibration of that particular circuit should be checked as well as the calibration of other closely related circuits lists the adjustments that may interact with a repair in a particular circuit The table is also useful as a list of calibration adjustments that should be checked if an adjustment is made when performing the Calibration procedure Perform a calibration check of each interac tion using the appropriate step in the Calibration procedure found in TB 11 6625 2735 35 1 Instrument Repackaging Save and re use the package in which your instrument was shipped If the original packaging is unfit for use or not available repackage the instrument as follows 1 Obtain a carton of corrugated cardboard having inside dimensions of no less than six inches more than the instrument dimensions this will allow
77. column carefully to see if any other equipment is available which might suffice Then check the Usage column to see what this item is used for If used for a check or adjustment that is of little or no importance to your measurement re quirements the item and corresponding step s can be deleted 9 1 TM 11 6625 2735 14 1 1 Amplitude Calibrator 2 Sine Wave Generator 3 Time Mark Generator 4 Low Frequency Generator 5 Cable 2 required TABLE 5 1 Test Equipment Required For Performance Check Minimum Description Specifications Examples Amplitude accuracy within 0 2596 Signal amplitude 2 millivolts to 20 volts output signal 1 kilohertz square wave Frequency 350 kilohertz to above 200 megahertz output amplitude variable from 15 millivolts to 4 volts peak to peak output impedance 50 ohms reference frequency 50 to 350 kilohertz ampli tude accuracy constant with in 396 of reference frequency as output frequency changes Marker outputs 2 nano seconds to 0 5 second marker accuracy within 0 196 trigger output 1 milli second to 0 1 microsecond lime coincident with markers Frequency 10 Hertz to 50 kilohertz output amplitude variable from 10 millivolts to 4 volts peak to peak Impedance 50 ohms length 42 inches connectors BNC Vertical checks Trigger view a Tektronix PG 506 Cali gain check External Z Axis bration Generator check b Tektronix 067 0502 01
78. emitter junction of Q420 Common base amplifier Q430 provides the final amplification and isolates the output from the internal amplifier circuitry Output im pedance of the amplifier is equal to the parallel combina tion of RA31 and R432 approximately 50 ohms Normal Trigger Pickoff Amplifier The trigger signal for NORM trigger operation is obtained from a sample of the vertical deflection signal that is available from pin 15 of U370 Normal Trigger DC Center Adjustment R425 sets the DC level of the normal trigger output signal so that the sweep is triggered at the 0 level of the displayed signal when the Triggering LEVEL control is set to 0 Q390 and Q396 are connected as a non inverting feedback amplifier Gain of the stage is ap proximately 2 75 Scale Factor Switching Circuits The vertical deflection factor for each channel is indicated by back lighting the appropriate figures im printed on the flange of each VOLTS DIV knob For purposes of explanation only the circuit action of the Channel 1 Scale Factor Switching circuit is discussed TM 11 6625 2735 14 1 With a cable or an X1 probe connected to the CH 1 OR X input connector the probe coding ring terminal on the connector is not contacted and therefore presents an open to the base of Q312 This causes Q312 to be biased off and the X10 display factor bulb to be off The base level of Q314 is held low by this action thus Q314 is biased on and conducts current to light t
79. female to BNC female adapter to a BNC T connector to two 18 inch 50 ohm BNC cables to CH 1 input and B TRIGGER external input c Set the low frequency generator for 50 kilohertz then set the generator for a 5 division display and set CH 1 VOLTS DIV to 50 mV d CHECK That a stable triggered display can be obtained in AC LF REJ HF REJ and DC positions of B TRIGGER COUPLING with adjustment of B TRIGGER LEVEL e Set CH 1 VOLTS DIV to 5 mV f Set the low frequency generator for a 3 division 50 kilohertz display then set CH 1 VOLTS DIV to 50 mV g CHECK That a stable triggered display can be obtained in AC and DC positions of B TRIGGER COUPLING with adjustment of B TRIGGER LEVEL h Set the low frequency generator for a 2 division 50 kilohertz display then set B TRIGGER SOURCE to EXT 100 millivolts at external input TM 11 6625 2735 14 1 CHECK Repeat part d of this step j Set CH 1 VOLTS DIV to 10 mV k Set the low frequency generator for a 5 division 50 kilohertz display 50 millivolts at external input then set CH 1 VOLTS DIV to 50 mV l CHECK Repeat part g m Set B TRIGGER SOURCE to NORM set CH 1 VOLTS DIV to 5 mV and set TIME DIV to 10 ms n Set the low frequency generator for a 5 division 60 Hertz display then set CH 1 VOLTS DIV to 50 mV o CHECK That a stable triggered display can be obtained in HF REJ DC and AC positions of B TRIGGER COUPLING with adjustment of B TRIGGER L
80. fluids or compressed air supplies d Adjust To maintain within prescribed limits by bringing into proper or exact position or by setting the operating characteristics to the specified parameters e Align To adjust specified variable elements of an item to bring about optimum or desired performance f Calibrate To determine and cause corrections to be made or to be adjusted on instruments or test measuring and diagnostic equipments used in precision measurement Consists of comparisons of two instruments one of which is a certified standard of known accuracy to detect and adjust any discrepancy in the accuracy of the instrument being compared g Install The act of emplacing seating or fixing into position an item part module component or assem bly in a manner to allow the proper functioning of the equipment or system h Replace The act of substituting a serviceable like type part subassembly or module component or assembly for an unserviceable counterpart i Repair The application of maintenance services inspect test service adjust align calibrate replace or other maintenance actions welding grinding riveting straightening facing remachining or resurfacing to restore serviceability to an item by correcting specific damage fault malfunction or failure in a part subassembly module component or assembly end item or system j Overhaul That maintenance effort service action necess
81. for cushioning Refer to the following table for carton test strength requirements 2 Surround the instrument with polyethylene sheeting to protect the finish of the instrument 3 Cushion the instrument on all sides by tightly packing dunnage or urethane foam between carton and instru ment allowing three inches on all sides 4 Seal carton with shipping tape or industrial stapler SHIPPING CARTON TEST STRENGTH Gross Weight Ib Carton Test Strength Ib 0 10 200 10 30 275 30 120 975 120 140 500 140 160 600 TM 11 6625 2735 14 1 TABLE 4 5 CALIBRATION INTERACTION AFTER REPAIR OR ADJUSTMENT 5 T IF 2 je ADJUSTMENTSTO 8E l 5 o ADJUSTMENTS TO z1Q12 a eee Fiet tb SLT E 5 wl 2 Soo 2 z o 9 A lat 2 12155 SIS e 1318 sl gt 91 alc 212 5 2 lt lt 581 1854 152551555 zs lays 1215 b eje 146 Sessa ss isosists AREA Uiololz 2 510101 1410151 1 lt 16 Li 2 5 amp NEAT a Qu a maler aez ais 2 all 4 9 2 Ae
82. from U470 connects directly to the deflec tion plates of the CRT S505 A TRIGGER GENERATOR BS General The A Trigger Generator circuit produces the trigger pulse used to start the Sweep Generator circuit that provides the A portion of the CRT display The trigger pulse is derived from the internal trigger signal from the vertical deflection system an external signal connected to the external trigger input connector or a sample of the line voltage connected to the instrument Controls are provid ed to select trigger level slope coupling and 3 5 shows a detailed block diagram of the A Trigger Generator circuit A schematic of this circuit is shown on Diagram 5 at the rear of this manual S375 A SOURCE TRIG CH 1 EMITTER Ure oa VIEW FOLLOWER AMPL gt CH 1 Q502 TRIG Q672 Q674 SIGNAL PU X EMVPEER TO VERTICAL FOLLOWER CHANNEL SWITCHIN CH2 Q504 3308 INPUT SOURCE CIRCUIT TRIG A COUPLING FOLLOWER SIGNAL Q522 Q524 PARAPHASE NORM EMITTER 0526 AMPL FOLLOWER U520 NORMAL 0506 SOURCE COUPLING 558 A TD RESET SON AE SWITCHING SWITCHING v 9 AND HOLDOFF W R530 A TD GATE cad TD DRIVERS YA TRIG LEVEL 7 cRs66 SIGNAL LEVEL 0552 0556 gt TRIGGER Q562 Q566 EXTERNAL 511 Q R537 TRIG 530 mo SIGNAL R512 _ 1 Fig 3 5 Detailed block diagram o the A Trigger Generator circuit 3 10 Trigger Source Trigger SOURCE switch S505 selects t
83. initiates the B sweep when B TRIG SOURCE is set to STARTS AFTER DELAY or enables the B Trigger Tunnel Diodes in all other positions of B TRIG SOURCE switch When the Delaying Sweep resets Q926B again conducts and Q926A is turned off This switches C938A and B back to their original states Non Delaying Sweep Generators There are two Non Delaying Sweep Generators In any position of the HORIZ DISPLAY switch one of these generators will be running They generate the displayed sweep in the A position of the HORIZ DISPLAY switch and the B portion of a display in the remaining positions The B TIME DIV switch DLY D SWEEP knob selects the sweep rate for these generators One generator provides the 0 5 second through 1 microsecond sweep rates while the other generator provides the 0 5 microsecond through 0 01 microsecond sweep rates Either the Main Gate or the Delayed Gate can initiate sweep generation by the Non Delaying Sweep Generators When the HORIZ DISPLAY switch is in the A position and the TIME DIV knobs are locked a positive voltage is applied to the emitter of Q992 through R922 and Q1062 Q992 is forward biased and the Main Gate is passed on to the Non Delaying Sweep Generators through CR922 and CR971 or CR1001 In all the other positions of the HORIZ DISPLAY switch and when the TIME DIV knobs are unlocked a negative voltage is applied to the emitter of Q922 to reverse bias Q992 and prevent the Main Gate from reaching the
84. marks and connect trigger output through a 42 inch 50 ohm BNC cable to a 50 ohm BNC termination to A TRIGGER external input if a 2901 time mark generator is used set trigger selector for 0 1 microsecond triggers Insert a 500 megahertz filter between the 50 ohm BNC termination and CH 1 input Adjust the filter for minimum unwanted modulation from the time mark generator as necessary whenever 2 or 5 nanosecond time marks are used in this step c Set CH 1 VOLTS DIV to maintain a convenient display amplitude and set A TRIGGER LEVEL for a stable display lt may be necessary to adjust A TRIGGER HOLDOFF for best triggered display through this step d CHECK TIME DIV settings from 0 01 to 0 05 us division for accuracy at first and 11th graticule lines within 296 from 20 C to 30 C within 496 from 15 C to 55 e That accuracy is within 5 0 1 division over any 2 division interval at ail TIME DIV settings see following note NOTE If waveform has modulation check 2 division ac curacy between adjacent time marks of equal amplitude Turn INTENSITY full on note the start of sweep and exclude the first 25 nanoseconds from start of sweep or first 2 major unblanked divisions at normal intensity whichever is greater and all beyond the 100th division f Remove the trigger cable setup from A TRIGGER external input set A TRIGGER SOURCE to NORM and set A TRIGGER COUPLING to AC Remove the 500 m
85. of all stages in the 8 Volt Supply is the same as described in previous supplies The reference level for this supply 0 volt is established by the ground connection through R1463 to pin 2 of Feed back Amplifier U1464A Feedback voltage to pin 3 of U1464A is provided by divider R1464 R1465 between 50 volts and the 8 Volt Supply output The divider ratio of R1464 R1465 is 10 1 so the level at pin 3 is O volt when the supply is operating properly Any change in the output level of the supply is compared at U1464A which produces a correction signal of the same polarity as its output pin 1 This change is coupled to the 8 volt Series Regulator Q1468 through Q1466 to correct the change in output voltage Transistor Q1464 provides current limiting foldback operation if the supply load increases beyond preset limits or becomes shorted to ground 15 Volt Supply Basic operation of all stages in the 15 Volt Supply is the same as described in the 8 Volt Supply The reference level for this supply 0 volt is established by the ground connection through R1473 to pin 6 of Feedback Amplifier U1464B The feedback voltage 0 volt to pin 5 of U1464B is provided by divider R1474 R1475 between 50 volts and the 15 Volt Supply output Any change in the output voltage of the supply is compared at U1464B which produces a correction signal of the same polarity at its output pin 7 This change is coupled to the base of 15 Volt Ser
86. of logic pulses as the Logic Comparator in the Delaying Sweep Generator circuit The positive going pulse at the collector of Q1034 signals the end of the Non Delaying Sweep and the negative going pulse at the collector of Q1044 blanks the display at the end of the Non Delaying Sweep However the logic pulses from this comparator are not always allowed to pass to the Sweep and Z Axis Logic circuits 3 19 TM 11 6625 2735 14 1 In the A INTEN position of the HORIZ DISPLAY switch 5 volts is connected to the anode of CR1049 This forward biases CR1044 which sets the collector of Q1044 at approximately 0 7 volts This keeps CR1046 reversed biased and prevents completely blanking the CRT at the end of the Non Delaying Sweep portion of the display In the A INTEN MIX and B DLY D positions of the HORIZ DISPLAY switch 8 volts is connected to the anode of CR1036 through R1090 This turns off the diode gate CR1034 and CR1037 preventing a Non Delaying Sweep end of sweep pulse output from Q1034 collector which would terminate the Delaying Sweep This pulse is allowed to reset the Non Delaying Sweep through Q788 In the A position of the HORIZ DISPLAY switch knobs locked a more positive voltage is connected to the anode of CR1036 This enables CR1034 and CR1037 thus allowing the Main Sweep end of sweep pulse to pass to the Sweep Logic circuit The logic levels are generated by the HORIZ DISPLAY switch Q1062 Q1066 and Q1099 TIME DI
87. operating instructions for the test equipment are not given in this procedure Refer to the instruction manual for the test equipment if more information is needed Minimum test equipment specifications must include the use of any special required accessories such as the precision output cable included with the SG503 Refer to Maintenance Allocation Chart inLAppendix DI of this manual for approved test equipment Special Calibration Fixtures opecial Tektronix calibration fixtures are used only where they facilitate checking instrument performance These special calibration fixtures are available from Tektronix Inc Order by part number through your local Tektronix Field Office or representative Performance Check Equipment Alternatives All of the listed test equipment is required to completely check this instrument However complete checking may not always be necessary or desirable The user may be satisfied with checking only selected characteristics thereby reducing the amount of test equipment actually required The equipment listed in the Performance Check Procedure is based on the first item of equipment given as an example of applicable equipment When other equip ment is substituted control settings or equipment setups may need to be altered to meet the requirements of the substitute equipment If the exact item of test equipment given as an example in the Test Equipment list is not available first check the Specifications
88. or more time marks division as each TIME DIV setting is selected throughout the horizontal check procedure 5 16 c CHECK TIME DIV settings from 10 ms to 0 5 s division for accuracy at first and 11th graticule lines within 2 from 20 C to 30 C within 3 from 15 to 55 23 Check A INTEN Timing Accuracy a Set HORIZ DISPLAY to A INTEN set TIME DIV to 0 05 us and set time mark generator for 50 nanosecond time marks DELAY TIME POSITION should be fully counterclockwise b CHECK TIME DIV settings from 0 088 to 0 5 s division for accuracy at first and 11th graticule lines within 2 from 20 C to 30 within 3 from 15 C to 55 C 24 Check A INTEN Magnified timing Accuracy a Set TIME DIV to 0 05 ws set time mark generator for 5 nanosecond time marks and press X10 MAG to on b CHECK TIME DIV settings from 0 05 to 0 5 s division for accuracy at first and 11th graticule lines within 3 from 20 C to 30 C within 4 from 15 to 55 C see following note NOTE Turn INTENSITY fully on note the start of sweep and exclude the first 25 nanoseconds from start of sweep or first 2 major unblanked divisions at norms intensity whichever is greater and all beyond the 100th division 25 Check A Magnified Timing Accuracy Set TIME DIV to 0 01 A TRIGGER SOURCE to EXT and set A TRIGGER COUPLING to LF REJ b Set the time mark generator for 2 nanosecond time
89. oscilloscope provides protection by interrupting power to the unit if the internal temperature exceeds a safe operating level Power is automatically restored when the temperature returns to a safe level Operation in confined areas or near heat producing equipment may cause the thermal cutout to actuate The normal operating position of the oscilloscope is horizontal setting on a flat surface on the 4 feet provided on the bottom surface However under difficult operating conditions such as limited space the oscilloscope may be used in other positions without impairment of the electrical characteristics including setting the cabinet on the six protective bumpers on the rear surface It is important to remember that in positions other than the normal horizontal position characteristics such as cooling and resistance to shock and vibration are altered therefore operation in other than the normal position should be for short periods only and with more than normal care exercised to protect the oscilloscope from damage Power Requirements The oscilloscope is designed to be operated from either a 115 volt nominal or 230 volt nominal line voltage source In addition one of three accordance with the instructions of DA Pam 738 750 The equipment should be placed in service even though a minor assembly or part that does not affect proper func operating ranges may be selected around each nominal line voltage The voltage selector jumpe
90. position of the TIME DIV switch 5 volts is connected directly to the anodes of CR1103 CR1104 and CR1111 This accomplishes three things First the emitter base junction of Q1114 is reverse biased which prevents the Horizontal POSITION and FINE controls from having any effect on the display Second relay K1103 is energized which connects the X axis signal from the Channel 1 Preamplifier to the input to the Horizontal Amplifier Third 5 volts is connected to the Channel 1 Scale Factor Switching circuit so that both deflection factor indicators are operating When operating in the X Y mode H1102 adjusts for correct X axis gain and L1103 adjusts to reduce the phase differences between the horizontal X and vertical Y signal paths Gain Setting Amplifier Q1152 and Q1162 are an emitter coupled push pull amplifier stage The gain of this stage is adjusted to match the CRT sensitivity When the BEAM FINDER pushbutton is pushed R1168 is switched into the circuit This reduces the current through this stage thereby limiting horizontal deflection to within the limits of the CRT viewing area Q1152 and Q1162 operate in an overdriven mode This means at the extremes of signal amplitude one side will be turned off while the other side is still conducting This condition generates some common mode signal differences between Q1152 and Q1162 Q1164 monitors any common mode signal differences through R1165 and H1167 and conducts to minimize th
91. pull cascode amplifier and two discrete field effect transistors FET mounted on a ceramic substrate with the thick film resistors The stage is a paraphase amplifier and converts the single ended input signal to push pull output signals CR104 and CR107 provide protection for the input to U120 if large negative going signals or DC levels are applied to the CH 1 OR X input connector 3 5 TM 11 6625 2735 14 1 This input amplifier stage contains the CH 1 VAR VOLTS DIV control This control provides continuously variable uncalibrated vertical deflection factors between the calibrated positions of the VOLTS DIV switch With the VAR control in its calibrated detent wiper at ground the output transistors of U120 whose collectors connect to pins 5 and 9 are conducting the output transistors whose collectors connect to pins 6 and 8 are biased off Thus the current available to the following amplifier stage is that flowing from pins 5 and 9 When the VAR control is rotated out of its calibrated detent the transistors whose collectors connect to pins 6 and 8 begin to conduct The current they conduct is robbed from the other output transistors This causes two things to occur 1 The current flowing in the collectors of the tran sistors connected to pins 5 and 9 is less now than when the VAR control was in its calibrated detent 2 The current available to the following amplifier stage is the algebraic sum of the currents in the co
92. that the requirements for instrument power and user safety are met Power Cord Conductor Identification Conductor Color Alternate Color Ungrounded Line Brown Black Grounded Neutral Blue White Grounding Earthing Green Yellow Green Yellow This instrument is designed to operate from a single phase power source with one of the current carrying conductors the neutral conductor at ground earth potential Operation from power sources where both current carrying conductors are live with respect to ground such as phase to phase on a 3 wire system is not recommended since only the line conductor has over current fuse protection within the instrument This instrument has a 3 wire power cord with a 3 terminal polarized plug for connection to the power source and safety earth The ground terminal of the plug is directly connected to the instrument frame For electric shock protection insert this plug in a mating outlet with a safety earth contact If a 3 to 2 wire adapter is used to connect this instrument to a 2 wire ac power system be sure to connect the ground lead of the adapter to earth ground Failure to complete the ground system may allow the chassis of this instrument to be elevated above ground potential and pose a shock hazard TM 11 6625 2735 14 1 Section 2 475 Service INFORMATION Operating Power Sources This instrument can be operated from either a 115 volt or 230 volt nominal line voltage sourc
93. the Power Supply board chassis one screw each at the front and rear of the Power Supply board chassis near the top of the 475 main chassis Remove one remaining screw from the main chassis to the power supply chassis accessible through the space along the bottom of power transformer A long Phillips screwdriver is necessary to remove all three screws 5 Remove the power supply chassis from the instru ment using care to prevent damage to interconnecting wires that pass through the hole in the main chassis 6 Remove a piece of tape from the insulation wrap to gain access to the board components 7 Remove the two screws holding the Power Supply circuit board to the power supply chassis 8 Remove three Keps nuts and a plastic bar that hold a transistor and two integrated circuits to the power supply chassis 9 Unsolder two ribbon cables noting the color codes and wire positions If board replacement is intended connect the wires to the new board To install the Power Supply circuit board reverse the removal procedure 4 27 TM 11 6625 2735 14 1 Main Interface Board Removal If repair is necessary on the reverse side of the Main Interface circuit board it may be possible to gain access to that area by removal of one or two circuit boards as outlined previously Consider this first or proceed with the Main Interface board removal procedure The Main Interface circuit board can be removed as follows 1 Remove the
94. the amplifier to the other The lower amplifier drives the horizontal deflection plate is basically the same as the upper except for two things Q1188 is a relatively constant current source for Q1182 and Q1184 VR1216 shifts the DC level of the signal from the collectors of Q1182 and Q1184 to the emitter level of Q1214 LOW VOLTAGE POWER SUPPLY 4 General The Low Voltage Power Supply circuit provides the operating power for this instrument from six regulated power supplies and one unregulated power supply Electronic regulation is used to provide stable low ripple output 2 shows a detailed block diagram of the Power Supply circuit A schematic of this circuit is shown on Diagram 11 at the rear of this manual 3 21 TM 11 6625 2735 14 1 105 160 V 110 V SERIES REGULATOR Q1496 AMPL Q1490 Q1494 REGULATING _ 50 V RANGE RECTIFIER UMP UNREGULATED CR1412 50 V AMPL 01418 81416 50 V SERIES REGULATOR sea Q1424 Q1426 VR1416 Q1432 EAS 50 V R1430 50 VOLTS A R1432 LINE TRIGGER SIGNAL 15 RECTIFIER UNREGULATED CR1442 50 V FEEDBACK AMPL U1454A LINE VOLTAGE R1444 NO 15 V SERIES SELECTOR REGULATOR 1403 01444 01446 15 V POWER R1445 Q1448 INPUT T1400 5 V RECTIFIER CR1452 50 V FEEDBACK AMPL U14548 1454 5 V SERIES REGULATOR 5 Q1454 Q1456 51401 8 v RECTIFIER CR1462 50V FEEDBACK AMPL U1464A
95. the collector winding of T1320 This produces a corresponding voltage increase in the feedback winding of T1320 which is connected to the base of Q1318 and Q1318 conducts even harder Even tually the rate of collector current increase in Q1318 becomes less than that required to maintain the voltage across the collector winding and the output voltage drops This turns Q1318 off by way of the feedback voltage to the base The voltage waveform at the collector of Q1318 is a sine wave at the resonant frequency of T1320 Q1318 remains off during the negative half cycle while the field collapses in the primary of T1320 When the field is collapsed sufficiently the base of Q1318 becomes forward biased into conduction again and the cycle begins anew The amplitude of sustained oscillation depends upon the average current delivered to the base of Q1318 The frequency of oscillation is approximately 50 kilohertz Fuse F1318 protects the unregulated 15 volts supply in the event the High Voltage Oscillator stage becomes shorted C1318 and L1318 decouple the 15 volt supply line and prevent the current changes present in the circuit from affecting the 15 volt regulated supply Hiigh Voltage Regulator Feedback from the CRT cathode 2450 volt supply is applied to the base of Q1306 through R1303A Any change in the level at the base of Q1306 produces an error signal at the collector of Q1306 which is amplified by Q1308 and Q1316 and applied to the ba
96. the output voltage from the 110 Volt Supply through divider R1486 R1487 is connected to the base of Q1490 The base of Q1494 is connected to the 50 Volt Supply to provide a reference voltage The error output at the collector of Q1494 reflects the difference if any between these 2 inputs This error output drives Q1496 and controls the output voltage of the power supply Regulation occurs as follows If the output level of this supply decreases due to an increase in load for example the voltage at the base of Q1490 decreases also This decreased voltage when compared to the reference voltage at the base of Q1494 results in a decreased voltage at the collector of Q1494 A portion of this decreased voltage is connected to the base of Q1496 causing increased conduction The output voltage increases thereby achieving regulation of the 110 volt power supply A current limiting stage Q1497 protects the 110 Volt Supply if excess current is demanded from this supply All output current from the 110 Volt Supply must flow through R1489 Transistor Q1497 senses the voltage drop across R1489 Under normal operating conditions Q1497 is biased off However when excess current is demanded from the 110 Volt Series Regulator due to a short circuit or similar malfunction at the output of this supply the voltage drop across R1489 increases until it is sufficient to forward bias Q1497 The collector current of Q1497 pulls the base of Series Reg
97. to remove Do not use tweezers or other hard cleaning too Is on the filter as the special finish may be damaged 5 When not in use store the mesh filter in a lint free dust proof container such as a plastic bag Air Filter The air filter should be visually checked every few weeks and cleaned or replaced if dirty More frequent inspections are required under severe operating con ditions The following procedure is suggested for cleaning the filter If the filter is to be replaced order new air filters 1 Remove the filter by pulling it out of the retaining frame on the rear panel Be careful not to drop any of the accumulated dirt into the instrument 2 Flush the loose dirt from the filter with a stream of hot water 3 Place the filter in a solution of mild detergent and hot water and let it soak for several minutes 4 Squeeze the filter to wash out any dirt which remains 5 Rinse the filter in clear water and allow it to dry 6 Coat the dry filter with an air filter adhesive 7 Let the adhesive dry thoroughly 8 Install the filter in the retaining frame TM 11 6625 2735 14 1 Visual Inspection The instrument should be inspected occasionally for such defects as broken connections broken or damaged ceramic strips improperly seated semiconductors damaged or improperly installed circuit boards and heat damaged parts The corrective procedure for most visible defects is obvious however particular care
98. trouble possibilities before proceeding with extensive troubleshooting The first few checks ensure proper connection operation and calibra tion If the trouble is not located by these checks the remaining steps aid in locating the defective component When the defective component is located it should be replaced following the replacement procedure given under Corrective Maintenance 1 Check Control Settings Incorrect control settings can indicate a trouble that does not exist If there is any question about the correct function or operation of any control see the Operating Instructions section of this manual 2 Check Associated Equipment Before proceeding with troubleshooting of the 475 check that the equipment used with this instrument is operating correctly Check that the signal is properly connected and that the inter connecting cables are not defective Also check the power source 3 Check Instrument Calibration Check the calibra tion of this instrument or the affected circuit if the trouble exists in only one circuit The apparent trouble may only be a result of misadjustment and may be corrected by calibration Complete calibration instructions are given in the Calibration section of this manual 4 Visual Check Visually check the portion of the instrument in which the trouble is located Many troubles can be located by visual indications such as unsoldered connections broken wires damaged circuit boards damage
99. vinyl coated aluminum alloy Circuit Boards Glass laminate etched wiring Overall Dimension Height With Feet and Pouch 7 5 inches 19 1 cm Without Pouch 6 2 inches 15 7 cm Width With Handle 12 9 inches 32 8 cm Without Handle 11 5 inches 29 2 cm Depth Including Panel Cover 18 1 inches 46 cm Handle Extended 20 3 inches 51 5 cm Weight With Panel Cover Acces 25 3 pounds 11 5 kg sories and Accessory Pouch Without Panel Cover Ac 22 8 pounds 10 3 kg cessories and Accessory Pouch Domestic Shipping Weight 32 7 pounds 14 8 kg Export Shipping Weight Approximately 48 0 pounds 21 8 kg Standard Accessories Standard accessories supplied with the 475 are listed in the Mechanical Parts List in this Service manual For optional accessories available for use with the 475 see the Tektronix Inc catalog Installation The following paragraphs include instructions for unpacking inspecting and installing the instrument and the basic information required to operate the oscilloscope within the design environmental power and space limitations For more detailed information on specifica tions refer to table 1 1 Unpacking Unpack the oscilloscope as outlined in the following procedure NOTE If storage space is available it is recommended that all packing material be saved for possible future use Thus unpacking should be accomplished carefully so as not to damage the packing material 1 Open top of
100. 01456 ATTACHING PARTS SCREW MACHINE 2 56 X 0 312 INCH RDH STL WASHER NONMETAL 0 09 ID X 0 121 OD NYLON INSULATOR PLATE TRANSISTOR HEAT SINK ELEC TRANSISTOR VA cm TRANSISTOR CHAS MTG Q1482 ATTACHING PARTS ASSEM WSHR 2 56 X 0 312 INCH PNH STL as pon w C ASHER NONMETAL 0 09 ID X 0 121 OD NYLON ko a r 7 31 TM 11 6625 2735 14 1 FO 8 Index No Qty 12345 Name amp Description 17 123 INSULATOR PLATE TRANSISTOR 124 CLAMP LOOP 0 062 INCH DIA 125 2 EXTENSION SHAFT 4 14 INCH LONG 126 EXTENSION SHAFT 0 123 OD X 5 7 INCH LONG 127 2 CPLG SHAFT RGD O 128 ID X 0 312 OD X O S L 2 SETSCREW 4 40 X 0 094 INCH HEX SOC STL 128 EXTENSION SHAFT 9 312 INCH LONG 129 EXTENSION SHAFT 0 125 OD X 1 455 INCH LONG 130 EXTENSION SHAFT 0 125 OD X 1 7 INCH LONG 131 EXTENSION SHAFT 0 125 OD X 1 05 INCH L 132 2 CPLG SHAFT FLEX FOR 0 125 INCH DIA SHAFTS 4 SETSCREW 4 40 X 0 188 INCH HEX SOC STL CPLG SHAFT FLEX FOR 0 125 INCH DIA SHAFTS 4 SETSCREW 4 40 X 0 125 INCH HEX SOC STL 133 BOARD ASSY INTERFACE 9 ATTACHING PARTS 134 7 SCR ASSEM WSHR 4 40 X 0 312 DOUBLE SEMS TERMINAL LUG 0 14 ID PLAIN BRASS ami m AS ume um BOARD ASSY INCLUDES 135 4 CONN RCPT ELEC CKT BD MT 3 PRONG 7 136 LINK TERM CONNE 0 086 DIA X 2 375 INCH L 137 SOCKET PIN TERM 0 188 INCH LONG SOCKET PLUG IN 3 PIN SQUARE SOCKET PLUG IN 3 PIN LOW PROF
101. 07 3 TERMINAL PIN 0 365 L X 0 25 PH BRZ GOLD PL 108 SOCKET PIN TERM 0 188 INCH LONG SOCKET PLUG IN 3 PIN SQUARE SOCKET PLUG IN 3 PIN LOW PROFILE 109 3 SPACER SLEEVE 0 11 ID X 0 25 OD X 0 28 H 7 27 7 28 blank TM 11 6625 2735 14 1 FO amp Index No Qty 12345 Name 8 Description ATTACHING PARTS FOR EACH 2 1 SCREW MACHINE 4 40 X 0 375 INCH PNH STL 3 1 SPACER SLEEVE 0 25 OD X 0 188 INCH LONG CKT BOARD ASSY GAIN SWITCH ATTENUATOR ATTACHING PARTS E 2 SCR ASSEM WSHR 4 40 X 0 312 DOUBLE SEMS o ATTENUATOR ASSY INCLUDES 5 2 COVER CHASSIS ATTENUATOR A FROM A 2499 Palm ATTACHING PAR FOR EACH l TS 56 INCH PNH STL 6 SCR TPG THD FOR 2 32 X 0 7 1 WASHER FLAT 0 109 ID X 0 25 INCH OD STL 8 4 SCREW MACHINE 4 40 X 0 25 INCH PNH STL 9 4 WASHER FLAT 0 119 ID X 0 375 INCH OD STL 10 2 CONNECTOR RCPT BNC MALE 3 ATTACHING PARTS FOR 11 WASHER LOCK INT 0 521 ID X 0 625 INCH OD 12 1 WASHER FLAT 0 500 ID X 0 625 INCH OD STL 13 NUT PLAIN DODEC 0 500 28 X 0 90 INCH BRS ow CHASSIS SCOPE ATTENUATOR ATTACHING PARTS FOR EACH TA AS an BA wert Aa rarer FVOl ELEC MECH 0 333 LUNU 4 16 2 SCREW MACHINE 4 40 X 0 312 INCH PNH STL 17 6 WASHER LOCK 4 INTL O O15THK STL CD BL 18 2 SCREW MACHINE 2 56 X 0 25 INCH PNH STL 19 2 WASHER LO
102. 1 De on e ____________ _______________ D 863 2284 2 7698 6920ca 89 9864 amp 6 nines 5 o Laj Picts d 4 d 0894 X lt mon 895 C2 4942 867 75719 CR 9 289492C3 m 654 666 2659 I 88 427 z 849 0091 8 Gj 3 OS 844225 8525 ross 96 896 N e mM mm 79 am we Cc F 6489 A 2084 10942 4 a 8674 j e mp x 5 5649 66745 20835 2618 7649 106 lt lt 7 11 EL6UG011 Fig 7 7 A8 board component locations Sheet 3 of 3 TM 11 6625 2735 14 1 can 81344 a T G E ca wen S 86612 w 2 it D rset a lt sm 595 ole etm 21 25 EDITT umi o a 2451 5 E lt 4 SFE ji SE Gy Es e 2165 lt U x 74615 o 8912 ug EA en EL6UGO12 Fig 7 8 A9 board component locations Sheet 1 of 8 7 12 TM 11 6625 2735 14 1 ON BACK OF BOARD PREFIX ALL REF DES WITH A9 pas mmng e 2 01989 d 21395 Fe 21393 CR1337 0 1335 8 81385 l oi ener 5 lt 599 Ww R11
103. 1 6625 2735 14 1 TABLE 1 1 cont ELECTRICAL Characteristics Sensitivity Deflection Accuracy Variable Range X Axis Bandwidth DC to 3 MHz Same as vertical deflection system Same as vertical deflection system Input Capacitance Input Resistance Same as vertical deflection system Same as vertical deflection system CALIBRATOR 300 mV within 1 0 Approximately 1 kHz 30 mA within 296 Maximum Input Voltage Phase Difference Between X and Y Axis Amplifiers X Axis Low Frequency Linearity Output Voltage 0 to 40 C 15 C to 55 C Repetition Rate Output Resistance Output Current 20 to 30 C 15 to 55 C Z AXIS INPUT Sensitivity 5 V P P signal causes noticeable mod ulation at normal intensity DC to 50 MHZ Useable Frequency Range Maximum Input Voltage 1 8 Performance Requirements X Y OPERATION Same as vertical deflection system Same as vertical deflection system Supplemental Information Extreme counterclockwise position of TIME DIV switch CH 2 OR X Y button of VERT MODE switch must be pushed Within 19 from DC to 1 MHz Within 3 from 1 MHz to 2 MHz 0 2 div or less compression or ex pansion of a 2 div signal at center screen positioned to horizontal extremes of display area Adjusted to within 0 5 at 25 5 300 mV within 1 5 Within 25 Approximately 9 4 0 30 mA within 2 596 Positive going signal f
104. 19 CABINET AND RACK ADAPTER Standard Parts Page 4 19 REMOVAL Special Parts Page 4 19 Standard Cabinet Removal Ordering Parts Page 4 19 The standard instrument cabinet can be removed in the followi Soldering Techniques Page 4 19 1 Disconnect the instrument power from the Small Component Replacement Page 4 20 power source General Page 4 20 Transistor and Replacement Page 4 20 2 Install the front panel cover and set the instrument face on a flat surface Interconnecting Pin Replacement Ceramic Terminal Strip Replacement 3 Unwrap the power cord from the instrument feet Fuse Replacement ge 4 Cam Switch Replacement 4 Remove the 6 screws indicated in and Circuit Board Replacement Page 4 remove the rear cabinet frame with feet and screws from the instrument as an intact assembly Vertical Preamp Board Removal Page 4 2 Vert Mode Gain Switch Board Removal Page 4 2 Trigger Generator And Z Axis Logic Board Removal Page 4 2 Timing Board Removal Vertical Output Board Removal Fan Motor Board Removal Page 4 2 Inverter Board Removal Option 7 only Page 4 2 Power Supply Board Removal 475 DM 43 U U c D D no o O and DM 40 only age 2 4 Main Interface Board Removal Pao 8 Power Transformer Removal Cathode ray Tube Removal Pao 8 4 2 5 Lift the cabinet up until it is separated from the instrument and power cord WARNING Dangerous potentials exist a
105. 25 2735 14 1 EL6UG023 FO 17 Left side and bottom exploded view ZON RECOMMENDED CHANGES TO EQUIPMENT TECHNICAL PUBLICATIONS SOMETMING WRONG WITH THIS PUBLICATION FROM PRINT YOUR UNIT S COMPLETE ADDRESS Commander DOPE ABOUT IT ON THIS ANSTA g epot FORM CAREFULLY TEAR IT IN THE MAIL PIN POINT WHERE IT IS BE EXACT IN THIS SPACE TELL WHAT IS WRONG AND WHAT SHOULD BE DONE ABOUT IT Recommend that the installation antenna alignment procedure be changed to specify a 2 antenna lag rather than 19 A REASON Experience has shown enat a 19 as tha antanna corvo evcta 1c tan sensiti ve to wind 45480 lt 1 1111 ww XM m A LAZA wIiiJ AL AVA VY LIINI en venn a M eee EE done GEE 23 See ea gusting in excess of 25 knogs and has a tendency to rapidly accelerate and dec at as it hunts causing strain to the drive train ing 1S minimized by adjusting the lag to 2 without degradation of gt YOY a 7 FAULT in alls for a 3 db 500 watts adjust ment to li ache TRANS POWER FAULT indicator yo u Add new step f 1 to read Replace cover plate removed REASON Th gdjustment procedure the the TRANS POWER step e 1 above REABON To replace the cover plate n J e 24 VDC to 5 VDC pre NJ m tb 2 Zone 3 5 4 ar 9
106. 261B and OS 261C V 1 U Power Supply 1106 Battery Pack TM 11 6625 2735 14 1 SECTION 0 INTRODUCTION Scope This manual describes Oscilloscope OS 261B V 1 U OS 261C V 1 U and provides instructions for opera tion and maintenance Throughout this manual the OS 261B V 1 U is referred to as Tektronix Model 475 with option 04 and the OS 261C V 1 U is referred to as Tek tronix Model 475 with option 07 Consolidated Index of Army Publications and Blank Forms Refer to the latest issue of DA Pam 310 1 to determine whether there are new additions changes or additional publications pertaining to the equipment Maintenance Forms Records nd Reports a Heports of Malntenance and Unsatisfactory Equipment Department of the Army forms and pro cedures used for equipment maintenance will be those prescribed by DA Pam 738 750 as contained in Maintenance Management Update b Report of Packaging and Handling Deficiencies Fill out and forward SF 364 Report of Discrepancy ROD as prescribed in AR 735 11 2 DLAR 4140 55 NAVMATINST 4355 73A AFR 400 54 MCO 4430 3 Discrepancy in Shipment Report DISREP SF 361 Fill out and forward Discrepancy in Shipment Report DISREP SF 361 as prescribed in AR 55 38 NAVSUPINST 4610 33C AFR 75 18 MCO P4610 19D DLAR 4500 15 Reporting Equipment Improvement Recommendations EIR lf your OS 261B V 1 U and OS 261C V 1 U needs improvement let us know Send us an EIR You the use
107. 3400 LiIIGZ 375 vice d 500 2 15y 5 2 i dyes H av EV E DEPL PCPL 2 PL TO EMITTERS s 9 t 4 a 4 5 CesT Jus H Y 5 9 d 1 un re m RI254 91254 G C165 2165 Cili 1 3 eus Sy i 0 35 108 TOU I DH y tone ML y T uen Mi 8y 5 5 a RIBS ig BOU d pe A ee 282 i see gt ER v a A v OE HORIZONTAL AMPLIFIER FO 11 Horizontal amplifier schematic diagram VOLTAGES AND WAVEFORMS The voltages and waveforms shown on this diagram were obtained by using the recommended test equipment and test set ups listed below RECOMMENDED TEST EQUIPMENT ITEM SPECIFICATIONS Test oscilloscope Deflection factor RECOMMENDED TYPE Frequency response DC to 75 MHz Tektronix 7603 equipped with 7A13 1 mV to 5 V Div Amplifier and 7B50 Time base units or Input impedance 1 20 pF equivalent Sweep rate 50 ns Probe Fast rise 10X attenuation probe com Tektrorix 6053 or equivalent patible with vertical amplifier of test oscilloscope Voltmeter Non loading Input Impedance Digital Multimeter Hange 475 Control Settings Display Controls INTENSITY Midrange FOCUS Midrange SCALE ILLUM Midrange Vertical Controls CH 1 and CH 2 POSITION Center trace on graticule VOL
108. 35 4 SV uS Caa 4 demi ii ea 1 RISIS 50 21516 127 81517 i SC SON MA ei tva ae A ate 1698 08067 cRIE99 A CREBO6E E C1698 C8064 8634 R054 280 9 FAN MOTOR HOUSING 88045 BI690 cp T CRI696 46 L iMac ge ROTER EARN AIC S AN SA NP Lo 14 4 A 16908 ye REE USO6IT Ul69oc ABAZ ane LL 5 KT1696 RT 8038 5K G SR zon M PORA e RS sli oa Pp vos CALIBRATOR 30O 30 FY ik Hz TM 11 6625 2735 14 1 j P1690 P8062 gt 15v AS RBO36G Bok N 54977 CO kk Er I RA ALATE TOR 52 a TR AN A EN e gt 9 CAUTION NOTE ORIENTATION P8962 P1690 BEFORE DISCONNECTING INDEX MAY BE MISLABELED ON SOME BOARDS CALIBRATOR AND FAN CIRCUIT EL6UGO60 FO 14 Calibrator and fan circuit schematic diagram TM 11 6625 2735 14 1 EL6UGO21 FO 15 Front panel and chassis exploded vlew TM 11 6625 2735 14 1 EL6UGO22 FO 16 Right side exploded view TM 11 66
109. 35 14 1 Qty 12345 Name amp Description aw wo i va jn gen M gwo Y EXTENSION SHAFT 10 384 INCH LONG W KNOB ACTUATOR SWITCH POWER SWITCH TOGGLE POWER 51401 ATTACHING PARTS NUT PLAIN HEX 0 25 40 X 0 312 INCH BBS WASHER LOCK INTL 0 26 ID X 0 40 OD STL 9 SWITCH SLIDE LINE SELECTOR S1403 ATTACHING PARTS SCREW MACHINE 4 40 X 0 25 100 DEG FLH STL m m cues CON INV SW HOLS BRACKET ELEC SW ALUMINUY ATTACHING PARTS NUT PLAIN 4 40 X 0 188 INCH BRS WASHER FLAT 0 125 ID X 0 25 OD STL SCR ASSEM WSHR 4 40 X 0 312 INCH PNH BRS NUT PLAIN HEX 4 40 X 0 25 INCH STL a mn SUPPORT BD ACETAL CKT BOARD ASSY TRIG GEN 6 Z AXIS LGC AB ATTACHING PARTS SCR ASSEM WSHR 4 40 X 0 312 DOUBLE SEMS m m CKT BOARD ASSY INCLUDES TERM TEST POINT BRS CD PL LINK TERM CONNE 0 086 DIA X 2 375 INCH L CONN RCPT ELEC CKT BD MT 3 PRONG SOCKET PIN TERM 0 188 INCH LONG SOCKET PLUG IN 3 PIN SQUARE SOCKET PLUG IN 3 PIN LOW PROFILE SOCKET PLUG IN 20 LEAD DIP CKT BD MTG TERMINAL PIN 0 365 L X 0 25 PH BRZ GOLD PL TERM SET PIN 36 0 525 L X 0 025 SQ CONNECTOR RCPT 2 CONTACT CONNECTOR RCPT 10 CONTACT CONNECTOR RCPT 12 CONTACT STUD SELF LKG 4 40 X 0 35 INCH LONG COVER HALF XSTR FOR DUAL TO 18 CASE COVER HALF XSTR FOR DUAL TO 18 CS 2 56 THD ATTACHING PARTS FOR EACH SCREW MACHINE 2 56 X 0 312 INCH RDH STL
110. 4 1 Simplified Block Diagram See Figure 6 2 The dc source is applied to the turn off level circuit the start circuit and the primary of T1400 If he dc source is above the level set by Turn Off Level adjustment R1613 the turn off circuit does not operate The start circuit provides a large current surge through 1631 secondary to the bases of Q1652 Q1662 Q1654 and Q1664 This starts the inverter The turn off circuit is activated in two ways In 24 V operation Q1622 is turned on by the source voltage dropping below 22 V In 12 V mode of operation Q1626 is turned on by the accidental application of 24 V dc Turn Off Level Circuit For the following description refer to The voltage reference for the base of Q1606 is set by R1604 VR1604 and VR1605 for about 9 1 V This es tablishes the junction of R1607 and the emitters of Q1606 and Q1608 at about 9 7 V C1605 helps to hold the 9 1 V level preventing inverter transients from activating the turn off circuit and prevents Q1608 from turning on when the inverter is started This allows the power source time to recover after providing the initial start surge 3 8 TURN OFF CIRCUIT RNOFF SANN T c L INVERTER ane 1862 Source voltages higher than 22 V dc cause increased current through R1607 Q1606 and R1609 Q1608 is kept cut off by the increased voltage across R1609 and the resulting change across divider R1611 R1613 R1614 Th
111. 40 C12 INPUT e CH 1 OR X 199 NO R10 GAIN PEN ATTENUATORS ce ow ud t m R164 A170 R194 Y e CH 1 VERTICAL SIGNAL TO R24 CH 1 R165 R185 BAL 5 mV T i GAIN POSITION n t INPUT feed one nn See L COUPLING A128 S20A 1 TO SCALE FACTOR CH 1 SWITCHING CIRCUIT VOLTS DIV EL6UGO29 Fig 3 2 Detailed block diagram of the Channel 1 Vertical Preamplifier circuit Input Coupling Signals applied to the input connector can be AC coupled DC coupled or internally disconnected from the input to the Vertical Input Amplifier circuit When Input Coupling switch S20A is set for DC coupling the input signal is coupled directly to the Input Attenuator stage When AC coupled the input signal passes through capacitor C12 This capacitor prevents the DC component of the signal from passing to the amplifier In the GND position S20A opens the signal path and connects the input of the amplifier to ground through R24 This provides a ground reference without the need to dis connect the applied signal from the input connector Resistor R22 connected across the input coupling switch allows C12 to be pre charged in the ground position which prevents generation of large voltage transients at the input to the amplifier and allows the trace to remain on screen when switched to the AC position Input Attenuator The effective o
112. 475 A GATE rear panel through a 42 inch 50 ohm BNC cable to test oscilloscope external trigger input Set test os cilloscope triqger source to external and set vertical input for ac coupling For waveforms which have the horizontal centerline labeled 0 V set the test oscilloscope vertical COUPLING AC tfor d ling LEVEL inpu r dc coupling SLOPE Set test oscilloscope VOLTS DIV and TIME DIV con SOURCE NORM tro s as indicated on readout symbols on each waveform TRIG MODE AUTO A TRIGGER HOLDOFF NORM Tolerance of voltages and waveforms shown are 20 281260 504 lt VOLTAGE MULTIPLIER VOLTAGE amp WAVEFORM CONDITIONS TM 11 6625 2735 14 1 FROM 349 2 AXIS UN BLANK FROM 694 RIB3SA 6 83356 SANGED SRI cpiras vaki HSY 1 DCPLI a 1195 dd 1 LRIZ41 DC COUPLED 1 yon 270 TPISL A sav ant Psi 1 Cuu BOARD ELDERLY eoep L EXTRA m 2 1542 gt 31330 174 5 4t Ba CRIBS A kran 25 3 434 d ees a 107 OY LA 4 Meise 1 4 TT OA TAF CAQP BLANKING fan eise ns me 25 ovg CRIS7A T giv a 174 4 tour tisy Y T 5 3 21 1386 S 8v ince TRACK 2 RO
113. 5 C845 Ss REIS TO P300 3 5 1 20K 539 j a 698 msso 150 PARTIAL AS 5 av INTERFACE BOARD 6 591 3593 25597 QUT socal S 79572 K o By Sy START R556 0200 459 Renz 1000 MONDOLIT WIC i 2 SWEEP TE huto 8953 TO RC L T KOUT 245 J3 77 Siauro 15v DISABLE VOLTAGE 5 WAVEFORM CONDITIONS B 287 0288 150K SEE FIGB 9 PRESET For BGAR LOCATION ager Sete TIMING 600 J3 n 68 M c START sw se OUT RSAZ RSS 542 c e lenge TRIG D 2825 280 4ROZIZ Swe TRIG 78 EN 35v nc pe 1 PePLZZ crt RA an 6647 S MAIN GATE HOLDOFF 32 5 j l FROM CRIOGO T le READY p 72 T 5 650 fon ak 25 ESE GPAARGE Fou ae 327 YR i 8826 A tyres m 58 av a A ACT SV ENAIT My Saaga ba 644 4223 7 35 7 T 6 T a nps ENDS A AV 5 OPEN K FULL CW POSITION OF Ris d SWEEP amp Z AXIS LOGIC ChRO39 15 50Y TM 11 6625 2735 14 1 E 1
114. 516 OUT CH2 VERT SIG OUT Muere gu oon AMP 2 0420 pa X SIGNAL A NORMAL TRIGGER TRIOGER PICKOFF AMF 300 Q662 Q672 4 EE 03 0664 0674 Y SWEEP END H START DIFFERENCE 77 Qssa AMPLIFIER 7 ve SAN TRIGGER TIME DIY 0596 r a a HIGH 224 SWITCH YOLTAGE 1380 i MULTIPLIER 01327 RS SWEEP END gt DIFFERENCE H AMPLIFIER a SWEEP i i ro i y CONTROL Ao DET TEES 7 j U600 i j pu 1 4 i TO DELAYING ATRIGGEA SWEEP LATCH TO RESET 4 Q612 Le 4 A Q628 4 TO DELAY i i PICKOFF i i COMPARATOR attiGGER panamas lt EIER 57 i 1 INPUT amp MAIN GATE MAIN GATE OUTPUT AMPLIFIER TRIG MPT je i Q502 0522 ael DeiveRS potab C MPARATOR AMPLIFIER aa DI ee AMPLIF ER i S l i 051416524 28556 Q572 0902 7 2940 5 asc 9526 0532 0562 md Sa 2955 e i i li Osga 5 21099 JUNE Gene nee eee AMPLIFIER 2 j Y CHOP BLANKING Q1332 Q1352 i wy AMP bh H l 01062 Y oime 4 LINE TRiG me P ud 49 01382 FROM LY 4 H T FROM POWER SUPPLY 9798 i 2 AXIS
115. 652 01654 01662 01664 EP PARTS NUT PLAIN EXT W 4 40 X 0 25 INCH STL RETAINER XSTR INSULATOR PLATE 0 70 X 3 INCHES LONG M o la 12 re 13 14 GROMMET PLASTIC U SHP 0 625 X0 658 INCH GROMMET PLASTIC 0 25 INCH DIA wo m p 15 FUSEHOLDER 3AG FUSE ATTACHING PARTS SCREW MACHINE 6 32 X 0 312 INCH PNH STL WASHER LOCK INTL 0 146 IDX 0 288 OD STL NUT PLAIN HEX 6 32 X 0 25 INCH BRS d 16 17 2 18 CABLE ASSY PWR 3 WIRE 6 INCHES LONG e jw pwi pa p e n n e n n nen ete l INSULATOR FILM l X 2 55 INCH Loo OO O aQ e nM M su Ma MM 6 28 Change 1 ee pret MP IEE EE EO r gt m b 0 m 3 gt gt p gt REPLACEABLE MECHANICAL PARTS PARTS ORDERING INFORMATION For complete part information refer to TM 11 6625 2735 24 1 SPECIAL NOTES AND SYMBOLS X000 Part first added at this serial number OOX Part removed after this serial number FIGURE AND INDEX NUMBERS ltems in this section are referenced by figure and index numbers to the illustrations INDENTATION SYSTEM This mechanical parts list is Indented to indicate item relationships Following 15 an example of the indentation system used in the description column 12345 Name De
116. 672 to allow signal amplification Trigger View Centering adjustment R673 adjusts for correct DC balance in the circuit Normally the output of the Vertical Channel Switching circuit is applied to the input of the Delay Line When the TRIG VIEW pushbutton is pushed the signal from the Vertical Channel Switching circuit is removed and the output from the Trigger View Amplifier is applied in its place B TRIGGER GENERATOR lt gt The Trigger Generator circuit produces the trigger pulse used to start the Sweep Generator circuit that provides the B portion of the CRT display The B Trigger Generator circuit is virtually the same as the A Trigger Generator circuit and only the differences between the two are discribed here A schematic of this circuit is shown on Diagram 6 at the rear of this manual 3 12 Trigger Source The B Trigger Generator circuit has no LINE or EXT 10 positions on its Trigger SOURCE switch If the Generator is to be triggered from a line voltage signal or the external trigger signal is to be attenuated it must be accomplished in some other manner The B Trigger SOURCE switch does have a STARTS AFTER DELAY position however the A Trigger SOURCE switch does not This position allows the B portion of a display to start immediately after the selected delay time without waiting for a triggering signal SWEEP AND Z AXIS LOGIC General The Sweep and Z Axis Logic Circuit derives the logic
117. 8 ID X 0 312 OD X O S L 4 SETSCREW 4 40 X 0 188 INCH HEX SOC STL 70 2 CONTACT ELEC GROUNDING CLIP 4 SETSCREW 4 40 X 0 094 INCH HEX SOC STL ATTACHING PARTS 71 SCREW MACHINE 4 40 X 0 25 INCH PNH STL 72 WASHER LOCK SPLIT O 118 ID X 0 212 00 STL 73 WASHER FLAT 0 125 ID X 0 25 OD STL w a Wee 74 1 BOARD ASSY VERT PREAMPL ATTACHING PARTS 75 7 SCR ASSEM WSHR 4 40 X 0 312 INCH PNH BRS 76 POST ELEC MECH 0 538 INCH L Fk a BOARD ASSY INCLUDES 77 2 CONN PLUG ELEC 2 FEMALE BLADE CONT 78 3 SOCKET PLUG IN 14 CONTACT LOW CLEARANCE 79 SOCKET PIN TERM 0 188 INCH LONG SOCKET PLUG IN 3 PIN SQUARE SOCKET PLUG IN 3 PIN LOW PROFILE Ww o joune 7 30 FO amp Index No 17 80 81 82 89 90 91 92 93 95 QA 97 98 99 100 10 10 103 104 10 106 10 108 109 110 11 l 2 5 7 l 112 113 114 2511 116 11 118 5 7 119 Qty wo own IN e P p p jan pant jant pant pan jen 11 6625 2735 14 1 12345 Name amp Description TERM TEST POINT BRS CD PL TERMINAL PIN 0 365 L X 0 25 PH BRZ GOLD PL CONTACT ASSY EL CAM SWITCH TOP CONT ASSY ELEC CAM SWITCH BOTTOM ATTACHING PARTS RIVET TUBULAR 0 051 OD X 0 115 INCH LONG Se A rum ums BEAT SI
118. 83 ak 118 89 Cw f VBDI14 14 24 2 3 1212 C1253 7 S VA ru Vo 1212 935 81208 i22 1211 1255 EC ene 8 gren e C12 ev a akel S nes 1214 0227 21307 ax C1302 S i 5 8125 ome EL6UG013 Fig 7 8 A9 board component locations Sheet 2 of 6 TM 11 6625 2735 14 1 2 C1595 en N _ n kan N o noun A rn EET 6 61386 EL6UG014 Fla 7 8 A9 board component locations Sheet 3 of 6 7 14 TM 11 6625 2735 14 1 aa Sea CRM e dane VA amann KL SY om Bo A 21485 681 EL6UG015 PREFIX ALL REF DES WITH A9 847145 Bro 7 8 A9 board component locations Sheet 4 of 6 09 14 gt 94914 n F1318 USED WITH OPTION 07 Change 1 7 15 TM 11 6625 2735 14 1 PREFIX ALL REF DES WITH A9 ee 3 2172 ik oW E 87714 9827182 3 A 8001 P e 620032 Eu swaf CRI452 a H Bl 38 J 1488 J E a Q H
119. A 50 OHMS RG 58 U 18 IN 6145 00 916 8025 EQUIVALENT TO TEKTRONIX PART No 012 0076 00 16 ADAPTER GR TO BNC FEMALE EQUIVALENT TO 5835 00 765 5481 TEKTRONIX PART No 017 0063 00 17 ADAPTER CONNECTOR GR874 TO BNC MALE 5935 00 984 5563 EQUIVALENT TO TEKTRONIX PART No 017 0064 00 Change 1 D 5 TM 11 6625 2735 14 1 SECTION Ill TOOL AND TEST EQUIPMENT REQUIREMENTS FOR OSCILLOSCOPE OS 261B V 1 U AND OS 261C V 1 U TOOL OR TEST MAINTENANCE NATIONAL NATO CATEGORY NOMENCLATURE STOCK NUMBER TOOL NUMBER H D ADAPTER CONNECTOR BNC FEMALE TO BNC FEMALE 5935 01 033 1478 EQUIVALENT TO TEKTRONIX PART No 103 0028 00 19 H D ADAPTER CONNECTOR ELBOW BNC MALE TO BNC FEMALE EQUIVALENT TO TEKTRONIX PART No 103 0031 00 20 H D T CONNECTOR BNC EQUIVALENT TO TEKTRONIX 5935 00 284 1962 PART No 103 0030 00 21 H D ATTENUATOR X10 20dB BNC EQUIVALENT TO 5985 00 572 7438 TEKTRONIX PART No 011 0059 02 22 H D ATTENUATOR X5 14dB BNC EQUIVALENT TO 6625 00 009 4694 TEKTRONIX PART No 011 060 02 23 H D ATTENUATOR X2 6dB BNC EQUIVALENT TO 5805 00 103 1875 TEKTRONIX PART No 011 0069 02 24 H D TERMINATION 50 OHM FEED THRU 2 EA 5985 00 087 4954 EQUIVALENT TO TEKTRONIX PART No 011 0049 01 25 H D FILTER 500 MHz EQUIVALENT TO TEKTRONIX PART No 067 0684 00 26 H D ADAPTER CONNECTOR BNC MALE TO MINIATURE 5935 00 482 1776 PROBE TIP EQUIVALENT TO TEKTRONIX PART No 013 0084 01 27 H D TOOL KIT ELECTRONIC EQUIP
120. AL Standard Cabinet Removal Standard Cabinet Installation Rack Adapter Removal Rack Adapter Installation PREVENTIVE MAINTENANCE Introduction Cleaning Visual Inspection Lubrication Semiconductor Checks Recalibration TROUBLESHOOTING Introduction Troubleshooting Aids Troubleshooting Equipment Troubleshooting Techniques Special Troubleshooting Information CORRECTIVE MAINTENANCE Introduction Obtaining Replacement Parts Soldering Techniques Small Component Replacement Circuit Board Replacement Power Transformer Removal Cathode Ray Tube Removal Cathode Ray Tube Installation High Voltage Multiplier Removal Delay Line Removal Recalibration After Repair Instrument Repackaging 5 PERFORMANCE CHECK Introduction Using This Procedure TEST EQUIPMENT REQUIRED General Special Calibration Fixtures Performance Check Equipment Alternatives OUTLINE FOR PERFORMANCE CHECK PRELIMINARY PROCEDURE FOR PERFORMANCE CHECK Operating Voltage Power Source Warm Up Operating Temperature DISPLAY AND VERTICAL SYSTEM CHECK TRIGGER SYSTEM CHECK HORIZONTAL SYSTEM CHECK GATE OUTPUTS EXTERNAL Z AXIS AND CALIBRATOR CHECKS 6 SCHEMATIC DIAGRAMS amp OPTIONS 04 AND 07 Page 4 2 SEES PARARE ABAR 4 22 C2 3 ge Be 6 7 7 REPLACEABLE MECHANICAL PARTS_7 1 TM 11 6625 2735 14 1 TABLE OF CONTENTS CONT Page Page APPENDIX A REFERENCES Co
121. ANSISTOR CHAS MTG Q1426 166 TRANSISTOR CHAS 01448 ATTACHING PARTS FOR EACH 167 1 SCREW MACHINE 4 40 X 0 375 INCH PNH STL 168 WASHER SPR TNSN 0 146 ID X 0 323 OD STL a 169 3 INSULATOR PLATE XSTR 0 675 X 0 625 X 0 001 170 COIL DEFLE TRACE 1 1386 171 CHASSIS SCOPE MAIN 172 CONTACT SPRING 1 188 X 0 375 X 0 25 INCH ATTACHING PARTS l EYELET METALLIC 0 20 DIA X 0 093 INCH LONG m Ke 173 FT WIRE ELECTRICAL 2 WIRE RIBBON 1 74 FT WIRE ELECTRICAL 3 WIRE RIBBON 175 FT WIRE ELECTRICAL 4 WIRE RIBBON 176 FT WIRE ELECTRICAL 5 WIRE RIBBON 177 FT WIRE ELECTRICAL 6 WIRE RIBBON 178 FT WIRE ELECTRICAL 7 WIRE RIBBON 179 FT WIRE ELECTRICAL 10 WIRE RIBBON 180 2 HLDR TERM CONN 1 WIRE BLACK 181 2 HLDR TERM CONN 2 WIRE BLACK 182 4 HLDR TERM CONN 3 WIRE BLACK 4 HLDR TERM CONN 4 WIRE BLACK 183 2 CONN BODY PL EL 5 WIRE BLACK 184 CONN BODY PL EL 6 WIRE BLACK 185 CONN BODY PL EL 7 WIRE BLACK 186 CONN BODY PL EL 10 WIRE BLACK 64 CONNECTOR TERM 22 26 AWG BRS amp CU BE GOLD 187 2 CONTACT ELEC FOR NO 26 AWG WIRE 188 4 CONTACT ELEC FOR NO 22 26 AWG WIRE 189 5 EYELET METALLIC 0 152 OD X 0 245 INCH L BRS 190 5 EYELET METALLIC 0 126 OD X 0 23 NCH L BRS 2 CLAMP LOOP 0 062 INCH DIA 7 23 7 24 blank 12 13 14 15 16 17 18 19 20 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 41 42 43 TM 11 6625 27
122. Amplifier U1418 A sample of the output voltage from the 50 Volt Supply is connected to the negative input of U1418 through divider R1430 R1431 R1432 R1430 in this divider is adjustable to set the output level of the 50 Volt Supply The 2 input voltages at Feedback Amplifier U1418 are compared and any error between the 2 inputs is amplified The amplified error output from U1418 drives Q1424 and Q1426 and controls the output voltage of the power supply Regulation occurs as follows If the output level of this supply decreases due to an increase in load for example the voltage across divider R1430 R1431 R1432 decreases also This results in a more negative feedback level at pin 2 of U1418 than that established by the reference voltage at pin 3 The difference in voltage levels is amplified and polarity is inverted by U1418 The result is that voltage increases at pin 1 of U1418 This increase in voltage causes a more positive voltage at the base of Q1424 More current is allowed to flow through Q1424 to result in increased conduction of the 50 volt Series Regulator Q1426 The output voltage increases thereby achieving regulation of the 50 volt power supply The 50 volt Current Limiting stage Q1432 protects the 50 Volt Series Regulator if excess current is demand ed from this supply Since the load is connected to this supply through R1426 all current must flow through this resistor When excess current is demanded from the 50 Vo
123. At the Vertical Preamp board unsolder one end of a wire braid that connects between the bottom of the Vertical Preamp and the Main Interface board under the high voltage shield 9 Disconnect three ribbon cables from the Vertical Mode Gain Switch board and confirm the number of wires in each cable with its plug number in the following list Note locations of cables to facilitate correct reinstallation a Disconnect a six wire cable from P329 b Disconnect a seven wire cable from P160 Disconnect a ten wire cable from P260 10 At a feed through terminal near U120 and U220 unsolder two 30 ohm resistors that connect each attenuator to the Vertical Preamp board Loosen attenuator screws for clearance if necessary 11 Remove the Vertical Preamp board mounting hardware at eight locations described in the following list A small Phillips screwdriver is required a Remove the screw cabinet ground spring and hexagonal post at center of the board b Remove two screws that mount the board to two long posts on the main chassis near top and bottom center of the Vertical Preamp board c Remove three screws that mount the board to the rear preamp bracket at left edge of board d Remove two screws at the right edge of the board one screw mounts each attenuator chassis to the board 12 Remove the Vertical Preamp circuit board using care to prevent damage to any of the components as the board is removed To install the
124. B TRIGGER COUPLING with adjustment of A and B TRIGGER LEVEL controls j Disconnect all test equipment 17 Check TRIG MODE NORM Operation a Set HORIZ DISPLAY to A set TIME DIV to 1 ms set X10 MAG to off button out set INTENSITY if necessary for a convenient trace intensity and set B TRIGGER COUPLING to AC b Set the amplitude calibrator for a 50 millivolt output and connect to CH 1 input through a 42 inch 50 ohm BNC cable c Set A TRIGGER LEVEL for a stable triggered display d Set TRIG MODE to NORM e CHECK For a stable triggered display f Remove the test signal from CH 1 input g CHECK For no visible trace 5 14 18 Check TRIG MODE SINGL SWP Operation a Return the test signal cable to CH 1 input b Press and release SINGL SWP pushbutton c Remove the test signal cable from CH 1 input d Press and release SINGL SWP pushbutton e CHECK That READY light turns on f Return the test signal cable to CH 1 input 9 CHECK That READY light is extinguished h Press and release SINGL SWP pushbutton i CHECK For a single sweep display 1 sweep only j Set TRIG MODE to AUTO 19 Check TRIG VIEW Operation a Move signal cable from CH 1 input to A TRIGGER external input and set A TRIGGER SOURCE to EXT b Set the amplitude calibrator for a 200 millivolt output c Press TRIG VIEW and hold it in d Position the waveform for a maximum amplitude display with A TRIGGER LEVE
125. CATION NUMBER PUBLICATION DATE PUBLICATION TITLE TM 11 6625 2735 14 17 Jun 182 Oscilloscope 0S 261B V 1 U BE EXACT PIN POINT WHERE IT IS IN THIS SPACE YELL WHAT 15 WRONG PAGE PARA FIGURE TABLE AND WHAT SHOULD BE DONE ABOUT IT NO GRAPH NO NO DATE SENT ee PRINTED NAME GRADE OR TITLE ANO TELEPHONE NUMBER SIGN HERE PREVIOUS EDITIONS P S IF YOUR OUTFIT WANTS TO KNOW ABOUT YOUR ARE OBSOLETE RECOMMENDATION MAKE A CARBON COPY OF THIS AND GIVE IT TO YOUR HEADQUARTERS Tuts 2028 2 REVERSE OF DA FONW 2029 2 FILL IN YOUR UNIT S ADDRESS DEPARTMENT OF THE ARMY POSTAGE AND FEES PAID DEPARTMENT OF THE ARMY DOD 314 OFFICIAL BUSINESS PENALTY FOR PRIVATE USE 300 Commander US Army Communications Electronics Commond ATTN DRSEL ME MQ Fort Monmouth New Jersey 07703 JN 6319503434 SNOW 9931 By Order of the Secretary of the Army E C MEYER Official General United States Army Chief of Staff ROBERT M JOYCE Brigadier General United States Army The Adjutant General DISTRIBUTION To be distributed in accordance with Special List GOVERNMENT PRINTING OFFICE 1989 0 242 451 1654 PIN 051123 000
126. CH 1 input DC coupled using a 50 42 RG58A U cable terminated in 50 at CH 1 input At least 2 51 0 1 division or less compression or expansion of 2 division signal at center screen positioned to the upper and lower extremes of the graticule area With GAIN set at 5 mV DIV CH 1 and CH 2 at all deflection factors from a 50 2 terminated source 1 Hz or less with 10X probe 3 dB point between 15 MHz and 20 MHz 3 dB point between 75 MHz and 125 MHz Characteristics Step Response Positive Going Step Aberrations 0 C to 40 C At 5 mV DIV Negative Going Step Added Mode Common Mode Rejection Ratio ADD Mode with CH 2 inverted Trace Shift as VAR is Rotated INVERT Trace Shift Channel Isolation Position Range Signal Delay Between CH 1 and CH 2 Maximum Input Voltage Chopped Mode Repetition Rate TABLE 1 1 cont ELECTRICAL Performance Requirements TM 11 6625 2735 14 1 Supplemental Information VERTICAL DEFLECTION SYSTEM cont DC coupled 250 V DC peak AC or 500 V P P AC at 1 kHz or less AC coupled 500 V DC peak AC or 500 V P P AC at 1 kHz or less Approximately 1 MHz 4 496 4 P P Add 3 to positive going step aberrations Add 3 to positive going step aberrations 20 1 at 1 kHz for common mode sig nals of 8 divisions or less Adjusts to 2 divisions or less Within 1 division from center screen when switching from normal to in
127. CK INTL 0 092 ID X 0 175 0D STL 20 2 WASHER FLAT 0 09 ID X 0 188 OD BRS 2 NUT PLAIN HEX 2 56 X 0 188 INCH BRS 22 2 BOARD ASSY CH1 CH2 ATTEN A1 A2 23 10 CONT ASSY ELEC CAM SWITCH BOTTOM 10 CONTACT ASSY EL CAM SWITCH TOP ATTACHING PARTS 10 RIVET TUBULAR 0 051 OD X 0 115 INCH LONG 24 36 CONTACT ELEC 0 178 INCH LONG 2 SOCKET PIN TERM 0 138 INCH LONG 25 SHLD ELECTRICAL CAM CONTACTS 26 2 EXTENSION SHAFT 0 123 OD X 6 1 INCH LONG 27 2 ACTUATOR SWITCH ATTACHING PARTS FOR EACH 28 l SCREW CAP SCH 2 56 X 0 375 HEX HD STL am m gt 2 CONTACT ELEC GROUNDING MAY BE REPL BY INDEXED PART NUMBERS 41 6 42 ON AVAILABILITY OF STOCK 2 SW ACTR AS VOLTS DIV ATTACHING PARTS FOR EACH 29 6 SCR ASSEM WSHR 4 40 X 0 312 INCH PNH BRS mm EACH ACTUATOR ASSY INCLUDES 30 2 CONTACT ELEC GROUNDING 31 2 SPRING FLAT RED COLORED 32 2 ROLLER DETENT 2 NUT PLAIN HEX 4 40 X 0 188 INCH BRS l 34 BEARING CAM SW FRONT ATTACHING PARTS 35 RING RETAINING 0 338 ID X 0 025 THK STL 36 l SHAFT CAM SW 37 1 ACTUATOR CAM SW DC GND AC 7 29 TM 11 6625 2735 14 1 FO amp Index No Qty 12345 Name amp Description 17 38 4 NUT PLAIN HEX 4 40 X 0 188 INCH BRS 39 BEARING CAM SW CENTER REAR ATTACHING PARTS 40 l RING RETAINING 0 328 FREE IDX 0 448 OD w W 4 1
128. Check CH 2 VERT SIGNAL OUT 33 Check EXT Z Axis Operation 34 Check CALIBRATOR Operation 5 20 PRELIMINARY PROCEDURE FOR PERFORMANCE CHECK Operating Voltage Before applying power to the instrument check that the line voltage selector and the regulating range selector are in the correct positions for the line voltage the instrument will be operated on Power Source Connect the 475 to a power source that meets the voltage and frequency requirements of this instrument 5 4 Warm Up Turn on the 475 and allow at least 20 minutes before starting the Performance Check procedure Operating Temperature The performance of this instrument can be checked at an ambient temperature within 15 C to 55 C unless stated otherwise in the procedure This instrument should be checked at an ambient temperature of 20 C to 30 C for best overall accuracy Equipment Required Amplitude Calibrator Sine Wave Generator TM 11 6625 2735 14 1 DISPLAY AND VERTICAL SYSTEM CHECK 42 inch 50 Ohm BNC Cable 2 required 18 inch 50 Ohm BNC Cable 2 required 10X Probe sed Table 5 1 10X Probe examples Control Settings POWER ON Display INTENSITY Midrange FOCUS Midrange SCALE ILLUM Midrange Vertial CH 1 and CH 2 POSITION Midrange VOLTS DIV 5 mV VAR VOLTS DIV Calibrated detent AC GND DC DC INVERT Off button out VERT MODE CH 1 100 or 20 MHz BW 20 Trigger A and B COUPLING LEVEL SLOPE A TRIGGER SO
129. Delay Time and Differential Time Measurement Accuracy sea Fig 1 2 Delay Pickoff Jitter Delay Range TM 11 6625 2735 14 1 TABLE 1 1 cont ELECTRICAL Performance Requirements Supplemental Information HORIZONTAL DEFLECTION SYSTEM cont Within 0 5 division from graticule center at 1 ms DIV when switching X10 magnifier from on to off Start of sweep must position to right of graticule center End of sweep must position to left of graticule center Check made at 1 ms DIV Exclude dial settings of 0 00 thru 0 50 for 0 5 sec through 1 us DIV de laying sweep rates Exclude dial set tings of 0 00 thru 1 00 for 5 5 thru 05 us DIV delaying sweep rates 15 to 35 C 15 C to 55 C 600F to 95 F 45 F to 131 0 01 Major 0 02 Major Dial Division Dial Division 3 15 to 55 C MAXIMUM MEASUREMENT ERROR Major DELAY TIME POSITION Dial Divisions of Measurement EL6UGO25 Fig 1 2 Detailed Delay Time and Differential Time Measure ment accuracy Within 0 00296 less than one part in 50 000 of the maximum available de lay time when operating the instru ment on power line frequencies above 52 Hz decreasing to 0 005 less than one part in 20 000 on power line frequencies of 48 to 52 Hz From 0 05 us or less to at least 5 seconds after the start of the de laying A sweep Maximum avaliable delay time is ten times the setting of the A TIME DIV switch 1 7 TM 1
130. E to NORM and A TRIGGER COUPLING to AC i Disconnect all test equipment 15 Check A 200 Megahertz Triggering NOTE It may be necessary to change to a sine wave generator with a 200 megahertz output a Connect the sine wave generator output cable through a GR to BNC female adapter to the through signal input of the 50 ohm signal pickoff Connect the through signal output of the signal pickoff to a GR to BNC male adapter to a 10X BNC attenuator to a 50 ohm BNC termination to a BNC elbow to A TRIGGER external input b Connect the 1096 signal output of the signal pickoff to an 18 inch 50 ohm BNC cable to a 50 ohm termination to CH 1 input c Set the sine wave generator for a 1 5 division 200 megahertz display d Set TIME DIV to 0 01 us and press X10 MAG to on e CHECK That a stable triggered display with no more than 0 2 division of jitter can be obtained in AC LF REJ and DC positions of A TRIGGER COUPLING with adjustment of A TRIGGER LEVEL TM 11 6625 2735 14 1 f Set TIME DIV to 0 1 ms and set A TRIGGER SOURCE to EXT g Set the sine wave generator for a 5 division display of reference frequency 250 millivolts at external input then set to 200 megahertz NOTE If generator has no reference frequency setting set for 5 megahertz h Set TIME DIV to 0 01us i CHECK That a stable triggered display with no more than 0 2 division of jitter can be obtained in AC and DC positions of A TRIGGER CO
131. EVEL p Set B TRIGGER COUPLING to LF REJ q CHECK That a stable triggered display cannot be obtained with adjustment of B TRIGGER LEVEL r Set CH 1 VOLTS DIV to 5 mV and set B TRIGGER COUPLING to AC s Set the low frequency generator for a 3 division 60 hertz display then set CH 1 VOLTS DIV to 50 mV t CHECK That a stable triggered display can be obtained in AC and DC positions of B TRIGGER COUPLING with adjustment of B TRIGGER LEVEL u Set the low frequency generator for a 2 division 60 hertz display then set B TRIGGER SOURCE to EXT 100 millivolts at external input v CHECK Repeat part o w Set B TRIGGER COUPLING to LF REJ x CHECK Repeat y Set B TRIGGER COUPLING to AC 5 11 TM 11 6625 2735 14 1 z Set the low frequency generator for a 1 division 60 Hertz display 50 millivolts at external input It may be necessary to maintain triggering as amplitude is reduced aa CHECK That a stable triggered display be obtained in and DC positions of TRIGGER COUPLING with adjustment of B TRIGGER LEVEL ab Disconnect all test equipment NOTE Use a sine wave generator with an output of 100 megahertz and below for the followlng parts ac Connect the sine wave generator output cable to a BNC female to BNC female adapter to a BNC T connector to two 18 inch 50 ohm BNC cables Connect an 18 inch cable through a 50 ohm termination to CH 1 input and connect the other 18
132. FERENCES The following is a list of applicable references that are available to the operator and maintenance personnel DA Pam 310 1 DA Pam 738 750 SB 38 100 TB 434118 TB 43 180 TM 750 244 2 TM 11 6625 2735 14 NAVELEX 0969 LP 170 1090 TO 33A1 13 498 1 TM 11 6625 2735 24P NAVELEX 0967 LP 170 1100 TO 33A1 13 498 4 TM 11 6625 2735 24P 1 Consolidated Index of Army Publications and Blank Forms The Army Maintenance Management System TAMMS Preservation Packaging Packing and Marking Materials Supplies and Equipment Used by the Army Field Instructions for Painting and Preserving Electronics Command Equipment Including Camouflage Pattern Painting of Electrical Equipment Shelters Calibration Requirements for the Maintenance of Army Materiel Procedures for Destruction of Electronics Materiel to Prevent Enemy Use Electronics Command Operator s Organizational Direct Support and General Support Maintenance Manual Including Depot Maintenance for Oscilloscope 05 261 U NSN 6625 00 127 0079 Organizational Direct Support and General Support Maintenance Repair Parts and Special Tools Lists Including Depot Maintenance Repair Parts and Special Tools for Oscilloscope OS 261 U NSN 6625 00 127 0079 Organizational Direct Support and General Support Maintenance Repair Parts and Special Tools Lists Including Depot Maintenance Repair Parts and Special Tools for Oscilloscope OS 261B V I U NSN 6625 01 101
133. GGER GENERATOR A J510 A EXTERNAL 5 TRIGGER MN e S INPUT SWEEP 8 Z AXIS HORIZONTAL AMPL DELAYING SWEEP GENERATOR LOGIC TRIGGER SIGNAL E B NON DELAYING TRIGGER SWEEP GENERATOR GENERATORS B J720 EXTERNAL TRIGGER e 1 IT UNT M ch Z AXIS a SWEEP UNBLANKING AMPL VOLTAGE LOW VOLTAGE me POWER SUPPLY OAE AN BLOCKS INPUT ALIBRATOR 13 FAN MOTOR CIRCUIT lt gt CALIBRATOR ELGUGO28 Fig 3 1 Basic block diagram of the 475 TM 11 6625 2735 14 1 The A and B Trigger Generator circuits produce an output pulse that initiates generation of the sawtooth sweep signals produced by the A or B Sweep Generator circuits The input signal to the Trigger Generator circuits can be individually selected from the Channel 1 signal Channel 2 signal the signal s displayed on the NORM a signal connected to the external trigger input connectors or a sample of the line voltage applied to the instrument Each trigger circuit contains separate level slope coupling and source controls There are three sweep generator circuits in the 475 For purposes of explanation they are called Delaying Slow Non Delaying and Fast Non Delaying The Delaying oweep generates a range of sweep rates from 0 5 second to 0 05 microsecond division The Slow Non Delaying Sweep generator provides the 0 5 second through 1 microsecond division swe
134. H 1 and CH 2 inputs c Set the amplitude calibrator for a 10 millivolt output and center the display on graticule using equal settings of CH 1 and CH 2 POSITION controls d CHECK For a display of 4 divisions within 3 0 12 division e Press INVERT pushbutton f CHECK That display amplitude reduces to ap proximately O g Return INVERT pushbutton to normal button out h Disconnect all test equipment 6 Check ALT Mode Operation a Set VERT MODE to ALT set 100 OR 20 MHz BW control to full bandwidth position and set A TRIGGER LEVEL fully clockwise 5 7 TM 11 6625 2735 14 1 b Position the 2 traces approximately 4 divisions apart c CHECK That the traces alternate at all settings of TIME DIV except X Y 7 Check CHOP Mode Operation Set VERT MODE to CHOP set TIME DIV to 1 CH 1 and CH 2 AC GND DC switches to GND and adjust A TRIGGER LEVEL for a stable display b CHECK For complete blanking of switching tran sients between chopped segments c CHECK That the duration of 1 cycle is ap proximately 1 division 8 Check Vertical Amplifier Bandwidth a Set VERT MODE to CH 1 set TIME DIV to 0 5 ms and set CH 1 and CH 2 AC G ND DC switches to DC NOTE See test equipment required Table 5 1 for selection of sine wave generator with a 200 megahertz output b Connect the sine wave generator output cable to a 10X BNC attenuator to a 50 ohm termination to CH 1 input
135. HING PARTS 80 l RING RETAINING 0 338 ID X 0 025 THK STL a a o e 81 l NUT PLAIN HEX 4 40 X 0 188 INCH BRS 82 1 SPRING FLAT GREEN COLORED 1 SPRING FLAT RED COLORED 83 2 ROLLER DETENT 84 l BEARING SW FRONT l SHAFT CAM SW W DRIVER WASHER NONMETAL 0 109 ID X 0 25 INCH OD 85 1 RES VAR NONWIR R1070 86 1 SPACER SWITCH PLASTIC 87 1 CPLG SHAFT RDG FOR 0 08 TO 0 125 DIA SHAFT 2 SETSCREW 3 48 X 0 062 INCH HEX SOC STL l SETSCREW 4 40 X 0 094 INCH HEX SOC STL 88 CKT BOARD ASSY TIMING A7 89 SOCKET PIN TERM 0 188 INCH LONG SOCKET PLUG IN 3 PIN SQUARE SOCKET PLUG IN 3 PIN LOW PROFILE 90 19 TERMINAL PIN 0 365 L X 0 25 PH BRZ GOLD PL 91 43 CONTACT ELEC CKT BD SW SPR CU BE 92 32 CONTACT ELEC F SHAPED 93 1 SW PUSH BUTTON TRIG MODE S600 94 4 SPACER PUSH SW 0 13 W X 0 375 INCH L PLSTC 95 2 LAMPHOLDER 96 1 SW PUSH BUTTON HORIZ 51090 97 4 SPACER PB SW 0 164 INCH LONG 98 l ELEC SHLD CKT BOARD MOUNT BRS 99 l SHIELD ELEC DELAY LINE ATTACHING PARTS 100 6 SCR TPG THD CTG 4 24 X 0 25 INCH PNH STL e cmo w Ar 101 1 BOARD ASSY VERTICAL OUTPUT AS ATTACHING PARTS 102 2 SCR ASSEM WSHR 4 40 X 0 312 DOUBLE SEMS 103 NUT PLAIN HEX 6 32 X 0 25 INCH STL 104 WASHER FLAT 0 147 ID X 0 312 OD BRS e NO s BOARD ASSY INCLUDES 105 MICROCIRCUIT 0470 106 1 BRACKET GND MICROCIRCUIT BRASS 1
136. ICAL IF YOU CANNOT TURN OFF THE ELECTRICAL POWER PULL PUSH OR LIFT THE PERSON TO SAFETY USING A WOODEN POLE OR A ROPE OR SOME OTHER INSULATING MATERIAL SEND FOR HELP AS SOON AS POSSIBLE AFTER THE INJURED PERSON IS FREE OF CONTACT WITH THE SOURCE OF ELECTRICAL SHOCK MOVE THE PERSONA SHORT DISTANCE AWAY AND IMMEDIATELY START ARTIFICIAL RESUSCITATION Change 1 C TM 11 6625 2735 14 1 WARNING HIGH VOLTAGE IS used in the operation of this equipment DEATH ON CONTACT may result if personnel fail to observe safety precautions Never work on electronic equipment unless there is another person nearby who is familiar with the operation and hazards of the equipment and who is competent in administering first aid When the technician is aided by operators They must be warned about dangerous areas Be careful not to contact high voltage connections or 115 volt ac input connections when installing or operating this equipment Whenever the nature of the operation permits keep one hand away from the equipment to reduce the hazard of current flowing through the body WARNING Do not be misled by the term low voltage Potentials as low as 50 volts may cause death under adverse conditions For Artificial Respiration refer to FM 21 11 D Change 1 TM 11 6625 2735 14 1 SAFETY PRECAUTION A periodic review of safety precautions in TB 385 4 Safety Precautions for Maintenance of Electrical Electronic Equipment is recom
137. ILE 138 WASHER NONMETAL 0 312 ID X 0 875 OD RBR 140 CONNECTOR 12 CONTACT 141 CLIP ELECTRICAL FOR 0 25 INCH DIA FUSE 142 26 TERM TEST POINT BRS CD PL 143 25 TERMINAL PIN O 365 L X 0 25 PH BRZ GOLD PL 144 24 CONTACT ELEC F SHAPED 145 HEAT SINK ELEC XSTR 0 72 OD X 0 375 H 146 TERMINAL BOARD 5 NOTCH CERAMIC CLIP MTD MOUNT TERM BD 0 577 INCH H 2 139 2 CONNECTOR RCPT 10 CONTACT l 2 2 147 TERMINAL BOARD 3 NOTCH CERAMIC CLIP MTD MOUNT TERM BD 0 577 INCH H 148 TERMINAL BOARD 1 NOTCH CERAMIC CLIP MTD l MOUNT TERM BD 0 577 INCH 149 TERMINAL STUD 0 812 L INSULATED ATTACHING PARTS 150 NUT PLAIN EXT W 4 40 X 0 25 INCH STL volu dem M a 151 l INSULATOR BSHG 0 25 DIA X 0 188 INCH L 152 RES VAR NONWIR FOCUS 380 ATTACHING PARTS 153 l NUT PLAIN HEX 0 25 32 X 0 312 INCH BRS 154 WASHER FLAT 0 25 ID X 0 375 INCH OD STL 155 WASHER LOCK INTL O 26 ID X 0 40 OD STL w 156 SUPPORT VAR RES CIRCUIT CARD MOUNTING 157 SEMICOND DEVICE VOLT MULTIPLIER U1321 ATTACHING PARTS 158 2 NUT PL EXT WSHR 8 32 X 0 344 HEX NYLON 159 1 SW PUSH BUTTON X10 51110 160 2 SPACER PB SW 0 133 INCH LONG 161 l SW PUSH BUTTON BEAM FINDER S450 162 2 SPACER PB SW 0 164 INCH LONG 163 RES VAR NONWIR INTENSITY R1335A B 164 1 SPACER SWITCH PLASTIC 165 l RES VAR NONWIR
138. L 6 LI 2 L E 2 j ul Li A ig a E H e His rz so 4 H nsf zo e H cad ka La lt i 3 FRONT AM OF 50501 S Sweeter 4 TIT tLe i io a EAT esa T Ran EIS LETTE zs d pa j LAS wo Lb 1 E ents Meee SES ee Gate ac ee 52 11 6625 2735 14 1 UC TEAR The LT fel yote Det abicaTes CLOSED 23000 4 LOWE 1 17 DEL LLL L leise LLEL i 1 B 1 1 1 1 1 i 1 1 i SIDA gt a 1 1 l i 1 Bou RIT AL 1 1 1 1 ois z Cien you i 4 1 ZE i R95 6 1 i d 1 1 1 Me 1 fuic RIOS9 E EET i i 2 See hou 4 oM 1 i OAK 1 to 1 o Riess ROMS D RIETS sa oS Rie rinks ROSA 1 E ti 1 1 1 O IM Seer ESIC EE oak e 1 5 9052 7 j at 1 1 1 Vote 4 3 E EC Totus 7 Mu 1 1 1 1 1
139. L control e CHECK For approximately 4 divisions of display f Release TRIG VIEW g Disconnect all test equipment TM 11 6625 2735 14 1 HORIZONTAL SYSTEM CHECK Equipment Required 4 500 MHz Filter 1 Time Mark Generator 5 42 inch 50 Ohm BNC Cable 2 required 2 Sine Wave Generator 6 50 Ohm BNC Termination 2 required 3 Amplitude Calibrator 7 10X Probe sed Table 5 1 10X Probe examples Control Settings Sweep POWER ON A TIME DIV 1 ms B TIME DIV 1 ms VAR TIME DIV Calibrated detent Display DELAY TIME POSITION Fully counterclockwise INTENSITY Midrange HORIZ DISPLAY A FOCUS Midrange X10 MAG Off button out SCALE ILLUM Midrange POSITION Horiz Midrange FINE Midrange Vertical CH 1 and CH 2 POSITION Midrange VOLTS DIV 0 5 V new setting VAR VOLTS DIV Calibrated detent AC GND DC DC a Set the time mark generator for 5 millisecond time ks and connect through a 42 inch 50 ohm BNC cable INVERT Off button out ugn VERT MODE CH 1 to a 50 ohm BNC termination to CH 1 input 100 OR 20 MHz BW Full bandwidth push in b Set A TRIGGER LEV L for a stable triggered display then set VAR TIME DIV fully counterclockwise Trigger A and B COUPLING AC VAR TIME DIV UNCAL light is il LEVEL 0 SLOPE A TRIGGER SOURCE NORM new setting d CHECK For at least 6 time marks between first and B TRIGGER SOURCE STARTS AFTER DELAY last graticule lines new setting TRIG MODE AU
140. MENDED TYPE freouency response DC to 75 MHz Deflection factor 1 mV to 5 V Div Input impedance 1 20 pF Swoep rate 50 ns Tektronix 7603 equipped with 7A13 Amplifier and 7859 Time base unts equivalent Probe Voltmeter Non loading Digital Multimeter 475 Control Settings Display Controls iINTENSITY FOCUS SCALE ILLUM Vertical Controls CH 1 and POSITION VOLTS DIV VOLTS DIV Calibrated detent Fast rise 10X attenuation probe com with vertical amplifier of test allascope Tektronix P6053B or ecuivalent Input Impedance 10 0 to 500 v Tektranix DM 501 Digital Mult meter or equivalent Sweep Controls TIME DIV 0 1 ms Midrange VAR TIME DIV Calibrated detent Midrange DFLAY TIME Midrange POSITION Full counterclockwise HORIZ DISPLAY A X10 MAG Off button out POSITION Horiz Midrange FINE Midrange CH 21 Center trace on graticule 2 mV tor dc voltages Voltage Measurements 100 mV for waveforms Voltage measurements are taken with no signal applied and the trace positioned to the center horizontal graticule AC GND DC DC line The voltmeter common is connected to chassis INVERT Off button out ground VERT MODE CH 1 100 or 20 MHz BW Trigger Contro s A and Bi Full bandwidth Push in then release Waveform Conditions Apply the 475 calibrator signal to CH 1 input through a P6075 10X probe supplied with 475 Connect
141. MENT TK 100 G 5180 00 605 0079 28 H D MULTIMETER AN USM 223 6625 00 999 7465 29 H D TEST SET TRANSISTOR TS 1836 D U 6625 00 138 7320 THE NATIONAL STOCK NUMBERS THAT ARE MISSING FROM THIS LIST HAVE BEEN REQUESTED AND WILL BE ADDED BY A CHANGE TO THE LIST UPON RECEIPT D 6 Change 1 TM 11 0625 2735 14 1 SECTION IV REMARKS REFERENCE CODE A Replace lamps and knobs D 7 D 8 blank TM 11 6625 2735 14 1 APPENDIX E EXPENDABLE SUPPLIES AND MATERIALS LIST Section INTRODUCTION E 1 SCOPE This appendix lists expendable supplies and materials you will need to operate and maintain the oscilloscope These items are authorized to you by CTA 50 970 Expendable Items Except Medical Class V Repair Parts and Heraldic Items E 2 EXPLANATION OF COLUMNS Column l Item number Not used b Column 2 Level This column identifies the lowest level of maintenance that requires the listed item enter as applicable C Operator Crew Organizational Maintenance Direct Support Maintenance H General Support Maintenance c Column 3 National Stock Number This is the National stock number assigned to the item use it to request or requisition the item d Column 4 Description Indicates the Federal item name and if required a description to identify the item The last line for each item indicates the Federal Supply Code for Manufacturer FSCM in parentheses followed by the part number e Column
142. MODE in full bandwidth position is viewed with an increase in signal amplitude LINE The power line signal is displayed at an amplitude ap proximately equalling full ver tical graticule deflection EXT The signal present at the A TRIGGER external input con nector will be displayed 10 The signal present at the A TRIGGER external input connector will be displayed but will be reduced approximately 10 times of that viewed in EXT Pushbutton switch that inverts the Channel 2 display Selects the vertical mode of operation CH 1 Displays Channel 1 only ALT Dual trace display of signals using both channels Display is switched between channels at the end of each sweep ADD Signals applied to the CH 1 OR Xandthe CH 2 OR Y connectors are algebraically added and the sum is displayed on the crt The INVERT switch in Channel 2 allows the display to be CH 1 CH 2 or CH 1 CH 2 CHOP Dual trace display of signals on both channels Display is switched between channels at an approximate repetition rate of 1 megahertz TM 11 6625 2735 14 1 CH 2 OR X Y Displays Channel 2 only Must be pushed when operating in X Y mode A and B Triggering both where applicable COUPLING SOURCE Determines the method used to couple signal to input of trigger Circuits AC Rejects DC and attenuates signals below about 60 Hz Accepts signals above about 60 Hz LF REJ Rejects DC and atten uates sign
143. NCE CHECK Length three inch shaft bit size 3 32 inch Used for High Speed Timing a Tektronix 500 MHz Filter DISPLAY AND VERTICAL SYSTEM CHECK 5 Check ADD Mode Operation 1 Check Display Controls 6 Check ALT Mode Operation 2 Check Vertical Input Functions 7 Check CHOP Mode Operation 3 Check CH 1 and CH 2 Gain 8 Check Vertical Amplifier Bandwidth 9 Check Bandwidth Limit Operation 4 Check CH 2 and CH 1 VAR VOLTS DIV Range 10 Check Cascaded Bandwidth U v ap lol fool TM 11 6625 2735 14 1 TRIGGER SYSTEM CHECK 11 Check A Low Frequency Triggering 12 Check B Low Frequency Triggering 13 Check B40 Megahertz Triggering 14 Check A 40 Megahertz Triggering 15 Check A 200 Megahertz Triggering 16 Check B 200 Megahertz Triggering 5 13 17 Check TRIG MODE NORM Operation 18 Check TRIG MODE SINGL SWP Operation 19 Check TRIG VIEW Operation 5 14 HORIZONTAL SYSTEM CHECK 20 Check VAR TIME DIV RANGE 21 Check Sweep Length and Horizontal POSITION Range 5 16 22 Check A Timing Accuracy 23 Check A INTEN Timing Accuracy Page 5 16 24 Check A INTEN Magnified Timing Ac curacy 25 Check A Magnified Timing Accuracy 26 Check Differential Delay Time Ac curacy 27 Check Delay Time Jitter 5 18 28 Check MIX Mixed Sweep Timing Ac curacy 29 Check X Gain 5 19 30 Check X Bandwidth 5 19 GATE OUTPUTS EXTERNAL Z AXIS AND CALIBRATOR CHECKS 31 Check A and B GATE Outputs 32
144. NG LEVEL SLOPE SOURCE TRIG MODE A TRIGGER HOI DOFF Center trace on 2 mV for dc voltages 100 mV for waveforms Calibrated detent DG Off button out CH 1 Full bandwidth Push in then release AC 0 NORM AUTO for waveforms SINGL SWP ifor dc voltages READY light off NORM SPECIFICATIONS Frequency response DC to 75 MHz Fast rise 10X attenuation probe com patible with vertical amplifier of test 10 MO 0 tc 500 V RECOMMENDED TYPE Tektronix 7603 equipped with 7A13 Amplifier and 7B50 Tima base units or equivalent 1 mV to 5 V Div 1 20 pF 50 ns Tektronix P6053B or equivalent Tektronix OM 501 Digital or equivalent Sweep Controls TIME DIV 0 1 ms VAR TIME DI Calibrated detent DELAY TIMF POSITION Full counterclockwise HORIZ DISPLAY A X10 MAG Off buttan out POSITION Horiz Midrange FINE Midrange Voltage Measurements Valtage measurements are taken with no signal applied and the trace positioned to the center horizontal graticule line The voltmeter common is connected lo chassis ground Waveform Conditions Apply the 475 calibrator signal to CH 1 input througha P6075 10X probe supplied with 475 Connect 475 A GATE rear panel through a 42 inch 50 ohm BNC cable to test oscilloscope external trigger input Set test os cilloscope trigger source to external and set vertical input for ac coupling For waveforms which have
145. NK ELEC TRANSISTOR HEAT SINK ELEC TRANSISTOR CONN RCPT ELEC CKT BD MT 3 PRONG SW PUSH BUTTON INVERT S225 SPACER PUSH SW 0 13 W X 0 375 INCH L PLSTC ACTUATOR SWITCH MOMENTARY RES VAR NONWIR R185 RES VAR NONWIR R285 SWITCH MOMENI V 4 wee aviv MU MENT TA SPRING HLCPS 0 156 OD X 0 844 INCH LONG GUIDE SLIDE SW ACTR ASSY SL SW OUTPUT ATTEN CPLG SHAFT RGD FOR 0 125 INCH DIA SHAFT SETSCREW 4 40 X 0 125 INCH HEX SOC STL ACTUATOR SWITCH SLIDE BANDWIDTH LIMIT CDRDTNMAO ODECE AATADEN UNCON VVLWVINL 47 ROLLER DETENT 0 125 DIA X 0 125 INCH L GUIDE SLIDE SW GROMMET PLASTIC 1 24 X 0 739 X 0 108 OA BRACKET PREAMP REAR BRASS CU SN ZN PL ATTACHING PARTS NUT PLAIN EXT W 4 40 X 0 25 INCH STL POST ELEC MECH 0 250 HEX X 1 77 INCH LONG RES VAR FILM R1303A B C D ATTACHING PARTS SCREW MACHINE 6 32 X 0 312 INCH PNH STL TERMINAL LUG 0 146 ID LOCKING BRZ TINNED NUT PLAIN EXT W 6 32 X 0 312 INCH STL BRACKET RES ALUMINUM ATTACHING PARTS NUT PLAIN EXT W 4 40 X 0 25 INCH STL ee SHIELD ELEC HI VOLTAGE ATTACHING PARTS SCREW MACHINE 4 40 X 0 25 INCH PNH STL INSULATOR FILM 3 65 X 4 7 VOLTAGE INSULATOR FILM 5 10 X 12 4 INCH POST ELEC MECH 0 538 INCH L ATTACHING PARTS WASHER FLAT 0 125 ID X 0 25 OD STL wm TRANSISTOR CHAS
146. O On m 3 2604 DY VIEW SIG 55 SAY ZAN m 1 TO 73805 SSS paye ON Ek Resi l x i pes XXL 4 6 74662 pes TRIS VIEW sarge Re CENTER i TRIG H Rest 5 view hes EE E T EI ML 152 t KITE PUSA 47527 5 ao ANN aries TRIGGER VIEW 4 T Je 226 Y Gi 2 69 106 mV BOO va la Fe EZ EN 0674 a2 i 5y as x TTE ki 3 5 p P TRG VIEW SiG S 3 To 1 5 1 N 1 8 2 yon d fe v pi 5 5453 FAS d xir D TOR 95 PAES liy 525 os gt sw n 9559 a a av 42 4 6 9556 7 Ja tia Db EK 11127674 8v7 SEL ARMING gssa 28 TD RESET noL tels 9520 AV PUT e emi elle R505 T e TRIG SENSITIVITY ees 4 4 scu n COUPLED v PART OF ETCHED CIRCOIT BOARD BR Rid EL6UGOSZ2 FO 6 A trigger generator schematic diagram TM 11 6625 2735 14 1 VOLTAGES AND WAVEFORMS 5765 The voltages and waveforms shown on this diagram were obtained by using the recommended test equipment and CB TRIGGER SHOWN IN test set ups listed below SOURCE NORM PfCSITION
147. OLTS DIV 5 42 inch 50 ohm cable to BNC female to BNC VAR VOLTS DIV Calibrated detent female adapter to a BNC T connector to two 18 inch 50 AC GND DC DC ohm BNC cables to CH 1 input and A TRIGGER external INVERT Off button out input VERT MODE CH 1 100 OR 20 MHz BW Full bandwidth push in then release b Set the low frequency generator for a 5 division 50 kilohertz display then set CH 1 VOLTS DIV to 50 mV c CHECK That stable triggered display can be obtained in AC LF REJ HF REJ and DC positions of A Trigger A and B TRIGGER COUPLING with adjustment of A TRIGGER COUPLING AC EVE LEVEL 0 SLOPE d Set CH 1 VOLTS DIV to 5 mV A TRIGGER SOURCE NORM B TRIGGER SOURCE NORM new setting TRIG MODE AUTO e Set the low frequency generator for a 3 division A TRIGGER HOLDOFF NORM 50 kilohertz display then set CH 1 VOLTS DIV to 50 mv 5 9 TM 11 6625 2735 14 1 f CHECK That a stable triggered display can obtained in AC and DC positions of A TRIGGER COUPLING with adjustment of A TRIGGER LEVEL g Set the low frequency generator for a 2 division 50 kilohertz display then set A TRIGGER SOURCE to EXT 100 millivolts at external input h CHECK Repeat part c i Set CH 1 VOLTS DIV to 0 1 V and set A TRIGGER SOURCE to EXT 10 j Set the low frequency generator for a 5 division 50 kilohertz display 500 millivolts at inputs then set CH 1 VOLTS DIV to 0 5 V k CHECK Repeat
148. OSCILLOSCOPE 0S 61B V 1 U AND OS 261C V 1 U TOOL OR TEST MAINTENANCE NATIONAL NATO TOOL NUMBER pen CATEGORY NOMENCLATURE AUTOTRANSFORMER VARIABLE 510 0 EQUIVALENT 6120 00 054 7794 TO GENERAL RADIO W10MT3VM VARIAC AUTOTRANSFORMER 2 VOLTMETER DC PRECISION EQUIVALENT TO 6625 00 488 4093 FLUKE 893A 3 VOLTMETER DC VOM AN USM 210 EQUIVALENT TO 6625 00 019 0815 SIMPSON 269 4 OSCILLOSCOPE TEST OS 261B V 1 U EQUIVALENT TO 6625 00 127 0079 TEKTRONIX TYPE 475 5 AMPLITUDE CALIBRATOR AN USM 360 STANDARD 6625 00 192 0866 EQUIVALENT TO TEKTRONIX 06741502 01 CAL GEN 6 POWER SUPPLY PP 7208 U EQUIVALENT TO 6130 00 175 0832 LAMBDA LPD 422A FM 7 GENERATOR MEDIUM FREQUENCY CONSTANT 6625 00 520 5143 AMPLITUDE SIGNAL EQUIVALENT TO TEKTRONIX TYPE SG 503 8 GENERATOR TIME MARK EQUIVALENT TO TEKTRONIX 6625 00 520 5199 TYPE TG 501 TIME MARK GENERATOR 9 GENERATOR AN USM 269 LOW FREQUENCY SINE WAVE 6625 00 054 3476 EQUIVALENT TO GEN RADIO 1310 A 10 GENERATOR SQUARE WAVE EQUIVALENT TO 6625 00 520 5158 TEKTRONIX TYPE PG 506 11 PULSER TUNNEL DIODE EQUIVALENT TO TEKTRONIX 4831 01 018 6735 PART No 067 0681 01 12 SIGNAL PICKOFF EQUIVALENT TO TEKTRONIX 6625 00 374 8193 PART No 017 0061 00 13 PROBE CURRENT EQUIVALENT TO TEKTRONIX TYPE 6625 00 124 9355 P6022 935 Hz 200 MHz 14 CABLE COAXIAL 2 EA 50 OHMS RG 58 U 42 IN 6625 00 495 4831 EQUIVALENT TO TEKTRONIX PART No 012 0057 01 15 CABLE COAXIAL 2 E
149. OSITION Full counterclockwise 5 T MONOLITHIC sov i ipe we xao HORIZ DISPLAY 8238 PRE AMPLIFIER id gt i X10 MAG Off button out cel E POSITION Horiz Midrange dwa T deze 626 FINE Mi NT r2 1v 7 65 6 500 as drange CR103 RIN i 2150 ney e bsk E Fe Vertical Controls CH 1 and CH 2 r LEVEL as Magee POSITION Center trace on qraticule Ly ee f VOLTS DIV 2 mV for dc voltages Vollage Measurements ERU 207 14 2 AB VES 100 mV for waveforms Voltage measurements are taken with no signal applied av lt t k 8752 ate sav S DIV Calibrated detent and the trace positioned to the center horizontal graticule mun a E Ease Mee E AC GND DC DC line The voltmeter common is connected to chassis 4720 E AT ap 5 um abor 1 Off buttor out ground BEXT G XT pom Q VERT MODE CH 1 IN PUT pon R723 20k m Tu MNT i 100 or 20 MHz BW Ful bandwidth Push in Waveform Conditions IM zOpF 130 A i then reicase Apply the 4 5 calibrator signal to CH 1 input through a CENTERING P6075 10X probe supplied with 475 Connect 475 A EN I 1 GATE rear panel through a 42 inch 50 ohm BNC cable 9 R788 2 to test oscilloscope external trigger input Set test os 55558 1 P oon ti A cilloscope tr
150. OSITION control Q938A is off thereby causing both Q794 and Q796 to be off also The base level of Q794 sits at a more negative level than does the base of Q796 so that when Q938A turns on at the delay pickoff point Q794 will turn on and Q796 will remain off The resultant positive movement at the collector of Q794 is connected to the B Trigger TD Reset Circuit The end of sweep pulse from the Non Delaying Sweep Generators connects to the emitter of Q788 When this pulse steps positive at the end of a delayed sweep Q788 turns off and the current through R788 pulls the base of Q794 positive This turns off Q794 and causes Q796 to turn on The circuit remains in this state until the Delaying Sweep Generator ends its sweep and resets the Delay Pickoff Comparator In the B ENDS A position of the A TRIG HOLDOFF control 5 volts is connected to R798 This enables the diode gate composed of CR799 and CR592 Now when the end of sweep pulse signals the end of a delayed sweep the positive movement at the collector of Q796 is connected to the base of Q594 and ends the delayed sweep Instead of waiting until the end of the delaying sweep This mode of operation gives the fastest possible sweep repetition rate when operating in the delayed sweep mode B Trigger TD Reset Circuit Q790 and Q792 are connected as a Schmitt Trigger and form the B Trigger TD Reset Circuit At all times other than when the Non Delaying Sweep Generators are running Q790 is
151. P AND GAIN LOGIC D SET HORIZONTAL DISPLAY TO B DI Y D AND POSITION THE RISING PORTION OF ONE OF NO CHECK SWEEP GENERATOR CHECK SWEEP GENERATORS THE SQUARE WAVES TO THE LEFT GRATICULE AND B SWEEP LOGIC CHECK TIMING COMPONENTS LINE CHECK FOR ABOUT FIVE COMPLETE CYCLES 10 DIVISIONS lt gt lt gt YES STABLE DISPLAY A SET TRIGGER SOURCE NORM AND ADJUST CANNOT 8E OBTAINED CHECK B TRIGGER B TRIGGER LEVEL FOR A STABLE DISPLAY GENERATOR CIRCUIT STABLE DISPLAY SET HORIZ DISPLAY TO A INTEN AND TURN THE DELAY TIME POSITION CONTROL THROUGH ITS RANGE CHECK FOR AN INTENSIFIED PORTION OF DISPLAY WHICH JUMPS BETWEEN SQUARE WAVES CORRECT DISPLAY APPARENT TROUBLE MAY HAVE BEEN DUE TO INCORRECT CONTROL SETTINGS FOR A TROUBLE NOT COVERED BY THIS CHART USE THE TROUBLESHOOTING METHODS LISTED UNDER TROUBLESHOOTING TECHNIQUES OD INTENSIFIED PORTION DOES NOT MOVE CHECK B TRIGGER GENERATOR CHECK SWEEP AND LOGIC M M HM e t 1 66202 999 1 TM 11 6625 2735 14 1 If values less than these are obtained either the device is short circuited or no current is flowing in the circuit If values are in excess of the base emitter values given the junction is back biased or the device is defective Values in excess of those given
152. R TERM CONN 4 WIRE BLACK 2 CONTACT ELEC FEMALE 140 IMPLR FAN AXIAL 2 60 INCH OD PLASTIC 141 142 3 GROMMET PLASTIC 0 375 INCH DIA 143 GROMMET PLASTIC 1 24 X 0 739 X 0 108 OA 144 2 GROMMET PLASTIC 0 50 INCH DIA 2 GROMMET PLASTIC 0 625 INCH CIA 165 CLIP ELECTRICAL COMPONENT MOUNTING ATTACHING PARTS 146 1 SCREW MACHINE 4 40 X 0 25 INCH PNH STL 14 NUT PLAIN EXT W 4 40 X 0 25 INCH STL m 148 DELAY LINE ELEC DL380 ATTACHING PARTS 149 BRKT DELAY LINE ALUMINUM 150 NUT PLAIN EXT W 6 32 X 0 312 INCH STL 7 22 TM 11 6625 2735 14 1 FO amp index No Qty 12345 Name amp Description 15 DELAY LINE INCLUDES CONN DELAY LINE RETAINER WIRE E DELAY LINE TERMINAL 151 SW THERMOSTATIC 10A 240V OPEN 75 DEG ATTACHING PARTS 152 2 SCR TPG THD FOR 5 32 X 0 188 INCH PNH STL m aw m 153 1 XFMR PWR STPDN SEE T1400 EPL ATTACHING PARTS 154 2 SCREW MACHINE 6 32 X 0 312 100 DEG FLH STL 155 4 NUT PLAIN EXT W 6 32 X 0 312 INCH STL km TRANSFORMER INCLUDES 156 4 SCREW MACHINE 10 32 X 2 50 HEX HD STL 157 4 WASHER NONMETAL 10 FIBER 158 4 INSUL SLVG ELEC 0 19 ID X 1 875 LONG MYLAR 159 COVER XFMR 3 L X 2 5 W X 0 65 INCH H 160 4 WASHER LOCK SPLIT O 195 ID X 0 32 OD P BRZ 161 4 NUT PLAIN HEX 10 32 X 0 25 INCH BRS 162 BRACKET XFMR ALUMINUM 163 SHIELD ELEC TRANSFORMER 164 TRANSISTOR CHAS 01458 165 TR
153. RED 1 SETSCREW 5 40 X 0 125 STL BK OXD HEX 21 1 KNOB GRAY DLYD SWP 2 SETSCREW 5 40 X 0 25 INCH HEX SOC STL 22 1 RING KNOB SKIRT PLASTIC 1 45 INCH DIA 2 SETSCREW 6 32 X 0 188 INCH HEX SOC STL 1 SHAFT PUSH ACTR 0 76 L X 0 065 STEPPED 23 1 BRG KNOB SKIRT 0 789 ID X 0 866 0D PLASTIC 24 1 PUSH BUTTON GRAY A LOCK KNOBS 25 PUSH BUTTON GRAY MIX 26 1 PUSH BUTTON GRAY A INTEN 27 1 PUSH BUTTON GRAY B DLY D 28 1 PUSH BUTTON GRAY AUTO 29 l PUSH BUTTON GRAY NORM 30 l PUSH BUTTON GRAY SNGL SWP 31 2 KNOB GRAY SETSCREW 5 40 X 0 125 STL BK OXD HEX 32 2 KNOB GRAY 1 SETSCREW 5 40 X 0 125 STL BK OXD HEX 233 9 BUSHING SLEEVE 0 250 OD X 0 131 ID PRESS MT 3 BUSHING SLEEVE 0 125 ID X 0 234 THK PLSTC 2 NUT PLAIN HEX 0 312 18 X 0 50 INCH STL ATTACHING PARTS FOR EACH 1 NUT PLAIN HEX 0 25 32 X 0 312 INCH BRS 1 WASHER FLAT 0 25 ID X 0 375 INCH OD STL aw Wee 3 BUSHING PLASTIC 0 257 ID X 0 412 INCI OD 35 2 LENS LIGHT CLEAR ATTENUATOR 36 16 FR PUSH BUTTON GRAY PLASTIC 37 LENS LIGHT CLEAR 38 RES VAR WW R930 ATTACHING PARTS 39 1 DIAL CONTROL 10 TURN FOR 0 25 DIA SHAFT SETSCREW 4 40 X 0 125 INCH HEX SOC STL FO 15 Located in Back of Manual 7 19 TM 11 6625 2735 14 1 7 20 Index No 15 40 61 42 43 44 AE 46 47 48 49 50 51 52 53 5 1 55 56 57 58 59 60 61 62 63 64 65 ww 66 67 68
154. RTICAL CHANNEL SWITCHING 440 499 VERTICAL OUTPUT AMPLIFIER 500 570 R579 See LV POWER SUPPLY for more 500 series numbers 660 679 700 709 710 786 R789 571 629 640 649 680 699 787 829 SWEEP AND Z AXIS LOGIC 1492 1499 See LV POWER SUPPLY for more 1490 series numbers 900 1049 SWEEP GENERATORS 1050 1099 1100 1269 HORIZONTAL AMPLIFIER C507 R507 C508 R508 R529 C1335 LR1335 C1336 LR1336 1400 1490 R1495 Q1494 Q1496 Q1497 LV POWER SUPPLY 1300 1399 CRT CIRCUIT 1500 1519 CALIBRATOR 1690 1699 FAN CIRCUIT Diode Color Code The cathode end of each glass encased diode is indicated by a stripe a series of stripes or a dot For most silicon or germanium diodes with a series of stripes the color code identifies the three significant digits of the Tektronix Part Number using the resistor color code system e g a diode color coded pink or blue brown gray green indicates Tektronix Part No 152 0185 00 The cathode and anode ends of metal encased diodes can be identified by the diode symbol marked on the body A TRIGGER GENERATOR B TRIGGER GENERATOR Oo 9 TIMING AND HORIZONTAL DISPLAY SWITCHING Semiconductor Lead Configuration Eig 4 3 shows the lead configuration for the semiconductors used in this instrument as viewed from the bottom of these miconduc tors Troubleshooting Equipment The fo
155. S CHANNEL 2 VERTICAL POSITIONABLE i PREAMP Bic EX THE VE TEJ s BO DEFLECTION PLATE LEADS OT NEITHER CHANNEL CHECK VERTICAL APPEARS APPEARS POSITIONABLE TRACES NOT POSITIONABLE 4 AMPLIFIER TURN HORIZONTAL POSITION AND FINE CONTROLS TRACES POSITIONABLE d CONNECT CALIBRATOR TO BOTH VERTICAL INPUT CONNECTORIS SET INPUT COUPLING SWITCHES TO DC AND BOTH VOLTS DIV TO 0 1 CHECK FOR ABOUT 3 DIVISIONS DEFLECTION ON EACH CHANNEL CHANNEL SWITCHING G a AND HIGH VOLTAGE CHECK Z AXIS AMPLIFIER CIRCUITS 1 CHECK HORIZONTAL AMPLIFIER SPOT APPEARS CONNECT THE VERTICAL ANO HORIZONTAL DEFLECTION PLATE LEADS CHECK IF VAR VOLTS DIV CONTROLS ARE IN CALI BRATEO DETIENT NO Lt E S820 86c99 LE INL 9025011280 SLP 104 14842 p p 91 YES ves SET VERT MODE TO CH 1 SET A TRIGGER SOURCE TO NORM SET A TRIGGER COUPLING TO AC AND ADJUST LEVEL CONTROL FOR A STABLE DISPLAY STABLE DISPLAY CHECK FOR 300 mV PEAK TO PEAK SQUAREWAVE AT CALIBRATOR CURRENT LOOP WITH TEST OSCILLOSCOPE CHECK CALIBRATOR 4 CIRCUIT STABLE DISPLAY BE AINED A TRIG LIGHT ON ED t CHECK VERTICAL lt 5 lt a gt F N SYSTEM SET
156. SLVG SLEEVING AWG AMERICAN WIRE GAGE FLH FLAT HEAD NON WIRE NOT WIRE WOUND SPR SPRING BD BOARD FLTR FILTER OBD ORDER BY DESCRIPTION SQ SOUARE BRKT BRACKET FR FRAME or FRONT OD OUTSIDE DIAMETER SST STAINLESS STEEL BRS BRASS FSTNR FASTENER OVH OVAL HEAD STL STEEL BRZ BRONZE ET FOOT PH BRZ PHOSPHOR BRONZE SW SWITCH BSHG BUSHING FXD FIXED PL PLAIN or PLATE T TUBE CAB CABINET GSKT GASKET PLSTC PLASTIC TERM TERMINAL CAP CAPACITOR HDL HANDLE PN PART NUMBER THD THREAD CER CERAMIC HEX HEXAGON PNH PAN HEAD THK THICK CHAS CHASSIS HEX HD HEXAGONAL HEAD PWR POWER TNSN TENSION CKT CIRCUIT HEX SOC HEXAGONAL SOCKET RCPT RECEPTACLE TPG TAPPING COMP COMPOSITION HLCPS HELICAL COMPRESSION RES RESISTOR TRH TRUSS HEAD CONN CONNECTOR HLEXT HELICAL EXTENSION RGD RIGID V VOLTAGE COV COVER HV HIGH vOLTAGE RLF RELIEF VAR VARIABLE CPLG COUPLING IC INTEGRATED CIRCUIT RTNR RETAINER W WITH CRT CATHODE RAY TUBE ID INSIDE DIAMETER SCH SOCKET HEAD WSHR WASHER DEG DEGREE IDENT IDENTIFICATION SCOPE OSCILLOSCOPE XFMR TRANSFORMER DWR DRAWER IMPLR IMPELLER SCR SCREW XSTR TRANSISTOR 7 1 TM 11 6625 2735 14 1 A1R42 A2R62 A1C41 A2C61 A1R41 A2R61 A1R39 A2R39 A1R35 A2R35 A1R34 A2R34 is A1R33 A2R33 A1R32 A2R32 A1R24 A2R24 A1R22 A2R22 1 EL6UGOO Fig 7 1 A1 and A2 boards component locations 7 2 TM 11 6625 2735 14 1 PREFIX ALL REF DES WITH A3 eses 22464 86641 44681 0370 wa
157. SY A3 CIRCUIT CARD ASSY A5 CIRCUIT CARD ASSY A6 CIRCUIT CARD ASSY A7 CIRCUIT CARD ASSY A7A1 CIRCUIT CARD ASSY A8 3 MAINTENANCE FUNCTION Impact Test Calibrate Repair Repair Overhaul Inspect Test Repair Inspect Test Replace Repair Inspect Test Replace Repair Inspect Test Replace Repair Inspect Test Replace Repair Inspect Test Replace Repair Inspect Test Replace Repair Inspect Test Replce Repair Inspect Test Replace Repair 4 MAINTENANE CATEGORY TM 11 5 TOOLS AND EQPT 6625 2735 14 1 6 REMARKS Visual External Simple Opera tional 1 thru 29 1 thru 29 1 thru 29 1 thru 25 27 1 thru 29 1 thru 29 23 2 3 6 27 28 29 27 27 27 1 thru 29 27 27 27 1 thru 29 27 27 27 1 thru 29 27 27 27 1 3 6 27 28 27 27 27 1 thru 29 27 27 27 1 thru 29 27 27 27 1 thru 29 27 27 Change 1 D 3 TM 11 6625 2735 14 1 SECTION Il ALLOCATION CHART OSCILLSCOPE OS 201B V 1 U AND OS 201C V 1 U 4 1 3 MAINTENANCE CATEORY GROUP aq MAINTENANCE NUMBER 0 F H 07 CIRCUIT CARD ASSY A9 Inspect 0 1 Test 0 5 Replace 0 2 Repair 0 5 08 CIRCUIT CARD ASSY A10 Inspect 0 2 Test 0 5 Replace 0 2 Repair 0 5 09 DC TO AC INVERTER OPTION 07 Inspect 0 1 Test 12 Replace Repair 0 5 D 4 Change 1 TM 11 6625 2735 14 1 SECTION Ill TOOL AND TEST EQUIPMENT REQUIREMENTS FOR
158. T ELEC MECH HEX 1 593 INCH LONG CKT BOARD ASSY INCLUDES EXTENSION SHAFT 0 95 INCH LONG EXTENSION SHAFT 4 14 INCH LONG EXTENSION SHAFT 8 241 L X 0 081 INCH OD SWITCH PUSH MICRO 51099 f ar AOU ATTACHING PARTS HOLDER MICR NUT PLAIN EXT W 4 40 X SCREW MACHINE 4 40 X 0 WASHER LOCK INTL 0 092 0 25 INCH STL 375 100DEC FLH STL ID X O 18 STL NUT PLAIN HEX 2 56 X 0 188 INCH BRS w ACTUATOR SWITCH MICROSWITCH DRUM ASSY CAM 1050 ATTACHING PARTS 14144 AS wean SCREW CAP 4 40 X 0 500 SCH SST m COVER CAM 58 18 6 25 ELEMENTS ATTACHING PARTS SCREW MACHINE 4 40 X 0 25 INCH PNH STL WASHER LOCK 4 INTL O OISTHK STL CD PL DI NUT PLAIN HEX 40 x 0 188 INCH BRS SPRING FLAT GREEN COLORED SPRING FLAT RED COLORED ROLLER DETENT 0 125 DIA X 0 125 INCH L ROLLER DETENT BEARING CAM SW FRONT ATTACHING PARTS RING RETAINING 0 338 ID X 0 025 THK STL m Ek ACTR ASSY CAM S TIME CM FRONT NUT PLAIN HEX 4 40 X 0 188 INCH BRS BRACKET COVER ABS NUT PLAIN HEX 4 40 X 0 188 INCH BRS DELETED DELETED TM 11 6625 2735 14 1 FO 8 Index No Qty 12345 Name amp Description 16 77 1 SPRING HLCPS 0 125 OD X 0 3 INCH L l SPRING HLCPS 0 176 OD X 0 835 INCH LONG 78 l BEARING CAM SW 0 428 ID PLASTIC 79 l ACTR ASSY CAM S TIME CM REAR ATTAC
159. TATION tow Ra AAT 156 908 J 8v ALIGN 5ay EIE tomv T 3X c 4 Loca jest SHANAARAI i XE gut i ann Rison la CRI337 crios V IW P 3 Y 189v Qi308 MEGA FOCUS TELE a gen FI 510508 H 1 5 UE 2502 CRIB DE E 3 Rizoz 067 zou H Se Cies ATAF Delage wo NOTE SET TEST OSCILLOSCOPE TRIGGER SOURCE TO INTERNAL 2 24 5mm hu is aie R0 79 low Focus 21565 a 61 5 E 8 vRAT 2 69 34 4 kin 2 5 RISSA doy 3774 Ras al amp iS4 100 9 gt RA 47 Nov ciag Ou1 i 11394 eu o a 1 m 4 061382 1459v 051383 59 a CRT CIRCUIT Z AXIS AMPLIFIER 415 150 gx say a TS 1588 um 344 Du HM 8 a 59 l Zak L 24 EL UGOSI 13 CRT circuit and Z axia amplifier schematic diagram uw 7 150 7500
160. TM 11 6625 2735 14 1 TECHNICAL MANUAL OPERATOR S ORGANIZATIONAL DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL FOR OSCILLOSCOPE OS 261B V 1 U NSN 6625 01 101 1318 TEKTRONIX MODEL 475 WITH OPTION 04 This copy is a reprint which includes current pages from Change 1 HEADQUARTERS DEPARTMENTOFTHEA RM Y JUNE 1982 TM 11 6625 2735 14 1 C 1 CHANGE HEADQUARTERS DEPARTMENT OF THE ARMY No 1 Washington DC 10 September 1984 OPERATOR S ORGANIZATIONAL DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL OSCILLOSCOPE OS 261B V 1 U TEKTRONIX MODEL 475 WITH OPTION 04 NSN 6625 01 101 1318 AND OSCILLOSCOPE OS 261C V 1 U TEKTRONIX MODEL 475 WITH OPTION 04 AND OPTION 07 NSN 6625 01 119 7314 TM 11 6625 2735 14 1 17 June 1982 is changed as follows 1 Title of manual is changed as shown above 2 New or changed material 1s indicated by a vertical bar in the margin of the page Added or revised illustrations are indicated by a vertical bar in front of the figure caption 3 Remove old pages and insert new pages as indicated below Remove pages Insert pages and blank i through iv i through iv 1 0 0 1 1 9 and 1 10 and 1 10 1 13 1 14 blank blank 2 and 2 2 and 2 2 6 1 and 6 2 and 6 2 None 1 through 6 2 8 7 3 and 7 4 and 7 15 7 16 and 7 17 7 18 blank and 7 17 7 18 blank A 1 A 2 blank blank B 1 through B 5 through B 6 D 1 through D 6 through D 6 4 File this chang
161. TO A TRIGGER HOLDOFF NORM e Return VAR TIME DIV control to calibrated detent 5 15 TM 11 6625 2735 14 1 21 Check Sweep Length and Horizontal POSITION Range a Set time mark generator for 1 millisecond time marks b CHECK Sweep length for approximately 10 1 divisions c Turn POSITION and FINE Horiz controls fully clockwise Also check that each control will position the trace d That the start of sweep is to the right of graticule center e Turn POSITION and FINE Horiz controls fully counterclockwise f CHECK That the end of sweep is to the left of graticule center g Recenter POSITION and FINE Horiz controls 22 Check A Timing Accuracy a Set TIME DIV to 0 01 set the time mark generator for 10 nanosecond time marks set TRIG MODE to NORM and set A TRIGGER LEVEL for a stable triggered display NOTE Unless otherwise stated set POSITION and FINE Horiz controls so first time mark will coincide with first graticule line and check that a time mark will coincide with last vertical graticule line b CHECK TIME DIV settings from 0 018 to 5 ins division for accuracy at first and 11th graticule lines within 1 from 20 C to 30 C within 3 from 15 C to 55 C NOTE Turn INTENSITY full on note the start of sweep and exclude the first 25 nanoseconds from start of sweep when checking 0 01 and 0 02 us divislon Set time mark generator as necessary to provide 1
162. TS DIV 2 mV for dc voltages 100 mV for waveforms VAR VOLTS DIV Calibrated detent AC GND DC DC INVERT Off button out VERT MODE CH 1 100 or 20 MHz BW Full bandwidth Push in then release Trigger Controls A and B COUPLING Au LEVEL Q SLOPE SOURCE NORM TAIG MODE AUTO A TRIGGER HOLDOFF NORM 10 MO Tektronix DM 501 Digital Multimeter or 0 to 500 V equivalent _ Sweep Controls TIME DIV 51 ms VAR TIME DIV Calibrated detent DELAY TIME POSITION Full counterclockwise HORIZ DISPLAY A X10 MAG Off ibutton out POSITION Horiz Midrange FINE Midrange Voltage Measurements Voltage measurements are taken with no signal applied and the trace positioned to the center horizontal graticule linc The voltmeter common is connected to chassis ground Waveform Conditions Apply the 475 calibrator signal to CH 1 input through a P6075 10X probe supplied with 475 Connect 475 A GATE rear panel through a 42 inch 50 cable to test oscilloscope external trigger input Set test os cilloscope trigger source to external and set vertical input for ac coupling Set test oscilloscope VOLTS DIV and TIME DIV con trols as indicated on readout symbois on each waveform Tolerance of voltages and waveforms shawn are 20 11 6625 2735 14 1 3 EET 1 An nu d 4 Powe S l 545 e Pan
163. TS DIV to 50 mV retrigger if necessary then set the display to graticule center with CH 1 POSITION f Set VERT MODE to CH 2 and move the display to graticule center with CH 2 POSITION Retrigger if necessary g Return VERT MODE to CH 1 h CHECK That a stable triggered display can be obtained in AC and DC positions of B TRIGGER COUPLING with adjustment of B TRIGGER LEVEL i Return B TRIGGER COUPLING to AC CHECK That a stable triggered display can be obtained in NORM CH 1 and CH 2 positions of B TRIGGER SOURCE with adjustment of B TRIGGER LEVEL k Return B TRIGGER SOURCE to NORM 14 Check A 40 Megahertz Triggering a Set HORIZ DISPLAY to A and check that A TRIGGER SOURCE is in NORM and A TRIGGER COUPLING is in AC b CHECK That a stable triggered display can be obtained in AC and DC positions of A TRIGGER COUPLING with adjustment of A TRIGGER LEVEL c Return A TRIGGER COUPLING to AC d CHECK That a stable triggered display can be obtained in CH 1 and CH 2 positions of A TRIGGER SOURCE with adjustment of A TRIGGER LEVEL e Return A TRIGGER SOURCE to NORM and move test signal cable from CH 2 input to A TRIGGER external input f Set the sine wave generator for a 1 division 40 megahertz display then set A TRIGGER SOURCE to EXT g CHECK That a stable triggered display can obtained in AC and DC positions of A TRIGGER COUPLING with adjustment of A TRIGGER LEVEL h Return A TRIGGER SOURC
164. UPLING with adjustment of A TRIGGER LEVEL j Replace the 10X BNC attenuator in test signal setup with a 5X BNC attenuator 500 millivolts at external input and set A TRIGGER COUPLING to LF REJ That a stable triggered display with no more than 0 2 division of jitter can be obtained with adjustment of A TRIGGER LEVEL 16 Check B 200 Megahertz Triggering a Move test signal setup from A TRIGGER external input to B TRIGGER external input b Set A TRIGGER SOURCE to NORM set A TRIGGER COUPLING to AC set HORIZ DISPLAY to B DLY D set B TRIGGER SOURCE to EXT and set B TRIGGER COUPLING to LF REJ c That a stable triggered display with no more than 0 2 division of jitter can be obtained with adjustment of A and B TRIGGER LEVEL controls d Replace the 5X BNC attenuator with a 10X BNC attenuator 250 millivolts at external input e CHECK That a stable triggered display with no more than 0 2 division of jitter can be obtained in AC and DC positions of B TRIGGER COUPLING with adjustment of A and B TRIGGER LEVEL controls TM 11 6625 2735 14 1 f Set B TRIGGER SOURCE to STARTS AFTER DELAY and set TIME DIV to 1 us g Set the sine wave generator for a 1 5 division 200 megahertz display h Set B TRIGGER SOURCE to NORM and set TIME DIV to 0 01 i CHECK That a stable triggered display with no more than 0 2 division of jitter can be obtained in AC LF REJ and DC positions of
165. URCE B TRIGGER SOURCE TRIG MODE AC 0 NORM STARTS AFTER DELAY AUTO A TRIGGER HOLDOFF NORM Sweep A TIME DIV 1 ms B TIME DIV 1 ms VAR TIME DIV Calibrated detent DELAY TIME POSITION HORIZ DISPLAY X10 MAG POSITION Horiz FINE Fully counterclockwise A Off button out Midrange Midrange 6 10X BNC Attenuator 7 50 Ohm BNC Termination 2 required 8 BNC Female to BNC Female Adapter 9 BNC T Connector 10 Screwdriver 1 Check Display Controls a Turn the INTENSITY control through its range and return to a normal intensity setting b CHECK For control of trace intensity from minimum to maximum intensity c Turn CH 1 POSITION through its range and return to a midrange setting d CHECK That the trace can be positioned over the entire graticule area e Set VERT MODE to CH 2 turn CH 2 POSITION through its range and return to a midrange setting f CHECK That the trace can be positioned over the entire graticule area g Return VERT MODE to CH 1 and position the trace to the center horizontal graticule line h CHECK That the trace is aligned with the center horizontal graticule line i ADJUST TRACE ROTATION front panel screw driver adjustment to align the trace with the center hoizontal graticule line j Turn the SCALE ILLUM control through its range 5 5 TM 11 6625 2735 14 1 k CHECK For control of graticule illumination from minimum to maximum settings l S
166. V Functions Knobs Unlocked Normally when the HORIZ DISPLAY switch is set to A the Non Delaying Sweep Generator is being used to display A Sweep When the DLY D SWEEP control inner knob of TIME DIV is unlocked and set to a faster sweep rate the Non Delaying Sweep Generator is then being used to display A Sweep In this mode the A TIME DIV skirt knob must be used to control A Sweep rates HORIZONTAL AMPLIFIER General The Horizontal Amplifier circuit provides the output signals to the CRT horizontal deflection plates The signal applied to the input of the Horizontal Amplifier is deter mined by the TIME DIV switch The signal can be a sawtooth waveform generated within the instrument or some external signal applied to the CH 1 OR X input connector X Y mode of operation The Horizontal Amplifier also contains the X10 magnifier horizontal positioning controls and some beam finder circuitry 3 8 shows a detailed block diagram of the Horizontal Amplifier circuit A schematic of this circuit is shown on Diagram 10 at the rear of this manual 1050 SWEEP l IN R1119A R11198 X SIGNAL FROM VERTICAL OUTPUT AMPLIFIER 01172 01174 01182 AMPLIFIER Q1184 Q1188 Q1202 Q1152 Q1162 Q1204 Q1212 Q1214 Q1164 Q1234 Q1254 GAIN SETTING TO CAT HORIZONTAL DEFLECTION PLATES INPUT PARAPHASE AMPLIFIER Q1124 Q1140 Q1134 4 FINDER S450 NAT TO NI YO gt L
167. a brushless DC motor using Hall Effect devices The fan motor control circuitry varies the rotational speed of the fan as the operating temperature changes Two Hall Effect devices inside the motor and 4 transistors U8061A B C and D U1690 A D for early SN compose a sine wave generator to drive the motor windings Each of the 4 transistors is controlled by 1 2 of a Hall element to generate 1 4 of the sine wave cycle As the ambient temperature increases the value of thermistor RT8038 RT1696 for early SN decreases This biases Q8067 Q1698 for early SN on harder to conduct more current through the Hall devices and turn the motor winding control transistor on harder The harder the transistor is conducting the faster the fan rotates Typical fan speed variation with ambient temperature IS 15 C approx 800 RPM 25 C approx 2000 RPM 55 C approx 3100 RPM 3 27 3 28 blank TM 11 6625 2735 14 1 Section 4 475 Service MAINTENANCE This section of the manual contains directions for Circuit Board Illustrations Cabinet removal preventive maintenance troubleshooting and corrective maintenance of the 475 Adjustment Locations Illustrations Resistor Color Code age 4 6 Capacitor Color Code Diode Color Code Page 4 7 MAINTENANCE SECTION OUTLINE Semiconductor Lead Configuration Cabinet and Rock Adaptor Removal Troubleshooting Equipment Page 4 7 Standard Cabinet Removal 1 Semiconductor Tester Page 4 10 Standard
168. al input COUPLING AC for ac coupling LEVEL 0 SLOPE t Set test oscilloscope VOLTS DIV and TIME DIV con SOURCE NORM trols as indicated on readout symbois on each waveform TRIG MODE AUTO A TRIGGER HOLDOFF NORM Tolerance of voltages and waveforms shown are 20 TM 11 8625 2735 14 1 M W i ATTEN JSO i 1 1 eni i cei IM 99 i Rea 4 se oq ra pou E n R s R32 TU 1 i SON i 1 i i S t ix CHR TO SWITCH AG 3 SCALE SHOWN GNO M gt FACTOR YN Dc 001 SWITCHING POS TION AU SUR S29A PIZA L NOTE INDICATES SWITCH CLOSED B CONTACT WHEN 4 g j e TWO ARE PRESENT SwiTCA SROWN IN 2 V POSITION 4 208 1 FROM FROM FROM 4 Potan A di P eo 10 fy P2L0 9 VOLTAGE amp WAVEFORM i av T5V CONDITIONS 4297 R291 A 1291 47 C297 ZAF T 290 SIDE auc ONES 4 M 8 290 5 VERT SIGUAL 1 To 7 FROM A62 zepis PLS 15 i5Y eie OR to rt er eee TUM YAR e mn 22 24 2252 BAL Ser 5 SE ti T gt MES 252 TE F 5 1282 8 52258 5
169. al sweep display modes dependent upon the horizontal mode selected by the HORIZ DISPLAY switch One sweep generator maybe employed as a delay circuit for a second sweep generator permitting a variety of useful display modes Before the discussion of sweep generation it is helpful to become familiar with each principle mode of horizontal display and its associated sweep generator sweep gate and sweep display labeling SeB Table 3 2 for a list of sweep generator sweep gate and sweep display terminology whenever needed throughout the following sweep generators discussion The Sweep Generators produce the sawtooth voltages that are amplified by the Horizontal Amplifier to provide horizontal deflection on the CRT These sawtooth voltages are produced on command trigger pulses from the Trigger Generator circuits The Sweep Generator circuits also produce gate waveforms that are used by the Z Axis Logic circuit to unblank the CRT during sweep time and by the Sweep Logic circuit to terminate sweep generation There are three Sweep Generator circuits in the instrument Operation of all three is very similar therefore only the operation of the Delaying Sweep Generator and the ERR in operation of the three generators is discussed Fig 3 7 Fig 3 7 shows a detailed block diagram of the Sweep 2 schematic of the Sweep Generators is shown on Diagram 8 and a schematic of the Timing And Horizontal Display Switching is shown on Diagram 9 at the r
170. als below about 50 kHz Accepts signals above about 50 kHz HF REJ Accepts signals between 60 Hz and 50 kHz Rejects DC and attenuates all signals outside the above range DC Accepts all trigger signals between DC and 200 MHz or greater Selects source of trigger signal NORM Internal trigger signal obtained from Vertical Defect ion System Actual source is signal s displayed on crt CH 1 A sample of the signal connected to the CH 1 OR X input connector is used as a trigger signal CH 2 A sample of the signal connected to the CH 2 OR Y input connector is used as a trigger signal EXT Trigger signal obtained from signal connected to the External Trigger Input connec tor TM 11 6625 2735 14 1 SLOPE LEVEL A TRIG MODE EXT 10 A Trigger circuit only External trigger signal attenuated by a factor of 10 STARTS AFTER DELAY B trigger circuit only B sweep starts immediately after the delay time selected by the DELAY TIME POSITION dial and the DELAY TIME switch LINE A trigger circuit only Trigger signal obtained from a sample of the line voltage applied to the instrument Selects the slope of the trigger signal which starts the sweep Sweep can be triggered from the positive going portion of the trigger signal Sweep can be triggered from the negative going portion of the trigger signal Selects the amplitude point on the trigger signal at which the sweep is triggered
171. ame 8 Pull the power cord through the rear cabinet frame align a cutout portion in the frame for proper fit at the regulating range selector cover and work the frame into place TM 11 6625 2735 14 1 9 Set the feet and screws in place and exert a light downward pressure on the rear cabinet frame with 1 hand and arm Press lightly on the top and bottom sides of cabinet with the other hand checking that cabinet edge is properly seated in the gasket groove of both front and rear frames Continue to exert a downward pressure and tighten the 6 screws of the rear frame to a snug fit Do not over tighten these screws The standard cabinet protects this instrument from dust in the interior and also provides protection to personnel from the operating potentials present In addi tion the cabinet reduces the emi electromagnetic in terference radiation from the instrument and interference to the display due to other equipment The front panel cover provides a dust tight seal around the front panel and protects the front panel when storing or transporting the instrument Rack Adapter Removal The Rack Adapter can be removed from the instrument in the following manner 1 Remove the hardware that fastens the Rack Adapter to the rack and pull the adapter partially out Disconnect the instrument power cord from the power source and remove any interconnecting cables NOTE It it is desired to tilt the Rack Adapter and Instrument remo
172. amplitude calibrator for a 20 millivolt output and move signal cable to CH 2 input g CHECK The display for 4 divisions of amplitude h ADJUST CH 2 GAIN 5 mV adjustment through the lower 5 mV access hole at left side of cabinet for 4 divisions of amplitude i CHECK AII settings of CH 2 VOLTS DIV for ac curacy within 3 using the settings listed in Table 5 2 4 CHECK CH 2 and CH 1 VAR VOLTS DIV Range a Set the amplitude calibrator to 50 millivolts and set CH 1 and CH 2 VOLTS DIV to 10 mV b Turn CH 2 VAR VOLTS DIV fully counterclockwise c CHECK That the CH 2 UNCAL light turns on when the CH 2 VAR VOLTS DIV control is out of calibrated detent d CHECK That display amplitude reduces to 2 divisions or less TM 11 6625 2735 14 1 e Return CH 2 VAR VOLTS DIV to calibrated detent f Set VERT MODE to CH 1 and move signal cable to CH 1 input g Turn CH 1 VAR VOLTS DIV fully counterclockwise h CHECK That the CH 1 UNCAL light turns on when the CH 1 VAR VOLTS DIV control is out of calibrated detent i CHECK That display amplitude reduces to 2 divisions or less j Return CH 1 VAR VOLTS DIV to calibrated detent 5 Check ADD Mode Operation a Set VERT MODE to ADD and set CH 1 and CH 2 VOLTS DIV to 5 mV b Remove the test signal cable from CH 1 input Connect to the cable a BNC female to BNC female adapter a BNC T connector two 18 inch 50 ohm BNC cables and connect the cables to C
173. an be conveniently converted to 1 0 notation by disregarding the first letter of each step Thus 1 LO 0 It should be noted that not all of the integrated circuit devices in this instrument are digital logic devices The function of non digital devices are described individually using operating waveforms or other techniques to il lustrate their function OUTLINE FOR CIRCUIT DESCRIPTION BLOCK DIAGRAM General CHANNEL 1 PREAMP 1 General Input Coupling 3 5 Input Attenuator First Cascode Amplifier Second Cascode Amplifier 3 6 Third Cascode Amplifier CHANNEL 2 PREAMP lt gt General First Cascode Amplifier Page 3 Page 3 VERTICAL CHANNEL SWITCHING General age Channel Switch IC Page 3 Switching Logic Flip Flops Page 3 Two Megahertz Clock Page 3 Chop Blanking Amplifier Page 3 Channel 2 Signal Output Amplifier Normal Trigger Pickoff Amplifier Scale Factor Switching Circuits VERTICAL OUTPUT AMPLIFIER lt gt General First IC Amplifier Second IC Amplifier Page 3 A TRIGGER GENERATOR lt General age Trigger Source Page 3 1 Trigger Coupling Page 3 1 Input Source Follower Page 3 1 Paraphase Amplifier age Tunnel Diode Driver Trigger View Amplifier Page 3 11 B TRIGGER GENERATOR General Page 3 1 Trigger Source age U U J 4 4 D NO KO D Fo i OI 001 SWEEP AND 2 5 LOGICKD General Sweep Cont
174. applied to their clock inputs through Q338 and U330B In the CHOP mode the clock pulse generated by U330C and U330D switch the flip flops at a one megahertz rate Two Megahertz Clock U330C and U330D form an astable multivibrator having a repetition rate of two megahertz The rectangular output waveform connects to the Switching Logic Flip Flops through nand gate U330B Only in the CHOP position of the VERT MODE switch is a LO level applied to the input of inverter U330A This puts a logical in pin 13 of U330D which permits the astable multivibrator to free run At the same time Q338 is biased on which puts a logical HI on pin 5 of U330B Thus the signal present at pin 6 of U330B will be the two megahertz clock signal Chop Blanking Amplifier The Chop Blanking Amplifier Q348 provides an output pulse to the Z Axis Amplifier circuit which blanks out the transitions between the Channel 1 and Channel 2 traces when operating in the CHOP mode The inherent propagation delay of inverters U340A U340B and U340C are used to provide some signal delay to the chop blanking signal This allows the blanking signal and the channel switching transient to arrive in the CRT simultaneously Channel 2 Signal Output Amplifier Q420 and Q430 compose the Channel 2 Vertical Signal Output Amplifier A sample of the Channel 2 signal from pin 5 of Channel Switch IC U370 is amplified and inverted by Q420 CR422 provides thermal compensation for the base
175. are reversed gt A L CAUTION Y Do not measure funnel diodes with an ohmmeter use a dynarnlc tester such as a Tekfronix Type 576 Transisfor Curve Tracer Voltmeter checks on diodes can be performed in much the same manner as on transistor emitter to base junc tions Silicon diodes should have 0 6 to 0 8 volts across the junction when conducting Higher readings indicate that they are either back biased or defective depending on polarity c RESISTORS Check the resistors with an ohmmeter after disconnecting one end from the circuit Check the Electrical Parts List for the tolerance of the resistors used in this Instrument Resistors normally do not need to be replaced unless the measured value varies widely from the specified value 4 14 d INDUCTORS Check for open inductors by check ing continuity with an ohmmeter It may be helpful to disconnect one end of the inductor when checking continuity Shorted or partially shorted inductors can also be found by checking the waveform response when high frequency signals are passed through the circuit Partial shorting often reduces high frequency response increases roll off e CAPACITORS A leaky or shorted capacitor can be detected by checking resistance with an ohmmeter on the highest scale after disconnecting one end from the circuit Do not exceed the voltage rating of the capacitor some ohmmeters use 30 volts as source voltage The resistance rea
176. ary to restore an item to a completely serviceable operational condition as prescribed by maintenance stand ards 1 DMWR in appropriate technical publications Overhaul is normally the highest degree of maintenance performed by the Army Overhaul does not normally return an item to like new condition k Rebuild Consists of those services actions necessary for the restoration of unserviceable equipment to a like new condition in accordance with original manufacturing standards Rebuild is the highest degree of material main tenance applied to Army equipment The rebuild operation includes the act of returning to zero those age measurements hours miles etc considered in classifying Army equip ments components Change 1 D 1 TM 11 6625 2735 14 1 D 3 Column Entries a Column 1 Group Number Column 1 lists group numbers the purpose of which is to identify components assemblies subassemblies and modules with the next higher assembly b Column 2 Component Assembly Column 2 contains the noun names of components assemblies subassemblies and modules for which maintenance 15 authorized c Column 3 Maintenance Functions Column 3 lists the functions to be performed on the item listed in column 2 When items are listed without maintenance functions it is solely for purpose of having the group numbers in the MAC and RPSTL coincide d Column 4 Maintenance Category Column 4 spe cifies by the listing of a work
177. attempting to solder in the instrument Ordinary 60 40 solder and a 15 to 40 watt pencil type soldering iron can be used to accomplish the majority of the soldering to be done in the 475 If a higher wattage rating soldering iron is used on the etched circuit boards excessive heat can cause the etched circuit wiring to separate from the board base material The Vertical Preamplifier Attenuator circuit boards are made of material easily damaged by excessive heat When soldering to these boards do not use a soldering iron with a rating of more than ap proximately 15 watts Avoid prolonged applications of heat to circuit board connections Use only isopropyl alcohol when cleaning this circuit board The following technique should be used to replace a component on a circuit board Most components can be TM 11 6625 2735 14 1 replaced without removing the boards from the instru ment 1 Grip the component lead with long nose pliers Touch the soldering iron to the lead at the solder connection Do not lay the iron directly on the board as it may damage the board 2 When the solder begins to melt pull the lead out gently If unable to pull the lead without using force try removing the other end of component as it may remove easier NOTE The reason that some component leads seem troublesome to remove is due to a bend placed on each lead during machine insertion of the compo nent in the circuit board manufacturing process Th
178. blank out the switching transients between channels when in the chopped mode of operation The Vertical Channel Switching circuit also provides the CRT CIRCUIT 4 Channel 2 VERT SIG OUT signal available on the instrument rear panel as well as the signals used for 1 sweep triggering in the NORM CH 1 and CH 2 positions High Voltage Regulator Page 3 25 of the trigger SOURCE switches and the signal used for X High Voltage Rectifiers and Output axis deflection in the X Y mode of horizontal operation Control Grid DC Restorer CRT Control Circuits Z Axis Amplifier The output of the Vertical Channel Switching circuit connects to the Vertical Output Amplifier through the Delay Line The Delay Line provides a fixed amount of CALIBRATOR 4 signal delay through the vertical deflection system to allow viewing the leading edge of a triggering waveform General Page 3 27 The Vertical Output Amplifier circuit provides the final Multivibrator amplification for the signal before it is connected to the Output Amplifier Page 3 27 vertical deflection plates of the CRT This circuit includes the BEAM FINDER switch which limits the vertical and FAN MOTOR CIRCUIT horizontal deflection to within the viewing area and sets the display brightness to a normal viewing level to aid in General Page 3 27 locating an off screen display 3 2 TM 11 6625 2735 14 1 VERTICAL OUTPUT AMPL TRIGGER ZAN u TRI
179. by the transistors con nected to pins 5 and 9 in the 2 mV position of the VOLTS DIV switch is approximately 2 5 times the current conducted by the same transistors in all of the other VOLTS DIV switch positions This results in increased gain and a DC level shift at the signal output terminals of U140 The VOLTS DIV switch compensates for a shift in the DC level by shorting out part of the common mode resistance R157 when operating with 2 mV sensitivity Gain Switch Balance adjustment R135 adjust the DC balance of the stage so there is no baseline shift in the CRT display when switching between the 2 mV and 5 mV positions of the CH 1 VOLTS DIV switch The remainder of the components connected between pins 2 and 3 of U140 provide high frequency compensation for the stage Third Cascode Amplifier The third amplifier stage in the Channel 1 Preamplifier circuit is a discrete component cascode amplifier made up of Q172 Q178 Q182 Q184 and Q188 Q184 is a relatively constant current source for Q172 and Q182 Q172 and Q182 convert the input voltage signals into current signals which are in turn converted back to voltage signals by Q178 and Q188 respectively R172 and R182 provide thermal compensation and C172 and C182 AC couple the signal around R172 and R182 to reduce Miller effect C175 and R175 are variable high frequency compensation adjustments while CR170 CR174 and RT170 offset com pensation changes associated with variations in ambient
180. ced maintenance personnel should attempt replacement of these connectors It is recommended that the cable or wiring harness be replaced as a unit For cable or wiring harness part numbers see the Mechanical Parts List b CIRCUIT BOARD PINS To replace a pin which is mounted on a circuit board first disconnect any pin connectors Then unsolder the damaged pin and pull it out of the circuit board with a pair of pliers Be careful not to damage the wiring on the board with too much heat Remove the ferrule from the new interconnecting pin and press the new pin into the hole in the circuit board Position the pin in the same manner as the old pin Then solder the pin on both sides of the circuit board if the old pin was bent at an angle to mate with a connector bend the new pin to match the assoicated pins c CIRCUIT BOARD PIN SOCKETS The pin sockets on the circuit boards are soldered to the rear of the board To replace one of these sockets first TM 11 6625 2735 14 1 unsolder the pin use a vacuum type resoldering tool or a solder removing wick to remove excess solder Then Straighten the tabs on the socket and remove it from the hole in the board Place the new socket in the circuit board hole and press the tabs down against the board Solder the tabs of the socket to the circuit board be careful not to get solder into the socket NOTE The spring tension of the pin sockets ensures a good connection between the circuit boa
181. ck pin 17 of U600 for approximately 0 7 volt Check pin 6 of U600 for ap proximately 4 8 volts Check of U600 for ap proximately 0 2 volt Install Q574 and check the collec tor of Q984 for a repetitive sweep waveform A INTEN Sweep and Logic Remove all external signals to the instrument set TIME DIV to 1 ms lock knobs set HORIZ DISPLAY to A INTEN and set TRIG MODE to AUTO 1 Remove Q572 from its socket This will cause the A Intensified Sweep Generator A Sweep which normally should be in operation to stay at a low voltage level Check the collector of Q922 for approximately 0 3 volt Check the collector of Q1014 for approximately 16 4 volts Check the collector of Q984 for approximately 14 volts The A Sweep holdoff should now be in a reset condition Check TP588 for approximately 4 volts Check the emitter of Q644 for approximately O volt When Q572 was removed from its socket pin 16 of U600 went positive which is the equivalent of a holdoff start pulse Check pin 16 of U600 for approximately 2 5 volts Check pin 17 of U600 for approximately 1 7 volts Check TP572 for approximately 0 volt Check pin 3 of U600 for approximately 0 2 volt 2 Install Q572 and remove Q574 from its socket This will cause only the A Intensified Sweep Generator which normally should be in operation to stay at a start high voltage level Check the collector of Q922 for ap proximately 13 9 volts At this point
182. connectors However some connections are soldered to the board Observe the soldering precautions given under Soldering Techniques given in this section Always disconnect the instument from the power source before atternpting to remove circuit boards To aid in identifying and locating circuit boards in the instrument se Fig 4 5 the locations of circuit boards In the following circuit board replacement procedure determine the circuit board to be removed or replaced find the name of the board listed within this procedure and follow the removal or installation instructions To aid in identifying small components described in this procedure use the diagrams in Section 7 Mechanical Parts List in this manual TM 11 6625 2735 14 1 6 MOTOR A5 VERTICAL A3 VERTICAL OUTPUT PREAMP A4 VERTICAL MODE GAIN SWITCH A1 CHANNEL 1 ATTENUATOR A2 CHANNEL 2 ATTENUATOR 77 AND Z AXIS LOGIC Fig 4 5 Locations of circuit boards in the 475 Oscilloscope 4 23 A8 TRIGGER GENERATOR TM 11 6625 2735 14 1 Vertical Preamp Board Removal Remove the board as follows 1 475 DM 43 and DM 40 only Disconnect three ribbon cables from the DM 43 or DM 40 Main circuit board Remove the screws from the rear of the Main circuit board chassis and separate the board and chassis assembly from the instrument chassis 2 Remove both vertical POSITION control shafts This requires a 0 050 inch
183. ction factor 1 mV to 5 Amplifier and 7R 0 Time base crits or Input impedance 1 20 pF ecuivalent Sweep rate 50 ns Probe Fast rise 10X attenuation probe com Tektronix P6053B or equivalent patible with vertical amplifier of test oscilloscope Voitmeter Non loading nout Impedance 10 Tektronix DM 501 Digital Multimeter Digital Multimeter Range Q to 500 V equivalent 475 Control Settings Sweep Controls Display Controls TIME DIV rms INTENSITY Midranoe VAR TIME DIV Calibrated detent FOCUS Midrange DELAY TIME SCALE ILLUM Midrange POSITION Ful counterclockwise HORIZ DISPLAY A X10 MAG Off button cut POSITION Horiz Midrange FINE Midrange Vertical Controls CH 1 and CH 2 POSITION Center trace on graticule VOLTS DIV 2 mV for dc voltages Voltage Measurements 100 mV far waveforms Calibrated detent Voltage measurements are taken with no signal applied VAR VOLTS DIV and the trace positioned to the center horizartal graticule AC GND DC DC line The voltmeter comman is connected to chassis INVERT Off button out ground VERI MODE CH 1 100 or 20 MHz BW Full bandwidth Push in Wavelorm Conditions then release Apply the 275 calibrator signal to CH 1 input through a P6075 10X probe supplied with 475 Connect 475 GATE rear panel through a 42 inch 50 ohm BNC cable to test oscilloscope externa trigger input Set test os cilloscope trigger source to external and set vertical input for ac couplin
184. cun sd ERE pren CHECK POWER SUPPLIES FOR TOLERANCE AND _ _ TOLER STICLE ene CHECK OR ADJUST Ki ESSR TABLE 4 2 CORRECT VOLTAGE AFFECTED SETLIS TRACE WITHIN GIVEN TOLERANCE CENTEREO CHECK TRACE APPEARS WILI NOT pp 221 n on an Gates POSITION TO CENTER DISCONNECT DECAV sl SET VERTICAL AND HORIZONTAL POSITION TO NOT APPEAR 0 r LINE AT VERTICAL MIDRANGE TIME DIV TO 1 TRIG MODE TO _____ PRESS BEAM FINDER CENTER COMPRESSEO e BOARD 4 CHECK AUTO AND HORIZ DISPLAY TO A ADVANCE DISPLAY WITH POSITION CONTROLS ce VERTICAL INTENSITY CONTROL SETTING a 794 SPOT ONLY APPEARS Miei end AMPLIFIER TRACE TRACE REMAINS WITHIN DISPLAY AREA H SEL 4 MYEARS CHECK FOR AN A t TRACE NO TRACE OR SPOT A SWEEP SAWTOOTH n T ADJUST FOCUS AND ASTIG CONTROLS _ __ Ti 2 CHECK CRT c DA ECTOR FOR WELL OEFINEO TRACE CIRCUIT DISCONNECT THE ee VERTICAL DEFLECTION L PLATE LEADS AT CRT m TRACE CHANNEL CHECK THE CHANNEL SAWTOOTH FOCUSED POSITIONABLE THAT 15 NOT Wm APPEARS NO SAWTODIM 4 POSITIONABLE ON 2 NO TRA 4 VERTICAL PREAMP gt OR SPOT UMS e TEER CHECK SET VERT MODE TO CHOP OR ALT TURN CH 1 TRACE OR i CHECK A SWE T APPEARS HORIZONTAL 2 POSITION CONTROLS SPO DISCONNECT Tr THE HORIZONTAL AMPLIFIER LOGIC CIRCUIT EFLECTION PLAT A T CHECK CHANNEL 1 AND a cna 4 Q BOTH TRACE
185. d components etc 5 Isolate Trouble to a Circuit To isolate trouble to a particular circuit note the trouble symptom The symptom often identifies the circuit in which the trouble is located When trouble symptoms appear in more than one circuit check affected circuits by taking voltage and waveform readings Typical voltages and waveforms are given on the schematics in the Diagrams section 6 Circuit Troubleshooting Sequence If the instru ment is found to have inoperative functions in more than one area of the main oscilloscope circuits repair the circuits in the order specified in the following list a POWER SUPPLY Check 50 V 110 V 15 V 45V 15 V and 8 V supplies b HIGH VOLTAGE Check oscillator and regulator over voltage protection circuit and secondary load c A SWEEP Set TRIG MODE to AUTO repair until sweep is repetitive d HORIZONTAL AMPLIFIER Turn horizontal POSI TION repair until each deflection plate output has proper voltage swing e VERTICAL OUTPUT AMPLIFIER Turn vertical POSITION repair until each deflection plate output has proper voltage swing f Z AXIS set TRIG MODE to SINGL SWP repair until spot display is controlled by INTENSITY g All remaining inoperative functions The preceding recommended troubleshooting se quence is intended to be a quick approach to circuit troubleshooting See Special Troubleshooting informa tion listing in this section for detailed tr
186. ding should be high after initial charge of the capacitor An open capacitor can also be detected with a capacitance meter or by checking whether the capacitor passes ac signals f ATTENUATORS The thick film attenuators are best checked by substitution If only one channel of the 475 is not operating properly and there is reason to believe an attenuator is defective replace the suspected attenuator with the same attenuator from the other channel and check instrument operation If proper operation results order a new attenuator See Component Replacement for replacement instructions 10 Repair and Readjust the Circuit any defective parts are located follow the replacement procedures given in this section Be sure to check the performance of any circuit that has been repaired or that has had any electrical components replaced Recallbration of the affected circuit may be necessary Special Troubleshooting Information General The following information provides a procedure for troubleshooting some of the more complex circuits in the 475 A thorough understanding of the circuit operation is essential before troubleshooting in these areas Read the applicable portions of the Circuit Descrip tion in Section 3 before proceeding This troubleshooting procedure refers to the diagrams operating voltages and waveforms given in Section 8 Specifications for the equipment necessary to troubleshoot in these procedures are given earlier in t
187. e 48 to 440 Hertz The Line Voltage Selector switch in the instrument converts the instrument from a one nominal operating voltage to the other The Regulating Range Selector assembly on the instrument rear panel selects 1 of 3 regu lating ranges for each nominal line voltage and also con tains the line fuse for overload protection The instrument can also be operated from a 12 vdc or 24 vdc power source Line Voltage and Regulating Range To select the correct nominal line voltage regulating range and line fuse proceed as follows 1 Disconnect the instrument from the power source 2 Set the Line Voltage Selector switch located near the right rear of instrument to indicate the desired nominal line voltage 3 Loosen the 2 captive screws that hold the cover on the Regulating Range Selector assembly then pull on the cover to remove 4 Check Table 2 1 for the recommended rating of the line fuse to be used with the desired nominal line voltage Check the fuse in the selector switch cover for the recommended rating or install a fuse with the recommend ed rating The instrument Accessory Pouch should con tain a spare fuse for each nominal line voltage at anytime TABLE 2 1 Regulating Ranges Regulating Range Range Selector 115 Volts 230 Volts Switch Position Nominal Nominal LO Switch bar in 99 to 121 volts 198 to 242 volts lower holes M Switch bar in middle holes HI Switch bar in upper holes
188. e Anode Soldered in place top view All Others Coliector7 p Em Base collector 72 Base Emitter Socket top view 1 3V 1 3 ms 0 5 V 1 j DC LEVEL E a 24 SIGNAL VOLTAGE CONDITIONS The loed is an operating oscilloscope AN u me is the preferred test oscilioscope and voit 45 V meter ground The voltmeter is a 20 000 multimeter Mode switch set to 24 V Voltages and weveform amplitudes will vary with source voltage lt JC E L lt 0 8V and P are identical to and S respectively during 24 V operation During 12 V operation the amplitude at Q and P is reduced by a factor of 2 DO 60 L oe 3 0 V Figure 6 7 Typical idealized waveforms me man DEET EL6UGO6S Figure 6 6 Circuit board layout with test voltages EL6UGO67 6 2 6 Change 1 b Change the dc source to 12 V Operate the os cilloscope in the 12 V mode Vary the dc source from 14 V to 11 5 V CHECK Oscilloscope should operate over the voltage range Inverter Balance NOTE If the major oscilloscope use is with a 12 volt source do this step while operating the oscilloscope and dc source on 12 volts TM 11 6625 2735 14 1 Operate the oscilloscope in the 24 V mode Set the dc source to 24 V Connect the test oscilloscope between C1801 C and the common negative return A
189. e drops below 22 V and causes Q1622 to conduct Q1622 does not conduct during 12 V dc opera tion since the turn off level circuit is disabled CR1625 CR1626 CR1627 and CR1628 form a bridge rectifier The inverter waveform is rectified to provide operating power for the turn off circuit C1626 filters the inverter spikes to keep them from firing Q1626 scr R1623 prevents C1626 from charging to the peak to peak inverter spikes Q1622 saturates when it is turned on C1622 provides the high current path for feedback current via CR1625 or CR1626 Once the inverter is shut down R1622 es tablishes a path to discharge C1622 lf 24 V dc is accidentally applied when the mode switch IS in the 12 V position transformer T1400 attempts to produce two times the correct feedback This is sufficient to cause VR1622 to conduct VR1622 provides the firing current for the scr Q1626 Scr Q1626 fires and shorts out the bridge rectifier and the primary of T1631 stopping the inverter R1625 prevents Q1626 from being fired by inverter noise R1624 and C1626 provide holding current for Q1626 keeping it conducting until the surge current created by the over voltage conditions have terminated CR1624 permits rapid charging of C1626 NOTE Oo amp wOTES COMMON MPC AV WE ME A 4 OC INVERTER BOARD 4 MG CHASSIS MOUNTED NOT FURNISHED 56 DO NOT MEASURE NOISE INTRODUCED 1
190. e helpful The 50 volt supply is used as an example to identify component functions 1 Check for proper voltage and ripple from the diode bridge rectifier CR1412 in the 50 volt supply check at collector of the series regulator for any supply Instrument power cord should be removed from power source Readings taken with a digital ohmmeter see item 3 under Troubleshooting Equipment in this section Readings are normal if within 5096 of listed valve TM 11 6625 2735 14 1 2 Check that the current limiting transistor is off Q1432 in the 50 volt supply by measuring base to emitter voltage If the supply is current limiting remove the power from circuit boards individually until the supply voltage returns to normal and the circuit board drawing excess power is identified To remove power to circuit boards disconnect plugs or desolder and lift one end of decoupling networks or move circuit boards enough to clear interconnecting pins 3 Measure the reference voltage at the supply operational amplifier and check for proper voltage pin 3 of U1418 of 50 volt supply negative input of the operational amplifier of any supply Troubleshooting the High Voltage Circuit There are 3 major areas of concern when troubleshooting this cir cuitry the high voltage oscillator and regulator the over voltage protection circuit and the secondary load in cluding the crt and the high voltage multiplier By dis connecting the a
191. e purpose of the bent leads is to hold the component in place during a flow soldering manufacturing process that solders all components at once If a component lead is extremely difficult to remove it may be helpful to straighten the leads on the back side of the board with a small screwdriver or pliers while heating the soldered connection Desolder the component from the circuit board using heat on the component lead so that the solder will stay behind on the board If it is desired to remove solder from a circuit board hole for easier installation of a new compo nent a vacuum type resoldering tool or a solder removing wick should be used for this purpose 4 19 TM 11 6625 2735 14 1 3 Bend the leads of the new component to fit the holes in the board If the component is replaced while the board is mounted in the instrument cut the leads so they will just protrude through the board Insert the leads into the holes in the board so the component is firmly seated against the board or as positioned originally If it does not seat properly heat the solder and gently press the component into place 4 Touch the iron to the connection and apply a small amount of solder to make a firm solder joint To protect heat sensitive components hold the lead between the component body and the solder joint with a pair of long nose pliers or other heat sink 5 Clip the excess lead that protrudes through the board if not clipped in step 3
192. e sheet in the front of the publication By Order of the Secretary of the Army JOHN A WICKHAM JR General United States Army Official Chief of Staff ROBERT M JOYCE Major General United States Army The Adjutant General To be distributed in accordance with DA Form 12 36B requirements for 05 261 TM 11 6625 2735 14 1 SAFETY SUMMARY This manual contains safety information which the user must follow to ensure safe operation of this instrument WARNING information is intended to protect the operator CAUTION information is intended to protect the instrument The following general safety precautions must be observed during all phases of operation service and repair of this instrument Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design manufacture and intended use of the instrument Warning statements precede potentially dangerous procedures throughout this manual The instruc tions contained in the warnings must be followed The following warning statements are found in this manual WARNING Use a proper power source This instrument is intended to be operated from a single phase power source A suitable power source is one where both current carrying conductors are ungrounded since over current protection fuse is provided in both conductors Operation from a grounded power source is not recommended If the fuse in the grounded conductor opens the
193. ear of this manual TABLE 3 2 Horizontal Display Sweep Generator Terminology HORIZ DISPLAY Switch Setting CRT DISPLAY Portion of Sweep Sweep Generator Used for 88 Gate that Initiates Swoop B Last Portion Non Delaying Delayed A INTEN B Intensified Non Delaying Delayed Portion 3 16 Non Delaying After being delayed by Delaying Sweep Delayed TM 11 6625 2735 14 1 DELAY PICKOFF COMPARATOR DELAYING SWEEP 0944 0946 DELAY TIME POSITION R930 up m Q926 Q928 Q938 U930 P L LOGIC 1 COMPARATOR TO SWEEP AND Z AXIS LOGIC CIRCUIT SWEEP GATE T t HORIZONTAL OUTPUT AMPLIFIER BUFFER AMPL pipi ten DN 0940 0956 DISCONNELI MiLLEH AMPL 0904 INTEGRATOR Q920 0922 Ra ane a SWEEP START NON DELAYING AMPL Q988 SWEEP GENERATOR Q972 OUTPUT BUFFER MILLER AMPL Q1022 AIT C F ATAND n c dA CUm GF cu MIT Ct T Q980 Q984 n m Rt m 2 n SWEEP AND Z AXIS LOGIC CIRCUIT 5 NON DELAYING R1094 ha SWEEP GENERATOR LOGIC i EESTI COMPARATOR Q1034 Q1044 SWEEP START AMPL Q1018 Vcc DELAYING SWEEP B GATE AMPL Q996 ka Delaying Sweep Generator Basically the Delaying Sweep Generator is composed of Q904 Q920 Q922 and Q914 This generator
194. ects fixed components in the holdoff timing circuit and the A TRIG HOLDOFF control allows a variable holdoff setting in each position of the TIME DIV control When pin 8 goes HI pin 17 will go LO and allow the trigger tunnel diodes to fire on an incoming signal or generate an auto gate in the Auto mode if pin 6 is HI 3 13 TM 11 6625 2735 14 1 Pin 9 Ground terminal Pin 10 This is the holdoff output connected to ground in this application Pin 11 This terminal lights the READY light when operating in the single sweep mode Pin 12 This is the single sweep mode terminal When 5 volts is connected to this terminal the sweep operates in the single sweep mode when the terminal is left open or grounded the sweep operates in the repetitive mode Pin 13 Connected to ground in this application Pins 14 and 15 Single Sweep reset terminals Pressing the SINGL SWP pushbutton prepares the single sweep circuitry to respond to the next triggering event Also this action causes the READY light to be lit Pin 16 This is the holdoff start input terminal A HI on this pin resets the sweep and starts the holdoff period This sets pin 17 HI to reset and hold the trigger tunnel diodes LO and allows pin 3 to go HI Pin 17 This is the sweep disable output terminal The gate level at this terminal is HI during holdoff and LO otherwise Pin 18 This is the lockout input terminal 5 volts applied to this terminal disables all sweep act
195. ed in accordance with military specifications the format has not been structured to consider levels of maintenance Change 1 TM 11 6625 2735 14 1 TABLE OF CONTENTS SECTION 0 INTRODUCTION SECTION 1 GENERAL INFORMATION AND INSTALLATION Introduction Characteristics Installation 2 OPERATING INFORMATION La 4 PRELIMINARY INSTRUCTIONS Introduction Safety Information Operating Power Sources Line Voltage and Regulating Range Options CONTROLS AND CONNECTORS General Cathode Ray Tube CRI and Display Vertical Deflection System Channel 18 Channel 2 A and B Triggering A and B Sweep Calibrator and Power Rear Panel OBTAINING BASIC DISPLAYS Introduction Normal Sweep Display Magnified Sweep Display Delayed Sweep Displays Mixed Sweep Display X Y Display CIRCUIT DESCRIPTION Introduction Digital Logic OUTLINE FOR CIRCUIT DESCRIPTION BLOCK DIAGRAM CHANNEL 1 PREAMP CHANNEL 2 PREAMP VERTICAL CHANNEL SWITCHING VERTICAL OUTPUT AMPLIFIER A TRIGGER GENERATOR B TRIGGER GENERATOR SWEEP AND Z AXIS LOGIC SWEEP GENERATORS AND TIMING AND HORIZONTAL DISPLAY SWITCHING HORIZONTAL AMPLIFIER LOW VOLTAGE POWER SUPPLY CRI CIRCUIT CALIBRATOR FAN MOTOR CIRCUIT MAINTENANCE Maintenance Section Outline li Change 1 Page Bin 13 BREESE REENE 3688 B gi 4MAINTENANCE cont CABINET AND RACK ADAPTER REMOV
196. ed on the rear panel shows the front and rear panels of the 475 A brief description of each control and connector is given here More detailed operating information is given in the 475 Oscilloscope Operators Manual Cathode Ray Tube CRT and Display BEAM FINDER Limits the display to within the graticule area independently of display position applied signals and sets the display brightness to a normal viewing level INTENSITY Controls brightness of the dis play FOCUS Provides adjustment for op timum display definition SCALE ILLUM Controls graticule brightness ASTIG Screwdriver adjustment used in conjunction with the FOCUS control to obtain a well defined display Does not require read justment in normal use TRACE ROTATION Screwdriver adjustment to align the trace with the horizontal graticule lines Vertical Deflection System Channel 1 amp Channel 2 POSITION Controls the vertical position of the trace In the X Y mode of operation the CH 2 control positions on the Y axis ver tically and the CH 1 POSITION control positions on the X axis horizontally CH1 OR X Input connector for Channel 1 deflection signals or X axis deflection in the X Y mode of operation TM 11 6625 2735 14 1 CHANNEL 1 CRT AND DISPLAY A B 8 TRIGGERING VERTICAL 4 DEFLECTION CHANNEL 2 CRT AND DISPLAY CALIBRATOR A TRIGGERING SWEEP B FRONT PANEL EL6UGOZ6 Les
197. eep to be presented The Z Axis Logic circuit produces an unblinking gate signal to unblank the CRT so that the display can be presented This gate signal is coincident with the sawtooth produced by the sweep generator The Z Axis Logic Circuit also produces at the end of each sweep a gate signal that is supplied to the Vertical Channel Switching circuit This pulse switches the display between channels at the end of each sweep when the Vertical Deflection System is operating in the ALT mode 3 4 The outputs of the sweep generators are amplified by the Horizontal Amplifier to produce horizontal deflection for the CRT except in the fully counterclockwise X Y position of the TIME DIV switch The Horizontal Amplifier contains a 10X magnifier to increase the sweep rate by a factor of 10 in any A or B TIME DIV switch position Other horizontal deflection signals can be connected to the Horizontal Amplifier by using the X Y mode of operation When the TIME DIV switch is set to X Y the X axis signal is connected to the Horizontal Amplifier circuit through the Channel 1 Vertical Preamplifier circuit The Z Axis Amplifier circuit determines the CRT intensity and blanking The Z Axis Amplifier circuit sums the current inputs from the INTENSITY control the Vertical Channel Switching circuit chopped blanking the Z Axis Logic circuit unblinking and the external Z AXIS INPUT connector The output level of the Z Axis Amplifier circuit controls t
198. eflection plate leads from the Main Interface board at the crt neck pins accessible through an opening at center of the Main Interface board 8 Remove the crt bezel and implosion shield 9 Hold one hand on the crt base and slowly push the crt forward guiding the crt face with the other hand Guide the anode plug through the crt shield opening while slowly pulling the crt out of the instrument The plastic corner pads may fall loose when the crt is removed save them for reinstallation Set the crt on a soft material to prevent scratching Cathode ray Tube Installation 1 Position the crt rear support plastic centering bracket inside the crt shield approximately 1 1 2 inches from the rear of the shield 2 Check that the plastic corner pads are in place and seated at the front corners of the crt opening 3 Insert the crt into the shield Guide the crt anode lead through the hole in the shield 4 Slowly push the crt the rest of the way into the crt shield If the crt does not go in all the way pull it part way out and find the reason for binding It maybe necessary to reposition the rear support bracket or a plastic corner pad for best installation 5 Clean the crt faceplate implosion shield and bezel as directed under Cleaning Exterior information at the beginning of this section and install the parts Lightly tighten the four bezel screws approximately 5 inch pounds 6 Connect the crt base socket install the c
199. egahertz filter g Set TIME DIV to 0 1 set time mark generator for 10 nanosecond time marks and set CH 1 VOLTS DIV to maintain a convenient display amplitude h CHECK TIME DIV settings from O ius to 5 ins division for accuracy at first and 11th graticule lines within 296 from 20 C to 30 within 4 from 15 to 55 C 26 Check Differential Delay Time Accuracy a Set HORIZ DISPLAY to B DLY D and set TIME DIV to 0 05 Pull and unlock DLY D SW Pknob set to 0 01 us and set X10 MAG to off b Set time mark generator for 50 nanosecond time marks TM 11 6625 2735 14 1 c Turn DELAY TIME POSITION to 1 000 Adjust horiz ontal POSITION to set time mark at center graticule line d Turn DELAY TIME POSITION clockwise until adja cent time mark is at center graticule line and note dial reading e CHECK For a difference in dial reading of 1 000 0 010 from 15 C to 35 40 0020 from 15 C to 55 C f Turn DELAY TIME POSITION to set every adjacent time mark to coincide with graticule center and note reading g CHECK Each reading between any 2 adjacent time marks for 1 000 within 0 010 from 15 C to 35 within 0 020 from 15 C to 55 C Also check the difference between any time marks separated by more than 1 major dial division not to exceed maximum error as listed in Table 5 3 TABLE 5 3 Differential Delay Time Accuracy Difference Maximum Maximum in Major Error Error D
200. el A GATE GATE CH 2 VERT SIGNAL OUT EXT Z AXIS Input Regulating Range Selector PROBE POWER Rear Panel Feet Light that indicates the applied line voltage is below the lower limit of the regulating range selected by the Regulating Range Selector assembly Output connector providing a positive going rectangular pulse coincident with the A sweep time Output connector providing a positive going rectangular pulse coincident with the B sweep time Output connector providing a sample of the signal applied to the CH 2 input connector Input connector for intensity modulation of the crt display Selects the regulating range of the internal power supplies low medium high determined by specific line voltage applied to the instrument Connectors that make operating power available for active device probe systems Provide temporary support for the instrument and provide a convenient cord wrap to store power cord when instrument is not in use OBTAINING BASIC DISPLAYS Introduction The following instructions will allow the operator who is unfamiliar with the operation of the 475 to obtain the basic displays commonly used Before proceeding with these instructions preset the instrument controls as follows Vertical Controls VERT MODE Switch CH 1 VOLTS DIV Switches Proper position determined by amplitude of signal to be applied VOLTS DIV VAR Controls Calibrated detent Input Couplin
201. em TM 11 6625 2735 14 1 Output Amplifier The push pull signal from the Gain Setting Amplifier is connected to the Output Amplifier Each half of the Output Amplifier can be considered as a single ended feedback amplifier which amplifies the signal at its input to produce a voltage output to drive one of the horizontal deflection plates of the CRT Both halves of the Output Amplifier are basically the same with only minor differences therefore only the upper amplifier drives the horizontal deflection plate and the differences will be explained Q1172 and Q1174 are connected in a Darlington configuration Q1234 is a feedback amplifier in the feedback path for the output amplifier Q1234 sets DC levels and reduces the impedance of the feedback path Q1202 and Q1204 form a complementary amplifier that provides the output signal to drive the deflection plate of the CRT CR1173 clips excessive signal amplitudes and sets a sweep start voltage level for the positive deflection plate R1175 C1233 and C1179 are high frequency compensation adjustments R1256 centers the output signal swing within the dynamic swing capabilities of the output amplifier There are two signal paths through each half of the Output Amplifiers Slow signal transitions are applied to the CRT through Q1172 Q1174 and Q1204 with feedback via R1233 and R1235 C1235 C1233 and C1178 C1179 compensate the amplifier and provide a fast AC signal path from one side of
202. ements are taken with no signal applied and the trace positioned to the center horizontal graticule line The voltmeter common is connected to chassis ground Waveform Conditions Apply the 475 calibrator signa to CH 1 input through a P6075 10X probe supplied with 475 Connect 475 A GATE rear panel through a 42 inch 50 ohm BNC cable to test oscilloscope external trigger input Set lest os cilloscope trigger source to external and set vertical input for ac coupling For waveforms which have the horizontal centerline labeled 0 V DC set the test oscilloscope vertical input for dc coupling Set test oscilloscope VOLIS DIV and TIME DIV con trols as indicated on readout symbols on each waveform Tolerance of voltages and waveforms shown are 20 OO DELAYING i ee x y fey J LI LS Li e LL e ula si 2 e EMEN EL JO a so Sad t k che ss oa e L A an ie aje IG 4 L 5 lal H 2j e EE 1 tf EM RENE _ ___ 2 285 Lj 5 e i Sil Li L3 2 e _ le LI LI _ e 2521 H H g LI Li EA 7 ke e We gt e d t 2 L le LI e je LI Li L 4 LI Li LI L L i L
203. emoved as often as operating conditions require because dirt can cause overheating and component breakdown Dirt on com ponents acts as an insulating blanket and prevents efficient heat dissipation It also provides an electrical conduction path that can result in Instrument failure The best way to clean the interlor is to blow off the ac cumulated dust with dry low pressure air approximately 9 Ib in Remove any dirt that remains with a soft brush or a cloth damped with a mild detergent and water solution A cotton tipped applicator is useful for cleaning in narrow spaces or for cleaning ceramic terminal strips and circuit boards Exterior Loose dust accumulated on the outside of the 475 can be removed with a soft cloth or small paint brush The paint brush is particularly useful for dislodging dirt on and around the front panel controls Dirt that remains can be removed with a soft cloth dampened in a mild detergent and water solution Abrasive cleaners should not be used following manner 1 Hold the filter in a vertical position and brush lightly with a soft watercolor brush to remove light coatings of dust and lint 2 Greasy residues or dried on dirt can be removed with a solution of warm water and a neutral pH liquid detergent Use the brush to lightly scrub the filter 3 Rinse the filter thoroughly in clean water and allow to air dry 4 If any lint or dirt remains use clean low pressure air approximately 9 Ib in
204. ended voltage listed on the appropriate Vertical Preamp schematic diagram Connect the voltmeter between pins 5 and 9 of U140 and adjust CH 1 VOLTS DIV BAL R135 for O volt Measure from pin 5 or 9 of U140 to ground and check for the recommended voltage on the diagram Check the collectors of Q172 and Q182 for voltages listed on the diagram Connect the voltmeter between the collectors of Q178 and Q188 and adjust the vertical POSITION control for O volt Measure from the collector of Q178 or Q188 to ground and check for voltages listed on the diagram 4 18 Vertical Channel Switch Troubleshooting The collector voltages of Q178 and Q188 must by balanced as detailed in the preceding steps before starting this procedure Set VERT MODE to CH 1 and check the dc voltages in the channel switching circuitry for the voltages listed on the Vertical Channel Switching schematic diagram Do not check waveforms until dc operation is normal Vertical Output Amplifier Troubleshooting Disconnect the delay line connection on the Vertical Preamp board This requires the use of a soldering iron a 40 to 60 Watt iron works best to unsolder the delay line ground connection Check for the recommended voltages listed on the Vertical Output Amplifier diagram Troubleshooting the Z AXIS Circuit CRT Circuit Set TIME DIV to 1 ms lock knobs and set TRIG MODE to SINGL SWP Disconnect and lift one end of CR1343 Check the voltage at TP1364 for approx
205. ent and water solution Install only one implosion shield between the bezel and crt face The optional crt mesh filter can be cleaned in the Switch Contacts Most of the switching in the 475 is accomplished with circuit board mounted cam actuated contacts Care must be exercised to preserve the high frequency characteristics of these switches Seldom is switch cleaning necessary but if it is required observe the following precautions For cleaning the switch contacts isopropyl alcohol is the recommended solvent to use Apply the isopropyl alcohol with a camel hair brush Do not use cotton swabs as they tend to snag on contacts possibly causing damage and leave strands of cotton causing intermittent electrical contact WARNING Compressed air shall not be used for cleaning purposes except where reduced to less than 29 pounds per square inch psi and then only with effective chip guarding and personnel protective equipment Do no use compressed air to dry parts when TRICHLOROTRI FLUOROETHAIVE has been used Compressed air is dangerous and can cause serious bodily harm if protective means or methods are not observed to prevent chip or particle of whatever size from being blown into the eyes or unbroken skin of the operator of other personnel General Interior Dust in the interior of the instrument should be removed occasionally due to its electrical conductivity under high humidity conditions Ac cumulations of dirt should be r
206. ep rates and the Fast Non Delaying Sweep Generator provides the sweep rates of 0 5 through 0 01 microsecond division The Delaying Sweep runs when the instrument is operated in a delayed sweep mode MIX A INTEN or B DLY D and is displayed as the A portion of a MIX or A INTEN display In B DLY D mode the Delaying Sweep is used to delay the Non Delaying Sweep which is displayed on the CRT The sweep rate for the Delaying Sweep Generator is selected by the A TIME DIV switch skirt knob One of the Non Delaying Sweeps depending on the sweep rate selected will run and may be displayed in all modes of the HORIZ DISPLAY switch In the A mode knobs locked the Non Delaying Sweep is displayed as the A Sweep and in the MIX mode displayed as the B DLY D Sweep In the A INTEN mode the Non Delaying Sweep is displayed as the intensified portion and in the B DLY D mode is displayed as the B DLY D Sweep The sweep rate for the Non Delaying Sweep Generator is selected by the B TIME DIV switch DLY D SWEEP knob It may be helpful to sed Table 3 2 found later in this section The TRIG MODE switch controls the mode of operation of the sweep generator deriving the A portion of a display In the AUTO position the absence of an adequate trigger signal causes the sweep to free run In the NORM position a horizontal sweep is presented only when correctly triggered by an adequate trigger signal Pushing the SINGL SWP pushbutton allows one and only one sw
207. er Indicates the National stock number assigned to the item and which will be used for requisitioning c Part Number Indicates the primary number used by the manufacturer which controls the design and character istics of the item by means of its engineering drawings specifications standards and inspection requirements to identify an item or range of items d Description Indicates the Federal item name and if required a minimum description to identify the item e Location The physical location of each item listed is given in this column The lists are designed to inventory all items in one area of the major item before moving on to an adjacent area f Quantity Required Qty Reqd This column lists the quantity of each item required for a complete major item g Quantity This column is left blank for use during an inventory Under the Rcvd column list the quantity you actually receive on your major item The Date column is for your use when you inventory the major item at a later date such as for shipment to another site Change 1 B 1 TM 11 6625 2735 14 1 2 3 INSIDE POUCH SEE SHEET 2 B 2 Change 1 SECTION li INTEGRAL COMPONENTS OF END ITEM NUN B 1 OS 261B V 1 U and OS 261C V 1 U Sheet 1 of 3 TM 11 6625 2735 14 1 SECTION Il INTEGRAL COMPONENTS OF END ITEM A AN A AAA W lt L EL6UGO19 B 1
208. est equipment and test set ups risted below RECOMMENDED TEST EQUIPMENT SPECIFICATIONS ITEM Test oscilloscope Deflection factor Input impedance Sweep rate Probe Frequency response DC to 75 Fast rise 10X attenuation probe RECOMMENDED TYPE lektronix 7603 equipped with 7A13 Amplifier and 7850 Time base units or equivalent 1 mV to 5 1 20 pi 50 ns Tektronix P6053B orequivalent patible with vertical ampl tier of test oscilloscope Input Impedance 10 Tektronix DM 501 Digital Multsmeter or Range to 500 V equivalent Pu Uv a cn Voitmeter Non loading Digital Multimeter 475 Control Setlings Display Controls INTENSITY Midrange FOCUS Midrange SCALE ILLUM Midrangc Vertical Controls CH 1 and CH 2 POSITION Center trace on graticule VOLTS DIV 2 mV for dc voltages 100 mV for waveforms VAR VOLTS DIV Calibrated detent AC GND DC DC INVERT Off button out VERT MODE CH 1 100 or 20 MHz BW Full bandwidth Push in then release Trigger Controls A and B COUPLING AC LEVEL 0 SLOPE SOUACE NORM TRIG MODE AUTO for waveforms SINGL SWP for dc voltages READY light off A TRIGGER HOLDOFF NORM Sweep Controls TIME DIV 0 1 ms VAR TIME DIV Calibrated detent DELAY TIME POSITION Full counterclockwise HOHIZ DISPLAY A X10 MAG Off button out POSITION Horiz Midrange FINE Midrange Voltage Measurements Voltage measur
209. et the amplitude calibrator for a 20 millivolt output and connect to CH 1 input through a 42 inch 50 ohm BNC cable m Set A TRIGGER LEVEL for a stable display n CHECK For well defined focusing on front cor ners of the displayed waveform o ADJUST FOCUS control and ASTIG front panel screwdriver adjustment together for the best defined front corners on the displayed waveform p Turn INTENSITY fully counterclockwise and press BEAM FINDER pushbutton q CHECK For a compressed waveform of normal intensity within graticule area r Release BEAM FINDER pushbutton and return INTENSITY to a normal setting 2 Check Vertical Input Functions a Position the bottom of CH 1 display to the center horizontal graticule line b Set CH 1 AC GND DC switch to GND c CHECK For no vertical deflection and that trace is at center horizontal graticule line d Set CH 1 AC GND DC switch to AC e That display is centered in graticule area f Move test signal cable to CH 2 input and set VERT MODE to CH 2 g Position the bottom of CH 2 display to the center horizontal graticule line h Set CH 2 AC GND DC switch to GND 5 6 i CHECK For no vertical deflection and that trace is at center horizontal graticule line j Set CH 2 AC GND DC switch to AC k CHECK That display is centered in graticule area Disconnect all test equipment m CHECK That the light under 5 mV of CH 2 VOLTS DIV kn
210. etting Under these conditions the delaying sweep end of sweep pulse occurs before the delayed sweep end of pulse The positive movement on the collector of Q588 at the time of the delaying sweep end of sweep pulse turns Q798 on The negative move ment on the collector of Q798 pulls down on the collectors of Q794 and Q796 through CR793 and CR792 respective ly which in turn pulls down on the base of Q792 This turns off Q792 and causes Q790 to turn on which resets the B Trigger Tunnel Diodes to their LO states thereby ter minating the delayed sweep A GATE And B GATE Amplifiers Q584 and Q824 are the A GATE and B GATE amplifiers respectively They provide the GATE output signals available at the instrument rear panel These output gate signals are positive going rectangular waveforms approximately 5 volts in amplitude coincident with their respective sweep waveforms LOW LINE Indicator Circuit Q1492 Q1498 and their associated circuitry monitor the unregulated voltage in the 50 volt supply and provide a visual indication via the LOW LINE indicator on the front panel when the applied line voltage falls below the lower regulating limit selected by the Regulating Range Selector assembly Q1482 provides operating power to the CRT graticule lights that is adjustable via the SCALE ILLUM control R1480 TM 11 6625 2735 14 1 SWEEP GENERATORS TIMING AND HORIZONTAL DISLAY SWITCHING General The Sweep Generators provide sever
211. external input ac That a stable triggered display can be obtained in AC and DC positions of A TRIGGER COUPLING with adjustment of A TRIGGER LEVEL ad Disconnect ail test equipment NOTE Use a sine wave generator with an output of 100 megahertz and below for the following parts ae Connect the sine wave generator output cable to a BNC female to BNC female adapter to a BNC T connector to two 18 inch 50 ohm BNC cables Connect an 18 inch cable through a 50 ohm termination to CH 1 input and connect the other 18 inch cable through a 50 ohm termination to A TRIGGER external input af Set TIME DIV to 0 5 us ag Set the sine wave generator for a 2 division 3 megahertz display 100 millivolts at external input ah Set A TRIGGER COUPLING to HF REJ ai CHECK That a stable triggered display cannot be obtained with adjustment of A TRIGGER LEVEL aj Set CH 1 VOLTS DIV to 5 mV set TIME DIV to 2 us and set A TRIGGER SOURCE to NORM ak Set the sine wave generator for a 5 division 1 megahertz display then set CH 1 VOLTS DIV to 50 mV al CHECK Repeat part ai am Return A TRIGGER COUPLING to AC an Disconnect all test equipment 12 Check B Low Frequency Triggering a Set TIME DIV to 50 CH 1 VOLTS DIV to 5 mV and set HORIZ DISPLAY to B DLY D B DLY D sweep will not appear when not triggered b Connect the low frequency generator output to a 42 inch 50 ohm BNC cable to a BNC
212. fastest possible sweep repetition rate for delayed sweep presentations Input connectors for external trigger signals Provides variable sweep delay between 0 00 and 10 00 times the delay time indicated by the DELAY TIME switch A AND B TIME DIV AND DELAY TIME VAR UNCAL X10 MAG Indicator READY HORIZ DISPLAY A TIME DIV switch clear plastic outer flange selects the basic delay time to be multiplied by the DELAY TIME POSITION dial setting for delayed sweep operation The B TIME DIV switch inner dark knob selects the sweep rate for A only dis plays or for the B portion of a delayed sweep display VAR control must be in the calibrated detent for calibrated sweep rates Disables sweep for X Y operation Provides continuously variable uncalibrated sweep rates between the calibrated settings of the TIME DIV switch Varies the A Time Base sweep rate in the nondelayed mode of horizontal operation and the B Time Base sweep rate in the delayed sweep mode Extends the slowest sweep rate to at least 1 25 seconds division Sweep rate is calibrated when the control is rotated fully clockwise to the calibrated de tent Light that indicates when the VAR TIME DIV control is out of the calibrated detent and the horizontal sweep rate is un calibrated Light that indicates when the X10 MAG is turned on Light that indicates that A Sweep has been prepared to present a single sweep upon receipt of an adequate
213. for emitter collector could indicate either a non saturated device operating normally or a defective open circuited transistor lf the device is conducting voltage will be developed across resistances in series with it if it is open no voltage will be developed across resistances in series with it unless current is being supplied by a parallel path When troubleshooting field effect transistors the voltage across its elements can be checked in the same manner as transistors However it should be remembered that usual operation has the gate to source junction reverse biased or 0 biased as is used in many circuits in the 475 IC s integrated circuits can be checked with a voltmeter test oscilloscope or by direct substitution A good understanding of circuit operation is essential to troubleshooting circuits using IC s Use care when check ing voltages and waveforms around the IC s so that adjacent leads are not shorted together A convenient means of clipping a test probe to the 14 and 16 pin IC s is with an IC test clip This device also doubles as an extraction tool The lead configuration for the semicon ductors used in this instrument are shown o b DIODES A diode can be checked for an open or shorted condition by measuring the resistance between terminals after disconnecting one end from the circuit With an ohmmeter set to the R X 1 k scale the resistance should be very high in one direction and very low when the leads
214. fore atternptlng to replace components General The exploded view drawings associated with the Mechanical Parts List located at rear of manual may be helpful in the removal or disassembly of individual components or sub assemblies Transistor and IC Replacement Transistors and IC s Integrated circuits should not be replaced unless they are actually defective If removed from their sockets during routine maintenance return them to their original sockets Unnecessary replacement or switching of semiconductor devices may affect the calibration of the Instrument When a transistor is replaced check the operation of the part of the instrument that may be affected Any replacement component should be of the original type or a direct replacement Bend the leads to fit the Socket and cut the leads to the same length as on the component being replaced See lor lead figurations and basing used in this instrument If a replacement transistor is made by a different manufacturer than the original check the manufacturer s basing diagram for correct basing All transistor sockets in this instrument are wired for the standard basing as used for metal cased transistors The chassis mounted power supply transistors and their mounting bolts are insulated from the chassis In addition silicone grease is used to increase heat transfer capabilities Install the insulators and replace the silicone grease when replacing these transisto
215. g For waveforms which have the horizontal Trigger Controls and B 4 99 centerline labcled 0 V set the test osc lloscope vertical rn UR x input for dc coupling SLOPE i Set test oscilloscope VOL TS DIV and TIME DIV con SOURCE NORM trols as indicated on readout symbols on each waveform TRIG MODE AUTO A TRIGGER HOLDOFF NORM Tolerance of voltages and waveforms shown are 20 TM 11 6625 2735 14 1 DOWD M Hae tuus UMS 0020 i es Ha ue eMe uu XM SPAT LO Une STU OLEAN TEE RT 222 oos SEE B 9 Fok COMPOUDCDOT CATIONS sy 10724 Sar Tae 422 CRIT i 42 50 Gan Riess 11 6 4HORIZ 3er 2 TO RIGHT x A cn CEFL PLATL 12 1 122 1 i VOLTAGE amp WAVEFORM E CONDITIONS isl 332 n Sa at 5 RIZ 1152 Rize 120 Cl 243 1 1 1 SWEEP In gt FROM QA5e 77 91022 POSITION E Fus i d ROT L 8SK in 5 5Y RI239 EIS z Es Bw rave PO 150 8 93 zan CP FINE CRI en eee 5 R258 mS F5 2 16 2 ened Fi sak i 1 i bc PL so Ruoa oroa ATK GAIN 3 N X SIGNAL nan t vo FROM
216. g Switches AC Vertical POSITION Controls Midrange 100 or 20 MHz BW Switch Not limited Yellow band not visible INVERT Switch Button out INTENSITY Control Fully counterclockwise FOCUS Control Midrange SCALE ILLUM Control Midrange Trigger Controls both A and B if applicable SLOPE Switch LEVEL Control 0 SOURCE Switch NORM COUPLING Switch AC TRIG MODE Switch AUTO A TRIG HOLDOFF Control NORM Horizontal Sweep Controls TIME DIV Switches Locked together at 1 ms TIME DIV VAR Calibrated detent HORIZ DISPLAY Switch A X10 MAG Switch POSITION Control FINE Control Off button out Midrange Midrange Normal Sweep Display 1 Pull the POWER switch to on button out Allow several minutes for instrument warmup 2 Connect an external signal to the CH 1 input connector 3 Advance the INTENSITY control until the display is visible If the display is not visible with the INTENSITY control at midrange press the BEAM FINDER pushbutton and adjust the CH 1 VOLTS DIV switch until the display is reduced in size vertically then center the compressed display with the vertical and horizontal POSITION con trols release the BEAM FINDER pushbutton Adjust the FOCUS control for a well defined display 4 Set the CH 1 VOLTS DIV switch and CH 1 POSITION control for a display that remains in the display area vertically 5 Adjust the A Trigger LEVEL control for a stable display 6 Set the TIME DIV switch and the horizontal
217. generators Now only the B Gate can initiate sweep action in the Non Delaying Sweep Generators B Gate Amplifier Q996 is the B Gate Amplifier stage The negative going waveform from the Sweep Logic circuit is applied to the base of Q996 The amplified and inverted waveform at the collector of Q996 is applied to the Non Delaying Sweep Generators through CR996 and CR971 or CR1001 to initiate sweep generation TM 11 6625 2735 14 1 Non Delaying Sweep Generator Differences Basically the Non Delaying Sweep Generators operate in the same manner as the Delaying Sweep Generator The fast generator Q1004 Q1010 Q1014 and Q1018 has only one timing capacitance the parallel combination of C1008 and C1009 The capacitance is variable to achieve precise timing accuracy Timing resistors are selected by the B TIME DIV switch to provide the fastest six sweep speeds listed on the front panel Q988 and Q1018 are Sweep Start Amplifiers and establish the DC level starting points for the sweeps The slow generator Q974 Q980 Q984 Q988 and Q972 has an additional emitter follower Q972 This emitter follower increases the current gain of the loop to speed up the retrace time of the generator determined by the time required to discharge the timing capacitor Mixed Mode Operation Normally Q1086 is an emitter follower with a fixed dc level at its base established by R1094 and R1095 The fixed level at the emitter of Q1086 in turn
218. grid Quiescently its output voltage is more negative than the CRT cathode by an amount set by the voltage level across VR1374 the setting of Grid Bias adjustment R1375 and the voltage at the output of the Z Axis Amplifier When the secondary winding output of T1320 swings positive C1372 charges through C1326 R1326 R1372 CR1379 and R1379 to a voltage level that equals the voltage determined by VR1374 and the setting of Grid Bias adjustment R1375 At this voltage level approximately 15 volts CR1373 turns on preventing any additional 3 26 increase in positive voltage When the secondary winding output swings negative CR1373 turns off then CR1371 turns on and clamps the less positive voltage swing at C1372 to the voltage level of the Z Axis Amplifier During this less positive voltage swing C1372 discharges through CR1377 into C1371 Capacitor C1371 holds the voltage constant at the CRT control grid it also provides a path for the fast rising and falling portions of the Z Axis Amplifier output to be coupled to the CRT control grid for blanking and unblinking CRT Control Circuits Focus of the CRT display is controlled by FOCUS control R1380 The Focus Tracking control R1335B located in a series resistor network with the FOCUS control is ganged with the INTENSITY control to reduce focus variations when changing the INTENSITY setting The ASTIG adjustment R1397 which is used in conjunc tion with the FOCUS control to prov
219. he X1 display factor bulb When an X10 probe with a scale factor switching connector is attached to the CH 1 OR X input connector the probe coding ring terminal on the connector is contacted the base of Q312 is connected through R311 R310 and an 11 000 ohm resistor within the probe to ground Now Q312 conducts through X10 display factor bulb DS312 The positive level at the collector of Q312 turns Q314 off the X10 display factor bulb is on and the X1 display factor bulb is off VERTICAL OUTPUT AMPLIFIER General The Vertical Output Amplifier provides the final amplification for the vertical deflection signal This circuit includes the BEAM FINDER function The BEAM FINDER pushbutton when pressed limits the vertical and horizon tal deflection to within the viewing area and sets the trace intensity to a normal viewing level to aid in locating an off screen display A schematic of the Vertical Output Amplifier is shown on Diagram 4 at the rear of this manual First IC Amplifier The first amplifier stage in the Vertical Output Amplifier is integrated circuit U450 U450 is basically an emitter coupled push pull cascode amplifier cell Biasing is arranged so that there is no phase inversion through the stage The signal from the delay line is applied to the amplifier through C441 L441 L442 C445 and L444 These inductances and capacitances are part of the etched runs of the circuit board and provide some high frequency
220. he source of the trigger signal The sources available to the A Trigger Generator circuit are the signal being displayed NORM Channel 1 CH 1 Channel 2 CH 2 the instrument line voltage LINE and external signals EXT and EXT 10 Emitter followers Q502 Q504 and Q506 provide isolation between the input to the A Trigger Circuit and the output of the Vertical Channel Switching Circuit In the LINE mode of triggering a sample of the power line frequency is obtained from the secondary of the power transformer T1400 in the Low Voltage Power Supply circuit The Trigger COUPLING switches should not be in the LF REJ mode when using the instrument line voltage as a trigger signal source Trigger Coupling The Trigger COUPLING switches offer a means of accepting or rejecting certain components of the trigger signal In the AC LF REJ and HF REJ mode of trigger coupling the DC component of the trigger signal is blocked by coupling capacitors C515 or C516 Frequency components below about 60 Hz are attenuated when using AC or HF REJ coupling and below about 50 kHz when using LF REJ coupling The higher frequency components of the trigger signal are passed without attenuation In the HF REJ mode of trigger coupling the high frequency components of the trigger signal above about 50 kHz are attenuated while the lower frequency components between about 60 Hz and 50 kHz are passed without attenuation The DC mode of trigger coupling pa
221. he trace intensity through the CRT circuit The CRT circuit provides the voltages and contains the controls necessary for operation of the cathode ray tube The Power Supply circuit provides the low voltage power necessary for operation of this instrument This voltage is distributed to all of the circuits in the instrument The Calibrator circuit provides a square wave output with accurate voltage and current amplitudes which can be used to check the calibration of the instrument and the compensation of probes The CALIBRATOR current loop provides an accurate current source for calibration of current measuring probe systems CHANNEL 1 PREAMP lt General Input signals for vertical deflection on the CRT can be connected to the CH 1 OR X input connector In the X Y mode of operation the input signal connected to the CH 1 OR X connector provides the horizontal X axis deflec tion TIME DIV switch set to X Y VERT MODE switch set to CH 2 OR X Y The Channel 1 Preamp circuit provides control of input coupling vertical deflection factor gain and DC 5 detailed block diagram of the Channel 1 Preamp circuit A schematic of this circuit is shown on Diagram 1 at the rear of this manual TM 11 6625 2735 14 1 VOL TS DIV BAL CH 1 R135 VERTICAL CHANNEL 3RD VOLTS DIV SS SS ee a e 1 CASCODE SWITCHING CIRCUIT 1ST AMPL S208 CASCODE 2ND Q172 Q178 R22 AMPL CASCODE 0182 0184 193 pen l AMPL Q188 91
222. his section under Troubleshooting Equipment Troubleshooting the L V Power Supplies Incorrect operation of all circuits often indicates trouble in the power supply Check first for correct voltage of the individual supplies A defective component elsewhere in the instrument can appear as a power supply trouble and may also affect the operation of other circuits Table 4 2 lists the tolerances of the power supplies in this instru ment Check or repair the power supplies in the sequence specified in Table 4 2 These voltages are measured between the power supply test points and ground power supply voltage is within the listed tolerance the supply can be assumed to be working correctly If outside the tolerance the 50 volt supply may be misadjusted or other supplies may by operating incorrectly Use the procedure given in TB 11 6625 2735 35 1 to adjust the 50 volt supply if adjustment is necessary TABLE 4 2 Power Supply Tolerance and Ripple Typical Ripple Power Supply Tolerance peak to peak 50V 0 596 250 mV 2 mV 110V T5V 2 mV 5V 1 5 75 mV 2 mV 15 2 mV 8V 1 5 120 mV 2 Connect the 475 to variable autotransformer Then check each power supply for correct ripple with a test oscilloscope while varying the autotransformer throughout the regulating range of this instrument see rear panel regulating range selector cover for regulating range Table 4 2 lists the typical ripple of the power supp
223. ial Divisions 15 C to 35 C 15 C to 55 C 1 000 0 010 0 020 2 000 0 019 0 029 3 000 0 027 0 042 4 000 0 033 0 053 5 000 0 039 0 064 6 000 0 043 0 073 7 000 0 047 0 082 8 000 0 049 0 089 9 000 0 050 0 095 h CHECK Display time accuracy as directed in part g at all settings listed 5 4 not to exceed maximum error listed in Table 5 3 TM 11 6825 2735 14 1 TABLE 5 4 Delay Time Settings DELAY TIME A TIME DIV POSITION Switch Exclusions Setting Exclude dial settings of 0 000 through 0 2 us 1 000 0 5 us 14s 5 us 10 us 20 us Exclude dial 50 us settings of 0 1 ms 0 000 through 0 2 ms 0 050 0 5 ms 1 ms 2 ms 5 ms 10 ms 20 ms 50 ms 0 25 0 55 kai o o ojo B TIME DIV Time Mark Switch Generator Setting Setting 50 nanosecond 0 1 microsecond 0 2 microsecond 0 5 microsecond 1 microsecond 0 2us 2 microsecond 0 5us 5 microsecond 14s 10 microsecond 20 microsecond 50 microsecond 0 02 us 0 05 us 0 1 10 0 1 millisecond 20 0 2 millisecond 50 us 0 5 millisecond 0 1 ms 1 millisecond 0 2 ms 2 millisecond 0 5 ms 5 millisecond 1 ms 10 millisecond 2 ms 20 millisecond 5 ms 50 millisecond 10 ms 0 1 second 20 ms 0 2 second 50 ms 0 5 second If the time mark generator being used does not have 1 2 5 sequence set for 1 more time marks division on DELAY TIME POSITION dial 27 Check Delay Time Jitter a Set DLY D SWP to 0 2 ws
224. ide a well defined display varies the positive level on the astigmatism grid Geometry adjustment R1390 varies the positive level on the horizontal deflection plate shields to control the overall geometry of the display Two adjustments control the trace alignment by vary ing the magnetic field around the CRT Y Align adjustment R1385 controls the current through L1385 which affects the CRT beam after vertical deflection but before horizon tal deflection Therefore it affects only the vertical Y components of the display TRACE ROTATION adjust ment R1386 controls the current through L1386 and affects both vertical and horizontal rotation of the beam Z Axis Amplifier The Z Axis Amplifier circuit controls the CRT intensity level from several inputs The effect of these input signals is to either increase or decrease the trace intensity or to completely blank portions of the display The input transistor Q1338 is a current driven low input im pedance amplifier It provides termination for the input signals as well as isolation between the input signals and the following stages The current signals from the various control sources are connected to the emitter of Q1338 and the algebraic sum of the signals determines the collector conduction level Q1344 Q1352 Q1354 Q1358 and Q1362 compose a feedback amplifier stage R1369 is the feedback resistor and C1352 provides high frequency compensation Q1344 is an emitter follower that
225. ier whose emitter is current driven by the signal The Output Buffer Amplifier provides the output sawtooth signal current to the Horizontal Amplifier and provides a measure of isolation between the Sawtooth Generator and the Horizontal Amplifier Intensified Gain adjustment R950 adjusts the gain of the stage to match the output signal amplitude with that of the Non Delaying Sweep Generators The Delaylng Sweep Output Buffer Amplifier passes the signal to the Horizontal Amplifier when the HORIZ DISPLAY switch is in the A INTEN position and the TIME DIV switches are not in the X Y position When the TIME DIV switches are in the X Y position the anode of CR956 is connected to 5 volts This sets the base of Q956 at a positive enough level to reverse bias Q956 and prevent passage of the Delaying Sweep signal to the Horizontal Amplifier With the TIME DIV switches not in the X Y position and the HORIZ DISPLAY switch in the INTEN position R955 is connected to 8 volts through Q1099 in the Horizontal Display Switching circuit and the anode of CR956 is not connected to any voltage This forward biases CR955 and sets the base of Q956 at a DC level of approximately 4 3 volts Now Q956 is forward biased and the Delaying Sweep signal is passed to the Horizontal Amplifier 3 18 Delaying Sweep End Difference Amplifier Q944 and Q946 are connected as a voltage comparator and generate the logic pulses that signal the end of sweep and blank the CRT dis
226. ies Regulator Q1478 to correct the change in output voltage Transistor Q1474 provides current limiting foldback operation if the supply load increases beyond preset limits or becomes shorted to ground CRT CIRCUIT 4 General The CRT Circuit provides the voltage levels and control circuits necessary for operation of the cathode ray tube Eig 3 10 shows a detailed block diagram of the CRT Circuit A schematic of this circuit is shown on Diagram 12 at the rear of this manual TM 11 6625 2735 14 1 Z AXIS en COMPENSATION 2222 INTENSITY R1335 INPUT AMPL R1369 SWEEP TU d me Q1306 Q1310 012080 01219 1125 SKI 9 6 Q1316 AMPL Q1332 CHOP T AMPI BLANKING qii 01352 01358 TIT 571 Z AXIS A Pm N HIGH VOLTAGE CATHODE OSCILLATOR CR1320 Q1318 T1320 Ch1321 Z AXIS i REGULATING HIGH VOLTAGE v1380 V MULTIPLIER Le S ROTATION tf R1386 C1370 CR1377 C1371 CR1379 1378 Fig 3 10 Detailed block diagram of the CRT circuit High Voltage Oscillator Q1318 and associated circuitry compose the high voltage oscillator that produces the drive for high voltage transformer T1320 When the instrument is turned on current through Q1316 provides forward bias for Q1318 Q1318 conducts and the collector current increases which develops a voltage across
227. iggos source to external and set vertical in put 50 TAZV ISY 5Y av Trigger Contro s and for ac coupling For waveforms which have the horizontal TM 4 pe C COUPLING AC 1 V set the test osc lloscope vertical VOLTAGE amp WAVEFORM amp LEVEL 8 CONDITIONS 29558 Ji l PRA dEYERATCR A Ce Econ SU Eien SE gis tee d URGE ORE Set test oscilloscope VOLTS DIV and TIME DIV con J5 T 4553 T e trols as indicated on readout symbols on eact waveform 4 d 5 av TRIG MODE AUTO o as e A TRIGGER HOLDOFF NORM Tolerance of voltages and waveforms shown are 20 D 8 8 TRIGGER GENERATOR 7 B irigaer qenerator diagram VOLTAGES AND WAVEFORMS The voltages and wayeforms shown on this diagram were obtained by using the recommended test equipment test set ups listed below ITEM Test oscilloscope Prube Voltmeter Non loading Digital Multimeter 475 Contro Settings Display Controls INTENSITY FOCUS SCALE ILLUM RECOMMENDED TEST EQUIPMENT Deflection factor input impedance Sweep rate oscilloscope Input Impedance Range Midrange Midrange Midrange Vertical Controls CH 1 and CH 2 POSITION VOLTS DIV VAR VOLTS DIV AC GND DC INVERT VERT MODE 100 or 20 MHz BW Trigger Controls A and B COUPLI
228. imately 6 volts Press the BEAM FINDER pushbutton and check the voltage at TP1364 for approximately 25 volts If these voltages cannot be obtained check the voltage across VR1362 for approximately 6 2 volts Remove Q1362 from its socket and check the voltage at the base of Q1352 for approximately 1 3 volts Check the base of Q1344 for approximately 0 6 volt If the above mentioned voltages can be obtained disconnect and lift one end of CR1341 Check the voltage swing at the collector of Q1338 for approximately 17 8 volts to 1 3 volts while turning INTENSITY control from full counterclockwise to full clockwise If these voltages cannot be obtained check the voltage at the base of Q1338 for 1 75 volts Remove Q1332 from its socket Disconnect J1333 and J1334 coaxial type end lead con nectors from their sockets Repeat the voltage swing check at the collector of Q1338 as performed previously Connect J1333 J1334 CR1343 and CR1341 to the circuit board Install Q1362 01332 in their sockets CORRECTIVE MAINTENANCE Introduction Corrective maintenance consists of component replacement and instrument repair Special techniques required to replace components in this instrument are given here Obtaining Replacement Parts Refer to Repair Parts and Special Tools List TM 11 6625 2 35 24P 1 for correct part number and identification Soldering Techniques Always disconnect the instrument from the power source before
229. inch cable through a 50 ohm termination to B TRIGGER external input ad Set TIME DIV to 0 5 us and set B TRIGGER SOURCE to STARTS AFTER DELAY ae Set the sine wave generator for a 2 division 3 megahertz display 100 millivolts at external input af Set B TRIGGER COUPLING to HF REJ and set B TRIGGER SOURCE to EXT ag That a stable triggered display cannot be obtained with adjustment of B TRIGGER LEVEL ah Set CH 1 VOLTS DIV to 5 mV set TIME DIV to 2 and set B TRIGGER SOURCE to STARTS AFTER DELAY ai Set the sine wave generator for a 5 division 1 megahertz display then set CH 1 VOLTS DIV to 50 mV and set B TRIGGER SOURCE to NORM aj CHECK Repeat part ag ak Set B TRIGGER COUPLING to AC and set B TRIGGER SOURCE to STARTS AFTER DELAY 13 Check B 40 Megahertz Triggering Set TIME DIV to 0 05 usand set 100 OR 20 MHz BW to full bandwidth push in then release 5 12 b Set the sine wave generator for a 1 division 40 megahertz display then set B TRIGGER SOURCE to EXT 50 millivolts at external input c CHECK That a stable triggered display can be obtained in AC and DC positions of B TRIGGER COUPLING with adjustment of B TRIGGER LEVEL d Set B TRIGGER SOURCE to NORM set CH 1 VOLTS DIV to 5 mV set CH 2 VOLTS DIV to 50 mV and move signal cable setup from B TRIGGER external input to CH 2 input e Set the sine wave generator for a 3 division 40 megahertz display set CH 1 VOL
230. ined in other sections of this manual should be used along with the following information to aid in locating the defective component An understanding of the circuit operation is 4 6 helpful in locating troubles particularly where integrated circuits are used See the Circuit Description section for this information Troubleshooting Aids Diagrams Complete circuit diagrams are given on foldout pages in the Diagram section The component number and electrical value of each component in this instrument are shown on the diagrams see first page of the Diagrams section for definition of the reference designators and symbols used to identify components in this instrument Each main circuit is assigned a series of component numbers Table 4 1 lists the main circuits in the 475 and the series of component numbers assigned to each Important voltages and waveforms are also shown on the diagrams The portions of the circuit mounted on circuit boards are enclosed with blue lines Circuit Board illustrations To aid in locating circuit boards in the instrument a circuit board location illustra tion is placed on the back of the pullout page preceding the circuit diagram An illustration of the circuit board with circuit components of the following circuit diagram identified is also included on this page Each circuit board illustration is arranged to facilitate rapid physical location of components listed on the schematic diagrams Component
231. ing list a Disconnect a four wire cable near Q752 at the top of the board cable from B TRIGGER LEVEL control b Disconnect a four wire cable near J706 located two inches below the cable previously removed cable from A TRIGGER LEVEL control c Disconnect one wire cable near the left end of J3 at the bottom of the board d Disconnect a five wire cable from P644 at the bottom back of the board cable from A TRIG HOLDOFF control 5 Disconnect eight coaxial cables from the front and back sides of the board and confirm color coding of each cable with its jack number in the following list Record any exceptions to this procedure for reference when reassembling a Cable to J704 is white with a blue stripe b Cable to J702 is white with a green stripe 4 25 TM 11 6625 2735 14 1 c Cable to J706 is white with a yellow stripe d Cable to J664 is white with black and brown stripes e Cable to J674 is white with black and red stripes f Cable to J694 is white with black and orange stripes g Cable to J824 is white with an orange stripe h Cable to J584 is white with a red stripe 6 Unsolder two 33 ohm resistors from the external trigger input connectors 7 Remove the POWER switch mounting bracket from the board A 3 16 inch nut driver will be required to remove a mounting nut 8 Remove five board mounting screws two each at left and right edges and one screw at the top center of the board 9
232. ion Pin 19 This is the auto mode terminal Grounding this terminal enables auto sweep operation Pin 20 Input terminal for the 5 volt supply Main Gate Comparator Q1572 and Q574 form the Main Gate Comparator and are connected as a voltage comparator where both transistors do not conduct at the same time The input signal to the stage is the positive going trigger signal from the A Firing Trigger TD in the A Trigger Generator circuit The signal at the collector of Q574 is inverted by Q588 is connected to the Z Axis Logic Multivibrator to control CRT blanking and to Q584 to generate the A GATE output signal The signal at the collector of Q572 connects to the base of the Main Gate Amplifier stage Q902 in the Sweep Generators circult to initiate sweep generation 3 14 Delayed Gate Comparator Q802 and Q804 form the Delayed Gate Comparator and are connected as a voltage comparator where both transistors do not conduct at the same time The input signal to the stage is the positive going trigger signal from the B Firing Trigger TD in the B Trigger Generator circuit The signal at the collector of Q804 is inverted by Q826 and is connected to the Z Axis Logic Multivibrator to control CRT blanking and to Q824 to generate the B GATE output signal The signal at the collector of Q802 connects to the base of the Delayed Gate Amplifier stage Q996 in the Sweep Generators circuit to initiate sweep generation A Trigger TD Reset Ci
233. is permits no current through R1617 Since R1617 furnishes bias to Q1622 the transistor is cut off This permits the collector of Q1622 and the rest of the turn off circuit to rise to a voltage determined by the inverter circuit and the dc source voltage The collector of Q1622 may be about 24 V with respect to minus dc with a 12 V dc source and about 36 V with a 24 V dc source If the dc source voltage drops to less than 22 V the current through divider R1609 R1611 R1613 and R1614 is decreased Q1608 conducts taking current from Q1606 and causing less drop across R1609 This makes Q1608 conduct more and Q1606 is cut off Current flow through R1617 turns Q1622 on Q1622 saturates dropping its collector voltage to about 0 2 V R1618 limits the max imum base current of Q1622 During 12 V dc operation there is no current flow through VR1604 and VR1605 since their series rating about 18 volts exceeds the applied voltage The base current of Q1606 through R1605 turns Q1606 on enough to take all the current through R1607 which causes Q1608 to be cut off START S16018 START STOP Q1644 1 i Q1662 Ll R1613 pu ve Q1608 2 BALANCE POWER MODE S1665 EL6UGO61 TE HM Figure 6 2 Option 07 simplified block diagram 6 2 2 Change 1 Turn Off Circuit Q1622 is off under normal operating conditions until the dc sourc
234. isplay is visible If the display is not visible with the INTENSITY control at midrange press the BEAM FINDER push button and adjust the CH 1 and CH 2 VOLT DIV switches until the display is reduced in size both vertically and horizon tally then center the compressed display with the POSITION controls release the BEAM FINDER pushbut ton Adjust the FOCUS control for a well defined display 2 9 2 10 blank TM 11 6625 2735 14 1 Section 3 475 Service CIRCUIT DESCRIPTION Introduction This section of the manual describes the circuitry used in the 475 Oscilloscope The description begins with a discussion of the instrument using a basic block diagram Next each circuit is described in detail using detailed block diagrams when appropriate to show the relationships between the stages in each major circuit Digital Logic Digital logic techniques are used to perform many functions within this instrument The function and opera tion of the logic circuits are described using logic symbology and terminology All logic functions are described using the positive logic convention Positive logic is a system of notation where the more positive of two levels HI is called the true or 1 state the more negative level LO is called the false or 0 state The HI LO method of notation is used in this logic description The specific voltages that constitute a HI or LO state vary between individual devices NOTE The HI LO logic notation c
235. ixture 2 Test Oscilloscope Description Frequency response dc to 75 megahertz or greater deflection factor 1 millivolt to 5 volts division Input impedance 1 megohm 20 picofarads sweep rate 0 5 second division to 50 nanoseconds division A 10X 10 megohm voltage probe should be used to reduce circuit loading for waveform measurements A 1X 1 megohm voltage probe should be used for power supply ripple checks Purpose To check operating waveforms in this instru ment Hecommended type Tektronix 7603 Oscilloscope with 7A13 Amplifier and 7650 Time Base units Use a P6053 10X probe and a P6011 1X probe 3 Multimeter Description Non loading Digital Multi meter Voltmeter 10 megohm input impedance and 0 to 150 volts range dc voltage accuracy within 0 1596 display 4 1 2 digits Ohmmeter 0 to 20 megohms Purpose To check voltages and for general troubleshooting in this instrument Recommended type Tektronix DM 501 Digital Multi meter requires a TM 500 series power module 4 Variable Autotransformer Description Output variable from 010 140 volts 1 2 amperes minimum rating Must have 3 wire power cord plug and receptacle Purpose To vary the input line voltage when troubleshooting in the power supply 4 10 Recommended type General Radio W8MT3VM or W10MT3W Metered Variac Autotransformer Troubleshooting Techniques This troubleshooting procedure is arranged in an order which checks the simple
236. k t 5 i H a wou av amp EY 15 523 4 po A 27062 w SLOW XS MOLDOFF FROM S A 4 250047 CREO Ree 4 X Locket 32 5 i e 5552 79 om Lit 5 c Riess DE JAM 24 43 pass 4 Lael 21295 P9 xa 2 126 45v m To gS 95989 ro o 3 6 5 i 10 2 25 4 vp i 22 2 BAND 2 5 54 5 54 9 196 12 i 54 An e rariss apes aces KAN man MAIL GATE 4OLBOEF TO 44 7 CR Go I 99541 Ei Q912 C722 EYB CKGAD qp eres 27 8 8 3 ce C99 1 6910 F914 son omaa ELGUGOS e CR 56 CRICLS amp be CRuo2 CR Cen goos TIMING AND HORIZONTAL DISPLAY SWITCHING 40 Timi and harizantal dinmlav switching schematic diagram VOLTAGES AND WAVEFORMS The voltages and waveforms shown on this diagram were obtamed by using the recommended test equipment and test set ups listed below RECOMMENDED TEST EQUIPMENT ITEM SPECIFICATIONS RECOMMENDED TYPE Test oscilloscope Frequency response DC to 75 MHz Tektronix 7603 equipped with 7413 Defle
237. ken on y by experienced maintenance personnel Switch alignment and spring tension of the contacts must be carefully maintained for proper operation of the switch For this reason it is recommended that the switch assembly be replaced as a unit 4 22 If a cam switch must be removed from a circuit board the circuit board containing the cam switch must be removed from the instrument See the circuit board replacement part of this section for circuit board removal instructions Disconnect the flexible coupling between cam switch and variable controls Remove two connecting screws from each support block that holds the cam to the circuit board Carefully lift the cam assembly from the circuit board and perform an inspection cleaning or replacement as intended Reassemble the cam switch assembly by reversing the previous process Give careful attention to alignment and spacing of support blocks as the cam is mated to its circuit board Do not bend circuit boards at any time in reassembly and use a very low torque to tighten the mounting screws two fingers on the screwdriver is enough torque Circuit Board Replacement Occasionally it may be necessary to gain access to the reverse side of a circuit board or to remove one circuit board to gain access to another The following procedures outline the necessary steps to facilitate instrument dis assembly Most of the connections to the circuit boards in the instrument are made with pin
238. l Information At least 15 lines division At least 15 lines division 0 1 division or less of tilt or bowing 0 1 division or less Approximately 18 000 V Adequate to align trace with hori zontal center line Characteristics Temperature Operating AC Storage Altitude Operating Storage Humidity Operating and Stor age Vibration Operating Shock Operating and Non operating Transportation TABLE 1 2 ENVIRONMENTAL Performance Requirements 15 to 55 55 to 75 15 000 feet Maximum operating temperature decreased 1 C 1 000 feet above 5 000 feet To 50 000 feet 5 cycles 120 hours referenced to MIL E 16400F 15 minutes along each of three major axes at a total displacement of 0 025 inch P P 4 g s at 55 Hz with frequency varied from 10 Hz to 55 Hz to 10 Hz in one minute sweeps After sweep vibration in each axis hold frequency steady at each major res onance for 3 minutes or if no such resonances are found hold at 55 Hz for three minutes 30 g s 1 2 sine 11 ms duration 2 shocks per axis each direction for a total of 12 shocks Meets the limits of National Safe Transit Committee test procedure 1A with a 30 inch drop TM 11 6625 2735 14 1 Supptemental Information TM 11 6625 2735 14 1 TABLE 1 3 PHYSICAL Characteristics Information Construction Chassis Aluminum alloy Panel Aluminum alloy with anodized finish Cabinet Blue
239. lar code D 4 Tool and Test Equipment Requirement Section 11 a Tool or Test Equipment Reference Code The num hers in this column coincide with the numbers used in the tools and equipment column of the MAC The numbers indicate the applicable tool or teat equipment for the main tenance functions b Maintenance Category The codes in this column indi cate the maintenance category allocated the tool or test equipment c Nomenclature This column lists the noun name and nomenclature of the tools and test equipment required to perform the maintenance functions d National NATO Stock Number This column lists the National NATO stock number of the specified tool or test equipment e Tool Number This column lists the manufacturer s part number of the tool followed by the Federal Supply Code for manufacturers 5 digit in parentheses D 5 Remarks Section IV a Reference Code This code refers to the appropriate item in section II column 6 b Remarks This column provides the required explan atory information necessary to clarify items appearing in section II 1 GROUP NUMBER 00 01 0101 0102 02 03 04 05 0501 06 SECTION MAINTENANCE ALLOCATION CHART FOR OSCILLOSCOPE 0S 261B V 1 U AND OS 261C V 1 U 2 COMPONENT ASSEMBLY OSCILLOSCOPE OS 261B V 1 U AND 0S 261C V 1 U ELECTRONIC COMPONENTS ASSEMBLY MP179 CIRCUIT CARD ASSY M CIRCUIT CARD ASSY A1 CIRCUIT CARD AS
240. layed sweep display that will exhibit less jitter set the B Trigger SOURCE switch to the same position as the A Trigger SOURCE switch and adjust the B Trigger LEVEL control for a stable display If the A Trigger SOURCE switch is in the LINE position a sample of the line voltage will have to be supplied to the B Trigger circuit externally Mixed Sweep Display 1 Preset the instrument controls and follow steps 1 through 6 for obtaining a Normal Sweep Display 2 Pull out the B TIME DIV switch knob and turn clockwise to the desired sweep rate Adjust the INTEN SITY control to achieve the desired display brightness 3 Set the HORIZ DISPLAY switch to MIX The crt display now contains more than one time factor on the horizontal axis The first portion of the display is at the A Time Base sweep rate and the latter part is at the B Time Base sweep rate The start of the B Time Base portion of the display can be changed by adjusting the DELAY TIME POSITION control X Y Display 1 Preset the instrument controls and turn the instru ment power on Allow several minutes for instrument warm up 2 Set the TIME DIV switch to X Y and the VERT MODE to CH 2 Apply the vertical signal to the CH 2 OR Y input connector and the horizontal signal to the CH 1 OR X input connector The CH 2 POSITION control will provide vertical positioning and the CH 1 POSITION control will provide horizontal positioning 3 Advance the INTENSITY control until the d
241. lent Tektronix DM 501 Digital Multimeter or equivalent 475 Control Settings Sweep Controls Display Controls TIME DIV 0 1 ms INTENSITY Midrange TIME DIV Calibrated detent FOCUS Midrange DEC TIME SCALE ILLUM Midrange POSITION Full counterclockwise HORIZ DISPLAY A X10 MAG Off button out POSITION Horiz Midrange FINE Midrange Vertical Controls CH 1 and CH 2 POSITION VOLTS OIV VAR VOLTS DIV AC GND DC INVERT VERT MODE 100 or 20 MHz BW Trigger Controis A and B COUPLING LEVEL SLOPE SOURCE TRIG MODE A TRIGGER HOLDOFF Center trace on graticule 2 inV for ac voltages 100 mV for wavetorms Calibrated detent DC Off ibutton out CH 1 Full bandwidth Push in then release AC NORM AUTO NORM Voltage Measurements Voltage measurements are taken with no signal applied and the trace positioned to the center horizontal graticule fine The voltmeter common is connected to chassis ground Waveform Conditions Apply the 475 calibrator signa to CH 1 input through a P6075 10 probe supplied with 475 Connect 475 A GATE rear panel through a 42 inch 50 ohm BNC cable to test oscilloscope external trigger input Set test os cilloscope trigger source to external and set vertical input for ac coupling Set test oscilloscope VOLTS DIV and TIME DIV con trols as indicated on readout symbols on each waveform Tolerance of voltages and waveforms shown are 20 SIG SIG
242. levels necessary to control the sequence of events associated with sweep generation and CRT unblinking The A and B GATE signals are also generated in this circuit Positive logic terminologies and symbologies are used in the following explanation of circuit operation Fig 3 6 shows a detailed block diagram of the Sweep and Z Axis Logic circuits A schematic of this circuit is shown on Diagram 7 at the rear of this manual Q584 MAIN GATE COMPARATOR Q572 Q574 Q588 A TUNNEL DIODES v Q902 0798 RESET AND HOLDOFF Q612 Q628 HORIZONTAL DISPLAY LOGIC HOLOOFF START NCAA 115227 0596 UU 2 7 SWEEP GENERATORS END OF SWEEP PULSE FROM CR1037 AND CR945 AND HOLDOFF START PULSE TM 11 6625 2735 14 1 A GATE NO TO Z AXIS AMPLIFIER piki Q1338 Z AXIS Q824 GATE 0996 DELAYED GATE 7 COMPARATOR Q802 Q804 O826 FAST BLANKING DELAYING SWEEP NON DELAYING END OF SWEEP Tar 77 ba 7 PULSE FROM Q1034 FROM DELAY PICKOFF COMPARATOR 0938 A EL6UG033 Fig 3 6 Detailed block diagram of the Sweep and Z Axis Logic circuits Sweep Control Integrated Circuit U600 is the Sweep Control Integrated Circuit Several functions are performed in this stage depending on the mode of operation of the instrument sweep generators The f
243. lies in this instrument Measure the ripple between the power supply test points and ground A malfunction in the power supply can be caused by one or more supplies being shorted to ground Check the resistance of the individual supplies to ground against the typical resistances listed in Table 4 3 Be sure the instru ment is not connected to a power source when making these measurements to prevent error in resistance readings and to prevent possible meter damage TM 11 6625 2735 14 1 TABLE 4 3 Power Supply Resistance Check Typical Resistance To Ground Ohmmeter Lead Lead Supply At Supply At Supply 110V kn 93kn 50 V 2 7 2 7 kQ 153 63 0 TEV 160 15 V 2K 480 8 V 2K 32 32 UNREG 20 K 50 V 2K cvv 500 105 20 K ko 160 V 2K 1kQ lf any of the supplies are shorted to ground repair them until normal resistance readings are obtained Connect the instrument to the correct power source and check the supplies for proper voltages listed if Table 4 2 If two or more of the individual supplies have incorrect voltages repair them in the order listed Table 4 2 The 50 volt supply is the reference for all other supplies and must be repaired first The 15 volt supply and the 5 volt supply should be working properly before repair on the 8 volt supply or the 15 volt supply is attempted When repairing a power supply in the 475 the following Information may b
244. lized Waveforms circuit Inverter Balance Detailed block diagram of the Sweep and Z Axis Logic circuits Option 07 Exploded View Detailed block diagram of the Sweep Generator A1 and A2 Boards Component Locations Ircuits A3 Board Component Locations Detailed block diagram of the Horizontal Amplifier circuit A4 Board Component Locations Detailed block diagram of the Power Supply circuit A5 Board Component Locations Detailed block diagram of the CRT circuit A6 Board Component Locations Removing the standard cabinet A8 Board Component Locations Color codes for resistors and capacitors A9 Board Component Locations Lead configurations of semiconductors used in this instrument E E BS EERE a 1014 LN ID fon loj INI IN 7 2 7 3 7 5 Cabinet Exploded View mkbmsgsmss d E ka Bese co N D ro m TI Oscilloscope OS 261B V 1 U and OS 261C V 1 U j 8868 Troubleshooting chart for the 475 Oscilloscope 5 ENTERS Change TM 11 6625 2735 14 1 LIST OF ILLUSTRATIONS CONT a Page Fig Page No No No FO 1 Block Diagram Located FO 10 Timing and Horizontal Display Switching Located back of Schematic Diagram back of FO 2 Channel 1 Vertical Preamplifier Schematic Mane Manual Diagram EC T1 Horizontal Amplifier Schematic Diagram FO 3 Channel 2 Vertical Prea
245. llectors tied together i e pins 8 and 9 and pins 5 and 6 Since the two collectors tied together have signals of opposite polarity the signal available to the following amplifier stage is less than that when the VAR control was in its calibrated detent The component values selected for the variable function provide a variable attenuation ratio of ap proximately 2 5 to 1 The Channel 1 Variable Balance adjustment R110 adjusts for no trace shift in the display when rotating the VAR control The Channel 1 UNCAL light indicates when the Channel 1 VAR control is out of its calibrated detent The components connected between pins 2 and 3 of U120 provide high frequency compensa tion for the stage Second Cascode Amplifier The second amplifier stage in the Channel 1 Preamplifier circuit is U140 U140 is an integrated emitter coupled push pull cascode amplifier similar to that used in U120 It is used as a push pull amplifier and has 2 mV and 5 mV gain adjustments that determine the overall gain of the Channel 1 Preamplifier circuit The output signals available to the next stage for amplification are taken from pins 5 and 9 of U140 3 6 The gain of U140 is determined by biasing the output transistors connected to pins 6 and 8 to conduct more or less current As more current is conducted through the transistors connected to pins 6 and 8 that much less is conducted through the transistors connected to pins 5 and 9 The current conducted
246. llowing equipment is useful for troubleshooting in the 475 4 7 TM 11 6625 2735 14 1 COLOR CODE COMPOSITION RESISTORS CERAMIC CAPACITORS DIPPED TANTALUM ELECTROLYTICS METAL FILM SMALL DISC RESISTORS CAPACITORS 7 ana 3 1ST 2ND AND 3RD SIGNIFICANT FIGS AND OR 19 COLOR CODE MAY NOT V MULTIPLIER T TOLERANCE BE PRESENT ON SOME CAPACITORS T TEMPERATURE COEFFICIENT P POLARITY AND VOLTAGE RATING RESISTORS CAPACITORS TOLERANCE MULTIPLIER TOLERANCE VOLTAGE OVER 10pF UNDER 10pF BLACK 13 911 DIN YELLOW 10 or 10K 10 or 10 000 a 20VDC GREEN 10 or 100K 1 296 41 0 5pF 25VDC 6 10 or RAY 10 0 01 0 260F G 20 R we pow To qu gt EL6UGO40 Fig 4 2 Color codes for resistors and capacitors 4 8 TM 11 6625 2735 14 1 E METAL CASE TRANSISTOR TRANSISTOR P NEU L PLASTICCASE L DUAL METAL TRANSISTOR ET CASE FET G Is U B D INTEGRATED CIRCUITS ELGUGO41 Fig 4 3 Lead configurations of semiconductors used in this instrument TM 11 6625 2735 14 1 1 Semiconductor Tester Description Dynamic type tester Must be capable of measuring reverse breakdown voltages of at least 400 volts Purpose To test the semiconductors used in this instrument Recommended type Tektronix 576 Curve Tracer or Tektronix 577 Di or D2 Curve Tracer with 177 Test F
247. location of the components and connections 2 Pry or pull the damaged strip from the chassis 4 21 TM 11 6625 2735 14 1 3 If the spacers come out with the strip remove them from the stud pins for use on the new strip spacers should be replaced if they are damaged REPLACEMENT 1 Place the spacers in the chassis holes 2 Carefully press the studs of the strip into the spacers until they are completely seated If necessary use a soft mallet and tap very lightly directly over the stud to seat the strip completely 3 If the stud extends through the spacers cut off the excess 4 Replace all components and connections Observe the soldering precautions given under Soldering Techni ques in this section Fuse Replacemerit Table 4 4 gives the rating location and functions of the fuses used in this instrument TABLE 4 4 Fuse Rating Location and Functions Circuit Number Location Function F1401 1 5 A Fast 115 volt line F1401 0 75 A Fast 230 volt line F1318 1 5 A Fast Rear of Main High Interface Voltage Board F1601 15 A Fast Front of Inverter Inverter Input Chassis Option 7 Only Cam Switch Replacement A complete cam switch is actually a cam switch assembly Each assembly consists of a delrin material cam that is rotated by a front panel knob and a set of contacts mounted on an adjacent circuit board that are actuated by the lobes on the cam CAUTION Repair of cam type should be underta
248. lt Series Regulator due to a short circuit or similar malfunction at the output of this supply the voltage drop across R1426 increases causing a higher positive voltage at the emitter of Q1426 than the supply output voltage This increased voltage is coupled through the emitter to base junction of Q1426 to voltage divider R1424 and R1425 Under normal conditions this divider sets the base level of Q1432 for a biased off condition However when the power supply load increases beyond preset limits or the supply output becomes short circuited the positive going change across the divider R1424 R1425 causes Q1432 to become biased on The collector current of Q1432 reduces the voltage at the base of Q1424 to limit the conduction of current through Q1426 and R1426 to a preset value This mode of operation is called foldback because both the supply voltage and current are reduced during overload The supply automatically returns to normal operation when the overload is removed 3 23 TM 11 6625 2735 14 1 110 Volt Supply CR1412 functions as a full wave center tapped rectifier and provides an unregulated out put voltage approximately 136 volts for the 110 Volt Power Supply This voltage is filtered by C1412 and is connected to the 110 Volt Series Regulator Q1496 to provide sufficient collector supply for stable regulation over a wide range of ac power line voltages Transistors Q1490 and Q1494 are connected as a comparator A sample of
249. ltage comparator circuit and is used to improve the switching capabilities of the stage The reference voltage for the Delay Pickoff Comparator stage is provided by DELAY TIME POSITION control R930 U930 is an integrated circuit containing two high gain amplifier cells used in a feedback amplifier configuration They provide accurate fixed voltages determined by settings of Delay Start R938 and Delay Stop R936 connected to the DELAY TIME POSITION control to allow precise delay pickoff The instrument is calibrated so that the major dial divisions of the DELAY TIME POSITION control correspond to major divisions of horizontal deflection on the CRT graticule For example if the DELAY TIME POSITION control is set to 5 00 the Non Delaying Sweep Generator is delayed five divisions of the Delaying Sweep time before it can produce a sweep The sawtooth voltage waveform from the Delaying Sweep Generator is connected to the gate of Q926B The quiescent level of the delaying sawtooth biases Q926B on and its drain is negative enough to bias Q938B on Q926A and Q938A are off and not conducting As the Delaying Sweep sawtooth voltage goes down the gate of Q926B also goes down When it goes more negative than the level at the gate of C926A established by the DELAY TIME POSITION control C926A conducts and Q926B turns off This also switches the states of Q938A and B and produces a positive going rectangular current pulse at the collector of Q938A This
250. ltage measurements are taken with no signal apptiiec and the trace positioned to the center horizontal graticule line The voltmeter comman is connected to chassis ground Waveform Conditions Apply ne 4 5 Zatibrator signal to 1 tnrough a P6075 10X probe isapplied with 475 Connect 475 GATE panel tircugh a 42 inch 50 ohm BNC cable to 1251 oscniosconpe external trigger input Set test os Ciiioscope trigger source to externa and set vertical input for ac coupling For which have the horizontal centering labeled 0 V set the test oscilluscune vertical input for dc coupling Set test ose l oscooe VOLTS ADIV and TIME DIV can trols as indicated on readout symbols on waveform Tolerance of voltages and waveforms shown are 20 INT THIG SIGNAL FROM usc amp 9 LINE SIGNAL FROM R507 5510 CROS 70 VULTASES Shown wiTh De YF ESSE VOLTAGE amp WAVEFORM CONDITIONS cc cates NORM POSITION AC POSITION RTOS Lok 8e gt 42 1 tet fa fat A EXT TRIG INPUT m 1 52 510 des MOVOLITHAC PRE AMALIFIER L a NORM TRIG SIL e CHA NT TRIG SIG TO 472 Ch INT TRIGGER GENERATOR 6 11 6625 2735 14 1 tek M gt
251. lumn Entries BICOMPONENTS OF END ITEM LIST Test Equipment Requirement D 2 Section I INTRODUCTION CE emarks D 2 SCOPE GENERAL Section Il MAINTENANCE ALLOCATION CHART M I INTEGRAL COMPONENTS OF END ITEM B5 OS 261B V 1 U Ill BASIC ISSUE ITEMS IV REMARKS APPENDIX C ADDITIONAL AUTHORIZATION LIST EXPENDABLE SUPPLIES AND Not Applicable MATERIALS LIST Section I INTRODUCTION D MAINTENANCE ALLOCATION Scope E T Section I INTRODUCTION Explanation of Columns E General D 1 I EXPENDABLE SUPPLIES AND Maintenance Function D 1 MATERIALS 2 Fig Page No No No Oscilloscope OS 261B V 1 U and OS 261C V 1 U E EE Locations of circuit boards in the 475 Delay Time and Differential Time Measurement Oscilloscope 4 23 Accuracy Detailed Locations of power transformer secondary Regulating Range Selector and Line Fuse wires Front panel and rear panel controls and connectors 2 Option 04 Schematic Diagram Basic block diagram of the 475 l EE Option 07 Simplified Block Diagram Detailed block diagram of the Channel 1 Vertical Preamplifier circuit Option 07 DC Inverter Detailed block diagram of the Channel 2 Vertical Option 07 Primary Winding Preamplifier circuit Typical Battery Pack Discharge Curves Detailed block diagram of the Vertical Channel Switching circuit Circuit Board Layout with Test Voltages Detailed block diagram of the A Trigger Generator Typical Idea
252. ly recalibrated instruments This procedure does not check every facet of the in strument s calibration rather it is concerned primarily with those portions of the instrument that are essential to measurement accuracy and correct operation Removing the instrument cabinet is not necessary to perform this procedure All checks are made from the front panel This procedure is also useful as an aid in troubleshooting and preventive maintenance Using This Procedure Outline To aid in locating a step in the Performance Check an outline is given preceding the Performance Check procedure Partial Procedures A partial check of performance is often desirable after replacing components or to verify performance of a portion of the instrument between major recalibration To check only part of the instrument set the controls as given under the nearest preceding Control Settings and use the Equipment Required list preceding the desired portion of the procedure TEST EQUIPMENT REQUIRED General The following test equipment and accessories or its equivalent is required for a complete performance check of the 475 Specifications given for the test equipment are the minimum necessary for accurate calibration Therefore some of the specifications listed here may differ from the actual performance capabilities of the test equipment All test equipment is assumed to be correctly calibrated and operating within the listed specifications Detailed
253. mended When the equipment is operated with covers removed DO NOT TOUCH exposed connections or components MAKE CERTAIN you are not grounded when making connections or adjusting components inside the test instrument 1 E F blank This manual contains copyright material reproduced by permission of Tektronix Inc TM 11 6625 2735 14 1 TECHNICAL MANUAL HEADQUARTERS DEPARTMENT OF THE ARMY No 11 6625 2735 14 1 Washington DC 17 June 1982 OPERATOR S ORGANIZATIONAL DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL OSCILLOSCOPE OS 261B V 1 U TEKTRONIX MODEL 475 WITH OPTION 04 NSN 6625 01 101 1318 AND OSCILLOSCOPE OS 261C V 1 U TEKTRONIX MODEL 475 WITH OPTION 04 AND OPTION 07 NSN 6625 01 119 7314 REPORTING ERRORS AND RECOMMENDING IMPROVEMENTS You can help improve this manual If you find any mistakes or if you know of a way to improve the procedures please let us know Mail your letter DA Form 2028 Recommended Changes to Publications and Blank Forms or DA Form 2028 2 located in the back of this manual direct to Commander US Army Communications Electronics Command and Fort Monmouth ATTN DRSEL ME MP Fort Monmouth New Jersey 07703 5007 In either case a reply will be furnished direct to you This manual is an authentication of the manufacturer s commercial literature which through usage has been found to cover the data required to operate and maintain this equipment Since the manual was not prepar
254. mplifier Schematic FO 12 Low Voltage Power Supply Schematic Diagram Diagram FO 4 Vertical Channel Switching Schematic FO 13 CRT Circuit and Z Axis Amplifier Schematic Diagram 9 FO 14 Calibrator and Fan Circuit Schematic FO 5 Vertical Output Amplifier Schematic Diagram Diagram FO 6 A Trigger Generator Schematic Diagram FO 15 Front Panel and Chassis Exploded View FO 7 B Trigger Generator Schematic Diagram FO 16 Right Side Exploded View FO 8 Sweep and Z Axis Logic Schematic Diagram FO 17 Left Side and Bottom Exploded View FO 9 Sweep Generators Schematic Diagram Table Page Table Page No No No No T ELECTRICAL 1 2 Power Supply Resistance Check 1 2 ENVIRONMENTAL T 11 4 4 Fuse Rating Location and Functions 4 22 PHYSICAL 4 5 Calibration Interaction After Repair or Adjustment 4 33 Regulating Ranges 5 1 Test Equipment Required for Performance 5 2 3 1 Input Output Logic for U370 3 8 Vertical Deflection Accuracy Horizontal Display Sweep Generator Terminology 3 16 Circuit Number to Diagram Locator 4 7 Differential Delay Time Accuracy 5 17 4 2 Power Supply Tolerance and Ripple 4 15 5 4 Delay Time Settings 2 18 1 TM 11 6625 2735 14 1 Fig 1 1 Oscilloscope OS 261B V 1 U and OS 261C V 1 U NOTE UNITS WITH OPTION 07 POWER SUPPLY PP 7549 U TEKTRONIX MODEL 1106 WILL USE TM 11 6625 2973 14 FOR POWER SUPPLY MAINTENANCE Fig 1 1 1 Oscilloscope OS
255. mposed on center horizontal graticule line then set VERT MODE to CH 1 c Connect CH 2 VERT SIGNAL OUT output connec tor on rear panel to CH 1 input through a 42 inch 50 ohm BNC cable d Set amplitude calibrator for a 20 millivolt output and connect to CH 2 input through a 42 inch 50 ohm BNC cable e Set A TRIGGER LEVEL for a stable triggered display f CHECK The square wave display for approximately 1 division of amplitude near center horizontal graticule line 5 20 g Set CH 1 VOLTS DIV to 50 mV and insert a 50 ohm termination between CH 1 input and the connected BNC cable h CHECK Repeat part f i Disconnect all test equipment 33 Check EXT Z AXIS Operation a Set amplitude calibrator for a 5 volt output and connect to EXT Z AXIS input connector on rear panel through a 42 inch 50 ohm BNC cable b CHECK For noticeable modulation at normal in tensity Adjust VAR TIME DIV if necessary to observe modulation then return to calibrated detent c Disconnect all test equipment 34 Check CALIBRATOR Operation a Set CH 1 VOLTS DIV to 10 mV and set TIME DIV to 1 ms b Connect a 10X probe with a scale factor switching connector between CH 1 input and CALIBRATOR current loop NOTE Use a probe listed in test equipment required Table 5 7 under 10X Probe examples c CHECK The square wave display for 3 divisions of amplitude and for approximately 1 cycle division d Disconnect all te
256. must be taken if heat damaged components are found Overheating usually indicates other trouble in the instrument therefore it is important that the cause of overheating be corrected to prevent recurrence of the damage Lubrication The fan motor and most of the potentiometers used in the 475 are permanently sealed and generally do not require periodic lubrication The switches used in the 475 both cam and lever type are installed with proper lubrication applied where necessary and will only rarely require any additional lubrication It is recommended that a regular periodic lubrication program not be performed on any of the components used in the 475 Semiconductor Checks Periodic checks of the transistors and other semicon ductors in the 475 are not recommended The best check of semiconductor performance is actual operation in the instrument Recalibration To ensure accurate measurements check the calibra tion of this instrument in accordance with TB 43 180 In addition replacement of component may necessitate recali bration of the affected circuits The calibration procedure can also be helpful in localizing certain troubles in the instrument In some cases minor troubles maybe revealed and or corrected by recalibration Complete calibration instructions are given in TB 11 6675 2735 35 1 TROUBLESHOOTING Introduction The following Information is provided to facilitate troubleshooting of the 475 Information conta
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258. n come from the Main Gate Com parator via Q588 and CR681 or from the Delayed Gate Comparator via Q826 and C684 The negative going signals turn off Q688 and cause Q698 to turn on The positive going signals that return the multivibrator to its original state thereby blanking the CRT display come from Q588 via CR682 and CR683 or from Q680 via CR680 and CR683 Q680 is used primarily to ensure proper early turn off of the CRT display at faster sweep rates In the MIX or A INTEN positions of the HORIZ DISPLAY switch some additive unblinking is accomplished to slightly increase the intensity of the B portion of the display In these positions of the switch 8 volts is connected to the cathodes of CR693 and CR694 through R692 Now when the Z Axis signal from the collector of Q826 steps negative at the beginning of the B portion of the display CR693 is made to conduct less current which makes a slight amount of additional unblinking current available to the Z Axis Amplifier through CR694 and R692 Delaying Sweep Latch Circuit Q788 Q794 and Q796 form the Delaying Sweep Latch Circuit The circuit function is used during the three delayed sweep modes of operation that the instrument is capable of MIX A INTEN and B DLY D Q938A in the Delay Pickoff Comparator of the Delaying Sweep Generator is the current source for the emitters of Q794 and Q796 Prior to the end of the delay time selected by the A TIME DIV switch and DELAY TIME P
259. nal and the output signal at pin 9 is in phase with respect to the input signal When the SLOPE switch is set to the position the output signal at pin 8 is in phase with respect to the input signal and the output signal at pin 9 is inverted with respect to the input signal Tunnel Diode Driver Q552 Q556 Q562 and Q566 are common emitter amplifier stages that provide the signal currents necessary to switch the triggering tunnel diodes CR556 and CR566 are ten milliampere tunnel diodes Quiescently CR556 and CR566 are biased into their low voltage states and Q566 cannot provide sufficient current to switch CR566 to its high voltage state When the input signal increases the current in Q556 slightly above its quiescent state this current and the current through R555 is sufficient to bias CR556 into its high voltage state The anode of CR556 steps positive to an approximately 0 5 volt level Since less current is required to maintain a tunnel diode in its high voltage state than is required to switch it to its high voltage state approximately 6 mA of current is additional ly available to switch CR566 to its high voltage state Thus the next time Q566 conducts signal current CR566 steps to its high voltage state sending a positive pulse to the logic circuit to initiate sweep action The A Trig Sensitivity adjustment R565 adjusts the tunnel diode bias to the proper level that will not allow CR566 to be switched to his high voltage s
260. ob is on n Connect a 10X probe with a scale factor switching connector to CH 2 input NOTE Use a probe listed in test equipment required Table under 10X Probe examples o CHECK That the light under 5 mV is extinguished and the light under 50 mV comes on p Set VERT MODE to CH 1 That the light under 5 mV of CH 1 VOLTS DIV knob is on r Move the 10X probe to CH 1 input s CHECK That the light under 5 mV is extinguished and the light under 50 mV comes on t Remove the 10X probe 3 Check CH 1 and CH 2 GAIN a Set the amplitude calibrator for a 20 millivolt output and connect to CH 1 input through a 42 inch 50 ohm BNC cable b Set CH 1 and CH 2 AC GND DC switches to DC c CHECK The display for 4 divisions of amplitude d ADJUST CH 1 GAIN 5 mV adjustment through the upper 5 mV access hole at left side of cabinet for 4 divisions of amplitude e CHECK AIl settings of CH 1 VOLTS DIV for ac curacy within 396 using the settings listed in Table 5 2 TABLE 5 2 Vertical Deflection Accuracy VOLTS DIV Amplitude Vertical Maximum Switch Calibrator Deflection Error for 396 Setting Output in Divisions Accuracy 2 10 millivolts 0 15 div 5 mV 20 millivolts Previously set 10 mV 0 15 div 20 mV 0 15 div 50 mV 0 12 div 01 V 0 15 div 02 V 0 15 div 05 V 0 12 div 0 15 div 2 10 volts 0 15 div 5 V 20 volts 0 12 div f Set VERT MODE to CH 2 set
261. ol Settings POWER ON Display INTENSITY Midrange FOCUS Midrange SCALE ILLUM Midrange Vertical CH 1 and CH 2 POSITION Midrange VOLTS DIV 2 V new setting VAR VOLTS DIV Calibrated detent AC GND DC DC INVERT Off button out VERT MODE CH 1 new setting 100 OR 20 MHz BW 20 new setting Trigger A and B COUPLING AC LEVEL Fully clockwise new setting SLOPE A TRIGGER SOURCE NORM B TRIGGER SOURCE STARTS AFTER DELAY TRIG MODE AUTO A TRIG HOLDOFF NORM Sweep A TIME DIV 10 us new setting B TIME DIV 10 us new setting VAR TIME DIV Calibrated detent DELAY TIME POSITION HORIZ DISPLAY Fully counterclockwise A INTEN new setting X10 MAG Off button out POSITION Horiz Midrange FINE Midrange 5 19 TM 11 6525 2735 14 1 31 Check A and B GATE Outputs a Connect A GATE output connector on rear panel to CH 1 input through a 42 inch 50 ohm BNC cable b CHECK The display for a positive pulse amplitude of approximately 5 volts it may be necessary to increase INTENSITY to view leading edge of positive pulse c Move cable from A GATE to B GATE output connectors on rear panel d CHECK Repeat part b e Disconnect the cable between B GATE and CH 1 connectors 32 Check CH 2 VERT SIGNAL OUT a Set HORIZ DISPLAY to A set TIME DIV to 0 5 ms set CH 1 VOLTS DIV to 0 1 V and set CH 2 VOLTS DIV to 5 mV b Set VERT MODE to CHOP set CH 1 and CH 2 POSITION controls for 2 traces superi
262. ollowing is a brief explanation of the function associated with each pin of the IC Pin 1 This is the positive tunnel diode input The signal connected here comes from the A Firing TD in the A Trigger Generator circuit The voltage level switches from Oto 0 5 volts and is compared with pin 2 internally Pin 2 This is the negative tunnel diode input A fixed DC level established by R602 and R603 provides the reference for comparison with pin 1 Pin 3 This is the positive tunnel diode output terminal In the AUTO mode of operation TRIG MODE set to AUTO at the end of the holdoff time period pin 1 pin 16 and pin 19 are LO and pin 8 is HI This causes the gate level at pin 3 to step LO to turn Q574 on which initiates a sweep Pin 4 This is the negative tunnel diode output terminal connected to 5 volts in this application Pin 5 Input terminal for a negative 5 volts through VR608 from the 8 volt supply Pin 6 This is the auto RC timing terminal R609 and C609 determine the amount of time between loss of trigger signal and the generation of an auto gate at pin 3 when TRIG MODE is set to AUTO Pin 7 This terminal lights the TRIG light when a triggering gate has occurred causing pin 1 to go Hl Pin 8 This is the holdoff timing terminal The time between the end of an individual sweep and the start of the next sweep is determined by RC components that affect the time constant of voltage of pin 8 The TIME DIV control sel
263. on which holds the trigger tunnel diodes in the B Trigger Generator circuit in their LO states At the end of the delay time selected by the A TIME DIV switch and DELAY TIME POSITION control the positive movement at the collector of Q794 turns on Q792 and causes Q790 to turn off The tunnel diodes in the B Trigger Generator are capable of being biased into their HI states Also if the B TM 11 6625 2735 14 1 Triggering SOURCE switch is in the STARTS AFTER DELAY TIME position the negative movement at the collector of Q792 reverse biases CR81 1 letting the 8volt supply pull down on the base of Q804 in the Delayed Gate Comparator This turns on Q804 and causes Q802 to turn off which initiates a delayed sweep Main Sweep Holdoff Gate and Delayed Sweep Over ride Amplifier During the interval of the main gate Q798 functions as a holdoff gate and is biased off to provide a forward bias on Q1002 Q1002 is located on diagram 9 This turns on Q1002 discharges the holdoff capacitors and maintains a current path to keep the capacitors discharged During the delayed sweep Q798 functions as an override amplifier It is possible with the right combina tion of control settings to achieve a delayed sweep presentation where the delayed sweep would normally want to continue running after the end of the delaying sweep For instance if the TIME DIV controls are set only 1 or 2 ranges apart and the DELAY TIME POSITION control is set to a 8 50 s
264. or approxiately 16 4 volts Check the collector of Q922 for approximately 146 volts Set TIME DIV to 0 5 or faster This should cause the Slow Non Delaying Sweep Generator to run up and the Fast Non Delaying Sweep Generator to run down Check the collector of Q984 for approximately 16 4 volts and check the collector of Q1014 for approximately 0 3 volt At this point the A Sweep holdoff should be in a reset condition Check TP588 for approximately 4 volts Check the emitter of Q644 for approximately 0 volt When Q572 was removed from its socket pin 16 of U600 went positive which is the equivalent of a holdoff start pulse Check pin 16 of U600 for approximately 2 5 volts Check pin 17 of U600 for approximately 1 7 volts Check TP572 for approximately 0 volt Check pin 3 of U600 for approximately 0 2 volt 3 Install Q572 and remove Q574 from its socket This will cause only the Fast Non Delaying Sweep Generator which normally should be in operation to stay at a start high voltage level Check the collector of Q1014 for approximately 14 volts Set TIME DIV to 1 ms Check the collector of Q984 for approximately 14 volts At this point the A Sweep holdoff should be at a high level Check TP588 for approximately 2 volts Check the emitter of Q644 for approximately 4 3 volts Now pin 3 of U600 should have a low auto gate voltage Check TP572 for approximately O volt Check pin 16 of U600 for approximately O volt Che
265. orms shown on this diagram were obtainec by using the recommended test equ pment and test set ups listed below RECOMMENDED TEST EQUIPMENT Test oscilfoscope Deflection actor Input impedance Sweep rate Probe Fast rise 10X attenuation probe com patible with vertical amplifier of test oscilloscope SPECIFICATIONS DC to 75 MHz 1 mV to 5 V Div 1 MQ 20 pF 50 ns Frequency resporse Voitmeter Non loading Input Impedance Digital Multimeter av Los 475 Control Settings Display Controls INTENSITY M crange FOCUS M crange SCALE iLLUM Midrange Vertical Controls CH 1 and CH 21 POSITION Center trace on araticule TS DIV 2 mV for dc voltages 100 for waveforms VOLTS DIV 5raten detent AC GND DC INVERT Olf outi VERT MODE CH 100 20 MHz BW Fu candwidtn ush in io D Trigger A and Bi COUPLING AC LEVEL 0 SLOPE SOURCE NORAN TEIG MODE TRIGGER HOLDOFF NORM 10 MQ U to 500 V RECOMMENDED TYPE Tektronix 7603 equinpedwitn A 3 Amplifier and 7850 Time base units or eauivalent Tektronix P6053B cr equivaient Tektronix DM 501 Digital Multimeter or equivalent Sweep Controls TIME DIY 0 1 rs VAR TIME DIV Calibrated cetent DELAY TIME POSITION Full counterclockwise HORIZ DiSPLAY A X10 MAG button out POSITION Hor zi Midrange FINE Midrange Voltage Measurements Vo
266. oscilloscope Input Impedance Range Midrange Midrange Midrange Vertical Controls CH 1 and CH 2 POSITION VOLTS DIV VAR VOLTS DIV AC GND DC INVERT VERT MODE 100 or 20 MHz BW Trigger Controls A and B COUPLING LEVEL SLOPE SOURCE TRIG MODE A TRIGGER HOLDOFF Center trace on graticule 2 mV for dc voltages 100 mV for waveforms Calibrated detent DC Off button cut CH 1 Full bandwidth Push in then release NORM AUTO waveforms SINGL SWP for dc voltages READY light off NORM amplifier of test 10 MO Tektronix DM 501 Digital Multimeter or G to 500 V equivalent Sweep Controls TIME DIV 01 ms VAR TIME DIV Calibrated detent DELAY TIME POSITION Full counterclockwise HORIZ DISPLAY A X10 MAG Off bu ton out POSITION Horiz Midrange FINE Midrange Voltage Measurements Voltage measurements are taken with no signal applied and the trace positioned to the center horizontal graticule line The voltmeter common is connected to chassis ground Waveform Conditions Apply the 475 calibrator signal to CH 1 input through P6075 10X probe supplied with 475 Connect 475 A GATE rear panel through a 42 inch 50 ohm BNC cable ta test ascilloscope external trigger input Set test os cilloscope trigger source to external and set vertical input for ac coupling For waveforms which Fave the horizontal centerline labeled 0 V DC set the test oscilloscope vertical input for dc coupling
267. oubleshooting instructions Fig 4 4 provides a guide in locating a defective circuit This chart may not include checks for all possible defects use steps 7 through 9 in such cases Start from the top of the chart and perform the given checks on the left side of the page until a step is found which does not produce the indicated results Further checks and or the circuit in which the trouble is probably located are listed to the right of this step After the defective circuit has been located it may be helpful to read the applicable part of the Circuit Descrip tion section and Special Troubleshooting Information part of this section to aid in locating defective components After doing this see steps 7 through 9 for additional information T Check Circuit Board Interconnections After the trouble has been isolated to a particular circuit check for loose or broken connections at circuit board interconnec ting pins plugs and end lead connectors 8 Check Voltages and Waveforms Often the defective component can be located by checking for the correct voltage or waveform in the circuit Typical voltages and waveforms are given on the diagrams TM 11 6625 2735 14 1 NOTE Voltages and waveforms given on the diagrams are not absolute and may vary slightly between in nstruments To obtain operating conditions similar to those used to take these readings see the voltage and waveforms page with each schematic diagram On this page
268. ow ing settings 100 MHz When TRIG VIEW button is pulled to the first de tent 100 indicated on yellow band of TRIG VIEW knob the upper bandwidth of the com plete Vertical Deflection System is limited to ap proximately 100 MHz 20 MHz When TRIG VIEW button is pulled to the second detent 100 and 20 indicated on yellow band of TRIG VIEW knob the upper bandwidth of the complete Vertical Deflec tion System is limited to ap proximately 20 MHz TRIG VIEW When the TRIG VIEW button is pushed and held the output of the Vertical Preamplifier is interrupted and the trigger signal selected by the setting of A TRIGGER SOURCE switch is displayed on the crt When the TRIG VIEW button is pushed and held the crt display available is explained in each of the following settings of the A TRIGGER SOURCE switch NOTE The signals displayed are affecfed by the coupling characteristics of the A TRIGGER COUPLING switch positions see A Trigger Coupling informa tion in this section The A TRIGGER LEVEL control affects the trigger ing and the vertical positioning when using a TRIG VIEW display NORM Any signal that is dis played in full bandwidth posi tion is viewed with an increase in signal amplitude CH 1 Any signal that is dis played in CH 1 of VERT MODE in full bandwidth position is viewed with an increase in signal amplitude INVERT VERT MODE CH 2 Any signal that is dis played in CH 2 of VERT
269. part f 1 Set CH 1 VOLTS DIV to 10 mV and set A TRIGGER SOURCE to EXT m Set the low frequency generator for a 5 division 50 kilohertz display 50 millivolts at external input then set CH 1 VOLTS DIV to 50 mV n CHECK Repeat part f o Set A TRIGGER SOURCE to NORM set CH 1 VOLTS DIV to 5 mV set TIME DIV to 10 ms and set 100 OR 20 MHz BW control to 20 p Set the low frequency generator for a 5 division 60 Hertz display then set CH 1 VOLTS DIV to 50 mV CHECK That a stable triggered display can be obtained in DC HF REJ and AC positions of A TRIGGER COUPLING with adjustment of A TRIGGER LEVEL r Set A TRIGGER COUPLING to LF REJ s That a stable triggered display cannot be obtained with adjustment of A TRIGGER LEVEL t Set CH 1 VOLTS DIV to 5 mV and set A TRIGGER COUPLING to AC 5 10 u Set the low frequency generator for a 3 division 60 Hertz display then set CH 1 VOLTS DIV to 50 mV v CHECK That a stable triggered display can be obtained in AC and DC positions of A TRIGGER COUPLING with adjustment of A TRIGGER LEVEL w Set the low frequency generator for a 2 division 60 Hertz display then set A TRIGGER SOURCE to EXT 100 millivolts at external input x CHECK Repeat y Set A TRIGGER COUPLING to LF REJ z CHECK Repeat part s aa Set A TRIGGER COUPLING to AC ab Set the low frequency generator for a 1 division 60 Hertz display 50 millivolts at
270. peaking by forming a T coil circuit without mutual coupling Most of the remaining external com ponents connected between pins 2 and 3 of U450 provide high frequency compensation for the delay line Connected between pins 2 and 3 of U450 internally a resistor approximately 33 ohms has a large effect on the gain of the stage RT452 changes in value with variations in ambient temperature to compensate for temperature associated changes in amplifier gain The BEAM FINDER pushbut ton when pressed removes 8 volts from the top of R459 This reduces the dynamic swing capabilities of the stage to limit the display on the CRT to within the viewing area The gain of the Vertical Output Amplifier section is adjusted in this stage by adjusting Vertical Output Gain R449 3 9 TM 11 6625 2735 14 1 Second IC Amplifier The second amplifier stage in the Vertical Output Amplifier is integrated circuit U470 U470 is a multi stage cascode amplifier cell The input signal is applied to pins 1 and 5 with the inverted output signal taken from pins 9 and 12 Pins 2 and 4 are emitter connections Some of the components connected between pins 2 and 4 provide slower time constants to compensate for signal rolloff that occurs in the delay line while the remaining components compensate for thermal considerations in the stage The Output Bias adjust R487 sets the DC levels within the stage to optimize the operating performance of U470 The output signal
271. play at the end of the sweep Prior to the generation of a sawtooth voltage waveform by the Delaying Sweep Generator the base of Q944 is at an approximate 1 6 volt level The base of Q946 is held at about 3 volts by the divider made up of R948 and R949 Therefore Q946 is reversed biased and not conducting and Q944 is forward biased and is conducting When the sweep voltage at the emitter of Q940 begins to go in a negative direction the base of Q944 follows until the base of Q944 goes more negative than the base of Q946 Q944 turns off and Q946 turns on generating a positive pulse at the collector of Q944 and a negative pulse at the collector of Q946 The positive pulse at the collector of Q944 signals the end of sweep and starts the holdoff period The negative pulse at the collector of Q946 signals the Z Axis Logic circuit to blank the CRT and prevent any further display Delay Pickoff Comparator The Delay Pickoff Comparator stage allows selection of the amount of delay from the start of the Delaying oweep Generator before one of the Non Delaying Sweep Generators is turned on The amount of delay available is variable from 0 00 to 10 00 times the setting of the A TIME DIV switch The sweep rate of the Delayed non decaying Sweep Generator is determined by the setting of the B TIME DIV switch Q926A and Q926B are connected as a voltage com parator Q928 is a relatively constant current source for Q926 Q938 is also connected as a vo
272. power source voltage appears on the internal primary wiring causing a possible shock hazard during troubleshooting WARNING Ground the instrument This instrument has a three wire power cord with a three terminal polarized plug for connection to the power source and safety earth The safety earth terminal of the plug is directly connected to the instrument frame For electric shock protection insert this plug only in a mating outlet with a safety earth contact or otherwise connect the frame to a safety earth system Failure to complete the ground system may allow the chassis of this instrument to be elevated above ground potential and pose a shock hazard WARNING Avoid live circuits Dangerous voltages exist at several points throughout this instrument When the instrument is operated with the covers removed do not touch exposed connections or components Some transistors have voltages present on their cases Disconnect power before cleaning the instrument or replacing parts WARNING Avoid contact with chemicals Handle silicone grease with care Avoid getting silicone grease in eyes Wash hands thoroughly after use WARNING Use care when handling the crt Protective clothing and safety glasses should be worn when handling a crt Avoid striking it on any object which might cause it to crack or implode When storing a crt place it in a protective carton or set it facedown in a protected location on a smooth surface with a soft mat under
273. ppropriate circuit the high voltage should come up It may be helpful to use the following information in sequence to troubleshoot an inoperative high voltage circuit Remove the high voltage circuit cover Refer to figure 7 8 for component locations 1 Check the collector of Q1316 for approximately 0 7 volts to approximately 1 6 volts 2 Check the positive end of C1318 for approximately 21 volts 3 Check the collector of Q1318 for approximately 21 volts 4 Disconnect and lift one end of CR1329 5 Disconnect the crt base socket to eliminate crt loading 6 Check or replace C1316 7 the oscillator still does not come up the high voltage multiplier could be defective Remove the Vertical Preamp board to expose the multiplier and disconnect the center tap of the high voltage transformer from the multiplier tie point 4 16 Troubleshooting the Sweep Circuits The sweep cir cuits should be repaired in the following order A Sweep A INTEN Intensified Sweep B DLY D Sweep MIX Sweep A Sweep and Logic 1 Remove all external signals to the instrument set TIME DIV to 1 ms lock knobs set HORIZ DISPLAY to A and set TRIG MODE to AUTO 2 Remove Q572 from its socket This will cause only the Slow Non Delaying Sweep Generator A Sweep which normally should be in operation to stay at a low voltage level Check the collector of 3984 for ap proximately 0 3 volt Check the collector of Q1014 f
274. provides drive to the output complementary amplifier made up of Q1352 Q1354 and Q1358 Q1358 is a device with higher frequen cy characteristics than Q1354 and is used to improve the overall frequency capabilities of the Z Axis Amplifier On the fast positive going output signal peaks Q1358 depletes the charge on C1358 Then on the negative going signal peaks Q1362 is pulsed on to renew the charge on C1358 CR1367 provides protection to the Z Axis Amplifier circuitry in the event of short duration arcing in the CRT High Voltage Power Supplies In the 0 1 s 0 2 s 0 5 s and X Y positions of the TIME DIV switch the anode of CR1337 is connected to ground This limits how negative the operating level at the emitter of Q1338 can go to reduce the unblinking capabilities of the amplifier thereby reducing the possibility of inadvertently burning the CRT phosphor When the BEAM FINDER pushbutton is pressed 8 volts is connected to the junction of R1342 and R1346 This biases Q1338 off which in turn causes CR1343 to be reverse biased Now the output of the Z Axis Amplifier is isolated from all of the circuit s normal signal inputs The output level of the amplifier is set at a nearly fixed level approximately 25 volts determined by the parallel value of R1343 and R1346 divided into the feedback resistance of the amplifier This sets the sweep intensity to a normal viewing level CALIBRATOR lt gt General The Calibrator circuit p
275. r 14 5X Attenuator 15 Termination 2 required 16 10X Probe 17 500 MHz Filter 18 Screwdriver TM 11 6625 2735 14 1 TABLE 5 1 cont Minimum Specifications Connectors GR874 to BNC Female Examples a Tektronix Part Number 017 0063 00 Trigger checks Connectors GR874 to BNC Used in Trigger System a Tektronix Part Number Male procedure for signal intercon 017 0064 00 nection a Tektronix Part Number 103 0031 00 Used in Trigger System pro cedure for signal intercon nection Connectors BNC Male to BNC Female a Tektronix Part Number 103 0030 00 Used throughout procedure for signal interconnection Connectors BNC a Tektronix Part Number 011 0059 02 Vertical bandwidth check Trigger checks Ratio 10X impedance 50 ohms connectors BNC Ratio 5X impedance 50 Trigger checks a Tektronix Part Number ohms connectors BNC 011 0060 02 Impedance 50 ohms con Used throughout procedure Tektronix Part Number nectors BNC for proper signal termination 011 0049 01 a Tektronix P6075 Probe supplied with 475 oscil loscope Scale factor check Cali brator check Scale factor switching con nector ENC b Tektronix P6065 Probe Impedance 50 ohms fre quency adjustable con nectors BNC calibration fixture Part Number 067 0684 00 Used to adjust TRACE a Xcelite R 3323 ROTATION ASTIG GAIN OUTLINE FOR PERFORMA
276. r are the only one who can tell us what you don t like about your equipment Let us know why you don t like the design Put it on an SF 368 Quality Deficiency Report Mail it to Commander US Army Communications Electronics Command and Fort Monmouth ATTN DRSEL ME MP Fort Monmouth New Jersey 07703 5007 We ll send you a reply Administrative Storage To prepare the equipment for administrative storage ascertain its operability and reliability In addition use the proper packing materials Destruction of Army Electronics Materiel Destruction of Army electronics materiel to prevent enemy use shall be in accordance with TM 750 244 2 Change 1 0 1 TM 11 6625 2795 14 1 Section 1 475 Service GENERAL INFORMATION AND INSTALLATION Introduction The 475 Oscilloscope is a 200 megahertz bandwidth portable instrument designed to operate in a wide range of environmental conditions The lightweight compact design combines accurate high frequency measurement capability and ease of transportation The dual channel DC to 200 megahertz vertical deflection system provides calibrated deflection factors from 2 millivolts to 5 volts division A BW TRIG VIEW switch permits limiting the bandwidth of the vertical system to reduce interference from high frequency signals when viewing lower frequency low level signals The switch also permits displaying of the signal applied to the A Trigger Generator on the CRT The trigger circuit
277. r chassis Do not overtighten these screws 4 4 7 Install 2 setscrews at the top front of the Rack Adapter chassis A 0 125 inch Allen wrench is requred to install the setscrews 8 Mount the Rack Adapter slide sections to the rack slide assemblies connect the power cord connect any interconnecting cables push the Rack Adapter into final operating position and install the adapter to rack hardware The Rack Adapter cabinet Part No 016 0556 00 for the 475 provides the proper electrical environment for the instrument reduces dust collection reduces handling damage to a minimum and provides a means for mounting the instrument solidly to a surface such as a rack or console PREVENTIVE MAINTENANCE Introduction Preventive maintenance consists primarily of cleaning and visual inspection When performed on a regular basis preventive maintenance can prevent instrument breakdown and improves the reliability of this instrument The severity of the environment to which the 475 is subjected will determine the frequency of maintenance A convenient time to perform preventive maintenance is just prior to recalibration of the instrument Cleaning The cabinet provides protection against dust in the interior of the instrument Operation without the cabinet in place necessitates more frequent cleaning The front cover provides a measure of dust protection for the front panel and the crt face The front panel cover should be install
278. r on the rear panel tioning is missing 3 Check to see whether the equipment has been modified Equipment which has been modified will have the MWO number on the front panel near the nomenclature plate Check also to see whether all currently applicable MWO s have been applied Current MWO s applicable to the equiment are listed in BDA Pam 310 1 Environmental Requirements The following paragrahs describe the environmental operating conditions for the oscilloscope allows selection of the oprating voltage With option 07 installed the oscilloscope may be operated from either a 12 vdc or 24 vdc power source Space Requirements The oscilloscope is provided with feet on the bottom surface to provide space for cooling air flow Maintain this clearance by always setting all four feet solidly on a flat surface In addition always maintain at least 2 inches of clearance at both sides top and rear of the unit Change 1 1 13 1 14 blank OPERATING PRELIMINARY INSTRUCTIONS Introduction This section of the manual is intended to allow the operator to become familiar with the instrument s power requirements functions of controls and connectors and how to obtain a few basic displays Safety Information This instrument may be damaged if operated with the Line Voltage Selector Switch or the Regulating Range Selector set for the wrong applied line voltage Please read the following instructions before operating to be sure
279. ransformer leads still connected to the board TM 11 6625 2735 14 1 Perform repairs on the reverse side of the Main Interface board if repair is intended To reinstall the board reverse the removal procedure If intentions are to replace the Main Interface circuit board continue with this procedure 20 Unsolder the power transformer wires from the Main Interface board and confirm each wire color with its location in Record any exceptions to this procedure to facilitate reassembly VIO v w ET LET ORANGE EL6UGO45 Fig 4 6 Locations of power transtormer secondary wires 21 Remove the Main Interface circuit board using care to prevent strain on any of the wires 22 Remove the solder from the holes in the circuit board wire terminal pads where wires were removed in this procedure to facilitate installation To install the Main interface circuit board reverse the removal procedure Power Transformer Removal The Power Transformer can be removed as follows 1 Remove the Trigger Generator and Z Axis logic circuit board as outlined previously 2 Remove the regulating range selector cover and the blue rear panel of the instrument 4 29 TM 11 6625 2735 14 1 3 Option 4 only Remove the power line input filter emi filter 4 Remove the transformer leads from the regulating range selector body The leads may be installed by simply pushing them into place Record the color and location of each
280. rcuit Transistors Q612 and Q628 are connected as a Schmitt Trigger circuit and form the A Trigger TD Reset Circuit A Schmitt Trigger circuit is a bistable pulse generator in which an output pulse of constant amplitude exists only as long as the input voltage exceeds a certain dc value At the start of holdoff pin 17 of U600 steps Hl This turns on Q612 and turns Q628 off The collector signal of Q612 connects to the Trigger Tunnel Diodes in the A Trigger Generator circuit and resets them to their LO state At the end of holdoff pin 17 steps LO Q612 turns off and Q628 turns on to allow the tunnel diodes to fire on the next trigger signal Holdoff Start Circuit Q594 and Q596 form the Holdoff Start Circuit The input signal to the stage is a momentary positive going end of sweep signal from the Sweep Generators circuit or from the Delayed Latch circuit The positive going signal turns Q594 on which in turn turns on Q596 The positive going signal at the collector of Q596 is connected to pin 16 of U600 to reset the sweep and start the holdoff period This signal is also used in the Vertical Switching Circuit to switch between channels in the ALT mode of operation Z Axis Logic Muitivibrator Q688 and Q698 are basically a Schmitt Trigger circuit and form the Z Axis Logic Multivibrator Quiescently with the CRT display blanked Q688 is on and Q698 is off The signal to switch states of the multivibrator and thereby unblank the CRT ca
281. rd and the pin This spring tension can be destroyed by using the pin sockets as a connecting point for spring loaded probe tips alligator clips etc e END LEAD PIN CONNECTORS The pin connectors used to connect the wires to the interconnecting pins are clamped to the ends of the associated leads To replace damaged end lead pin connectors remove the old pin connector from the end of the lead and clamp the replacement connector to the lead Some of the pin connectors are grouped together and mounted in a plastic holder the overall result is that these connectors are removed and installed as a multi pin connector To provide correct orientation of this multi pin connector when it is replaced an arrow is stamped on the circuit board and a matching arrow is molded into the plastic housing of the multi pin connector Be sure these arrows are aligned as the multi pin connector is replaced If the individual end lead pin connectors are removed from the plastic holder note the color of the individual wires for replacement Ceramic Terminal Stop Replacement Replacement strips including studs and spacers are supplied under separate part numbers However the old spacers may be re used if they are not damaged To replace a ceramic terminal strip use the following procedure REMOVAL 1 Unsolder all components and connections on the strip To aid in replacing the strip it may be advisable to mark each lead or draw a sketch to show
282. re series regulated supplies U1418 U1454A and B and U1464A and B are high gain amplifier cells with differential inputs These amplifiers monitor variations in the output voltages and generate error signals to maintain relatively constant output levels Each regulated supply contains a current limiting circuit that provides short circuit protection to prevent instrument damage if a supply is inadvertently shorted to ground Additionally unregulated voltages are used from the 15 volt and 50 volt supplies 50 Volt Supply The 50 Volt Power Supply provides the reference voltage for all remaining regulated supplies in the instrument The following discussion includes the description of the 50 Volt Series Regulator 50 Volt Feedback Amplifier 50 Volt Reference and 50 Volt Current Limiting stages Since these stages are closely related in the production of the 50 volt regulated output voltage their operation is most easily understood when discussed as a unit TM 11 6625 2735 14 1 CR1412 functions as a full wave center tapped bridge rectifier and provides an unregulated output voltage approximately 65 volts for the 50 Volt Power Supply This voltage is filtered by C1414 and is connected to the 50 Volt Series Regulator Q1426 to provide a sufficient collector supply for stable regulation over a wide range of ac power line voltages Zener diode VR1416 sets a reference level of about 9 volts at the positive input of Feedback
283. ree notch ceramic strip is white with an orange stripe h Wire to pad 14 lowest of a pair of wires between the large high voltage capacitors is white with brown and yellow stripes i Wire to pad 1 upper pad between the large high voltage capacitors is white with a brown stripe Wire to second notch on the five notch ceramic strip notch containing junction of a 0 01 microfarad capacitor a 10 megohm resistor and a diode is white with brown and red stripes 13 Remove the three power transistor mounting screws from Q1468 Q1426 and Q1448 on the rear subpanel bracket 14 Remove the mounting screw from transistor Q1456 near the lower rear corner of the board 15 Remove the mounting screw from transistor Q1482 near the top right corner of the board 16 Remove the four hexagonal posts that mount the high voltage shield Use a 3 16 inch nut driver 17 Remove seven Main Interface board mounting Screws 18 Disconnect the crt anode lead plug from the high voltage multiplier jack Ground this lead to the instrument main chassis to remove any stored charge Pry the multiplier jack from its mounting clip with a medium size screwdriver 19 Separate the Main Interface circuit board from the instrument chassis using care to prevent damage to components and wiring Carefully thread the interconnec ting cables through the board and chassis as necessary to avoid strain on any cable Let the board pivot on the power t
284. rmal circuit voltage Voltages across a transistor vary with the type of device and its circuit function Some of these voltages are predictable The emitter to base voltage of a conducting silicon transistor will normally be 0 6 to 0 8 volts The emitter to collector voltage of saturated transistors is approximately 0 2 volts Because these values are small the best way to check them is by connecting the voltmeter across the junction and using a sensitive voltmeter setting rather than by comparing 2 voltages taken with respect to ground both leads of the voltmeter must be isolated from ground if this method is used cL 910280111280 619 eui 10 ueu p p 614 2709 19713 PROCEED DOWN THIS COLUMN PERFORM THE CHECKS UNTIL A STEP 1S FOUND WHICH DOES NOT PRODUCE THE INDICATEO RESULTS START CONNECT THE 475 TO CORRECT POWER SOURCE AND SET POWER SWITCH TO ON SET SCALE ILLUM FULLY CLOCKWISE GRATICULE AND VOLTS DIV LIGHTS ON NO GRATICULE OR VOLTS DIV LIGHTS PERFORM ALL CHECKS GIVEN ON RIGHT SIDE OF STEP WHICH DOES NOT PRODUCE INDICATEO RESULTS CHECK POWER SOURCE LINE CORD LINE FUSES THERMAL CUTOUT POWER SWITCH POWER TRANSFORMER SCALE ILLUM CONTFIOL AND 5 VOLT UNREG SUPPL Y a
285. roduces a square wave output signal with accurate voltage and current amplitudes This output is available as a voltage or current at the CALIBRATOR current loop on the instrument front panel Fig 3 11 shows a detailed block diagram of the Calibrator circuit A schematic of this circuit is shown on Diagram 13 at the rear of this manual MULTIVIBRATOR Q LEALISRATOR R1517 Fig 3 11 Detailed block diagram of the Calibrator circuit TM 11 6625 2735 14 1 Multivibrator Q1502 and Q1504 along with their associated circuitry compose an astable multivibrator The basic frequency of the multivibrator is approximately one kilohertz and is essentially determined by the RC combination of C1505 R1502 and R1504 Q1502 and Q1504 alternately conduct producing a square wave signal that is taken from the collector of Q1504 Output Amplifier The output signal from the Multivibrator overdrives Output Amplifier Q1512 to produce a square wave at the output When the base of Q1512 goes positive Q1512 is cut off and the collector level drops down to ground When the base goes negative Q1512 biased into saturation and the collector of Q1512 rises positive to about 5 volts Amplitude adjustment R1515 adjusts the resistance between the collector of Q1512 and ground to determine the amount of current allowed to flow which in turn determines the voltage developed across R1517 FAN MOTOR CIRCUIT 4 General The fan motor used in the 475 is
286. rol Integrated Circuit Main Gate Comparator Delayed Gate Comparator A Trigger TD Reset Circuit Holdoff Start Circuit Z Axis Logic Multivibrator Delaying Sweep Latch Circuit B Trigger TD Reset Circuit Main Sweep Holdoff Gate and Delayed Sweep Override Amplifier A GATE And B GATE Amplifiers rad LOWLINE Indicator Circuit Page 3 12 TM 11 6625 2735 14 1 SWEEP GENERATORS BLOCK DIAGRAM TIMING AND HORIZONTAL DISPLAY SWITCHING General The following discussion is provided to aid in un aa Sweep Generator Fan 3 1 derstanding the overall concept of the 475 Oscilloscope Main Gate Amplifier 5ade 31 before the individual circuits are discussed in detail A Sweep Disconnect Amplifier Page 3 1 basic block diagram of the 475 Oscilloscope is shown in Sawtooth Sweep Generator 3 1 Only the basic interconnections between the p Sweep Start Amplifier individual blocks are shown on this diagram Each block Output Buffer Amplifier Paae 3 1 represents a major circuit within the instrument The Delaying Sweep End Difference numbered diamond in each block refers to the complete Amplifier 2 circuit diagram of that major circuit and this diagram can Delay Pickoff Comparator Page 3 1 be found in the Diagrams Section of this manual Non Delaying Sweep Generators B Gate Amplifier Non Delaying Sweep Generator A complete block diagram is located in the Diagrams Differences Section of this manual This block diagram shows the
287. rom ground decreases intensity 100 V DC plus peak AC 100 V P P AC at 1 kHz or less Characteristics CH 2 VERT SIGNAL OUT Output Voltage Output Resistance Bandwidth Output DC Level A and B GATE Outputs Output Voltage Output Resistance Line Voltage Ranges AC RMS 115V Low Medium High 230 V Low Medium High Direct Current option 07 Line Frequency Maximum Power Consumption TABLE 1 1 cont ELECTRICAL Performance Requirements SIGNAL OUTPUTS One division of deflection gives ap proximately 20 mV into 1 MQ load One division of deflection gives ap proximately 10 mV into 500 load DC to at least 50 MHz into 502 Approximately O V Approximately 5 V positive going POWER SOURCE 110 V 10 115 V 10 120 v 10 220 V 10 240 V 10 12 vdc 24 vdc 48 Hz to 440 Hz 100 watts at 115 V 60 Hz TM 11 6625 2735 14 1 Supplemental Information 99 V to 121 V 103 5 V to 126 5 V 108 V to 132 V 198 V to 242 V 207 V to 253 V 216 V to 264 V 11 5 vdc to 14 vdc 22 vdc to 28 vdc Change 1 1 9 TM 11 6625 2735 14 1 Characteristics CATHODE RAY TUBE Horizontal Resolution Vertical Resolution Display Area Geometry Raster Distortion Normal Accelerating Potential Trace Rotation Range Standard Phosphor Optional Phosphor TABLE 1 1 cont ELECTRICAL Performance Requirements 8 x 10 cm Supplementa
288. rrent loop h Disconnect four two wire cables near F1318 at the bottom left of the board The cable wires to 15 are red with a brown stripe The cable wires to 15 are violet with a brown stripe Cable wires to the pins nearest the fuse GND are black Cable wires to the remaining pins are red with a black stripe 7 Disconnect two coaxial cables from the left center of the board The cable to J1302 is white with a gray stripe and the cable to J1334 is white with black and orange stripes 8 Disconnect the horizontal deflection plate leads at the crt This requires a pair of long nose pliers or tweezers for best removal or reinstallation 9 Disconnect a three wire cable from the Vertical Output board 10 Disconnect a two wire cable from the Fan Motor board 11 Unsolder a 10 ohm 1 2 watt resistor from the center tap terminal of the ceramic thick film resistor mounted near the Vertical Output circuit board 12 Unsolder ten wires from the Main interface circuit board and confirm each wire color with its location in the following list all wires from crt socket a Wire to pad 5 is white with a green stripe b Wire to pad 10 is white with black and brown stripes c Wire to pad 7 is white with a violet stripe d Wire to pad 8 is white with a gray stripe e Wire to the one notch ceramic strip is white with a yellow stripe f Wire to the 2450 test point is solid red g Wire to the right hand notch on the th
289. rs The grease should be applied to both sides of the mica insulators and should be applied to the bottom side of the transistor where it comes in contact with the insulator WARNING Handle silicone grease wlth care Avoid getting silicone grease in the eyes Wash hands thoroughly after use NOTE After replacing a power transistor check that the collector is not shorted to ground before applying power Voltages are present on the exterior surface of the chassis mounted power supply transistors if the power is applied to the instrument and the POWER switch is on Also voltages may be present several minutes after the instrument is turned off Interconnecting Pin Replacement Two methods of interconnection are used in this instrument to connect the circuit boards with other boards and components When the interconnection is made with a coaxial cable a special end lead connector plugs into a socket on the board Other interconnections are made with a pin soldered onto the board Two types of mating connections are used for these interconnecting pins If the mating connector is on the end of a lead an end lead pin connector is used which mates with the interconnecting pin The following infor mation provides the replacement procedure for the various types of interconnecting methods a COAXIAL TYPE END LEAD CONNECTORS Replacement of the coaxial type end lead connectors requires special tools and techniques only experien
290. rt rear cover with two round head screws and install the blue plastic cover on the rear of the instrument with two flat head screws TM 11 6625 2735 14 1 7 Connect the crt anode lead and carefully connect the deflection plate leads After each lead is connected lightly pull on the lead to be sure that it will remain in place 8 475 DM 43 and DM 40 only install the DM 43 or DM 40 main circuit board chassis on the 475 chassis Install two screws at the rear of the main circuit board chassis and connect three ribbon cables to the board 9 If the crt was replaced part of the 475 calibration will need to be checked or adjusted Se Table 4 5 under Recalibration After Repair later in this section for a listing of calibration checks and adjustments that need to be checked after crt replacement High Voltage Multiplier Removal 1 Remove the Vertical Preamp circuit board as outlin ed previously 2 Remove the cathode ray tube as outlined previous ly 3 Remove the high voltage shield from the Main Interface circuit board and remove one screw near the INTENSITY potentiometer 4 Remove four hexagonal posts used to mount the high voltage shield from the Main Interface board with a 3 16 inch nut driver 5 Remove the two nylon nuts from the Main Interface board near C1328 6 Remove three screws holding the multiplier shield to the main chassis and remove the shield 7 Unsolder the black wire from the Multiplier at the
291. runs in the A INTEN MIX and B DLY D positions of the HORIZ DISPLAY switch and generates the A portion of the display In these modes the sweep rate is selected by the A TIME DIV switch skirt knob Main Gate Amplifier Q902 is the Main Gate Amplifier stage The negative going Main Gate waveform from the Sweep Logic circuit is applied to the base of Q902 The amplified and inverted waveform at the collector of C902 is applied to the Delaying Sweep Generator through CR903 or to both of the Non Delaying Sweep Generators through Q992 in the A sweep mode This initiates sweep generation DISCONNECT INTEGRATOR Q1010 Q1014 EL6UG034 AMPL 01004 MILLER etailed biock diagram of the Sweep Generator circuits Sweep Disconnect Amplifier Q904 is the Sweep Disconnect Amplifier The biasing on the base of this stage determines whether the Delaying Sweep Generator will run In the A position of the HORIZ DISPLAY switch the anode of CR907 is connected to 5 volts through R908 and the HORIZ DISPLAY switch circuit This biases the base of Q904 far enough positive that the positive going gates on the emitter cannot turn off Q904 Q904 therefore conducts all of the timing current through R905 R904 and timing resistor R charging timing capacitance C When the HORIZ DISPLAY switch is in any position other than A CR907 is reverse biased which lets the base of Q904 be biased at a level that will allow the positive going gates on
292. s prevents the CRT cathode supply from going more negative than ap proximately 3300 volts Higih Voltage Rectifiers and Output The high voltage transformer T1320 has two output windings One winding provides filament voltage for the cathode ray tube The filament voltage can be supplied from the High Voltage Supply since the cathode ray tube has a very low filament current drain The filament of the cathode ray tube is elevated to the cathode level to prevent cathode to filament arcing The other winding of T1320 is used to derive both the negative cathode potential and the positive anode accelerating potential The positive accelerating potential is supplied by High Voltage Multiplier U1321 Regulated output voltage is approximately 15 500 volts The negative cathode poten tial is supplied by a voltage doubler circuit C1320 CR1320 and CR1321 Voltage output is 2450 volts Variations in supply voltage are monitored by the High Voltage Regulator circuit to provide a regulated high voltage output Control Grid DC Restorer The Control Grid DC Restorer couples dc and low frequency components of the Z Axis Amplifier signal to the CRT control grid This allows the Z Axis Amplifier to control the CRT beam current intensity The potential difference between the Z Axis Amplifier output and the control grid about 2450 volts prohibits direct coupling The dc restorer is actually a cathode referenced bias supply for the CRT control
293. s provide stable sweep triggering to beyond the 200 megahertz bandwidth of the vertical deflection system Separate controls are provided to select the desired mode of triggering for the A and B sweeps The A sweep can be operated in one of three modes automatic triggering normal triggering or single sweep A variable trigger holdoff control permits the A sweep to trigger in a stable manner on aperiodic signals or complex digital words The horizontal deflection system has calibrated sweep rates from 0 5 second to 0 01 microsecond division A X10 magnifier increases each sweep rate by a factor of 10 to provide a maximum sweep rate of one nanosecond per division in the 0148s position The delayed and mixed sweep features allow the start of B sweep to be delayed a selected amount from the start of A sweep to provide accurate relative time measurements Calibrated X Y measurements can be made with Channel 2 providing the vertical deflection and Channel 1 providing the horizontal deflection TIME DIV switch fully counterclockwise and VERT MODE switch to CH 2 Regulated DC power supplies provide stable instrument performance over a wide range of line voltages and frequencies Maximum power consumption of the instru ment is approximately 100 watts Characteristics The following instrument specifications apply over an ambient temperature range of 15 C to 55 C unless otherwise specified Warmup time for specified ac curacies is 20 minutes
294. scription Assembly and or Component TM 11 6625 2735 14 1 Section 7 475 Service Detail Part of Assembly and or Component Attaching parts for Detail Part Parts of Detail Part Attaching parts for Parts of Detail Part Attaching Parts always appear in the same indentation as the item it mounts while the detail parts are indented to the right Indented items are part of and included with the next higher indentation The separation symbol attaching parts indicates the end of Attaching parts must be purchased separately unless otherwise specified ITEM NAME In the Parts List an Item Name is separated from the description by a colon Because of space limitations an Item Name may sometimes appear as incomplete For further ltem Name identification the U S Federal Cataloging Handbook H6 1 Attaching parts for Assembly and or Component can be utilized where possible ABBREVIATIONS INCH ELCTRN ELECTRON IN INCH SE SINGLE END NUMBER SIZE ELEC ELECTRICAL INCAND INCANDESCENT SECT SECTION ACTR ACTUATOR ELCTLT ELECTROLYTIC INSUL INSULATOR SEMICOND SEMICONDUCTOR ADPTR ADAPTER ELEM ELEMENT INTL INTERNAL SHLD SHIELD ALIGN ALIGNMENT EPL ELECTRICAL PARTS LIST LPHLDR LAMPHOLDER SHLDR SHOULDERED AL ALUMINUM EQPT EQUIPMENT MACH MACHINE SKT SOCKET ASSEM ASSEMBLED EXT EXTERNAL MECH MECHANICAL SL SLIDE ASSY ASSEMBLY FIL FILLISTER HEAD MTG MOUNTING SLFLKG SELF LOCKING ATTEN ATTENUATOR FLEX FLEXIBLE NIP NIPPLE
295. se of Q1318 through the feedback winding of T1320 Regulation occurs as follows If the output voltage at the 2450 volt test point starts to go positive less negative this positive going change is applied to the base of Q1306 Q1306 conducts harder which in turn causes Q1308 and Q1316 to conduct harder This results in greater bias current to the base of Q1318 through the feedback winding of T1320 Now Q1318 is biased closer to its conduction level so that it comes into conduction sooner to produce a larger induced voltage in the secondary winding or T1320 This increased voltage appears as a more negative voltage at the 2450 volt test point to correct the original positive going change By sampling the output from the CRT cathode supply in this manner the total output of the High Voltage Supply is held relatively constant 3 25 TM 11 6625 2735 14 1 Q1312 and Q1310 compose an overvoltage protection circuit In the event the regulating action of the circuit should cause the CRT cathode supply to approach approximately 3000 volts the voltage level at the emitter of Q1316 will be very close to 6 volts Normally Q1312 and Q1310 are biased off and do not conduct When the voltage level at the emitter of Q1316 reaches approximate ly 6volts Q1312 is biased into conduction which in turn biases Q1310 on Q1310 now starts to reduce the base drive applied to Q1318 and prevents the amplitude of oscillations from increasing Thi
296. set A TIME DIV to 1 ms and set time mark generator for 1 millisecond time marks b Set DELAY TIME POSITION to 1 000 on dial and position nearest time mark to graticule center c That jitter on the leading edge of the time mark does not exceed 1 division 60 Hertz line or 2 5 division 50 Hertz line Set DELAY TIME POSITION to view each time mark from 2 000 to 9 000 on dial and check delay time jitter for limits stated in part c 28 Check MIX Mixed Sweep Timing Accuracy a Set DLY D SWP to 0 02 us A TIME DIV to 0 05 us HORIZ DISPLAY to MIX and DELAY TIME POSITION fully clockwise b Set time mark generator for 50 nanosecond time marks 5 18 CHECK A TIME DIV settings from 0 0248 to 0 5 s division for accuracy at 2nd and 10th graticule lines 8 division timing within 396 Exclude the first 0 5 division from start of sweep when checking A sweep Set DLY D SWP at least 1 sweep setting faster than A sweep setting on all ranges Set time mark generator to maintain appropriate time marks d Set DELAY TIME POSITION fully coun terclockwise DLY D SWP to 0 05 A TIME DIV to 0 1 and set time mark generator for 50 nanosecond time marks e CHECK DLY D SWP settings from 0 05 8 to 0 5 s division for accuracy at 2nd and 10th graticule lines 8 division timing within 396 Exclude the first 0 2 division or 0 1 microsecond whichever is greater after the transi tion of A to B Set DLY
297. sses unattenuated all signals from DC to 200 MHz and above Input Source Follower Transistor Q522 is a FET field effect transistor con nected as a source follower It provides a high input impedance set primarily by R517 for the trigger signal it also provides isolation between the Trigger Generator circuit and the trigger signal sources CR519 provides input protection for Q522 if excessively high amplitude negative going input signals are present Q524 is a high impedance relatively constant current source for Q522 and provides a measure of temperature compensation for Q522 The output signal from the Source Follower is taken from Emitter Follower Q526 Paraphase Amplifier U520 is a paraphase amplifier stage that converts the single ended input from Emitter Follower Q526 into a dual ended push pull output which is applied to one of the Tunnel Diode Driver stages Trigger Centering adjust ment R534 sets the level at pin 14 of U520 through emitter follower Q532 so that the display is correctly triggered TM 11 6625 2735 14 1 when the LEVEL control is centered The LEVEL control varies the level at pin 14 of U520 to select the point on a trigger signal where triggering occurs The slope of the input signal that triggers the Sweep Generator circuit is determined by the setting of the SLOPE switch 5530 When the SLOPE switch is set to the position the output signal at pin 8 of U520 is inverted with respect to the input sig
298. st equipment TM 11 6625 2735 14 1 Section 6 475 Service SCHEMATIC DIAGRAMS AND OPTIONS 04 AND 07 Symbols and Reference Designators Electrical components shown on the diagrams are in the following units unless noted otherwise Capacitors Values one or greater are in picofarads pF Values less than one are in microfarads 4 F Resistors Ohms 52 Symbols used on the diagrams are based on USA Standard Y32 2 1967 Logic symbology is based on MIL STD 806B in terms of positive logic Logic symbols depict the logic function performed and may differ from the manufacturer s data The following prefix letters are used as reference designators to identify components or assemblies on the diagrams A Assembly separable or repairable H Heat dissipating device heat sink RT Thermistor circuit board etc heat radiator etc S Switch AT Attenuator fixed or variable HR Heater T Transformer B Motor HY Hybrid circuit TC Thermocouple BT Battery J Connector stationary portion TP Test point Capacitor fixed veriable K Relay U Assembiy inseperabie or non repairabie Circuit breaker L inductor fixed or variable integrated circuit etc CR Diode signal or rectifier LR Inductor resistor combination V Electron tube DL Deley line M Meter VR Voltage regulator zener diode etc DS indicating device lamp P Connector movable portion Y Crystal E Spark Gap Q Transistor or silicon controlled Z Phase shifter F Fuse rectifier
299. t several points throughout this instrument When the instrument is operated with the cabinent removed do not touch exposed connections or components Some tran sistors may have elevated cases Disconnect power before cleaning the instrument or replacing parts Standard Cabinet Installation The standard instrument cabinet should be installed in the following manner 1 Disconnect the instrument power cord from the power source 2 f the Vertical Output circuit board cover is not in place install the cover on the top of main chassis Where parts were removed or replaced check all sections of the instrument for proper assembly It may by helpful to use the diagrams in Section 7 Mechanical Parts List for the locations of parts 3 475 DM series only lf the DM series main circuit board is not in place install the board on the main chassis 4 Install the front panel cover and set the instrument face on a flat surface 5 Place the cabinet handle against the bottom of the cabinet bottom of cabinet is nearest the carrying handle pivot points 6 Pull the power cable through the cabinet and slide the cabinet over the instrument using care to avoid pinching cables or damaging components that protrude from circuit boards 7 Using both hands press lightly on the top and bottom sides of the cabinet until the front edge of the cabinet is inserted into the braided gasket groove around the full periphery of the front cabinet fr
300. tate until CR556 has been switched to its high voltage state At the end of the sweep time and during holdoff a negative level is applied to the junction of R558 and R566 thereby resetting both CR556 and CR566 to their low voltage states The reset level remains during holdoff time to ensure that a sweep gating signal is not generated until the sweep circuit has returned to its quiescent state Trigger View Amplifier The Trigger View Amplifier circuit amplifies a sample of the signal present in the A Trigger Generator circuit and passes it on to the Vertical Output Amplifier for display on the CRT when the TRIG VIEW pushbutton impressed This provides a method of making a quick and convenient check of the signal being used to trigger the oscilloscope and is intended primarily to be used to check the timing difference between the trigger signal and the vertical deflection signal TM 11 6625 2735 14 1 The amplifier consists of two emitter coupled push pull amplifier stages The emitter source voltage for Q662 and Q672 is switched on and off by the TRIG VIEW pushbutton With the TRIG VIEW bushbutton not pushed the emitters of Q662 and Q672 are returned to ground through R665 This reverse biases the base emitter junc tions of the transistors preventing any loading of the A Trigger Generator circuit When the TRIG VIEW pushbut ton is pushed the emitters are now returned to 15 volts through R663 and R679 This forward biases Q662 and Q
301. tely displayed on a shared time basis The Vertical Channel Switching circuit also provides several internal trigger signals to the Trigger Generator circuits the Channel 2 VERT SIGNAL OUT signal to a connector on the rear panel and the chopped blanking signal to the Z Axis Amplifier Fig 3 4 shows a detailed block diagram of the Vertical Channel Switching circuit A schematic of this circuit is shown on Diagram 3 at the rear of this manual 3 7 TM 11 6625 2735 14 1 X SIGNAL CH 1 TRIGGER SIGNAL CH 2 TRIGGER SIGNAL 53758 TRIG VIEW SIG OUT CH 1 PREAMP SIGNAL PREAMP SIGNAL A SCALE FACTOR 2 SWITCHING SWITCHING MEGAHERTZ LOGIC CIRCUITS CLOCK FLIP FLOPS Q312 Q314 Q322 Q324 U350A amp B ALTERNATE CHOP BLANKING TRACE SYNC TO CRT CIRCUIT PULSE ALTERNATE HOP SYNC AMP BLANKING AMP 11240 MJJO E Q430 CHANNEL DELAY SWI TCHING LINE CH 2 IC U370 DL380 TO VERTICAL OUTPUT AMPLIFIER dr FROM TRIGGER VIEW AMPLIFIER DELAY LINE DC CENTER NORMAL TRIGGER PICKOFF AMPL Q390 Q396 NORMAL TRIGGER SIGNAL R394 Fig 3 4 Detailed block diagram of the Vertical Channel Switching circuit Channel Switch IC The Channel Switch IC U370 determines which of the Preamp signals will be passed to the Vertical Output Amplifier The push pull Preamp signals connect between pins 2 and 3 Channel 2 and between pins
302. the emitter of Q904 to interrupt the current flow through Q904 When Q904 turns off the timing current starts to discharge timing capacitance 3 17 5 M TM 11 6625 2735 14 1 Sawtooth Sweep Generator Q920 and Q922 forma Miller integrator circuit When the current through the Sweep Disconnect Amplifier Q904 IS interrupted timing capacitance C begins to discharge through timing resistor The timing resistor and capacitance are selected by the A TIME DIV switch to provide the various sweep rates listed on the instrument front panel The output signal at the collector of Q922 is a negative going sawtooth voltage waveform Sweep Start Amplifier Just before the sweep starts to run down the levels at the bases of Q914 are approximately equal When the sweep starts to run down the base of Q914B goes negative which increases the forward bias on CR914B This in turn decreases the forward bias on CR914A which very shortly after the start of the sweep becomes reverse biased to interrupt the current through Q914A The circuit remains in this condition until after the sweep retrace is complete When the circuit returns to quiescence Q914A begins to conduct through R904 This sets the current through Q904 which in turn establishes the DC level starting point for the sweep Output Buffer Amplifier Q940 and Q956 form the Output Buffer Amplifier Q940 is an emitter follower and Q956 is a common base amplif
303. the faceplate to protect it from scratches TM 11 6625 2735 14 1 SAFETY SUMMARY CONT WARNING Adequate ventilation should be provided while using TRICHLOROTRIFLUOROETHANE Prolonged breathing of vapor should be avoided The solvent should not be used near heat or open flames the products of decomposition are toxic and irritating Since TRICHLOROTRIFLUOROETHANE dissolves natural oils prolongted contact with skin should be avoided When necessary use gloves which the solvent cannot penetrate If the solvent is taken internally consult a physician immediately WARNING Compressed air shall not be used for cleaing purposes except where reduced to less than 29 pounds per square inch psi and then only with effective chip guarding and personnel protective equipment Do not use compressed air to dry parts when TRICHLOROTRIFLUOROETHANE has been used Compressed air is dangerous and can cause serious bodily harm if protective means or methods are not observed to prevent chip or particle of whatever size from being blown into the eyes or unbroken skin of the operator or other personnel CAUTION Avoid crl phosphor damage Crt phosphor damage can occur under adverse conditions Avoid any condition where an extremely bright sharply focused spot exists on the crt TM 11 6625 2735 14 1 DO NOT TRY TO PULL OR GRAB THE INDIVIDUAL SAFETY STEPS TO FOLLOW IF SOMEONE IS THE VICTIM OF ELECTRICAL SHOCK IF POSSIBLE TURN OFF THE ELECTR
304. the horizontal centerline iabeled 0 V DC set the test oscilloscope vertical input for de coupling Set test oscilloscope VOLTS DIV and TIME DIV con trols as indicated on readout symbois on each waveform Tolerance of voltages and waveforms shown are 2095 a GATE DISABLE FROM 1067 35v DCPL 1 REN 93 w 9802 OUV 9804 END AF KON DELAYING SWEEP PULSE From 91054 FS c 8124 J RACI TD RESET DELAY PICKDFF gt ARA je Re gt wei 0790 8 325A BK 5 8 tbC 21 1j MAIN 220 100 5135 3195 1 ER Reto viv ER e 322 4 415 a H 2 0 2 4 zc tou i 8V 1 lt CR7IZ e CDS MA 4 mou CRM ARTIC cs cen CRIFE X7 ERIIG SOME BOARDS enne NE 3 MARKED Paoa sav w 3 525 RS12 2 ROSS A CRIN 08799 3 i d iN a pw pm RE B T 1 BC COUPLED ENDS lt TD GATE FROM 5 S 34448 lc CLOSED D m gum e T REM eu POS CF RG C596 R amp oT A JWE 75 2 4600 8595 SE END 4 RSet A t 9596 aS HOLDOFF START 33 5 33 LIT TRACE FROM CRIDNT gt 74 9594 4 1
305. the power transformer CHECKOUT Option 7 may be checked without removing it from the oscilloscope Test voltages are shown rl four 6 6 ideal lan ine reference letters A B etc refer to points indicated on the schematic and circuit board illustrations Equipment Required DC VOLTMETER 22 V to 28 V TEST OSCILLSOCOPE Used to verify the inverter balance adjustment If the instrument under test and Option 7 are operational and the power source has a negative ground they may be used as the test os cilloscope for this check DC POWER SOURCE Voltage from 22 V to 28 V and from 11 5 V to 14 V A source voltage of less than 22 volts will turn off Option 7 when it is operating in the 24 V mode Starting current in 24 V mode is approximately 4 to 10 A The dc source must be capable of handling this surge without dropping to 22 V or less The 12 V starting surge is approximately 15 A NOTE Option 7 is calibrated at the factory using a power supply having the specifications listed first under the equipment required list This permits the most accurate setting of the turn off volts and inverter balance adjustments Because this type of power supply may not be available several alternate possibilities are given The alternate power supplies have drawbacks including voltage stability vs time with high discharge rates see 1 Variable power supply with the aforementioned capabilities 2 Variable power supply with an adeq
306. the two screws that mount the board to two posts on the main chassis 9 Remove the Vertical Mode Gain Switch circuit board and attenuator assembly from the instrument using care to prevent damage to any of the components as the board is removed TM 11 6625 2735 14 1 To install the Vertical Mode Gain Switch circuit board and attenuator assembly reverse the removal procedure To align the VERT MODE switch pushbuttons hold the assembly in place with a slight forward pressure and use a small tool to reach through the front panel to align the buttons Do not tighten the circuit board securing screws until the securing nuts at the front of the attenuator chassis are tight and the circuit board is aligned properly Trigger Generator and Z Axis Logic Board Removal Remove the board as follows 1 475 DM 43 and DM 40 only Disconnect three ribbon cables from the DM 43 or DM 40 Main circuit board Remove two screws from the rear of the main circuit board chassis and separate the board chassis from the instrument chassis 2 Remove the LOW LINE READY and THIG light lenses Pry them away from the front panel with a fingernail and pull them straight out 3 Remove the POWER extension shaft from the power switch plastic actuator Use a small flat blade screwdriver to pry apart the coupling of the shaft and actuator using caution to prevent damage to the coupling 4 Disconnect four ribbon cables from the board as directed in the follow
307. time figure in the appro priate subcolmn s the lowest level of maintenance author ized to perform the function listed in column 3 This figure represents the active time required to perform that main tenance function at the indicated category of maintenance If the number or complexity of the tasks within the listed maintenance function vary at different maintenance cate gories appropriate worktime figures will be shown for each category The number of task hours specified by the worktime figure represents the average time required to restore an item assembly subassembly component module end item or system to a serviceable condition under typical field operating conditions This time includes preparation time troubleshooting time and quality assur ante quality control time in addition to the time required to perform the specific tasks identified for the maintenance functions authorized in the maintenance allocation chart Subcolumns of column 4 areas follows C Operator Crew O Organizational F Direct Support General Support D Depot D 2 e Column 5 Tools and Equipment Column 5 specifies by code those common tool sets not individual tools and special tools test and support equipment required to perform the designated function f Column 6 Remarks Column 6 contains an alphabetic code which leads to the remark in section IV Remarks which is pertinent to the item opposite the particu
308. tput circuit board cover is not in place install the cover on the top of the 475 main chassis Check all sections of the instrument where parts were removed or replaced for proper assembly It may be helpful to use the diagrams in Section 7 Mechanical Parts List for the locations of parts 3 Set the bottom of the Rack Adapter on a flat surface pull the power cord through the cabinet portion of the Rack Adapter and slide the instrument rearward using both hands front and rear to lift and guide the instrument until fully inserted Use care to avoid pinching cables or damaging components that protrude from circuit boards 4 Check that the front edge of the cabinet portion of the Rack Adapter is inserted into the braided gasket groove around the full periphery of the instrument front frame Pull the power cord through the blue plastic rear frame align a cutout portion in the plastic frame for proper fit at the regulating range selector cover and work the frame into place 5 Apply the rear support bracket to the rear of the Rack Adapter Install without tightening 6 screws that secure the rear support bracket through the blue plastic frame to the rear of the instrument and 4 screws that secure the rear support bracket to an angle bracket and to the Rack Adapter chassis 6 Check that all parts of the complete assembly are properly seated then tighten to a snug fit the screws at the rear of the instrument and the screws at the adapte
309. trigger signal Selects the horizontal mode of operation A Horizontal deflection provided by A TIME DIV switch Horizontal POSITION Horizontal FINE X10 MAG Pushbutton Calibrator and Power CALIBRATOR POWER TM 11 6625 2735 14 1 MIX The first part of the horizontal sweep is displayed at a rate set by the A TIME DIV switch and the latter part of the sweep at a rate set by the B TIME DIV switch Relative amounts of the display allocated to each of the two rates are determined by the set ting of the DELAY TIME POSITION dial A INTEN Displayed sweep rate determined by the A TIME DIV switch An inten sified portion appears on the display during the B sweep time This switch position provides a check of the duration and position of the B sweep delayed sweep with respect to the delaying sweep A B DLYD Sweep rate deter mined by the B TIME DIV switch with the delay time determined by the setting of the DELAY TIME A TIME DIV switch and the DELAY TIME POSITION dial Positions the display horizon tally Provides more precise horizon tal position adjustments Increases the displayed sweep rate by a factor of 10 A combination current loop s quarewave voltage output device Provides a 30 mA squarewave current 300 mV squarewave voltage signal with a repetition rate of ap proximately 1 kHz Turns instrument power on and off 2 7 TM 11 6625 2735 14 1 LOW LINE Indicator Rear Pan
310. uate current rating in series with items 4 or 5 TM 11 6625 2735 14 1 3 1106 Power Supply battery pack 4 Two 12 volt wet cell storage batteries in series tapped at 20 22 or 24 5 18 to 23 Ni Cd cells 4 0 amp hr D cells or greater furnishing 20 to 28 BATTERY CURRENT Figure 6 5 Typical battery pack discharge curves CAUTION This procedure is for an external dc source with the negative lead at ground potential negative ground system Operating Range a Connect the dc source to the oscilloscope equipped with Option 7 Operate the oscilloscope in the 24 V mode Connect the voltmeter between fuse F1601 B and the common negative return A Vary the dc source from 28 V to 22 V CHECK Oscilloscope should operate over the voltage range To set the turn off level the battery is charged above the cut off point 22 V An osciticecope is connected and the battery allowed to while voltage le being monitored As it reaches 22 V the turn off point is set to cut off Option 7 The turn off point on Option 7 approximately coincides with the meter zero 1700 me This does not permit accurate adjustment of the turn off level Ni Cd batteries can be used following the technique used for item 3 Change 1 6 2 5 TM 11 6625 2735 14 1 TURN OFF Semiconductor Electrode Configuration INVERTER LEVEL MAN A eS 5 SS 9 Q1626 SCR v jeu N Gate Cathod
311. uipped with 7A13 Amplifier and 7850 Time base units or equivalent Frequency response DC to 75 MHz Deflection factor 1 mV to 5 V Div Input impedance 1 20 pF Sweep rate 50 ns Test oscilloscope Fast rise 10X attenuation probe eom Tektronix P6053B cquivalent patible with vertical amplifier of test oscilloscope Tektronix DM 501 Digital Multimeter or equivalent Input Impedance 10 Range 0 to 500 V Voltmeter Non loading Digital Multimeter 475 Control Settings Sweep Controls Display Controls TIME DIV 0 1 m gt INTENSITY Midrange VAR TIME DIV Calibrated detent FOCUS Midrange DELAY TIME SCALE ILLUM Midrange POSITION Full counterclockwise HORIZ DISPLAY A X10 MAG Off button out POSITION Midrange FINE Midrange Vertical Controls CH 1 and CH 2 PCSITION trace on graticule VOLTS DIV 2 mV for dc voltages Voltage Measurements 100 TY for wavetorms 2 VAR VOLTS DIV ated detent Voltage measurements are taken with no signal applied AC GND DC DC and the trace positioned to the center horizontal graticule n line The voltmeter common is connected to chassis INVERT Off sutton out ground VERT MODE CH 100 or 20 MHz BW Fu bandwidth Push in Waveform Conditions n release Apply the 475 calibrator signal to CH 1 input through a P6075 10X probe supplied with 475 Connect 475 A GATE rear through a 42 inch 50
312. ulator Q1496 positive and turns it off The output current from the supply is then limited by R1488 and the 110 Volt Supply is thereby protected 15 Volt Supply Basic operation of all stages in the 15 Volt Supply is the same as for the 50 Volt Supply The 15 volt reference for this supply is established by divider R1444 R1445 between 50 volts and ground Any change in the output level of the supply is compared at Feedback Amplifier U1454A which produces a signal of inverted polarity at its output pin 1 This change is coupled to 15 Volt Series Regulator Q1448 through Q1446 to correct the change in output voltage Transistor Q1444 provides current limiting foldback operation if the supply load Increases beyond preset limits or becomes shorted to ground 3 24 5 Volt Supply Basic operation of all stages in the 5 Volt Supply is the same as described in the 50 Volt Supply and the 15 Volt Supply The 5 volt reference for this supply is established by divider R1454 R1455 between 50 volts and ground Any change in the output level of the supply is compared at Feedback Amplifier U1454B which produces a signal of inverted polarity at its output pin 7 This change is coupled to 5 Volt Series Regulator Q1456 to correct the change in the output voltage Transistor Q1454 provides current limiting fold back operation if the supply load increases beyond preset limits or becomes shorted to ground 8 Supply Basic operation
313. ve a screw from the rear of each slide section mounted to the Rack Adapter These securing screws are an important part of the mounting and should be installed when tilt operation is not necessary 2 Remove the Rack Adapter with instrument from the rack and set the bottom of the complete assembly on a flat surface 3 Remove 2 setscrews from the top front of Rack Adapter chassis A 0 125 inch Allen wrench is required to remove the setscrews It may be helpful to use the diagrams in Section 7 Mechanical Parts List for the locations of parts 4 Remove 10 screws that hold the rear support plate to an angle bracket on one side to the Rack Adapter chassis on the opposite side and to the rear of the instrument Remove the rear support plate and blue plastic rear frame 4 3 TM 11 6625 2735 14 1 5 Slide the instrument forward through the adapter cabinet using both hands front and rear to lift and guide the instrument until separated from the Rack Adapter Dangerous potentials exist at several points throughout this instrument When the instrument is operated with the Rack Adapter removed do not touch exposed connections or components Some transistors may have elevated cases Disconnect power before cleaning the instrument or replacing parts Rack Adapter Installation The Rack Adapter should be installed in the following manner 1 Disconnect the instrument power cord from the power source 2 lf the Vertical Ou
314. verall deflection factor of each channel of the 475 is determined by the appropriate VOLTS DIV switch setting The basic deflection factor of the Vertical Defection System is 5 millivolts division of CRT deflec tion To achieve the deflection factor values indicated on the front panel precision attenuators are switched into the circuit and in the 2 mV position the gain of the Second Cascode Amplifier stage is increased For the VOLTS DIV switch positions above 5 mV attenuators are switched into the circuit singly or in pairs to help produce the vertical deflection factors indicated These attenuators are frequency compensated voltage dividers In addition to providing constant attenuation at all frequencies within the bandwidth of the instrument the Input Attenuators are designed to maintain the same input RC characteristics for each setting of the VOLTS DIV switch Each attenuator contains an adjustable series capacitor to provide correct attenuation at high frequen cies and an adjustable shunt capacitor to provide correct input capacitance NOTE Each attenuator is a hybrid encapsulated plug in assembly therefore replacement of individual comp pnents within the attenuator are not possible Should defects occur the attenuator must be replac ed as a unit First Cascode Amplifier The first amplifier stage in the Channel 1 Preamplifier circuit is hybrid circuit U120 U120 basically consists of an integrated emitter coupled push
315. volt Check the voltages in the amplifier against the voltages listed on the Horizontal Amplifier schematic diagram Check the voltage at the bases of Q1124 and Q1134 for balance and apply this balance check procedure to each stage proceeding toward the amplifier output Install Q1114 Q956 and Q1026 in their sockets and check for a repetitive sweep Troubleshooting the Vertical System The instrument front panel TRIG VIEW control provides a quick way to find trouble in this circuitry Press the TRIG VIEW pushbutton and adjust A TRIGGER LEVEL control to bring the trace to the crt viewing area If unable to obtain a trace look for a problem in the Vertical Output Amplfier If a trace can be obtained look for a problem in the Channel 1 or Channel 2 Preamplifier or the Vertical Channel Switching circuitry When troubleshooting the vertical deflection system the best procedure is to start from the input and work to the output of the problem circuit area determined by previous checks using TRIG VIEW pushbutton Preamplifier Troubleshooting The following procedure can be used for Channel 1 or Channel 2 Preamplifier Channel 1 is described as an example to identify circuit functions Remove any external signal from the instrument input Check the input of U120 pin 13 for O volt Connect a voltmeter between pins 5 and 9 of U120 and adjust CH 1 VAR BAL R110 for O volt Measure from pin 5 or 9 of U120 to ground and check for the recomm
316. when storing or transporting the instrument Uu LS v CAUTION aS SO The volts division attenuators use a plastic material polyphenylene oxide that is easily damaged by the use of carbon based solvents Avoid the use of chemical cleaning agents which might damage the plastics used in this instrument Do not use chemicals that contain acetone benzene toluene xylene petroleum ether white kerosene carbon tetrachloride methylene chloride trichloroethane trichlorotrifluoroethane freon 113 tf ta tmc and trichlorethylene Recommended cleaning agent for general interior cleaning except switch contacts is isopropyl alcohol Read the information under Cleaning Switch Contacts before attempting to clean in the area of the volts division attenuators As a second choice in the absence of these cleaners it is safe to use ethyl alcohol fotocol ethanol and methyl alcohol methanol Most spray circuit coolants contain freon 12 as a propellant Because many freons adversely affect switch contacts check the contents and brand name before using a spray coolant Hecommended circuit coolant for the volts division attenuators is isopropyl alcohol TM 11 6625 2735 14 1 CRT Face Filter and Shields Clean the Individual blue or clear plastic implosion shields and the crt face with a soft lint free cloth dampened with denatured alcohol ethyl alcohol or a mild deterg
317. wire to facilitate correct reassembly 5 Option 7 only Unsolder five wires from the transformer terminals and confirm each wire color with its location in the following list a Wire to terminal 10 is white with a brown stripe b Wire to terminal 10A is white with a red stripe c Wire to terminal 11 is white with a gray stripe d Wire to terminal 12A is white with an orange stripe e Wire to terminal 12 is white with a yellow stripe 6 475 DM 43 and DM 40 only Unsolder five wires from the transformer terminals and confirm each wire color with its location in the following list a Wire to terminal 10 is white with a brown stripe b Wire to terminal 10A is white with a red stripe c Wire to terminal 11 is white with an orange stripe d Wire to terminal 12A is white with a yellow stripe e Wire to terminal 12 is white with a green stripe 7 Remove two screws and Keps nuts that hold the transformer bracket to the rear of the main chassis Remove two Keps nuts that hold the transformer bracket to the main chassis and the transformer electrical shield A 5 16 inch nut driver wrench is helpful for easiest removal of these nuts 4 30 8 Unsolder the wires from the thermal cutout on the transformer bracket and note the wire colors 9 Unsolder the transformer wires from the Main Interface board as directed in the Main Interface board removal procedure part 20 10 Remove the transformer from the instrument

TM 11-6625-2735-14-1

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