TROUBLESHOOTING - Jogis Roehrenbude
Contents
1. NOTES 1 VOLTAGE MEASUREMENTS TAKEN WITH 20 000 OHM3 PER VOLT METER VOLTAGE MEASUREMENTS ABOVE LEAD LINE RESISTANCE MEASUREMENTS BELOW LEAD LINE 3 ALL MEASUREMENTS YAKEK BETWEEN POINTS INDICATED AND GROUND 4 NO TUBE IN TEST SOCKETS 8 THE TV 2A U RESISTORS A40 AND 42 ARE MOUNTED ON THE REAR OF THE CHASSIS 6 SWITCH CONTROL POSITION p irap ELLE ALL SELECTORS METER B FULLY COUNTER CLOCKWISE ADJUST FOR 00 V on PLATE METER FULLY COUNTER CLOCKWISE a ALIGNED WITH INDEX MARKING PANEL AONUST FORRED LINE TM6625 3i8 35 03 Figure 13 Resistor mounting board voltage and resistance diagram Frobabie trouble Correction Bias supply filter capacitor Replace C3 short circuited H Transformer T2 secondary Replace T2 winding 26 28 open 5 SCREEN VOLTS meter does Sereen supply tube V3 Replace not indicate defective SCREEN VOLTS meter M6 Check meter and replace if defective necessary Screen supply filter capacitor Replace C4 C4 short cirenited Screen voltage multiplier re Replace defective resistor or poten sistor R56 or SCREEN volt tiometer age potentiometer R54 open Transformer secondary Replace T2 i winding 15 25 open 1 SIGNAL meter M4 does SIGNAL meter M4 defective Check meter M4 and replace if indicate defective Signal voltage di2. fig 21 Set the PLATE switch to position 5 5 Depress the PRESS TO TEST switch to its locked position Set the GM SIGNAL RANGE switch to position and all cther switches and controls to their neutral or OFF position vertical posi tion for switches extreme counterclockwise position for controls d Connect the AN URM 106 between pin 5 of the OCTAL tube test socket and a ground test point mounting screw on the tube tester Set the ON OFF switch to the ON position f Adjust the PLATE fine control and set the PLATE SCREEN RANGE switch to read its corresponding voltage on the PLATE meter as follows PLATE SCREEN RANGE switeh position Vokaga 250 125 125 62 5 35 29 ac NPOVARORe Ra g The voltages measured on the AN URM 105 will be equal to the voltages indicated on the PLATE meter 2 5 percent error at each de point and 6 percent error at each ac point 30 Screen Voltage Test fig 21 Set the SCREEN switch to position 4 b Depress the PRESS TO TEST P4 switch to its locked position Set the PLATE fine control in position as indicated paragraph 29f the GM SIGNAL RANGE switch to position A and all other switches and controls to their neutral or OFF position vertical position for switches extreme counterclockwise position for controls d Connect the AN URM 105 between pin 4 of the OCTAL tube test socket and a ground test AGO 148A point
3. HAPTER 2 TROUBLESHOOTING F AV r E Warning When servicing the tube tester be very careful of the high voltages Always dis connect the tube tester from the power source before removing the chassis from the case Before touching any exposed portion of the circuitry with the power off short circuit the part to ground dissipate any residual charge which may be retained by a capacitor 12 General Instructions Troubleshooting at fourth and fifth echelon maintenance levels includes ail the techniques outlined for organizational maintenance TM 11 6625 316 12 and any special or additional techniques required to isolate a defective part The field and depot maintenance procedures are not complete in themselves but are supplemented by the procedures described in TM 11 6625 316 712 The systematic troubleshooting procedure which begins with the checks that can be per formed at an organizational level must be com pleted by means of additional localizing and iso lating techniques 13 Organization of Troubleshooting Procedures General The first step in servicing de fective tube tester is to localize the fault to the circuit responsible for abnormal operation The second step is to isolate the fault to the defective part that is responsible for the abnormal condi tion Some faults such as a burned out resistor can often be located by sight or smell The majority of faults however must be localized by chec
4. for short cuits PILOT lamp 11 defective Check lamp I1 and replace if neces sary Power cord defective Check power cord and connector and replace if necessary 2 PILOT lamp 1 lights but FILA FILAMENT VOLTS meter Check meter and replace if MENT VOLTS meter 1 does defective necessary not indicate Filament transformer T1 Check resistance of T1 per 18 fg 8 detective Replace 1 if necessary FILAMENT RANGE switch Check switch S1 Replace switch 1 S1 defective if necessary 8 PILOT lamp Ii lights but PLATE Power transformer T2 pri Check primary windings of trans meter M5 SCREEN VOLTS mary winding open orshort former T2 fgs 4 and 12 per meter 6 GRID BIAS VOLTS circuited 186 Repair defective wiring or meter M2 and SIGNAL meter replace transformer if necessary do not indicate lt With FUNCTION switch 54 in Plate supply tube V1 Replace TEST position and PLATE defective SCREEN RANGE switch S3 in any position but OFF PLATE PLATE meter defective Check meter and replace if meter M6 indicates zero plate necessary voltage PLATE SCREEN RANGE Check switch S3 and replace if switch S3 defective Necessary Transformer 2 secondary Replace T2 winding 3 14 open 5 GRID BIAS VOLTS meter 2 does Bias supply tube V2 defective Replace V2 not indicate GRID BIAS VOLTS meter Cheek meter M2 and replace if 2 defective defective AGO HISA
5. 23 Set the PLATE switch to position 5 b Set the SUPPRESSOR switch to position 8 Set the PLATE SCREEN RANGE switch to position S d Set the GM SIGNAL RANGE switch to position E Set the SHUNT fine control to position 10 7 Set the PLATE fine control fully clockwise g Set all other switches and controls to their neutral or OFF positions vertical position for switches extreme counterclockwise position for controls Connect the test cords of the TS 682A GSM 1 to the COMMON and jacks on the test meter 4 Connect the test cord from the COMMON jack on the test meter to 8 of the OCTAL tube test socket on the tube tester j Connect the test cord from the jack on the test meter ta pin 5 of the OCTAL tube test socket on the tube tester k Set the ON OFF switch to the ON position L With the PRESS TO TEST P2 switch de pressed adjust the DIRECT CURRENT COARSE CONTROL and the DIRECT CUR RENT FINE CONTROL on the teat meter until the PERCENT QUALITY meter on the tube tester indicates full scale The TS 682A GSM 1 indicates 4 92 mil liamperes de 6 percent error T Set ON OFF switch tothe OFF position o Remove the test cord on the BMA jack and connect it to the 1MA jack on the TS 682A GSM 1 Set the SHUNT fine control to positlon 90 q Set the ON OFF switch to the ON position 7 With the PRESS TO TEST P2 switch de pressed adjust the D
6. 25 5 or 2 5 volts ac respectively The ME 80A U indicates 5 percent error at each point DUO Al 3 ni Nowa 335 1931 1531 9 170 g D AYER HLM VILALTA sen 1621 1931 39VL9A INIS V n 08 li AGO 10284 38 32 Filament Voltage Test B fig 22 Set th FIL switch to position 7 b Set the FIL switch to position 2 Set the GM SIGNAL RANGE switch to position A and all other switches amp nd controls to their neutral or OFF position vertical position for switches extreme counterclockwise position for controls d Connect the ME 30A U between pins 2 and 7 of the OCTAL tube test socket Set the ON OFF switch to the ON position f Set the FILAMENT RANGE switeh to each of its 19 voltage positions and adjust the FILAMENT fine control for the exact corres ponding voltage on the FILAMENT VOLTS meter g The voltages measured on the ME 30A U will be equal to the voltages indicated on the FILAMENT VOLTS meter 6 percent error at each point 33 Gas Test fig 21 Caution Be sure that the power switch is in the OFF position before performing the gas test a Set the GRID switch to position 4 8 Set the CATHODE switch to position 7 Set the FUNCTION switch to position VR d Set the GM SIGNAL RANGE
7. Depress PRESS TO TEST P4 switch 519 to its locking position 5 Set the SHORT TEST switch to OPER position 6 Set the FUNCTION switch to TEST position 7 Set the PRESS TO TEST P1 P2 P3 P5 and P6 switches to neutral position 8 Set all SELECTORS switches to 0 position 9 Set the FILAMENT RANGE switch to OFF position 5 Filament Circuit 1 Measure the de resistance between ter mtnals and 22 at the secondary of transformer T1 fig 8 and 12 2 The resistance should be about 20 ohms An infinite reading indicates that there is an open secondary wind ing or a faulty connection at one of the terminals 3 To detect a break check the dc resist ance from terminal to terminal If the resistance is zero across any two ter minals the circuits across the winding are short circuited or the winding itself is short circuited c Plate Supply Circuit 2 AGO 123A 2 terminal 34 of the 5 volt heater wind ing 83 35 of transformer T2 fig 4 and 12 and ground The resistance should be 250 000 ohma If the resistance is low or zero the plate high voltage circuit is grounded d Screen Supply Circuit 2 3 Measure the dc resistance between pin 7 of tube fig 11 and ground The resistance should be between 9 500 and 12 000 ohms this dependa on the setting of SCREEN fine control R54 If the resistance reading is very high or infinite potentiometer R64 bleeder
8. R potentiometer R46A and resistors R47 R49 and R50 for possible short circuits 165 oc CELI ao PLATE SUPPLY BIAS SUPPLY SCREEN SUPPLY vi v2 vs 83 6x4 6 4 NOTES SWITCH OR CONTROL POSITION SHORT TEST UNCTION ALL SELECTORS FILAMENT RANGE 625 AD JU OR 62 v ON FULLY COUNTERCLOCKWISE ADJUST FOR IOOV METER a ALIGNED WITH INDEX MARKING ON PANEL ADJUSY FOR RED LIME METER ju CENTERING Figure 11 Tube socket voltage and Figure 12 Located in back of m FULLY COUNTERCLOCKWISE 1 40 VOLTAGE MEASUREMENTS TAKEN WITH 1 000 OHMS PER VOLT METER DC VOLTAGE MEASUREMENTS TAKEN WITH 20 000 OHMS PER VOLT METER 2 VOLTAGE MEASUREMENTS ABOVE LINE RESISTANCE MEASUREMENTS BELOW LINE 3 ALL MEASUREMENTS WITH EXCEPTION OF FILAMENT VOLTAGES TAKEN BETWEEN POINTS INDICATED GROUND 4 NO TUBE IN TEST SOCKETS 5 SWITCH AND CONTROL POSITIONS AS SHOWA ON CHART 6625 316 35 1 resistance diagram Chasis voltage and resistance diagram annal AGO 128A AGO 14284 NOTES 1 VOLTAGE MEASUREMENTS TAKEN WITH 20 000 OHMS PER VOLI METER 2 VOLTAGE MEASUREMENTS A OVE LEAD LINE RESISTANCE MEASUREMENTS BELOW LEAD LINE ALL MEASUREMENTS TAKEN BETWEEN POINTS INDICATED AND GROUND 4 NO TUBE tN TEST SOCKET CN THE TV 2A U RESISTORS R40 AND A42 A
9. SCREEN selector switches Operate the PLATE selector switch to the 0 position d Operate the SCREEN selector switch to the position designated for the PLATE selector switch Operate the GM SIGNAL RANGE switch to tho position 7 Adjust the SCREEN fine control until the voltage specified on the chart for the PLATE meter is indicated on the SOREEN VOLTS meler Note It may be necessary to operate the PLATE SCREEN RANGE switch to a new setting moving the switeh in a counterclockwise direction that the SCREEN VOLTS meter can indicate the voltage specified for the PLATE meter g Adjust all other fine controls as required on the tube test data chart for the tube under test h Turn the SIGNAL VR fine control to its maximum counter clockwise position 4 Operate the FUNCTION switch to the VR position 2 Operate the SHUNT control to 0 k Depress the PRESS TO TEST P5 switch Be sure the proper voltages for the tube being tested appear on all other meters Note the rending on the 0 to 50 milliampere scale on the PLA TE meter 1 Release the PRESS TO TEST P5 switch m When the test is completed operate the ON OFF power switch to the OFF position remove the tube under test from the test socket and return all switches and controls to their safety positions par 154 Pentodes and beam power tubes may be tested in this method if a 100 Ohm 1 W resistor is connected across the plate and screen pins of the t
10. TV 2 U 45 2 100 micromhoa d The calculated mutual conductance of each 955 2 200 micromhos tube measured the TV 2 will be equal 5840 5 000 micromhos to the mutual conductance measured on the 2 200 silerombos Figure 24 MIL STD resistor color code markings Located in back of manual Figure 25 MIL STD capacitor color code markings Located in back ef manual Figure 26 Tent Set Eicetron Tube TV 2 U schematic diagram Lacated in back of manual Figure 27 Test Set Electron Tube TV 2 U chassis and resistor mounting board wiring diagram Lacated in back of manual Figure 23 Test Set Electron Tube TV U control and inatrument panel wiring diagram Located in back of manual 42 AGO 2 53 PLATECSCREER RANGE PLATE SUPPLY y 5 33 3300 EO E s2 Bias SuppL sit p such ss xa OR CATHOCE DF TUBE UNDER TEST SIGNAL VOLTAGE FOR TUEE UNCER TEST SCREEN SUPPLY va SCREEN VOLTAGE 6x4 OR Graw FOR TUBE UNCER EST PLATE Por TUBE TEST Figure Simplified power supply circuit megesett ac APUT se seco d ERE me me pw mo m BD WU 5 m t m woth fest unen sie En Est 73 5 I uw sis R59 Y PLATE tle sect 2 SCREEN I FRONT
11. mounting screw on the tube tester chassis Setthe ON OFF switch to the ON position f Adjust the SCREEN fine control and set the PLATE SCREEN RANGE switch to read its corresponding voitage on the SCREEN VOLTS meter as follows PLATE SCREEN RANGE switch position Voltage 225 180 2 135 180 L 138 M 90 N 90 P 46 9 The voltages measured on the AN URM 195 will be equal to the voltages indicated on the SCREEN VOLTS meter 5 volts error at each point 31 Signal Voltage Test A fig 22 Set the PLATE SCREEN RANGE switch to position S b Set the GM SIGNAL RANGE switch to position A Set the PLATE fine control fully clockwise d Set all other switches and controls to their neutral or position vertical position for Switches extreme counterclockwise position for controls e Set the ON OFF switch to the ON position f Adjust the SIGNAL V R fine control so that the SIGNAL meter indicator deflects to the redline g Set BIAS RANGE switch to position 10 Set the GRID switch to position 5 i Adjust the BLAS fine control so that the GRID BIAS VOLTS meter indicates 6 volts 1 Set the ON OFF switch to the OFF position k Connect the ME 30A U between pin of the OCTAL tube test socket and a ground test point mounting screw on the tube tester Set the ON OFF switch to the ON position Set the GM SIGNAL RANGE switch to position A B C D or E to read 25 25
12. necessary FILAMENT RANGE switch Check switch S1 Replace switch 1 S1 defective if necessary 8 PILOT lamp Ii lights but PLATE Power transformer T2 pri Check primary windings of trans meter M5 SCREEN VOLTS mary winding open orshort former T2 fgs 4 and 12 per meter 6 GRID BIAS VOLTS circuited 186 Repair defective wiring or meter M2 and SIGNAL meter replace transformer if necessary do not indicate lt With FUNCTION switch 54 in Plate supply tube V1 Replace TEST position and PLATE defective SCREEN RANGE switch S3 in any position but OFF PLATE PLATE meter defective Check meter and replace if meter M6 indicates zero plate necessary voltage PLATE SCREEN RANGE Check switch S3 and replace if switch S3 defective Necessary Transformer 2 secondary Replace T2 winding 3 14 open 5 GRID BIAS VOLTS meter 2 does Bias supply tube V2 defective Replace V2 not indicate GRID BIAS VOLTS meter Cheek meter M2 and replace if 2 defective defective AGO HISA 16 Voltage Measurements figs 11 12 and 13 4 Measure the tube socket voltage with the multimeter Refer to the tube socket diagram fig 11 for voltages normally present Be sure that the switches and controls are set as indi cated in the Notes column on figure 11 b Measure the voltage at the test points on the front rear and top of the chassis with the multimeter Refer to figures 11 and 12 for typi cal voltages
13. switch to position A and all other switches and controls to their neutral or OFF position vertical posi tion for switches extreme counterclockwise position for controls Connect the AN URM 105 between pins 4 and 7 of the OCTAL tube test socket f The AN URM 105 indicates a resistance of 180 000 ohms 10 percent error when the PRESS TO TEST P6 switch is depressed 34 Leakage Test Set the tube tester up according to the tube test data roll chart to test tube 6 6 b Insert the 6Y6 tube and perform the inter element leakage LK test Remove the 6V6 tube and insert a 450 000 ohm resistor between pins 4 and 8 of the OCTAL tube test socket d Set the SHORT TEST switch to position Set the ON OFF switch to the ON position f The PLATE meter indicates to the right of the 0 5 megohm point AGO 14284 g Set the ON OFF switch to the OFF position Remove the 450 000 ohm resistor and in sert 550 000 ohm resistor in its place i Setthe ON OFF switch to the ON position j The PLATE meter indicates to the left of the 0 5 megoh point 35 Short Test Set the tube tester up according to the tube test data roll chart to test tube 6V6 b Insert 3 000 ohm resistor between pins 8 and 7 of the OCTAL tube test socket Set the ON OFF switch to the ON position d The FIL CONT SHORT lamp glows con tinuously when the SHORT TEST switch is set to positions V W and Z Set the ON O
14. Be sure that the switches and con trols are set as indicated in the Notes column on figures 11 and 12 Measure the voltage at the test points on the resistor mounting board fig 13 with the multimeter Be sure that the switches and trols are set as indicated in the Notes column on figure 13 Troubleshooting Chart fig 26 17 Localizing Troubles amp General In the troubleshooting chart c below procedures are outlined for isolating troubles to a particular component part Voltage and resistance measurements are shown in fig ures 11 13 Depending on the nature of the op erational symptoms one or more of the localiz ing procedures will be necessary 5 Use of Chart The troubleshooting chart 18 designed to supplement operational checks that can be performed at an organizational level If previous operational checks have resulted in reference to a particular item of the chart go directly to th eferenced item If no operational symptoms are known begin with step 1 of the equipment performance checklist TM 11 6625 316 12 and proceed until a symptom of trou ble appears T Symptom Probable trouble Correction 1 PILOT lamp 11 does not light and Fuse Fi or F2 defective or Check fuses Fl and F2 Replace as tube tester fails to operate burned ont necessary If replaced fuse burns out check plate supply terminals 3 14 of transformer 2 and pacitors and
15. FF switch to the OFF position f Remove the 2 000 ohm resistor and insert it between pins 4 and 8 of the OCTAL tube test socket g Set the ON OFF switch to the ON position h The FIL CONT SHORT lamp glows con tinuously when the SHORT TEST switch is set to positions Y and 2 1 Setthe ON OFF switch to the OFF position j Remove the 3 000 ohm resistor and insert it between pins 5 and 8 of the OCTAL tube test socket k Set the ON OFF switch to the ON position L The FIL CONT SHORT lamp glows con tinuously when the SHORT TEST switch is set to positions X and Z 36 Cathode Bias Resistance Test D fig 21 Caution Be sure that the power switch is in the OFF position before performing the cathode b as resistance test Set the CATHODE switch to position 1 b Connect the AN URM 105 between pin 1 of the OCTAL tube test socket and a ground test point mounting screw on the tube tester chassis The resistance reading of the AN URM 105 is 47 94 141 188 or 288 ohms when the BIAS RANGE switch is set to position A B C D or E respectively 10 percent error at each point 37 Filament Confinuity Test c Check a IL4 tube known to have a closed filament 39 b FIL CONT SHORT lamp glows when checking for filament continuity t Check a IL4 tube known to have Rn open filament d The FIL CONT SHORT lamp does not glow when checking for filament continuity 38 Shunt Control Test fig
16. IRECT CURRENT COARSE CONTROL and the DIRECT CUR RENT FINE CONTROL on the TS 682A GSM 1 until the PERCENT QUALITY meter on the tube tester indicates full scale The TS 682A GSM 1 indicates 0 605 mil liampere dc 3 5 percent error AGO HMA 091 pines junys 92 82 asi 19130 nf 8A 80412312138 1621 9990906029 950690 0 o e e 9 e 3041802 3 wvo2 0 To 000 9 eooQ9 1 WE0 YZ89 51 33 1531 03130 4t AGO 39 Final Performance Test TRANSCONDUCTANCE meter on the AN Use the TV 2 U and Test Set Electron USM 81 10 percent error Tube AN USM 31 to measure and record the Tubes and rated mutual conductance for mutual conductance of each tube listed in tubes to be checked are as follows below b Use the FILAMENT PLATE SCREEN Tube Rated mutual conductance and BIAS voltages derived from the TV 2 3E29 8 500 mierorahos U tube test data roll chart for their correspond 6A6 3 160 mieromhos ing setting on the AN USM S1 GAT6 1 200 micromhoa Calculate and record the mutual conduct sve 4 100 micromhos ance by multiplying the rated mutual conduct Buon 1500 Neon ance listed In below t mes the percent quality 36 900 mierornhos value indicated for each tube on the PERCENT a 2 209 micromhom QUALITY meter of the
17. ORT lamp 12 does not light With tube tester adjusted for in terelement leakage test no deflec tion ean be obtained on PLATE meter when there is leskage between two or more elements of tube under test SHUNT potentiometer R33 open GM SIGNAL RANGE switch 85 PRESS TO TEST P4 switeh S19 defective Resistor R40 or R42 in trans conductance G test net work or GM CENTERING potentiometer R44 defective Wiring in grid circuit open Resistor R58 defective Wiring in plate or meter cir cuit open One of the current limiting resistors R19 through R26 in plate circuit defective Shunt resistor R30 R31 R40 R42 or GM CENTERING potentiometer R44 defec tive SHUNT potentiometer R33 defective SCREEN potentiometer R64 or SIGNAL V R potentio meter R46A defective Screen supply filter capacitor Ct short circuited FUNCTION switch 54 defec tive SIGNAL V R potentiometer 468 defective Signal voltage divider resis tor R47 R49 or R50 defec tive FIL CONT SHORT lamp 12 defective SHORT TEST switch S11 de fective FUNCTION switch 84 defec tive Multiplier resistor R38 defec tive Check switches 55 and 519 and re place if necessary Replace defective resistor or poten tiometer Check wiring and repair if defec tive Replace defective resistor Check wiring and repair if defect tive Replace defective resistor Replace defective resistor or po
18. RANGE ir FRON Er i s2 e PLATE d ss REAR ss REAR ag E REAR FE 9 v v Fear Figure 5 Transconductance measurement circuit of Test Set Electron Tubo TV 2 U NOTE SWITCH CONTACTS MADE WiLL VARY WITH THE OF TUBE UNDER TEST TM 625 36 35 6 90 Zero Adjustment of PERCENT QUALITY Meter When the procedures in paragraph 19 have been completed adjust tha PERCENT QUALITY meter to zero This adjustment should be made each time before testing any tube for transconductance GM Proceed as follows tlie GM SIGNAL RANGE switch to the F position 6 Depress the PRESS TO TEST P4 switch to its locking position Reset controls to give the exact meter readings specified in the METER SETTING columns of the tube test data sheet c Adjust the CENTERING control until the pointer of the PERCENT QUALITY meter set exactly to zero on the scale d Release the switch 28 Procedure for Reading Plate Current Less than 50 Milli amperes of Triode Tubes Perform the operations indicated in paragraphs 15 16 and 19 b Set all selector Switches as indicated on the tube test data chart with the exception of the PLATE and
19. RE MOUNTED ON THE REAR OF THE CHASSIS 6 SWITCH ANO CONTROL POSITION SWITCH OR CONTROL POSITION ALL SELECTORS ADJUST FOR 25V METER BAS RANGE es FULLY COUNTER CLOCKWISE PLATE SCREEN RANGE OC CAFE ADJUST FOR 100V 530 205v 06 on PLATE METER 96 825 1 0 FULLY COUNTER sm CLOCKWISE 130 67v 280 ALIGNED WITH INDEX MARKING ON PANEL ADAIST FOR RED LINE IONAL METER TMG625 316 58 15 Resistor mounting board voltage and resistance diagram 16 Voltage Measurements figs 11 12 and 13 4 Measure the tube socket voltage with the multimeter Refer to the tube socket diagram fig 11 for voltages normally present Be sure that the switches and controls are set as indi cated in the Notes column on figure 11 b Measure the voltage at the test points on the front rear and top of the chassis with the multimeter Refer to figures 11 and 12 for typi cal voltages Be sure that the switches and con trols are set as indicated in the Notes column on figures 11 and 12 Measure the voltage at the test points on the resistor mounting board fig 13 with the multimeter Be sure that the switches and trols are set as indicated in the Notes column on figure 13 Troubleshooting Chart fig 26 17 Localizing Troubles amp General In the troubleshooting chart c b
20. bility of amp re paired equipment Equipment that meets the minimum standards stated in the tests wil fur nish satisfactory operation equivalent to that of new equipment 25 Test Equipment Required for Final Testing In addition to the test equipment listed in paragraph 14 the following items are required for final testing Quantity 1 Tem Variable Transformer CN 16 U Resistor 3 000 ohms 1 1 watt 1 Resistor 450 000 ohms 1 1 watt 1 Resistor 550 000 ohms 251 1 wat 1 26 Test Facilities All tests should be conducted under the fol lowing conditions Test should be made at room temperature b The equipment should be ON at least 20 minutes before tests are made c Input voltage should be 115 volts 10 per cent 60 cycles single phase d Voltmeter Meter ME 30A U should be calibrated to an accuracy of 0 5 percent error for making ac voltage measurements Multimeter AN URM 105 should be cali brated to an accuracy of 1 percent error for making dc voltage measurements 27 Madification Work Orders The performance standards listed in the tests par 28 39 assume that the modification work orders listed below have been performed A list ing of current modification work orders wil be found in DA Pam 310 4 MWO No Date 2 Echelon Location of Remarks marking 11 6625 316 45 1 28 December 1959 Urgent 4 Near the nomen
21. bles In all these tents the possibility of intermittent troubles should not be overlooked If present this type of trouble may often be made to appear by tapping or jarring the equipment Check the wiring and con nections to the tube tester 14 Teols and Test Equipment Required The following chart lists the tools and test equipment required for troubleshooting the tube tester the associated technical manuals and the assigned common names 14284 Tool or test equipment 1 Technical mancal Common Too Equipment TK 21 G _ TM Y 125558 1 Tool equipment Meter Test Set TS 882A GSM 1 Test meter Multimeter AN URM 108 TM 11 6625 203 12 35 Multimeter Test Set Electron Tube AN USM 31 Navships 91735 j Tube tester Voltmeter Meter ME 30A7U TM 11 6625 320 12 Voltmeter 15 Checking Filament and High Voltage 1 Measure the dc resistance between Circuits for Opens and Short Circuits figs 8 4 11 12 and 13 Trouble in Test Set Electron Tube TV 2 U often ean be detected by checking the dc resistance of the filament plate screen bias and signa supply circuits fig 11 13 before power is applied to the unit Take all measure ments with the multimeter proceed as follows a Preparation 1 Disconnect the power cord from the ac supply Remove the chassis from the case and then remove the tubes 8 Set PLATE SCREEN RANGE switch S3 to position 4
22. cla None ture plate on the front panel MWO 11 6625 316 45 2 18 1960 Normal 4 Near the nomenela Equipment modified per MWO SIG 11 2661 1 28 Septem ber 1955 need not be remodified Test Sets 2 0 and TV 2A7U pre viously modified in accordance with MWO 11 266 1 25 February 1958 need not be modified ture plate on the front panel 28 Bias Voltage Test A fig 21 Set the GRID switch to position 5 b Set the BIAS and PLATE fine control fully clockwise 34 Set the GM SIGNAL RANGE switch to position all other switches and controls to their neutral or OFF position vertical position for switches extreme counterclockwise position for controls AGO 14954 1000 Ohms Volt VOM d Connect the Multimeter URM 105 be tween pin 5 of the OCTAL tube test socket and ground test point mounting screw on the tube tester Setthe ON OFF switch to the ON position AGO 14284 f The GRID BIAS VOLTS meter reads full scale on ranges 50 10 and 5 g The voltage measured the AN URM 105 will be equal to the voltage indicated on the GRID BIAS VOLTS meter on all ranges 2 2 5 percent error 35 782091 92000 pun IK LAE ELT 236 1831 1631 8 AGO 1426A 29 Plate Voltage Test
23. elow procedures are outlined for isolating troubles to a particular component part Voltage and resistance measurements are shown in fig ures 11 13 Depending on the nature of the op erational symptoms one or more of the localiz ing procedures will be necessary 5 Use of Chart The troubleshooting chart 18 designed to supplement operational checks that can be performed at an organizational level If previous operational checks have resulted in reference to a particular item of the chart go directly to th eferenced item If no operational symptoms are known begin with step 1 of the equipment performance checklist TM 11 6625 316 12 and proceed until a symptom of trou ble appears T Symptom Probable trouble Correction 1 PILOT lamp 11 does not light and Fuse Fi or F2 defective or Check fuses Fl and F2 Replace as tube tester fails to operate burned ont necessary If replaced fuse burns out check plate supply terminals 3 14 of transformer 2 and pacitors and for short cuits PILOT lamp 11 defective Check lamp I1 and replace if neces sary Power cord defective Check power cord and connector and replace if necessary 2 PILOT lamp 1 lights but FILA FILAMENT VOLTS meter Check meter and replace if MENT VOLTS meter 1 does defective necessary not indicate Filament transformer T1 Check resistance of T1 per 18 fg 8 detective Replace 1 if
24. ex marking the panel J1 With tube tester adjusted for trans PERCENT QUALITY meter Check meter 8 and replace if conductance G test end defective defective PRESS TO TEST P4 switch 819 in locked position PER Quality meter damping ca Replace C2 CENT QUALITY meter M3 does C2 short circuited not give proper indication Shunt resistor R39 R31 R40 Replace defective resistor or poten or R42or GM CENTERING tiometer potentiometer R44 or HESA Symptom Probable trouble Correction 12 13 14 15 16 17 18 18 Dc Resistances of Transformers T and T2 fig 3 4 and 12 The dc resistances of filament transformer T1 22 With GM SIGNAL RANGE switch S amp in F position PERCENT QUALITY meter M3 does give proper indication With PRESS TO TEST P6 switch 821 depressed indication on PER CENT QUALITY meter M3 drops to zero With tube tester adjusted for emis sion test and PRESS TO TEST P2 switch S17 depressed PER CENT QUALITY meter M3 does not indicate With tube tester adjusted for vol tage regulator test and PRESS TO TEST P5 switch S20 de pressed neither PECENT QUAL ITY meter M3 nor PLATE meter indicato Operation of SIGNAL V R con trol R46 does not affect indica tion on PLATE meter M5 With PRESS TO TEST switch S16 depressed and a tube known ta be good being tested FIL CONT SH
25. king resistances b Localization The tube tester can be used to check pilot lamps diode tubes amplifier tubes for transconductance gas and leakage between tube elements and to check tubes for shorts The first step in localizing troubles is to determine the circuit or circuits at fault by the following methods 1 Visual inspection The purpose of vis ual inspection is to locate faults with out testing or measuring circuits All meter readings and other visual signs 16 should be observed to try to localize the fault to a particular circuit Operational tests Operational tests frequently indicate the general loca tion of trouble In many instances the tests will help in determining the exact nature of the fault The equipment per formance checklist TM 11 6625 316 12 is a good operational test c Isolation The checks listed below will aid in isolating the trouble After the trouble has been isolated to a particular circuit isolate the frouble within that circuit to a particular part 1 Voltage and resistance measurements Use the schematic diagram fig 26 to find the value of the components Use voltage and resistance measurements pars 15 18 and figs 11 13 to find the value for normal readings pare them with readings taken 2 2 Troubleshooting chart The symptoms listed in the troubleshooting chart par 17c wiil aid in localizing trouble to a component part 3 Intermittent trou
26. resistor R55 is open If the re sistance reading is very low or zero the screen supply is short circuited Check filter capacitors C4A and C4B and screen supply dc load windings 15 95 of transformer for possible short circuits Bias Supply Circuit 2 Measure the resistance between pin 1 or 6 and pin 7 ground of tube 2 fig 11 With BIAS RANGE switch S2 in the 50 50 volt position the resistance should be approximately 1 000 ohms With BIAS RANGE switch 2 in another position the resistance will be considerably lower but it should be several thousand ohms 1f the resist ance is very high or infinite the wiring may be open or one of the bias voltage divider resistors R34 R26 R27 R28 or BIAS fine contro R29 may be open If the resistance is very low or zero the bias supply is short circuited Check filter capacitor C3 and the wir ing te bias supply rectifier tube V2 for short circuits f Signal Supply Circuit Measure the dc resistance between ter minals 29 and 30 of the signal supply 17 2 winding of transformer T2 figs 4 and 12 The resistance should be approximately 9 ohms If the resistance is high over 1 000 ohms the signal winding is open If the resistance is very low or zero the winding is short cireuited or 120v AC the ac voltage divider circuit across the winding is short circuited 3 Check the wiring to SIGNAL meter M4 SIGNAL V
27. ten tiometer Replace defective potentiometer Replace defective potentiometer Replace C4 Cheek switch S4 and replace if necessary Replace defective potentiometer Replace defective resistor Replace defective lamp Check switch 511 and replace if necessary Check switch S4 and replace if necessary Replace defective resistor and power transformer T2 windings are listed below Measure the resistances with the trans former disconnected from the circuit AGO 128A a Filament Transformer T1 fig 3 b Power Transformer T2 figs 4 and 12 Terminal Resistance Terminals D 1 2 13 12 23 3 4 23 3 4 1 4 5 4 5 1845 5 6 134 55 97 Less than 1 5 7 42 1 8 Less than 1 1 8 8 9 Less than 1 8 9 36 8 10 Less than 1 10 11 99 10 11 Less than 1 11 12 10 2 11 12 Less than 1 12 13 20 0 12 13 Less than 1 18 14 8 2 13 14 Less than 1 15 16 128 14 15 Less than 1 16 17 136 15 16 Less than 1 11 18 16 7 16 17 Less than 1 18 19 136 17 18 Less than 1 19 20 189 18 19 Less than 1 20 21 191 19 20 Less than 1 21 22 14 0 20 21 Less t 22 23 172 21 22 Less than 1 23 24 14 2 24 25 135 28 21 128 1 21 28 129 0 29 30 8 1 31 32 Less than 1 33 34 Less than 1 34 35 Less than 1 AGO 14284 23 CHAPTER 4 FIFTH ECHELON FINAL TESTING 24 Purpose of Final Testing tests outlined in this chapter are designed to measure the performance capa
28. ube under test
29. vider resis Replace defective resistor or poten tor R47 R49 R50 or 516 1 NAL V R potentiometer Transformer T2 secondary Replace 2 winding 29 30 open 8 No change in ge indication or PLATE SCREEN RANGE Check switch 53 and replace if incorrect indication on PLATE switch S3 defective necessary meter M5 and SCREEN VOLTS meter M6 when PLATE SCREEN RANGE switch S8 is rotated FILAMENT VOLTS meter M1 in Tube under test defective Check filament continuity of tube dicates but tube under test does under test not warm up FIL or FIL4 Selectors Replace 56 57 or S11 as necessary switch S6 and 5707 SHORT TEST switch 511 defective 10 With GRID SELECTORS switch CONT SHORT lamp 12 Replace lamp IZ H necessary 58 in position PLATE SELEC defective TORS switch S16 in position A and all other SELECTORS SHORT TEST switch Sil Check switch BIL and replaca 14 switch at 0 and with the A defective necessary E and B electrical clips short cir euited CONT SHORT lamp Wiring in short test circuit Check wiring and repair as neces I2 does not light in any position defective sary of SHORT TEST ewiteh 811 Voltage divider resistor R60 Replace defective resistor or bias supply bleeder resis tor R35 open PLATE potentiometer RAS in Adjust R45 so that the Index mark correctly adjusted ing on the knob lines up exactly with the ind
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