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HP_419A_DC_Null_Volt..

1. o 17 o RI T 518 OT E SCHEMATIC APPLIES TO SERIALS HP 419A DC Null Voltmeter max Model 419A 13 BAT TEST R49 CAL 12 Appendix C v 2259 TP EAT V pr Urn 2 TO 13V SIB R NOTE SCHEMATIC APPLIES TO SERIALS PREFIXED 5 4 532 AND 646 ONLY Figure C 2 01779 2 HP 419A DC Null Voltmeter max 1 o Amplifier and Am plifier Switching Schematic and Component Location Diagrams Serial Prefixed 514 532 646 C 3 C 4 Appehdix C Model 419A day oV AHO AUD yg LHM LHM OIA NY NYG LHM AYO LHM LHM A2 Board Ser ials Prefixed 514 sri tr x Of jo 14 a 9 110 N Figure C 4 6 tu OF xoc 20 89 Gu 371085 LN3Y YND NOJN 1 0 m wx cN gt og T iD 5 HP 419A DC Null Voltmeter max Figure 3 Neon Driver Serials Prefixed 514 01779 2
2. 4 2 4 19 Modulator Demodulator 4 2 4 23 AC Amplifier 4 2 4 26 DC Amplifier 4 2 4 30 Meter Circuit 4 2 4 33 Feedback Control 4 2 4 35 Power Supply and Neon Driver Figure 6 4 4 4 ny s 4 3 Number Page 1 1 Model 419A Specifications 1 0 1 2 Accessory Equipment Supplied 1 1 1 3 Accessory Equipment Available 1 1 4 1 Model 419A Attenuation and Gain Characteristics 4 1 01779 2 Table of Contents List of Tables TABLE OF CONTENTS Section V 5 1 Introduction 5 3 Test Equipment 5 5 Performance Tests 9 7 Voltmeter Accuracy Test 5 9 Bucking Voltage Test 9 11 Ammeter Accuracy Test 5 13 Response Time Test 5 15 Superimposed AC Rejection Test 5 17 Noise 5 19 Input Resistance Test 5 21 Repair Procedures 5 22 Cover Removal 5 24 Servicing Printed Circuit Boards 5 29 Adjustment and Calibration 5 31 Mechanical Zero Adjustment 5 33 Chopper Adjustment 5 35 Electrical Zero Adjustment 5 37 Full Scale Calibration 5 39 Battery Test Calibration 5 41 Troubleshooting 5 43 No Response to Input 5 45 Positive or Negativ Foldover 5 47 Excessive Noise 5 49 Troubleshooting the I
3. 56K 7 12 o I 9 i COPYRIGHT 1966 BY HEWLETT PACKARD COMPANY HP 419A DC Null Voltmeter max TER AMPLIFIER ASSEMBLY 00419 66504 13V 12V MES R3 R49 120K 2200 2834 R2 R28 220 178K 22K 12 4H 46V 012 R29 2200 e ovi 220K Q9 200 X E R6 5600 120 T 7 1 2 90 12V rn et R8 R9 475K 4 7M F RIO 4700 RII 2 2M 1 CSa 4 7 T R15 y IV ZERO LOK I3V 5 17 FROM FROM 52 21 52 23 HP 419A DC Null Voltmeter max Model 419A Section VI ET 925 J5 LEVEL lt Lt 926 J6 o X 21 901 011 BAT TEST hr 13V CAL 2 Kk LE Q 2 gt PEOR 1 RN ir 6 R45 R46 5OCK 390K CR9 165 52 M P 082 CRIO 97 76 CRI e 1 S d 5 2 Cil CI5 T E po gt 5 2 005V e 39 4 R47X R5I ME 2200 2 0 2 4 1 20 9 72 4 j V 2 S2RI 2700 3 2835 P 220 2200 o 9 R36 1 9 2200 6 7 8 ian 28 68K Qy STC CO R3
4. outside diameter TiO titanium dioxide inductor k linear taper ted circuit tog toggle logarithmic taper pe tol tolerance 12 trim trimmer milli 1073 BE picofarad s 10 TSTR transistor 3 farads milliampere s 10 piv peak inverse voltage V volt s amperes 46 p part of vacw alternating current megahertz 10 hertz pos position s working voltage megohm s 1076 ohms poly polystyrene var variable metal film pot potentiometer 7 direct current working manufacturer p p peak to peak voltage mounting 3 ppm parts per million millivolt s 107 volts prec precision temperature watt s micro 107 2 coefficient long term w with microvolt s 107 volts stability and or tol wiv working inverse voltage erance w o without Mylar 9 ww wirewound 10 E gresi tor optimum value selected amperes Rh rhodium at factory average normally closed rms root mean square value shown part may neon rot rotary be omitted normally open negative positive zero Se selenium standard type num zero temperature co sect section s ber assigned selected efficient Si silicon or special type Dupont de Nemours 7 1 HP 419A DC Null Voltmeter max Section VII REFERENCE DESIGNATOR 2 thru A2CR4 A2CR5 A2CR6 thru A2CR8 A2CR9 A2Q1 thru A2Q3 A
5. the AC Amplifier for noise A4Q1 or Q2 most probable 5 49 TROUBLESHOOTING THEINPUT ATTENUATOR 5 50 If trouble is suspected inthe input attenuator or feedback divider proceed as follows a Rotatethe range switch through all positions several times to clean the switch contacts b Check the 90MQ resistor S1R3 for dustac cumulation clean if necessary c If trouble persists carefully check the input attenuator and feedback divider resistors NOTE Parallel paths exist for several of the resistors Before re placing a suspected resistor un solder one lead and check the re sistor again 5 6 Model 419A 9 51 REPLACEMENT OF FACTORY SELECTED COMPONENTS 9 52 Certain components within the Model 419A are individually selected in order to compensate for slightly varying circuit parameters These components are identifiedby anasterisk onthe schematic diagrams andatypicalvalue is shown Thefollowing paragraphs describe the function of the factory selected components and give replacement instructions 9 93 A4R26 9 54 A4R26 is factory selected to provide proper amplifier response time Response time can be evalu ated by performing the Response Time Test Para graph 5 13 A4R26 should be replaced only if re Sponse time cannot be corrected by performing the chopper adjustment procedure Paragraphs 5 33 Paragraph 5 34 step e gives specific replacement in structions 9 55 4 47 9 56
6. Los Angeles Calif Burbank Calif Chicago lil Milwaukee Mis Commercial Plastics Co Chicago IIl The Cornish Wire Co New York N Y Chicago Miniature Lamp Works Chicago lli A 0 Smith Corp Crowley Div West Orange N J Cinch Mfg Corp Chicago Dow Corning Corp Midland Mich Eitel McCullough Inc Electro Motive Mfg Co Inc Willimantic Conn San Bruno Calil Coto Coil Co Inc Providence John E Fast amp Chicago 111 Dialight Corp Brooklyn N Y General Ceramics Corp Keasbey N J General Instrument Corp Semiconductor Div Newark N J Girard Hopkins Oakland Calil Drake Mfg Co Chicago Hugh H Eby Inc Philadelphia Pa Gudeman Co Chicago Ill Robert M Hadley Co Los Angeles Calif Ene Resistor Corp Erie Pa Hansen Mfg Co Inc Princeton ind H M Harper Co Chicago 11 Helipot Div of Beckman Instruments Inc Fullerton Calil HP 419A DC Null Voltmeter max Rochester N Y Code No 73293 73445 73490 73506 73559 73682 73734 73743 73793 73846 73899 73905 74276 74455 74861 74868 74970 75042 75173 75378 75382 75818 75915 76005 76210 76433 76487 76493 76530 76545 76854 77068 71075 77221 77250 11252 11342 71630 71638 17164 11969 18189 18283 78290 78452 78471 78488 78493 78553 78790 78947 79142 79251 79727 79963 80031 80120 80130 80131 80207 80223 80248 802
7. Peak to peak noise is less than 0 3 95 of the time since the noiseamplitude approximates a Gaussian distribution where the standard de viation which is also the rms value 20 075 pV AMPLIFIER Gain 110db maximurn at recorder output terminals Gain depends on range 1 0 Output 0 to 1 volt at 1 mA max for end scale reading Output level is adjustablefor convenience when used with recorders Output Impedance Depends on setting of output level control lt 35 ohms when output level is set to maximurn Noise 0 01 Hz to 5 Hz Sameas voltmeter referred to input gt 5 Hz rms noise lt 10 mV referred to output DC AMMETER Current Ranges 30pA 100 pA 300 pA 1nA 3 nA 10 nA and 30 nA Accuracy 3 of end scale 1 pA GENERAL Overload Voltages 50 Vdc max 3 pV to 3 mV ranges 500 Vdc max 10 mV to 300 mVranges 1200 Vdc max on 1 volt range and above Overload Recovery Time Meter indicates within 3 seconds for a 10 overload Input Terminals Positive and negative terminals are solid copper gold flashed Input Isolation 101 ohms shunted by 250 pF May be operated up to 500 Vdc or 350 Vac rms above ground Operating Temperature 0 to 50 C Storage Temperature 40 C to 60 C Power Source 4 internal rechargeable batteries furnished Thirty hour operation per recharge The 419A may be operated during rechargefrom line 115 230 V 1
8. Ward Leonard Electric Mt Vernon N Y Shallcross Co Selma Simpson Electric Co Chicago Sonotone Corp Sorenson amp Co Inc Spaulding Fibre Co Inc Sprague Electric Co Telex Inc Thomas amp Betts Co Tripplett Electrical Inc Union Switch and Signal Div of Westinghouse Air Brake Co Universal Electric Co Ward Leonard Electric Co Mt Vernon Western Electric Co Inc New York N Y Weston Inst Div of Daystrom Inc Newark N J Wittek Manufacturing Co Chicago 23 111 Wollensak Optical Allen Mfg Co Allied Control Co Inc Screw Prod Co Inc Garden City N Y Elmsford N Y So Norwalk Conn Tonawanda N Y North Adams Mass t Paul Minn Elizabeth 1 N J Bluffton Ohio Swissvale Owosso Mich Hartford Conn New York N Y Atlantic India Rubber Works Inc Chicago 111 Amperite Co Inc New York N Y Belden Mfg Co Chicago Il Bird Electronic Corp Birnbach Radio Co Boston Gear Works Div of Murray Co of Texas Bud Radio Inc Camloc Fastener Corp Cleveland Ohio New York N Y Quincy Mass Cleveland Ohio Paramus J Allen D Cardwell Electronic Prod Corp Plainville Conn Bussmann Fuse Oiv of McGraw Edison Co St Lovis Mo Chicago Condenser Corp Chicago fll CTS Corp Elkhart Ind Cannon Electric Co Cinema Engineering Co C P Clare amp Co Centralab Div of Globe Union Inc
9. 1250 W Dorothy Lane 513 298 0351 TWX 513 944 0090 OKLAHOMA Oklahoma City 405 235 7062 PENNSYLVANIA Lili vamp nii 717 737 6791 West Conshohocken 19428 144 Elizabeth Street 215 248 1600 and 828 6200 TWX 518 660 8715 Monroeville 15146 Monroe Complex Building 2 Suite 2 Moss Side 412 271 5227 TWX 710 797 3650 HP 419A DC Null Voltmeter max TEXAS Dallas 7 209 Box 7166 3605 Inwood Rd 214 357 1881 TWX 910 861 4081 Houston 77027 Box 22813 4242 Richmond Ave 713 667 2407 TWX 713 571 1353 UTAH Salt Lake City 84115 1482 Major St 801 486 8166 TWX 801 521 2604 VIRGINIA Richmond 23230 2112 Spencer Road 703 282 5451 TWX 710 956 0157 WASHINGTON Bellevue 98004 11656 N E 8th St 206 454 3971 TWX 910 443 2303 GOVERNMENT CONTRACTING OFFICE San Antonio Texas 78226 Hewlett Packard Contract Marketing Division 225 Billy Mitchell Road 512 434 4171 TWX 512 571 0955 CANADA Montreal Quebec Hewlett Packard Canada Ltd 8270 Mayrand Street 514 735 2273 TWX 610 421 3484 Telex 01 2819 Ottawa Ontario Hewlett Packard Canada Ltd 1762 Carling Avenue 613 722 4223 TWX 610 562 1952 Toronto Ontario Hewlett Packard Canada Ltd 1415 Lawrence Avenue West 416 249 9196 TWX 610 492 2382 Vancouver B C Hewlett Packard Canada Ltd 2184 W Broadway 604 738 7520 TWX 610 922 5059 Appendix B M
10. 00891 01121 01255 01281 01295 01349 01561 01589 01930 01961 02114 02286 02660 02735 02771 02777 03508 03705 03797 03877 03888 03954 04009 04013 04062 04222 04298 04354 04404 04651 04713 04732 04773 04777 04796 04811 04870 05006 05277 05347 05593 05616 05624 05728 05729 05783 05820 06004 06175 06402 06475 06540 06555 06751 06812 07088 Manufacturer Address S Common Any supplier of U S McCoy Electronics Mount Holly Springs Pa Sage Electronics Corp Humidail Co Westrex Corp Garlock Packing Co Electronic Products Div Aerovox Corp Rochester Colton Calif New York N Y Camden N J New Bedford Mass Amp Harrisburg Pa Aircraff Radio Corp Boonton N J Northern Engineering Laboratories Inc Burlington Wis Sangamo Electric Company Division Capacitors Goe Engineering Co Carl E Holmes Corp Allen Bradley Co Litton Industries Inc TRW Semiconductors Inc Texas Instruments Inc Transistor Products Div The Alliance Mfg Co Chassi Trak Corp Pacific Relays Inc Amerock Corp Pulse Engineering Co Fertoxcube Corp of America Cole Mfg Co Palo Alto Calif Amphenol Borg Electronics Corp Chicago Radio Corp of America Semiconductor and Materials Div Somerville N J Vocaline Co of America Inc Old Saybrook Conn Hopkins Engineering Co San Fernando Calif E Semiconductor Pr
11. 0684 1031 0698 3193 0698 4057 0698 5488 0811 0473 0698 5443 hp Part No hp Part No hp Part No hp Part No hp Part No hp Part No hp Part No hp 419A DC NULL VOLTMETER E Sp ccm Figure 5 1 5 0 HP 419A DC Null Voltmeter max Voltmeter Accuracy Performance Test Setup 01779 2 Model 419A Section V SECTION V MAINTENANCE 5 1 INTRODUCTION 9 2 This section contains the information necessary for maintenance ofthe Model 419A DC Null Voltmeter Included are performance tests repair procedures adjustment and calibration procedures and trouble shooting procedures 5 3 TEST EQUIPMENT 5 4 Thetest equipment required for maintenance of the Model 419A is listed in Table 5 1 Equipment having similar characteristics may be substituted for the equipment listed 5 5 PERFORMANCE TESTS 5 6 The performance tests presented in this section are front panel procedures designed to compare the Model 419A with its published specifications Table 1 1 These tests may be incorporated in periodic main tenance post repair and incoming quality control in spection These tests should be conducted before attempt is made at instrument calibration 9 7 VOLTMETER ACCURACY TEST 5 8 Thevoltmeteraccuracy performance test setup is illustrated in Figure 5 1 voltmeter calibrator hp Model738BR a 100 9 resistor hp Part No 0811 0398 anda 1 MQ resist
12. HP 419A DC Null Voltmeter max Model 419A Section V TEST OSCILLATOR hp 208A OF o o R2 6002 419 0291 hp 419A DC NULL VOLTMETER I RI Figure 5 3 Superimposed AC Rejection Performance Test Setup 9 19 INPUT RESISTANCE TEST 5 20 A Voltmeter Calibrator hp Model 738BR a 10 resistor hp Part No 0698 3193 a 100 resistor hp Part No 0698 4057 a 1 MQ resistor hp Part No 0757 1054 and a 10MQ resistor hp Part No 0698 4128 are required for this test a Connecta 10 resistor to Model 419A IN PUT terminal b Connect voltmeter calibrator dc output ter minalsto 10 resistor and INPUT terminal on the Model 419A c SetModel419A RANGE to 3mV set voltmeter calibrator output to 3 mV 003 V d The Model 419A should indicate 2 73m V which verifies an input resistance of 100 on the 3m V range asgivenbythefollowing formula x E n Rin m where Rin is the 419A input resistance Rg is the series resistance Em is the voltage indicated on the Model 419A meter and is the voltmeter calibrator output voltage NOTE The input resistance may vary slightly anda tolerance of 3 shouldbe allowed e Replace the 10 resistor with a 100 k Gre sistor f Set Model 419A RANGE to 10 mV set volt meter calibrator output to 10 mV 01 V Model 419A should read 9 09 mV which veri fiesan input resistance o
13. Model 419A d A2R12 CHOPPER CURRENT affects both the chopper frequency and current Adjust A2R12 for waveshape shown in Figure 5 3 with peak amplitude of 140 to 160 mV and frequency of 320 to 340 pps this corresponds to chopper rate of 160 to 170 pps as counter also counts smaller pulses e A1R26 should be between 10 and 39 KQ with a typical value of 22 KQ Figure 6 4 Substitute Figure C 3 and C 4 for the ones in Figure 6 4 Table 7 1 Change A2Q1 to hp Part No 1854 0039 Transistor Si 2N3053 Change A2Q2 A2Q3 to hp Part No 1854 0033 Transistor NPN R R R SO AFPA fxd fxd fxd fxd fxd fxd fxd comp comp comp comp comp comp comp 560 ohms 680 ohms 33 K ohms 3300 ohms 68 ohms 27 K ohms 47 K ohms Si 2N2925 Change A2Q4 A2Q5 to hp Part No 1854 0039 Transistor NPN Si 2N3053 Change A2R1 to hp Part No 0687 5611 10 1 2w Change A2R2 to hp Part No 0687 6811 10 1 2 w Change A2R3 to hp Part No 0687 3331 10 1 2 w Change A2R4 to hp Part No 0687 3321 109 1 2 w Change A2R5 to hp Part No 0687 6801 10 1 2w Change A2R6 to hp Part No 0687 2731 10 1 2 w Change A2R7 to hp Part No 0687 4731 10 1 2 w Change A2R8 A2R9 to hp Part No 0687 4701 fxd 10 1 2 w comp 47 ohms Change A2R10 to hp Part No 0687 1511 R fxd comp 150 ohms 10 1 2 w Change A2R
14. NOTE Remove resistive attenuatorbefore performing steps e and f e Set Voltmeter Calibrator for 1 mV output connect 419A to Point B adjust A4R43 1 MV for full scale deflection on 1 mV range 01779 2 Section V f Set Voltmeter Calibrator for 1 V output con nect 419A to Point B adjust A4R44 1 V for full scale deflection on V range 9 39 BATTERY TEST CALIBRATION 5 40 A DC Voltmeter hp Model 427A isrequired for the battery test calibration NOTE Batteries must be fully charged be fore performingthis procedure See Paragraph 3 13 a Remove 419A top cover and shield b Connect DC Voltmeter across 1 thru BT4 If DC Voltmeter indicates less than 26 V re charge battery power supply in accordance with Paragraph 3 13 If DC Voltmeter indi cates at least 26 V proceed to step c c Depress Model 419A BAT TEST Pushbutton adjust A4R25 BAT TEST CAL for Model 419A Meter reading 0 3 scale equal to DC Volt meter reading in step b h 9 5 41 TROUBLESHOOTING 5 42 This section contains information designed to assist in the isolation of malfunctions These checks should be undertaken only after it has been established thatthe trouble cannotbe eliminated by the Adjustment and Calibration Procedures Paragraph 5 29 NOTE The 419A operates erratically when the charge on the batteries is mar ginal Since the exact capacity of the Nickel Cadmium batteries cannotbe determinedby
15. Schematic and Com ponent Location Diagrams 01779 2 6 5 HP 419A DC Null Voltmeter max Model 7 1 7 2 replacement parts 419A INTRODUCTION Section VII SECTION REPLACEABLE This section contains information for ordering Table 7 1 lists parts in alpha meric order of their reference designators and indi cates thedescription hp part number of each part together with any applicable notes and provides the following Total quantity used in the instrument TQ column The total quantity of a part is given the first time the part number appears Description ofthe part tions below listof abbrevia Typical manufacturer of the part in a five digit code facturers See Appendix Afor list of manu d Manufacturer s part number Ag Al Au cer coef com comp conn dep DPDT DPST elect encap FET fxd GaAs GHz gd Ge grd Hz REV F 01779 assembly motor battery capacitor 7 diode delay line lamp misc electronic part silver aluminum ampere s gold capacitor ceramic coefficient common composition connection deposited double pole double throw double pole single throw electrolytic encapsulated farad s field effect transistor fixed gallium arsenide gigahertz 1079 nertz guard ed germanium ground ed henry ies mercury hertz
16. Tel 031 42 00 78 TAIWAN Hwa Sheng Electronic Co Ltd Box 1558 2 Nanking West Road Taipei Tel 46076 45936 TURKEY Telekom Engineering Bureau Box 376 Galata Istanbul Tel 49 40 40 UNITED KINGDOM Hewlett Packard Ltd Dallas Road Bedford England Tel 68052 VENEZUELA Citec C A Edif Arisan Of No 4 Avda Francisco de Miranda Chacaito Caracas Tel 71 88 05 YUGOSLAVIA Belram S A 83 Avenue des Mimosas Brussels 15 Belgium Tel 35 29 58 For Sales and Service Assistance in reas Not Listed Contact EUROPE Hewlett Packard S A 54 Route des Acacias Geneva Switzerland Tel 022 42 81 50 ELSEWHERE Hewlett Packard 1501 Page Mill Road Palo Alto California 94304 U S A Tel 415 326 7000 5 66 Model 419A Appendix C MANUAL BACKDATING CHANGES MODEL 419A Es DC NULL VOLTMETER Manual Serial Prefixed 707 hp Part No 00419 90002 This manual backdating sheet makes this manual applicable to earlier instru ments Instrument component values that differ from those in the manual yet are not listed in the backdating sheet should be replaced using the part number given in the manual Instrument Serial Prefix Make Manual Changes Instrument Serial Prefix Make Manual Changes 646 1 532 0401 and above n2 532 0400 and below 1 2 3 514 1 2 3 4 1 Figures 6 1 and 6 3 Substitute Figures C 1 and C 2 for the one
17. 10 INSTALLATION 2 11 The Model 419A is fully transistorized there fore no special cooling is required However the instrument should not be operated where the ambient temperature exceeds 509 1229F 2 12 BENCH MOUNTING 2 13 The Model 419A is shipped with plastic feet and tilt stand in place ready for use as a bench instru ment 2 14 RACK MOUNTING 2 15 The Model 419A may be rack mounted by using an Adapter Frame hp Part No 5060 0797 The 01779 2 Q adapter frame is a rack frame that accepts any com bination of submodular units It can be rack mounted only For additional information address inquiries to your hp Sales and Service Office See Appendix B for office locations 2 16 COMBINATION MOUNTING 2 17 The Model 419A may be mounted in combination with other submodular units by using a Combining Case hp Models 1051A and 1052A The Combining Case is a full module unit which accepts various combina tions of submodular units Being a full module unit it can be bench or rack mounted and is analogous to any full module instrument 2 18 REPACKAGING FOR SHIPMENT 2 19 Thefollowing paragraphs contain a general guide for repackaging of the instrument for shipment Re fer to Paragraph 2 20 if the original container is to be used 2 21 if it is not If you have any questions contact your local hp Salesand Service Office See Appendix B for office locations NOTE If the instrum
18. 3mV 30 nA 0dB zm 120 dB 10 dB 50 dB 10 mV 20dB 120 60 40 dB 30 mV 20dB 4120 dB dB 30 dB 100 mV 40 dB 4120 dB 60 dB 20 dB 300 mV 40 dB 4120 dB 10 dB 10 dB 1 V 6048 4120 dB 60 dB 0 dB 3 v 60 dB 4120 dB dB 10 dB 10 V 80dB 4 4120 dB 60 dB 20 dB 30 80dB 4120 dB 10 dB 30 dB 100 V 100 dB ya 120 dB 60 dB 40 dB 300 v 100 dB sys 120 dB 70 dB 50 dB 1000 V 120 dB 120 dB 60 dB 60 dB 01779 2 4 1 HP 419A DC Null Voltmeter max Section IV mode In the dc voltmeter mode the input voltage is applied to the Input Attenuator through the and INPUT terminals andthrough 51826 Inthe null volt metermode the inputis applied in the same manner butis opposedby the bucking voltage appliedto 51826 4 14 When the SET NULL Pushbutton is depressed the BT5 voltage is applied through R4 and R5 and the voltage divider network 5181 thru SIR11 to S1R26 The difference between the input voltage and the bucking voltage is indicated on the Meter M1 The bucking voltage is then adjusted through the use of course and fine NULLcontrols R4 and R5 untila nullis indicated on the Meter When the READ NULL Pushbutton is depressed the input voltage is disconnected and the polarity of the bucking voltageis reversed The value of the bucking voltage equal to input voltage is indi cated on the Meter M1 4 15 INPUT ATTENUATOR 4 16 All vo
19. 419A Component Location Diagram 51 TOP VIEW SI BOTTOM VIEW R R24 3 R26 R23 R25 R2I R22 R27 es 250 d y 23 L NS 27 S ais y 4 1 32 3 A RII RIS RI7 R4 R5 86 419A A 0976 RIG Figure 6 2 Range Switch S1 Component Location Diagram 6 2 01779 1 HP 419A DC Null Voltmeter max GRN BLK IV BAT TEST 34V MV IV Q0419 66504A CAL 2 O R8 IR is eS coc 03 55 29 01 Ri2 m 20 09 813 Re8 cR8 8 m cm R6 RI5 SL R34 22 2 CRI R R6 RIS QR4 CRI3 CRIO R46 2 0 CRIA i R48 89 R7 R50 R33 85 no Rie aso mc R2I Rig 26 UE R36 R35 R37 R24 49 Cio Rar R22 i CRI6 R39 015 CRIG L R233 CRI5 I NIN 22 hp Part No 00419 66504 ae ee FUNCTION SWITCH 419A 8 101 BOTTOM VIEW READ SET 0 FAST NULL NULL 509 ae or o 419A B 1002 HP 419A DC Null Voltmet
20. 5080 1278 0340 0159 0340 0100 00419 21701 5080 1277 0340 0159 0340 0100 00419 21701 1510 0011 0340 0099 1510 0010 1510 0011 1510 0011 0340 008 0340 0091 9100 1318 1120 0312 2100 1557 2100 2200 0698 3463 2100 2199 0687 2221 0687 1041 0687 2721 Table 7 1 TQ NNN Replaceable Parts Cont d DESCRIPTION fxd comp 2200 Q 10 1 2 W fxd comp 470 10 1 2 W fxd comp 220 10 1 2 W S PPP fxd comp 2200 9 10 1 2 W fxd comp 100 10 1 2 W fxd comp 3 9 MQ 10 1 2 W fxd comp 10 10 1 2 W fxd comp 100 Q 10 1 2 W var comp lin 250 20 1 8 W var lin 500 30 1 10 W fxd comp 390 kQ 10 1 2 W See Paragraph 5 55 fxd comp 68 kQ 10 1 2 W fxd comp 2200 9 10 1 2 W fxd comp 10 kQ 10 1 2 W fxd comp 2200 Q 10 1 2 W Battery rechargeable nickel cadmium 6 25 V Battery mercury 1 34 V cylindrical Lamp glow type NE 2 neon Fuse cartridge 1 8 amp 250 V Connector ac power cord receptacle Binding Post red with solder turret INPUT Insulator Cup binding post Insulator Spacer binding post Guard binding post threaded Binding Post black with solder turret INPUT Insulator Cup binding post Insulator Spacer binding post Guard binding post threaded Binding Post black with solder turret Insulator binding post Binding Post red with solder turret OUTPUT Binding Post black with s
21. 522 4359 MARYLAND Baltimore 21207 6660 Security Blvd 301 944 5400 TWX 710 862 0850 Rockvi le 20852 12303 Twinbrook Pkwy 301 427 7560 TWX 710 828 9684 MASSACHUSETTS Burlington 01803 Middlesex Turnpike 617 272 9000 TWX 710 332 0382 MICHIGAN Southfield 48076 24315 Northwestern Hwy 313 353 9100 TWX 313 357 4425 MINNESOTA St Paul 55114 2459 University Ave 612 646 7881 TWX 910 563 3734 MISSOURI Kansas City 64114 9208 Wyoming Place 816 333 2445 TWX 910 771 2087 St Louis 63144 2812 South Brentwood Blvd 314 644 0220 TWX 910 760 1670 NEW JERSEY Eatontown 07724 201 747 1060 Englewood 07631 391 Grand Avenue 201 567 3933 TWX 510 230 9709 MEXICO Albuquerque 87 108 6501 Lomas Blvd N E 505 255 5586 TWX 910 989 1655 Las Cruces 88001 114 5 Water Street 505 526 2486 TWX 910 983 0550 NEW YORK New York 10021 236 East 75th Street 212 879 2023 TWX 710 581 4376 Rochester 14623 39 Saginaw Drive 716 473 9500 TWX 510 253 5981 Poughkeepsie 12601 82 Washington Street 914 454 7330 TWX 914 452 7425 Syracuse 13211 5858 East Molloy Rd 315 454 2486 TWX 710 541 0482 Endicott 13764 1219 Campville Rd 607 754 0050 TWX 510 252 0890 NORTH CAROLINA High Point 27262 1923 N Main Street 919 882 6873 TWX 510 926 1516 OHIO Cleveland 44129 5579 Pearl Road 216 884 9209 TWX 216 888 0715 Dayton 45409
22. 8 W fxd comp 47 kQ 10 1 2 W fxd comp 51 Q 5 1 2 W var lin 100 kQ 30 1 8 W fxd comp 4700 Q 10 1 2 W fxd comp 1 MQ 10 1 2 W fxd comp 470 kQ 10 1 2 W DESEE Umm Transformer Transformer power neon driver Assembly Photochopper Subassembly Neon Driver Not Assigned C fxd my die 1 0 uF 10 50 vdew fxd my die 0 47 uF 10 100 fxd poly die 0 1 20 200 Not Assigned Diode Si 50 mA at 1 Vdc 20 piV Not Assigned fxd prec ww 100 9 0 1 1 2 W Photocells part of A3 not separately replaceable Assembly amplifier C fxd Al elect 10 uF 75 10 15 C fxd elect 200 uF 100 10 3 vdew C fxd cer die 0 001 uF 100 20 500 vdew C fxd Ta die 4 7 uF 10 35 vdew C fxd cer die 0 001 100 20 500 vdew HP 419A DC Null Voltmeter max MFR 56289 91418 56289 56289 93332 07910 93332 04713 86684 24446 04713 01121 01121 01121 01121 71450 01121 01121 71450 01121 01121 01121 28480 28480 28480 28480 56289 56289 84411 01281 01686 28480 28480 56289 56289 72982 56289 72982 Model 419A MFR PART NO Type 30D obd TA obd 30D106G025 BB4 192P10392 D3072 CD35658 D3072 5211327 253053 253391 5 4713 1511 7515 EB5611 EB3331 XQS 200 obd EB4731 EB 5105 XQS 200 obd 4721 1051 EB4741 9100 0172 9100 1319 00419 63001 1990 0214 148P obd 148P4791
23. Inc Boslon Mass Hoffmari Semiconduclor Div of Hoffman Electronics Corp Technology Instrument Corp of Calif Pasadena Calif So Pasadena Calif Mamaroneck N Y Redwood City Calif Minneapolis Minn Mineola N Y Wallham Mass Burbank Calif New York N Y Palo Alto Calif Evanston 111 Newbury Park Calif THE FOLLOWING H P VENDORS HAVE NO NUM BER ASSIGNED IN THE LATEST SUPPLEMENT TO THE FEDERAL SUPPLY CODE FOR MANUFAC TURERS HANDBOOK J0000 0000F 0000M 0000 00002 000AA 000AB 000AC 00088 000 OOONN 00000 000 000 000 S K Smith Co From Winchester Electronics Inc Santa Monica Calif Malco Tool and Die Los Angeles Calif Western Coil Div of Automatic Ind inc Redwood City Calif Ty Car Mfg Co inc Hollislon Mass Willow Leather Products Corp Newark N J British Radio Electronics Ltd Washington D C ETA England Indiana General Corp Elecl Div Indiana Precision Instrument Components Co Van Nuys Calif Hayward Calif San Jose 27 Calif Oakland Calif Burbank Calif Burlingame Calif Los Angeles 45 Calif Rubber Eng amp Development D Manufacturing Co Cooltron Control of Elgin Watch Co California Eastern Lab FSC Handbook Supplements H4 1 Dated DECEMBER 1964 H4 2 Dated MARCH 1962 Model 419A Appendix B SALES AND SERVICE OFFICES UNITED STATES and CANADA ALABAMA Huntsvilie 35802 2003 Byrd S
24. SWITCH orr 4 195 e m e Oo Oo o 419A J 0963 COF NOTES 7 4924 DENOTES WIRE COLOR COLOR CODE SAME AS RESISTOR COLOR CODE FIRST NUMBER IDENTIFIES BASE COLOR SECOND NUMBER IDENTIFIES WIDER STRIP THIRD NUMBER IDENTIFIES NARROWER STRIP e g 924 WHITE RED YELLOW WIRE COLOR 0 BLK BRN RED ORN YEL GRN BLU VIO GY WHT Qo o o0 gi wore 8 X AVERAGE VALUE SHOWN OPTIMUM VALUE SELECTED AT FACTORY SEE PARAGRAPH 5 51 FOR REPLACEMENT INSTRUCTIONS 9 DENOTES TWISTED PAIR 10 VOLTAGES INDICATED IN RED ARE MEASURED WITH VM PUSHBUTTON DEPRESSED 1 V RANGE INPUT SHORTED ALL VOLTAGES ARE 10 RANGE SiB R 4 lt 8 0 Ui ce M 8 SIR27 Q SIE F 15k a LU amp MCA 195 os CR3 y a 1 C2 C3 v2 9 i 1 0 47 D R3 9 00 PHOTO CHOPPER ASSEMBLY 00419 63001 SIR24 SS eee a 906K 51825 9 06 09 R3 90M 8 B ME La zm 419A J 0963 RANGE QSIB F 12V 0 75 Sey IV ZERO 5 04 0 1 518 8 2 lt 9 5 i 5 R8 R9 475 4 7 59 i RIO 47002 9 2 2 i L C8 it C5 L i fius 4 7 1 RE V 49 1 amp 9
25. Telephone and Radio Corp Clifton N J General Electric Co Schenectady N Y G E Lamp Division Nela Park Cleveland Ohio 00015 39 Revised February 1965 Code No 24655 26365 26462 26992 28480 33173 35434 36196 37942 39543 40920 42190 43990 44655 47904 48620 49956 52090 63743 54294 55026 55933 55938 56137 56289 59446 59730 60741 61775 62119 63743 64959 65092 66295 66346 70276 70309 70319 70485 70563 70903 70998 71002 71041 71218 71286 71313 71400 71436 71450 71468 71471 71482 71590 71616 71700 71744 71753 71785 71984 72092 72136 71707 72354 72619 72656 72699 72758 72765 72825 72928 72964 72982 73061 73076 73138 Manufacturer Address General Radio Co West Concord Mass Gries Reproducer Corp New Rochelle N Y Grobet File Co of America Inc Carlstadt N J Hamilton Watch Co Lancaster Pa Hewlett Packard Co Palo Alto Calif G E Receiving Tube Dept Owensboro Ky Lectrohm Inc Chicago Ill Stanwyck Corp Hawkesbury Ontario Canada P R Mallory amp Co Inc Indianapolis Ind Mechanical adustries Prod Co Akron Ohio Miniature Precision Bearings Inc Keene N H Muter Co Chicago C A Norgren Co Ohmite Mfg Co Polaroid Corp Precision Thermometer and Inst Co Raytheon Company Rowan Controller Co Englewood Colo Skokie Cambridge Mass Philadelphia Pa Lexington Mass Baltimore Md
26. diagrams Individual schematics are provided for the metering circuit and the power supply circuit 6 5 COMPONENT LOCATION DIAGRAMS 6 6 The physical configuration of the 419A is shown on the component location diagrams Each component is identified by reference designation REFERENCE DESIGNATIONS PARTIAL REFERENCE DESIGNATIONS ARE SHOWN PREFIX WITH ASSEMBLY OR SUBASSEMBLY DESIGNATION S OR BOTH FOR COMPLETE DESIGNATION COMPLETE ASSEMBLY SUBASSEMBLY COMPONENT DESIGNATION A2 NONE Q1 A2Q1 Ag A1 R1 A2A1R1 NONE NONE J1 J1 Assembly Reference Assembly Assembly Part Number Designation Name includes A2Al subassembly Jl mot mounted on Assembly A2 Number indicares pin of Plug and Jack Wire Color Color code same as resistor color code First number indicates base color second number indentifies wider strip third number indicates narrower strip E g 924 denotes WHT RED YEL wire 01779 2 Eyelet or standoff terminal may or may not be numbered Assembly A3 Pin 4 Jl of wire 4 6 1 Pin may or may not y be numbered PPFR ATOR 7I 22 6 Female pin connector on WHT RED wire Male standoff pin connector 5 0 1000 HP 419A DC Null Voltmeter max Section VI Model 419A Ii e T 4 is R3 SI 2 S2RI Figure 6 1 Model
27. hp Part No 0684 1031 and a 0 1 oun e a uF capacitor hp Part No 0170 0085 are required 2 001 V 100 pA 96 to 104 for this test 3 003 V 300 pA 290 to 310 4 01 V 1000 pA 970 to 1030 a Connect test setup illustrated in Figure 5 3 do not connect oscillator 5 03 V 3000 pA 2910 to 3090 b Depress 419A SETNULL pushbutton set NULL gb UE RAS control for 9 on 10 pV range 7 V 30 nA 29 1 to 30 9 c Connectoscillatorand set its out put frequency 9 13 RESPONSE TIME TEST 5 14 A strip chart recorder Sanborn Model 77014A a voltmeter calibrator hp Model 738BR a 100 Q resistor hp Part No 0811 0398 and a 1 MQ re sistor hp Part No 0811 0473 are required for this test for 60 Hz output voltage for 0 5 volts rms Model 419A reading should not vary more than 10 2 LV after the initial transient 5 17 NOISE TEST 5 18 No external test equipment is required for the noise test a Short 419A and INPUT terminals a Connectstrip chart recorder to 419A and OUTPUT terminals b Constructtestsetupillustrated in Figure 5 1 turn voltmeter calibrator dc output off and b setfor 30 mV output connect 419A terminal to Point A C Set 419A RANGE switch to 3 uV position de press VM AM pushbutton Zero 419A VM function on 3 mV RANGE c Ifnoisedisplayed on 419A meter exceeds 0 3 perform Chopper Adjustment graph 5 33 5 2 01779 2
28. of Texas Instruments Inc Spencer Prods Research Products Corp Rotron Manufacturing Co Inc Vector Electronic Co Western Washer Mfr Co Los Angeles Calif Carr Fastener Co Cambridge Mass New Hampshire Ball Bearing Inc Peterborough N H Darlington S C Los Angeles Calif Springfield N J Attleboro Mass Madison Wis Woodstock Glendale Calif Pyramid Electric Co Electro Cords Co Victory Engineering Corp Bendix Corp Red Bank Div Red Bank N J Hubbell Corp Mundelein 11 Smith Herman H Inc Brooklyn Central Screw Co Chicago Gavitt Wire and Cable Co Div of Amerace Corp Burroughs Corp Electronic Tube Div Eveready Battery Model Eng and Mfg Inc Brookfield Mass Plainfield N J New York N Y Huntington Ind Loyd Scruggs Co Festus Mo Arco Electronis Inc New York N Y A J Glesener Co inc San Francisco Calif Good Electric Mfg Co Ogallala Neb Sarkes Tarzian Inc Bloomington Ind Boonton Molding Company Boonton N J B Boyd San Francisco Calif CODE LIST OF MANUFACTURERS Sheet 2 of 2 Code No 85474 85660 85911 86197 86579 86684 87216 87473 87664 87930 88140 88220 88698 89231 89462 89473 89636 89665 90179 90970 91260 91345 91418 91506 91637 91662 91737 91827 91929 91961 92180 92196 92367 92607 93332 93369 93410 93788 APPENDIX Manufacturer Address
29. voltage measurements itisadvisabletochargethebatteries before troubleshooting 9 43 NO RESPONSE TO INPUT 5 44 If the meter does not respond to input usually accompanied by a constant offset near full scale after meter has been on for one or two minutes proceed as follows a If one neon is bad allthe pulses at A2TP2 will be the same amplitude If the blocking oscillator is bad there will be no pulses at A2TP2 b Check for approximately 8 volts dc at the emitter of Q4 to isolate between the blocking oscillator and its voltage regulator c Iftheneon waveform at A2TP2 is correct the trouble is in the amplifier 5 5 HP 419A DC Null Voltmeter max Section V 9 45 POSITIVE OR NEGATIVE FOLDOVER 5 46 Foldover is when the meter needle pegs and then returns on scale when the input is overloaded a If positive foldover occurs check A4Q12 for low gain b If negative foldover occurs check for low gain 4013 and for a leaky A4C8 or C12 9 47 EXCESSIVE NOISE 5 48 If the 419A meter noise is in excess of 0 3 uV peak to peak proceed as follows a Check the batteries for low charge b Check the chopper frequency in accordance with Paragraph 5 33 Misadjustment of chop per frequency or drive or a misfiring neon bulb will cause noise c Clean the connectors on the A4 board with a fiberglass brush ortypewriter eraser and ensure they are making good connections d Check the transistors
30. 0 50 to 1000 Hz ap proximately 3 watts Dimensions Standard hp 1 2 module 6 high 7 3 4 wide 8 deep 152 197 x 203 mm 01779 2 HP 419A DC Null Voltmeter max Model 419A Section I SECTION 1 GENERAL 1 1 INTRODUCTION 1 2 This section contains general information about the Model 419A DC Null Voltmeter Figure 1 1 In cluded are Specifications Description and Purpose Instrument Identification Accessory Equipment Sup plied and Accessory Equipment Available 1 3 SPECIFICATIONS 1 4 Table 1 1 contains the specifications for the Model 419A 1 5 DESCRIPTION AND PURPOSE 1 6 The Model 419A is housed standard hp 1 2 module case Arechargeablebattery power sup ply allows operation independent of ac line Range and function switching is accomplished by front panel controls 1 7 The Model 419A provides 18 end scale dc voltage ranges in a 1 3 10 sequence from 3 microvoltsto 1000 volts The Model 419A also provides 7 end scale dc current ranges from 30 picoamps to 30 nanoamps An internal bucking supply allows voltages up to 300 millivolts to be measured with infinite input impedance The input impedance for the higher ranges is 100 MQ 1 8 Recorder output terminals are provided onthe rear panel The voltage available is proportional to the meter deflection and is adjustable from 0 to 1 volt at full scale 1 9 INSTRUMENT MANUAL IDENTIFICATION 1 10 Hewlett Packardusesa two sectio
31. 11 to hp Part No 0687 3341 fxd comp 330 ohms 10 1 2w Change A2R12 to hp Part No 2100 0227 var ww 20 ohms 10 1 1 2 w Change A2T1 to hp Part No 9100 0172 Transformer power Change A2T2 to hp Part No 9100 1314 Transformer neon driver HP 419A DC Null Voltmeter max 01779 2 Figure C 1 Model 419A Component Location Diagram Serials Prefixed 514 532 646 Part of Figure C2 Al Amplifier 00419 66501 Serials Prefixed 514 532 646 HP 419A DC Null Voltmeter max NOTES PARTIAL REFERENCE DESIGNATIONS ARE SHOWN PREFIXWITH ASSEMBLY OR SUB ASSEMBLY DESIGNATION S OR BOTH FOR COMPLETE DESIGNATION SB 2 COMPONENT VALUES ARE SHOWN AS FOLLOWS UNLESS OTHERWISE NOTED E RESISTANCE IN OHMS RANGE CAPACITANCE IN MICROFARADS 3 52 FUNCTION SWITCH 197 50 243 DENOTES ASSEMBLY 4 3 100 10 5 rep i 2 3 4 5 E 4 DENOTES DC FEEDBACK PATH a FAST BAT SET READ 5 DENOTES AC FEEDBACK PATH 6 ee E NULL 2 9 4 100 3 6 DENOTES FRONT PANEL MARKING 30 10 14 DENOTES REAR PANEL MARKING 8 25 10 30 415 9 is n DENOTES SCREWDRIVER ADJUST 300 7 9 V DENOTES POWER SUPPLY COMMON MICROVOLTS voLTs 000 418 10 DENOTES SIGNAL COMMON i 11 DENOTES POWER LINE GROUND 1
32. 2 26 DENOTES COMPONENTS NOT MOUNTED ASSEMBLY s 13 DENOTES MAIN SIGNAL PATH 15 51826 iK 17 J J2 52 SIDIR SIA R 528 SID F SIE rg 41 o e 2 SIB R 3 2 o 3 5 BT5 4 1 35 8 2 5 7 1 6 8 9 o P 25 o 12 84 5 5 COARSE FINE i 5K 5 g 214 90K 27 o 14 14 is 5 5 8 15 15 o SIR22 T 6 6_ 216 6 ge o 17 t 17 18 18 18 1820 100 419 0 02678 HP 419A DC Null Voltmeter max eS M RANGE 1 AC DC AMPLIFIER ASSEMBLY 00419 6650 PREFIX WITH ASSEMBLY OR SUB LETE DESIGNATION SIBIR lt 3 UNLESS OTHERWISE NOTED 5 R3 X 4 120K o BACK PATH 6 RI R2 475 178K R4 iQORF R27 F 15 MF MF 16 iM 3 8 o MOUNTED ON ASSEMBLY R40 28 TT o 70 100 INAL PATH 5 ci 9 es uro D X 22 gt s E v 18 05 06 A3C4 O 4 7 nace 2 2201 SIB F 2 4 5 5 07 o8 o 2 ol 2 14 o E 1 1 L vov vov o OOO OO Ore y
33. 289 56289 56289 56289 56289 56289 93332 56289 24446 04713 24446 04713 24446 04713 24446 04713 19701 19701 01121 01121 01121 01121 01121 19701 01121 01121 01121 01121 71450 01121 01121 01121 01121 01121 01121 01121 01121 01121 01121 01121 Section VII MFR PART NO 30D106G015 BA4 30D107G015 DD4 148P 150D475X9035 B2 150D225X0020 AZ 30D107G015 DD4 Type 148P 150D226X9015 B2 DYS 150D396X9010 B2 DYS 150D226X9015 B2 DYS D3072 TN 56 2N3391 5 4713 253391 5 4713 253391 5 4713 253391 5 4713 1241 1041 5601 5621 1211 4751 4721 2251 5631 XQS 200 EB1031 EB1041 EB1241 EB1031 EB1021 EB1041 EB2231 EB1241 EB1021 EB1051 EB2231 obd obd obd obd obd 7 3 Section VII REFERENCE A4R29 A4R30 A4R31 thru A4R33 A4R34 thru A4R36 A4R37 A4R38 A4R39 A4R40 A4R41 thru A4R44 A4R45 A4R46 A4R47 A4R48 A4R49 A4R50 A4R51 BT1 thru BT4 BT DS1 F1 J1 J2 J3 J4 J5 J6 JT L1 L2 M1 R2 R3 R4 R5 R6 R7 R9 7 4 DESIGNATOR hp PART NO 0687 2221 0687 4741 0687 2241 0687 2221 0687 1041 0687 3951 0687 1031 0687 1011 2100 1795 2100 1470 0687 3941 0687 6831 0687 2221 0687 1031 0687 2221 1420 0015 1420 0004 2140 0008 2110 0021 1251 0148
34. 2Q4 A2Q5 A2R1 A2R2 A2R3 A2R4 A2R5 A2R6 A2R7 A2R8 A2R9 A2R10 A2R11 A2R12 A2T1 A2T2 A3 A3A1 1 A3C2 A3C3 4 1 ASCR2 A3CR4 1 A3R2 A4 4 1 A4C2 4 3 4 4 4 5 7 2 hp PART NO 00419 66502 0180 0149 0150 0093 0180 0059 0160 0161 1901 0025 1902 0048 1901 0025 1902 0563 1854 0039 1854 0033 1853 0010 0687 1511 0686 7515 0687 5611 0687 3331 2100 1410 0687 4731 0686 5105 2100 0362 0687 4721 0687 1051 0687 4741 9100 0172 9100 1319 00419 63001 1990 0214 0160 0859 0170 0064 0160 2446 1901 0156 0811 1505 1 thru A3V4 00419 63001 00419 66504 0180 0224 0180 0060 0150 0069 0180 0100 0150 0069 Table 7 1 ee Replaceable Parts DESCRIPTION Not Assigned Assembly Power Supply fxd Al elect 65 uF 100 10 60 C fxd 0 01 uF 80 20 100 vdew C fxd elect 10 pF 100 10 25 vdew C fxd 0 01 pF 10 Diode Si 100 mA at 1 V 100 piV 12 pF Diode breakdown 6 81 V 5 Diode Si 100 mA at 1 V 100 piV 12 pF Diode breakdown 100 uA 22 1 V 2 Transistor NPN Si 2N3053 Transistor NPN Si 2N3391 Transistor PNP Si fxd comp 150 Q 10 1 2 W fxd comp 750 Q 5 1 2 W fxd comp 560 Q 10 1 2 W fxd comp 33 kQ 10 1 2 W var lin 20 9 30 1
35. 419A DC NULL VOLTMETER OPERATING AND SERVICE MANUAL 5 HEWLETT PACKARD HEWLETT PACKARD CERTIFICATION The Hewlett Packard Company certifies that this instrument was thoroughly tested and inspected and found to meet its published specifications when it was shipped from the factory The Hewlett Packard Company further certifies that its calibration measurements are traceable to the U S National Bureau of Standards to the extent allowed by the Bureau s calibration facility WARRANTY AND ASSISTANCE Hewlett Packard products are warranted against defects in materials and workmanship This warranty applies for one year from the date of delivery or in the case of certain major components listed in the operating manual for the specified period We will repair or replace products which prove to be defective during the warranty period No other warranty is expressed or implied We are not liable for consequential damages For any assistance contact your nearest Hewlett Packard Sales and Service Office Addresses are provided at the back of this manual HP 419A DC Null Voltmeter max HP PART NO 00419 90002 MODEL 419A DC NULL VOLTMETER SERIALS PREFIXED 707 Appendix C Manual Backdating Changes adapts this manual to Serials Prefixed OPERATING AND SERVICE MANUAL 514 532 646 Copyright Hewlett Packard Company 1966 Box 301 Loveland Colorado 80537 U S A 017
36. 75 vm Dy osm 41 R42 250K Ga m ET X 2 nas 250K 51818 E bw Y 9 13V IV p 23 FROM ke i e 2 2 52 23 49 a ee 4 os D Figure 6 3 Amplifier and Amplifier Switching Schematic and Component Location Diagrams 01779 2 6 3 6 4 HP 419A DC Null Voltmeter max WHT CURRENT RED WHT BLK BLK FREQ T2 CR 419 8 0999 WHT WHT GRY WHT BRN BRN RED VIO WHT BLK WHT GRN YEL GRY BLK BLK GRY GRY A2 vio RED hp Part No 00419 66502 NOTES 1 PARTIAL REFERENCE DESIGNATIONS ARE SHOWN PREFIX WITH ASSEMBLY OR SUBASSEMBL Y DESIGNATION S OR BOTH FOR COMPLETE DESIGNATION 2 COMPONENT VALUES ARE SHOWN AS FOLLOWS UNLESS OTHER WISE NOTED RESISTANCE IN OHMS CAPACITANCE MICROFARADS Y 3 L DENOTES POWER LINE CHASSIS GROUND DENOTES POWER SUPPLY COMMON DENOTES ASSEMBLY 4 DENOTES SUBASSEMBLY 77777 DENOTES COMPONENTS NOT MOUNTED ON 77727 ASSEMBLY 5 ____ DENOTES REAR PANEL MARKING WII DENOTES SCREWDRIVER ADJUST 7 924 DENOTES WIRE COLOR COLOR CODE SAME AS RESISTOR COLOR CODE FIRST NUMBER IDENTIFIES BASE COLOR SECOND NUMBER IDENTIFIES WIDER STRIP THIRD NUMBER IDENTIFIES NARROWER STRIP e g 924 WHITE RED YELLOW WIRE C
37. 79 2 Printed DEC 1966 HP 419A DC Null Voltmeter max Model 419A Section Page I GENERAL INFORMATION 1 1 1 1 Introduction 1 1 1 3 Specifications 1 1 1 5 Description and Purpose 1 1 1 9 Instrument Manual Identification 1 1 1 11 Accessory Equipment Supplied 1 1 1 13 Accessory Equipment Available 1 1 Section Page II INSTALLATION 2 1 2 1 Introduction 2 1 2 3 Initial Inspection 2 1 2 5 Power Requirements 2 1 2 7 Grounding Requirements 2 1 2 10 Installation e 2 1 2 12 Bench Mounting 2 1 2 14 Rack Mounting 2 1 2 16 Combination Mounting 2 1 2 18 Repackaging for Shipment 2 1 Section Page III OPERATING INSTRUCTIONS 3 1 3 1 Introduction 3 1 3 3 Controls Indicators and Connectors 3 1 3 5 Operating Instructions 3 1 3 7 Turn On Procedure Battery 3 1 3 8 Turn On Procedure AC Line Operation 3 1 3 9 DC Voltage Measurements 3 1 3 10 DC Current Measurements 3 2 3 17 Applications 3 2 Section Page IV THEORY OF OPERATION 4 1 4 1 Introduction 4 1 4 3 General Description 4 1 4 11 Detailed Description 4 1 4 12 Bucking Supply See Figure 6 3 4 1 4 15 Input Attenuator 4 2 4 17 Input
38. 863 UW PS5553 E 20 obd 30D106G015 4 30D207G003 DC4 801 010X5G 01022 1500475 903 5 2 801 010X5G 01022 00419 63001 01779 2 Model 419A H al REFERENCE DESIGNATOR A4C6 A4C7 A4C8 A4C9 A4C10 A4C11 4 12 4 13 4 14 4 15 4 16 A4C17 4 1 thru 4 16 A4Q1 A4Q2 A4Q3 A4Q4 A4Q5 A4Q6 A4Q7 thru A4Q10 A4Q11 A4Q12 A4Q13 A4R1 A4R2 A4R3 A4R4 A4R5 A4R6 A4R7 A4R8 A4R9 A4R10 A4R11 A4R12 A4R13 A4R14 A4R15 A4R16 A4R17 10 NFNO A4R19 A4R20 A4R21 A4R22 A4R23 thru A4R25 A4R26 A4R27 A4R28 01779 2 hp PART NO 0180 0224 0180 0061 0160 0859 0180 0100 0180 0155 0180 0061 0160 0932 0180 0228 0180 0393 0180 0228 1901 0025 1854 0226 1854 0033 1853 0010 1854 0033 1853 0010 1854 0033 1853 0010 1854 0033 1853 0010 0757 0374 0757 0129 0687 1241 0687 1041 0687 5601 0687 5621 0687 1211 0757 0374 0687 4751 0687 4721 0687 2251 0687 5631 2100 1410 0687 1031 0687 1041 0687 1241 1091 UUO 1UO01 0687 1021 0687 1041 0687 2231 0687 1241 0687 1021 0687 1051 0687 2231 Table 7 1 Q 2 HM Hn Replaceable Parts Cont d DESCRIPTION fxd Alelect 10 uF 75 10 15 v
39. 94 80411 80486 80509 80583 80640 81030 81073 81095 81312 From Manufacturer Address Hughes Products Division of Hughes Aircraft Co Newport Beach Calif Amperex Electronic Co Div of North American Phillips Co Inc Hicksville Beckman Helipot Corp So Pasadena Calil Bradley Semiconductor Corp Hamden Conn Carling Electric Inc Hartlord Conn George K Garrett Co Inc Philadelphia Pa Federal Screw Prod Co Chicago Fischer Special Mfg Co Cincinnati Ohio The General Industries Co Elyria Ohio Goshen Stamping amp Tool Co Goshen Ind JFD Electronics Corp Brooklyn N Y Jennings Co San Jose Calif Signalite Inc Neptune N J J H Winns and Sons Winchester Mass Industrial Condenser Corp Chicago 111 R F Products Division of Amphenol Borg Electronics Corp Danbury Conn E F Johnson Co Waseca Minn International Resistance Co Philadelphia Pa Jones Howard Division of Cinch Mfg Corp Chicago 111 James Knights Co Sandwich 111 Kulka Electtic Corporation Mt Vernon N Y Lenz Mfg Co Chicago iii Littlefuse Inc Des Plaines M Lord Mfg Co Erie Pa C W Marwedel Micamold Electronic Mfg Corp James Millen Co Inc J W Miller Co Monadnock Mills Mueller Electric Co Oak Manufacturing Bendix Pacific Division of Bendix Corp Pacilic Metals Co Phaostran Instrument and Electronic Co Phoell Mfg C
40. A4R47 is factory selected to provide approxi mately 1 1 Vdc at the rear panel OUTPUT terminals into a 1 KQ load with the LEVEL control turned fully cw anda full scale input applied to the INPUT ter minals Once A4R47 hasbeen selected at the factory there should be no reason to change its value unless one of the output transistors A4Q12 and A4Q13 or one of the diodes A4CR13 A4CR14 is replaced Factory values of A4R47 range from 16 to 20 witha typical value of 18 A4R47 is an Allen Bradley com position 5 1 2 watt resistor If the value of A4R47 must be changed proceed as follows a Applya 1Vdc inputto the Model 419A INPUT terminals 1 V range b Connect a 1 load across the rear panel OUTPUT terminals c Turn LEVEL control fully cw d Measure the voltage across the load the voltage is lessthan 1 0 Vdc increase the value of A4R47 if the voltage isgreater than 1 15 Vdc reduce the value of A4R47 e After replacing A4R47 perform the Full Scale Calibration procedure Paragraph 5 37 01779 2 HP 419A DC Null Voltmeter max Model 419A Section VI SECTION VI CIRCUIT DIAGRAMS 6 1 INTRODUCTION 6 2 This section contains the circuit diagrams nec essary for the operation and maintenance of the Model 419A DC NullVoltmeter Included are schematic and component location diagrams 6 3 SCHEMATIC DIAGRAMS 6 4 The electricalconfiguration of the 419A is shown on the schematic
41. ANEL MARKING DENOTES REAR PANEL MARKING 6 DENOTES SCREWDRIVER ADJUST RANGE SWITCH jee HP 419A DC Null Voltmeter max DENOTES WIRE COLOR COLOR CODE SAME AS RESISTOR COLOR CODE FIRST NUMBER IDENTIFIFS BASE COLOR SECOND NUMBER IDENTIFIES WIDER STRIP THIRD NUMBER IDENTIFIES NARROWER STRIP e g 824 WHITE RED YELLOW WIRE COLOR BLK BRN RED ORN YEL GRN BLU VIO GY WHT 1924 00 10 Ui AVERAGE VALUE SHOWN OPTIMUM VALUE SELECTED AT FACTORY SEE PARAGRAPH 5 51 FOR REPLACEMENT INSTRUCTIONS DENOTES TWISTED PAIR VOLTAGES INDICATED IN RED ARE MEASURED WITH VM PUSHBUTTON DEPRESSED 1 V RANGE INPUT SHORTED ALL VOLTAGES ARE 109 MODULATOR 27 51827 SIAR pr Tr 280 ED 4u ys L2 a ME a Amc We L SIR2 2 2 S S 35 9 Ox 5 5 2 4 Eo e Ko amp ol o 184 o o i 047 09 Su Su 603 2 6 5 5186 0 4 SR al le 8 x gt io ol 5188 2 5 9 3 5189 SIR25 12K 9 06 SIRIO R6 3300 e 2200 D 40 D NULL R3 9 COARSE morcm FINE RC zoom B 35k 1500 E B A us n ER SIR23 29 90K 9 9 SIR22 E 9 SIR2I 900 51820 1007 2 FUNCTION
42. Controls Co Star Products Inc Avery Adhesive Label Corp Hammerlund Co Inc Stevens Arnold Co Inc Wallingford Conn New York N Y Chicago til Riverside Calif Columbus 16 Ohio Defiance Ohio Monrovia Calif New York N Y Boston Mass International Instruments Inc New Haven Conn Grayhill Co LaGrange Triad Transformer Corp Venice Calif Winchester Electronics Co Inc Norwalk Conn FSC Handbook Supplements H4 1 Dated DECEMBER 1964 H4 2 Dated MARCH 1962 Appendix A Code No 81349 81415 81453 81483 81541 81860 82042 82142 82170 82209 82219 82376 82389 82647 82866 82877 82893 83053 83058 83086 83125 83148 83186 83298 83315 83330 83385 83501 83594 83740 83777 83821 84171 84396 84411 84970 85454 85471 Monufacturer Address Military Specification PTT Wilkor Products Inc Cleveland Ohio Raytheon Mfg Co industrial Components Div Industr Tube Operations Newton Mass International Rectifier Corp El Segundo Calif The Airpax Products Ce Cambridge Mass Barry Controls Inc Watertown Mass Carter Parts Co Skokie Jeffers Electronics Division of Speer Carbon Co Du Bois Pa Allen B DuMont Labs Inc Clifton N J Maguire Industries Inc Sylvania Electric Prod Inc Greenwich Conn Electronic Tube Div Emporium Pa Astron Co East Newark N J Switchcraft Inc Chicago Metals and Controls Inc Div
43. DC NULL VOLTMETER 2 ee o lt gt lt Figure 5 2 Ammeter Accuracy Test Setup 5 11 AMMETER ACCURACY TEST d 9 12 The ammeter accuracy performance test is il lustrated in Figure 5 2 Avoltmeter calibrator hp Model 738BR a 9 MQ resistor hp Part No 0698 5443 anda 900 resistor hp Part No 0698 5488 are required for this test e a Connect test setup illustrated in Figure 5 2 b SetModel 419 Aand voltmeter calibrator con f trols as indicated in step 1 of Table 5 3 If Model 419A reading is not within the listed tolerances troubleshoot the input attenuator Paragraph 5 49 Start strip chart recorder and turn voltmeter calibrator dc output on if strip chart re corder does not show OUTPUT at 95 6 between 2and3seconds perform Chopper Adjustment Paragraph 5 33 Turn voltmeter calibrator dc output off and set for 100 mV output set 419A RANGE switch to 10 uV position Start strip chart recorder and turn voltmeter calibrator dc output on if strip chart re corder does not show OUTPUT at 95 within 1 second perform Chopper Adjustment graph 5 33 Table 5 3 Ammeter Accuracy Test 5 15 SUPERIMPOSED AC REJECTION TEST STEP 419A 419A 9 16 The superimposed ac rejection test setup is il DC OUTPUT RANGE READING lustrated in Figure 5 3 An oscillator hp Model 208A 600 resistor hp Part No 0727 0081 a 10 resistor
44. Fairchild Semiconductor Corp Mountain View Catif Minneapolis Minn Los Angeles Calif Technical Wire Products Springfield N J Continental Device Corp Hawthorne Calif Rheem Semiconductor Corp Mountain View Calif Shockley Semi Conductor Laboratories Boonton Radio Corp 0 5 Engineering Co Blinn Delbert Co Burgess Battery Co Niagara Falls Ontario Canada Burbank Calil Phoenix Ariz Bradford Pa Pasadena Calif Minneapolis Minn Elmira N Y New York N Y City of Industry Calif Los Angeles Calif Minnesota Rubber Co The Birtcher Corp Palo Alto Calif Boonton N J Los Angeles Calif Pomona Calif Sloan Company Cannon Electric Co Phoenix Div CBS Electronics Semiconductor Operations Div of 5 Mel Rain Babcock Relays Inc Texas Capacitor Co Atohm Electronics Electro Assemblies Inc Mallory Battery Co of Canada Ltd The Bristol Co General Transistor Western Corp Los Angeles Calil Berkeley Calif Niagara Falls N Y Berne Ind Lowell Mass Indianapolis Ind Costa Mesa Calif Houston Texas Sun Valley Calif Chicago 111 Toronto Ontario Canada Waterbury Conn Ti Tal Inc Carborundum Co CTS of Berne Inc Chicago Telephone of California Inc So Pasadena Calif Palo Alto Calil Santa Calif Microwave Electronics Corp Duncan Electronic Inc General Instrument Corporation Semiconductor Division
45. GE MEASUREMENTS a Turnon the Model 419A andzero it according tothe steps in Paragraph 3 7 battery opcration or Paragraph 3 8 AC Line Operation Allow at least ten minutes warmup time if low voltages below 1 mV are to be measured b Connecttest leads to and INPUT terminals See Table 1 3 list of test leads available c Set RANGE switch to range nearest above input voltage Ifindoubt start onthe 1000 V range and downrange as necessary TO PREVENT DAMAGE TO THE MODEL 419A DO NOT EXCEED THE FOLLOWING OVERLOAD LIMITS RANGE MAXIMUM INPUT VOLTAGE 3 uV to mV 50 Vdc 10 mV to 300 mV 500 Vdc 1 V to 1000 V 1200 Vdc 3 1 HP 419A DC Null Voltmeter max Section III d Connect test leads to voltage to be measured CAUTIONS 5 DO NOT FLOAT MODEL 419A IN PUT TERMINAL MORE THAN 500 VDC FROM GROUND e Depress VM AM pushbutton Read value of input voltage on meter scale NOTE If input voltage is 300 mV or less infinite input impedance maybe ob tained by proceeding with steps f thru h f Depress SET NULL pushbutton g Rotate NULL control until meter indicates exactly zero NOTE NULL control gives both coarse and fineadjustment Rotate con trol until pointer is slightly down scale from zero then reverse direction to obtain fine adjustment h Depress READ NULL pushbutton Read value of input voltage on meter 3 10 DC CURRENT MEASUREMENTS
46. K CONTROL 4 34 Control of feedback is accomplished through a deck of the RANGE switch The amount of feedback depends upon the position of the RANGE switch The closed loop gain of the amplifier may be determined by subtracting the feedback from the forward gain The feedback provided for each range is listed in Table 4 1 01779 2 HP 419A DC Null Voltmeter max Model 419A 4 35 POWER SUPPLY AND NEON DRIVER Figure 6 4 4 36 The power sourcefor the 419A is four recharge ablebatteries which supply a 13 V anda 13 V output The 419A may also be operated from line voltage which will trickle charge the batteries during operation 4 3 Theline input maybe either 115 V or 230 V from 50 to 1000 Hz Theinput is rectified by CR1 thru CR4 and applied to series regulator 01 4 38 Zener diode CR5 supplies a constant reference to the base of Q1 The emitter of Q1 is referencedto the voltage across R20r R3 the output current in creases Q1 will conduct less due to less emitter to base bias This will decrease the output current If either output decreases Q1 will conduct harder in creasing the output current 4 39 The neon driver consists of a series regulator circuit a blocking oscillator and a neon circuit Transistor 05 andzener diode CR9 provide a constant reference to series regulator Q4 The frequency of the blocking oscillator is controlled by varying the voltage across This is accomplished through ad
47. O 72 DESCRIPTION S1 00419 61901 1 Switch Assembly range 8181 0683 6845 1 fxd comp 680 5 1 4 W 182 0684 2241 1 fxd 220 KQ 10 1 4 W S1R3 0684 6831 1 fxd comp 68 kQ 10 1 4 W 5184 0684 2231 1 fxd comp 22 kQ 10 1 4 W 5185 0683 1255 1 fxd comp 1 2 MQ 5 1 4 W S1R6 0684 3941 1 fxd comp 390 10 1 4 W 8187 0683 1245 1 fxd comp 120 KQ 5 1 4 W S1R8 0683 3935 1 fxd comp 39 kQ 5 1 4 W 5189 0684 1231 1 fxd comp 12 KQ 10 1 4 W 81810 0684 3321 1 fxd comp 3300 Q 10 1 4 W 51811 0687 1031 fxd 10 kQ 10 1 2 W S1R12 0811 1505 R fxd prec ww 100 Q 0 1 1 2 W S1R13 0698 3373 1 fxd met flm 140 kQ 0 25 1 4 W S1R14 0698 3372 1 fxd prec met flm 40 0 25 1 4 W S1R15 0698 3371 1 fxd prec met flm 14 kQ 0 25 1 4 S1R16 0698 3370 1 fxd prec met flm 4000 9 0 25 1 4 W 81817 0698 3369 1 fxd prec met flm 1400 Q 0 25 1 4 W S1R18 0811 1506 1 fxd prec ww 400 Q 0 1 1 4 W S1R19 0686 3051 1 fxd 3 0 MQ 5 1 2 W S1R20 0698 3363 1 fxd prec c flm 100 9 0 5 1 2 W S1R21 0698 3364 1 fxd prec c flm 900 9 0 5 1 2 W S1R22 0698 3365 1 fxd prec c flm 9000 0 0 5 1 2 W S1R23 0698 3366 1 fxd prec c 90 20 59 1 2 W S1R24 0698 3367 1 fxd prec c flm 906 kQ 0 5 1 2 W S1R25 0698 3368 1 fxd prec c flm 9 06 MQ 0 5 1W S1R26 0686 1025 1 fxd comp 1000 Q 5 1 2 W 81827 0687 1531 1 fxd comp 15 10 1 2 W 52 3101 0803 1 Switch pus
48. OLOR BLK BRN RED ORN YEL GRN BLU VIO GY WHT Qo 8 INDIVIDUAL COMPONENTS ON ARE SEPARATELY REPLACEABLE SEE PARAGRAPH 5 27 HP 419A DC Null Voltmeter max Model 4192 POWER SUPPLY AND NEON DRIVER ASSEMBLY 00419 66502 POWER SUPPLY 53 CIE 115 2301 R2 750 IT 2 FUNCTION SWITCH P O 52 MB V orr FAST zero VM SET READ CHG TEST AM NULL NULL 22 Oo 9 9 G Z 2 52 2 2 Mi LL PHOTO CHOPPER ASSEMBLY 00419 63001 NEON DRIVER i l NEON SUBASSEMBLY 1990 0214 SEE NOTE 8 i R6 1 pe 13 4 94 D 0974 COPYRIGHT 1966 BY HEWLETT PACKARD COMPANY M 01779 2 HP 419A DC Null Voltmeter max Model 419A Section VI SSEMBLY 00419 66502 POWER SUPPLY RI 190 052 2 D 2 3 65 m 2 I H3 T 5 6 750 PTT P O 82 4 P 0 8267 lt 32 2 2 eR E 2 21 13V TO 2 4 15 Ko 227024 77 NEON DRIVER Q4 13V 4S m T 1 i 0 ou 2 2 3 Figure 6 4 Power Supply and Neon Driver
49. R M Bracamonte amp Co Koiled Kords Inc Seamless Rubber Co Clifton Precision Products Precision Rubber Products Corp Radio Corp of America RCA Electron Tube Div Philco Corporation Lansdale Division Western Fibrous Glass Products Co San Francisco Calif Seattle Wash Providence San Francisco Calif New Haven Conn Chicago 111 Clifton Heights Pa Dayton Ohio Harrison N J Lansdale Pa Van Waters amp Rogers Inc Tower Mfg Corp Cutler Hammer Inc Lincoln 111 Gould National Batteries Inc St Paul Minn General Mills Inc Buffalo N Y Graybar Electric Co Oakland Calif Waldes Kohinoor Inc Cambridge Mass General Electric Distributing Corp Schenectady N Y Carter Parts Div of Economy Baler Co Chicago Ill United Transformer Co Chicago U S Rubber Co Mechanical Goods Div Passaic N J Bearing Engineering Co Connor Spring Mfg Co Miller Dial amp Nameplate Co Radio Materials Co Augat Brothers Inc Dale Electronics Inc Elco Corp San Francisco Calif San Francisco Calif El Monte Calif Chicago Attleboro Mass Columbus Nebr Philadelphia Pa Gremar Mfg Co Inc Wakefield Mass K F Development Co Redwood City Calif Minneapolis Honeywell Regulator Co Microswitch Div Freeport Ill Nahm Bros Spring Co Oakland Calif Tru Connector Corp Peabody Mass Universal Metal Prod Inc Bassett Puente Ca
50. TION 2 4 This instrument was carefully inspected both mechanically and electrically before shipment It should be physically free of mars or scratches and in perfect electrical order uponreceipt Toconfirmthis the instrument should be inspected for physical damage in transit Also check for supplied accessories and test the electrical performance of the instrument using the procedure outlined in Paragraph 5 5 Ifthere is damage or deficiency see the warranty on the inside front cover of this manual 2 5 POWER REQUIREMENTS 2 6 The Battery Power Supply in the Model 419A can be charged from any source of 115 or 230 volts 410 at 50 to 1000 Hz With the instrument dis connected from the ac power source move the slide switch located on the rear panel until the desired line voltage appears Power Dissipation is approxi mately 3 watts 2 7 GROUNDING REQUIREMENTS 2 8 To protect operating personnel the National Electrical Manufacturers Association NEMA re commends that the instrument panel and cabinet be grounded This instrument is equipped with a three conductor power cable which when plugged into appropriate receptacle groundsthe instrument The offset pin on the power cable three prong connector is the ground wire 2 9 Topreservethe protection feature when operating the instrument from a two contact outlet use a three prongtotwo prong adapter andconnect the green pig tail on the adapter to ground 2
51. a Turnonandzero the Model 419A according to the steps in Paragraph 3 7 Battery Operation 3 8 Line Operation Allow at least ten minutes warmup time if low value currents below 10 nA are to be measured b Connect test leadsto and INPUT terminals c Set RANGE to range nearest above current tobe measured If indoubt start on 300nA position and reduce as necessary d Connect test leads in series with current to be measured e Depress VM AM pushbutton Read value of in put current on meter scale 3 11 Amplifier Output 3 12 The rear panel OUTPUT terminals providea dc voltage which is proportional tometer deflection The LEVEL control adjusts the maximum value of output voltage Withthe LEVELcontrol turnedfully cw the voltage varies from 0 to 1 Vdc into a 1 load Polarity of the voltage depends upon polarity of the meter deflection 3 2 Model 419A 3 13 Battery Charging Procedure 3 14 The batteries are automatically trickle charged whenever the Model 419A is connected to an ac power lineandthe ZERO VM AM SETNULLorREADNULL pushbutton is depressed The instrument may be used while trickle charging occurs except when the batteries have been almost completely discharged Under this condition the Model 419A may not operate properly and the batteries should be atleast partially recharged before using the instrument Generally 72 hours of trickle charging will restore the batteries to thei
52. arge on C1 insures that DS2 fires and 051 stays off This cycle continues with 051 and the DS2 firing as long as there is output from the oscillator CRi and CR2 prevent the capacitor from discharging through R1 and R2 4 3 HP 419A DC Null Voltmeter max Section V Table 5 1 Test Equipment Required Model 419A INSTRUMENT TYPE REQUIRED CHARACTERISTICS RECOMMENDED MODEL Voltmeter Calibrator Strip Chart Recorder Oscillator Oscilloscope Electronic Counter DC Voltmeter Capacitor Resistors VOLTMETER CALIBRATOR hp 7388R e 9 O Q NI E oQ 419A B 0290A DC Voltage Range 0 3 mV to 300 V Accuracy 0 2 Voltage Range 1 Vdc Speed 50 mm sec Frequency Response 5 Hz Output Voltage 0 5 V rms Horizontal Sensitivity 2 ms cm Vertical Sensitivity 50 mV cm 100 kHz Output Freq 60 Hz Frequency Response Counting Range 300 to 400 pps Accuracy 1 count Voltage Range 30 Vdc Accuracy 2 0 1 uF 20 10 Vac 100 Q 0 1 1 8 W ww in d 600 Q 1 1 8 W comp 4 10 0 25 1 8 W met flm 100 KQ 0 25 1 8 W met flm 900 KQ 0 5 1 2 W met flm 1 MQ 0 1 1 8 W ww 5 9 0 5 1 2 W met flm hp Model 738BR Voltmeter Calibrator Strip Chart Recorder Sanborn Model 7701A hp Model 208A Oscillator hp Model 130C Oscilloscope hp Model 5211A Electronic Counter hp Model 427A Voltmeter hp Part No 0170 0085 0811 0398
53. ceable Parts Cont d REFERENCE hp DESIGNATOR PART NO TQ DESCRIPTION MFR MFR PART NO 5000 0251 1 Label pushbutton OFF 28480 5000 0251 5000 3213 1 Label pushbutton READ NULL 28480 5000 3213 5000 3214 1 Label pushbutton SET NULL 28480 5000 3214 5000 3345 1 Label pushbutton VM AM 28480 5000 3345 5000 3215 1 Label pushbutton ZERO 28480 5000 3215 00419 90002 1 Manual Operating and Service 28480 00419 90002 00419 00201 1 Panel front 28480 00419 00201 00419 00202 1 Panel rear 28480 00419 00202 00419 00606 1 Shield bottom 28480 1 00419 00606 00419 00601 1 Shield front 28480 00419 00601 00419 00602 1 Shield rear 28480 00419 00602 00419 00604 1 Shield side left 28480 00419 00604 00419 00603 1 Shield side right 28480 00419 00603 00419 00605 1 Shield top 28480 00419 00605 1490 0032 1 Stand half module tilt stainless steel rod 91260 obd 7 6 01779 2 HP 419A DC Null Voltmeter max Model 419A APPENDIX CODE LIST OF MANUFACTURERS Sheet 1 of 2 Appendix A The following code numbers are from the Federal Supply Code for Manufacturers Cataloging Handbooks H4 1 Name to Code and H4 2 Code to and their latest supplements The date of revision and the date of the supplements used appear at the bottom of each page Alphabetical codes have been arbitrarily assigned to suppliers not appearing in the H4 handbooks Code No 00000 00136 00213 00334 00335 00373 00656 00779 00781 00815 00853 00866
54. cycle s per second 1 N Bo ERUmRU G impg incd ins kQ kHz L lin log mA MHz met flm mfr mtg mV 11 113 uV my nA NC Ne NO NPO PARTS 7 3 Miscellaneous parts are listed at the end of Table 7 1 7 4 ORDERING INFORMATION 7 5 To obtain replacement parts address order or inquiry to your local Hewlett Packard Field Office See Appendix B for list of office locations Identify parts by their Hewlett Packard partnumbers Include instrument model and serial numbers 7 6 NON LISTED PARTS 7 7 To obtain a part that is not listed include a Instrument model number b Instrument serial number c Description of the part d Function and location of the part DESIGNATORS fuse MP mechanical part TC thermocouple filter P plug V vacuum tube neon heater Q 7 transistor bulb photocell etc jack QCR transistor diode cable relay R resistor X socket inductor RT thermistor XDS lampholder meter S switch XF fuseholder microcircuit T transformer 2 network ABBREVIATIONS inside diameter ns s 1077 sl glide impregnated seconds SPDT single pole double incandescent nsr not separately replace throw insulation ed able SPST single pole single 3 throw kilohm s 1077 ohms Q ohm s kilohertz 103 hertz pad E order by escription TC temperature coefficient OD
55. dew fxd elect 100 100 10 15 vdew fxd my die 1 0 uF 10 50 fxd Ta die 4 7 10 35 fxd Ta elect 2 2 uF 20 20 fxd elect 100 pF 100 10 15 fxd my die 4 uF 20 30 vdew fxd Ta elect 22 uF 10 15 fxd Ta elect 39 uF 10 10 fxd Ta elect 22 uF 10 15 vdew Diode Si 100 mA at 1 V 100 piV 12 pF Transistor Transistor Transistor Transistor Transistor Transistor Transistor Transistor Transistor NPN Si NPN Si 2N3391 PNP Si NPN Si 2N3391 PNP Si NPN Si 2N3391 PNP Si NPN Si 2N3391 PNP Si PP AAAAD fxd prec met flm 475 KQ 1 1 2 W fxd prec met flm 178 kQ 1 1 2 W fxd comp 120 kQ 10 1 2 W fxd comp 100 10 1 2 W fxd comp 56 Q 10 1 2 W fxd comp 5600 Q 10 1 2 W fxd comp 120 Q 10 1 2 W fxd prec met fim 475 1 1 2 W fxd comp 4 7 MQ 10 1 2 W fxd comp 4700 9 10 1 2 W fxd comp 2 2 MQ 10 1 2 W fxd comp 56 KQ 10 1 2 W var lin 20 kQ 30 1 8 W fxd comp 10 kQ 10 1 2 W fxd comp 100 kQ 10 1 2 W fxd comp 120 kQ 10 1 2 W fxd 10 xQ 10 1 2 W fxd comp 1000 Q 10 1 2 W fxd comp 100 10 1 2 W fxd comp 22 kQ 10 1 2 W fxd comp 120 KQ 10 1 2 W fxd comp 1000 Q 10 1 2 W See Paragraph 5 53 R R fxd comp 1 MQ 10 1 2 W fxd comp 22 KQ 10 1 2 W HP 419A DC Null Voltmeter max MFR 56289 56289 56289 56289 56
56. e AC Amplifier is a six stage high gain amplifier Its output is applied to the Demodulator The Demodulator output is a dc level whose amplitude is proportional to the amplitude of the squarewave The Demodulator outputis applied to the DC Amplifier a three stage voltage and power amplifier 4 9 The forward gain provided by the AC and DC Amplifiersfor each range is listed inTable 4 1 The output of the DC Amplifier approximately 1 Vdc for end scale meter deflection is applied to M1 and is also available at the OUTPUT and terminals 4 10 The Feedback Control circuit is ganged to the Input Attenuator by the RANGE switch S1 The feed back provided by the Feedback Control circuit is listed in Table 4 1 Algebraic addition of attenuation factor forward gain and feedback gives the closed loop gain The closed loop gain provides 18 end scale ranges in 10 dB steps 4 11 DETAILED DESCRIPTION 4 12 BUCKING SUPPLY See Figure 6 3 4 13 Dc input voltages up to 200m V may be measured in either the dc voltmeter mode or the null voltmeter Table 4 1 Model 419A Attenuation and Gain Characteristics RANGE ATTENUATION FACTOR FORWARD GAIN FEEDBACK CLOSED LOOP GAIN 3 uV 30 pA 4150 dB 40 dB 4110 dB 10 uV 100 pA 0 dB 19 4150 dB 50 dB 4100 dB 30 uV 300 pA 0dB 34 4150 dB 60 dB 90 dB 100 uV 1000 pA 0 4 49 4150 dB dB 80 dB 300 1V 3000 pA 0dB 3 4130 dB 60 dB 70 dB 1mV 10nA 048 130 10 dB 60 dB
57. enceau Street Clemenceau Center Beirut Tel 220846 NETHERLANDS Hewlett Packard Benelux N V 23 Burg Roellstraat Amsterdam W Tel 020 13 28 98 NEW ZEALAND Sample Electronics N Z Ltd 8 Matipo Street Onehunga S E 5 Auckland Tel 565 361 NORWAY Morgenstierne amp Co A S Ingeniofirma 6 Wessels Gate Oslo Tel 20 16 35 PAKISTAN Mushko amp Company Ltd Oosman Chambers Victoria Road Karachi 3 West Pakistan Tel 54601 Mushko amp Company Ltd Zirat Chambers 31 Jinnah Avenue Dacca East Pakistan Tel 80058 PANAMA Electronico Balboa S A Box 4929 Panama City Tel 3 0833 PERU Fernando Ezeta B Av Petit Thouars 4719 Mira Flores Lima Tel 5 0346 PORTUGAL Telectra Rua Rodrigo da Fonseca 103 Box 2531 Lisbon 1 Tel 68 60 72 PUERTO RICO San Juan Electronics Inc Ponce de Leon No 150 Stop 3 Pta de Tierra Sta San Juan Tel 725 3342 SPAIN Ataio Ingenieros Enrique Laretta 12 Madrid 16 Tel 235 43 44 5 HP 419A DC Null Voltmeter max SOUTH AFRICA F H Flanter amp Co Pty Ltd Rosella House Buitencingle Street Cape Town Tel 3 3817 F H Flanter amp Co Pty Ltd Box 200 Bramley 715 Pretoria Main Road Wynberg Transvaal Tel 40 6871 SWEDEN HP Instrument AB Centralvagen 28 Solna Centrum Tel 08 83 08 30 HP Instrument AB Box 4028 Indunagatan 28A Molndal 4 Tel 27 68 00 SWITZERLAND Max Paul Frey Wankdorffeldstrasse 66 Berne
58. ent is to be shipped to Hewlett Packard for service or repair attach a tag to the in strument identifying the owner andindicatingthe service or re pairto be accomplished include the model number and full serial number of the instrument Inany correspondence identify the in strument by model number serial number and serial number pr efix 2 20 If original container is to be used proceed as follows a Place instrument in original container If original container is not available one can be purchased from your nearest hp Sales and Service Office b Ensure that container is well sealed with strong tape or metal bands 2 21 If original container is not to be used proceed as follows a Wrapinstrument inheavy paper or plastic be fore placing in an inner container b Place packing material around all sides of instrument and protect panel face with card board strips c Place instrument and inner container in a heavy carton or wooden box and seal with strong tape or metal bands d Mark shipping container with DELICATE INSTRUMENT FRAGILE etc 2 1 HP 419A DC Null Voltmeter max Section III Model 419A HEWLETT PACKARD 419A DC NULL VOLTMETER LINE ore Je res 26 D LEVEL HO O O re 5655 INDEX NO NAME Meter LINE Indicator and INPUT termi
59. equency of the neon oscil lator 4 22 The demodulator is operated by the neon oscil lator in the same manner It provides a dc output proportionalto the amplitude ofthe square wave input 4 23 AC AMPLIFIER 4 24 Amplification of the square wave output from the modulator is provided by a six stage direct coupled amplifier Dc feedback from the base of Q4to the base 4 2 Model 419A of Q1 provides bias stabilization feedback from the emitter of Q3 to the emitter of Q1 is used to vary the gain of Qlthru Q3 Thisisaccomplishedby varying the amount of feedback to Q1 due to the position of the RANGE Switch In the 3 uV to 1 mV range re sistor R7 is shorted out decreasing the negative feed back applied to Q1 4 25 Feedbackfrom the emitters of Q6 and Q7 is also controlled to vary the gain of Q4thru Inthe3j4V to 100 LV range resistor R16is shorted out decreasing the negativefeedback appliedto Q4 Capacitors A3C4 and A4C9 couple the ac input and output and block the dc bias voltages 4 26 DC AMPLIFIER 4 27 The output of the demodulator is applied toa four stage voltage and power amplifier Q9 provides temperature compensation for the circuit When Q8 and Q9 increase conduction due to a rise in tempera ture the emitter to base voltage of Q4 decreases which decreases the Q8 forwardbias This maintains Q8 conduction at a constant level 4 28 The final stage of amplification is compli mentary symmetry a
60. er max QSIAR PARTIAL REFERENCE WITH ASSEMBLY OR S FOR COMPLETE DESI COMPONENT VALUES WISE NOTED RESISTANCE IN C CAPACITANCE Id 3 4 DENOTES POWER WV DENOTES DENOTES SIGNAL 4 MM LLL DENOTES FRC ow DENOTES 6 DENOTES SCF SIRI SIRIT o9 9 99 9 5188 39K SIR9 12K SIRIO 3300 e 29 9 lo SI RANGE SWITCH O96 22 2 ou i 100 se o o 9 o 9 28 ok a R6 2200 NULL COARSE 300 MV MAX SIR26 IK 52 SIDR EE NAE 9 19 9 7 D kllk SIRII IOK 1 NOTES 1 PARTIAL REFERENCE DESIGNATIONS ARE SHOWN PREFIX T WITH ASSEMBLY OR SUBASSEMBLY DESIGNATION S OR ROTH FOR COMPLETE DESIGNATION 2 COMPONENT VALUES ARE SHOWN AS FOLLOWS UNLESS OTHER WISE NOTED RESISTANCE IN OHMS CAPACITANCE IN MICROFARADS 3 4 DENOTES POWER LINE CHASSIS GROUND WV DENOTES POWER SUPPLY COMMON V DENOTES SIGNAL COMMON drm L tus DENOTES ASSEMBLY DENOTES MAIN SIGNAL PATH gt DENOTES DC FEEDBACK PATH DENOTES AC FEEDBACK PATH 2 5 J DENOTES FRONT P
61. f 1 on the 10 mV range h Replace the 100 k Q resistor with a 1 MQ re sistor 01779 2 i Set Model 419A RANGE to 100 mV set volt meter calibrator output to 100 mV 1 V j Model 419A should read 90 9 mV which veri fies an input resistance of 10 MQ on the 100 mV range Replace the 1 MQ resistor with a 10 MQ re sistor Set Model 419A RANGE to 1 V set voltmeter calibrator output to 1 V m Model 419A should read 0 909 V which veri fies an input resistance of 100 1V range 5 21 REPAIR PROCEDURES 9 22 COVER REMOVAL 9 23 When it is necessary to repair or adjust the Model 419A one or more covers will have to be re moved Refer to the following stepsfor cover removal procedure TOP COVER Remove cover screws slide cover to rear and lift to remove b SIDE COVERS Remove four screws from side cover lift to remove c BOTTOM COVER Remove bottom cover Screwsatrear of cover Slide cover to rear and remove 9 24 SERVICING PRINTED CIRCUIT BOARDS _ 5 25 The Model 419A has two etched circuit boards Use caution when removing to avoid damaging mounted components The assembly and hp part number are etched on the interior of the circuit boardto identify them Refer to Section for parts replace ment and hp part number information 5 26 The etched circuitboards are a plated through type The electrical connection between sides of the board is made b
62. hbutton function S3 3101 0033 1 Switch slide DPDT non shorting 0 5 amp 125 Vdc 3 amp 125 Vac wil 8120 0078 1 Cable Assembly power MISCELLANEOUS 1251 0172 1 Connector 22 ribbon type contacts 5000 0716 1 Cover bottom 7x 8 5000 0702 2 Cover side 6x 8 5060 0717 1 Cover top7 x 8 241A 44A 1 Foot Assembly half module 5060 0728 1 Foot Assembly half module front 5040 4524 1 Holder battery BT1 thru BT4 5040 0615 1 Holder battery phenolic base BT5 1400 0084 1 Holder fuse extractor post type 00419 04301 1 Insert RANGE 0370 0121 7 Knob pushbutton rectangular gray plastic 0370 0137 2 Knob round 5 8 diam black ZERO and NULL 0370 0112 1 Knob skirted bar 3 4 diam black RANGE 5000 3217 1 Label pushbutton BAT TEST 5000 3216 1 Label pushbutton FAST CHG 01779 2 HP 419A DC Null Voltmeter max 07233 28480 28480 28480 28480 28480 28480 28480 74915 28480 28480 28480 28480 28480 28480 Section VII MFR PART NO 00419 619 CB6845 CB2241 CB6831 CB2231 CB1255 CB3941 CB1245 CB3935 CB1231 EB3321 EB1031 E 20 MF6C MF6C MF 6C MF6C MF6C E 20 EB3055 CVS CVS CVS CVS CVS DC 1 1025 EB1531 4633 KH 4147 250 22 30 210 5000 0716 5000 0702 5060 0717 241A 44A 5060 0728 5040 4524 5040 0615 342014 00419 043 0370 0121 0370 0137 0370 0112 5000 3217 5000 3216 01 obd obd obd obd obd obd 01 Section VII Model 419A Table 7 1 Repla
63. ifier Switching 5 1 Voltmeter Accuracy Performance Schematic and Component Location Test lx x OR CU 5 0 6 3 6 4 5 2 Ammeter Accuracy Test Setup 5 2 6 4 Power Supply and Neon Driver 9 3 Superimposed AC Rejection Per Schematic and Component Location formance Test Setup 9 3 Diagrams 5555 ok Oxo XR 6 5 iv 01779 2 HP 419A DC Null Voltmeter max Section I aee Es C vocTMETER Model 419A Figure 1 1 Model 419A DC Null Voltmeter Table 1 1 Model 419A Specifications VOLTMETER Ranges 3 uV to 1000 volts dc end scale in 18 zero center ranges Accuracy 2 of end scale 0 1 uV Limits of Zero Control 15 LV Input Resistance 3 to 3 mV ranges 100 infinite whennulled 10 mV to 30 mV ranges 1 MQ infinite when nulled 100 mV to 300 mV ranges 10 infinite when nulled 1 volt to 1000 volt ranges 100 Internal Bucking Voltage 120 end scale 3 jV through 300 mV range Response Time 95 of final reading within 3 sec on the 3 uV range 95 of final reading within 1 sec the 10 uV to 1000 V ranges Superimposed AC Rejection Ac voltages 60 Hz and above 80 db greater than end scale affects reading less than 2 Peak ac voltage not to ex ceed max overload voltage Drift lt 0 5 uV dayafter 30 minutes warmup T C lt 0 05 9 from 0 to 50 C Noise 0 3 uV peak to peak
64. imperial Electronic Inc Melabs Inc Philadelphia Handle C o Clarostat Mfg Co Nippon Electric Ltd Delta Semiconductor Inc Thermolloy Telefunken G M B H Midland Mfg Co Sem Tech Newark N J Buena Park Calif Palo Alto Calif Camden N J Dover N H Tokyo Japan Newport Beach Calif Dallas Texas Hannover Germany Kansas City Kansas Newbury Park Calif Calif Resistor Corp Santa Monica Calif American Components Inc Conshohocken Cornell Dubiliet Elec Corp So Plainfield N J Williams Mfg Co San Jose Calif Webster Electronics Co Inc Brooklyn N Y Adjustable Bushing Co N Hollywood Calif Twentieth Century Coil Spring Co The Daven Co Spruce Pine Mi a Co Computer Diode Corp De Jur Amsco Corporation Long Island City 1 N Y Delco Radio Div of G M Corp Kokomo Ind Thermonetics Inc Canoga Park Calif Tranex Company Mountain View Calif Radio industries Des Plaines Ill Curtis Instrument Inc Mt Kisco N Y DuPont and Co Inc Wilmington Del Eclipse Pioneer Div of Bendix Aviation Corp Thomas A Edison Industries Div of McGraw Edison West Orange N J Electra Manufacturing Co Kansas City Mo Electronic Tube Corp Philadelphia Pa Executive Inc New York Santa Clara Calif Livingston N J Spruce Pine N C Lodi N J Teterboro N J Fansteel Metallurgical Corp No Chicago The Fafnir Bearing Co New Britain Conn Fed
65. ion of external recorder Enables selection of either 115 or 230 Vac line voltage Accepts fuse for protection of primary power circuits Accepts 3 pin power cord Front and Rear Panel Controls Indicators and Connectors 01779 2 HP 419A DC Null Voltmeter max Model 419A SECTION INSTRUCTIONS OPERATING 3 1 INTRODUCTION 3 2 The Model 419A functions asa dc voltmeter with full end scale ranges from 3 uV to 1000 V in ternal bucking supply allows essentially infinite input impedance tobe achieved 3 uV to 300 mV ranges The Model 419A can also measure low level dc cur rents with full end scale ranges from 30 pA to 30 nA This section describes the operating procedures and presents some applications for the Model 419A 3 3 CONTROLS INDICATORS AND CONNECTORS 3 4 Eachoperating control indicator and connector located onthe Model 419A is identified in Figure 3 1 The description of each component is keyed to the il lustration of that com ponent which is included within the figure 3 5 OPERATING INSTRUCTIONS 3 6 The Model 419A may be operated on its internal battery power supply or from anac line The instru ment operates on its internal batteries whenever the ac power cable is removed from the ac power con nector Line operation occurs automatically whenever the power cable is connected to the power connector NOTE Best isolation characteristics and freedom from ground loop prob lems
66. justable resistor R9 which controls the bias on the base of Q4 4 40 Due to inherent characteristics either Q2 or Q3 willconduct harder when powerisapplied Assume that Q2 conducts more than Q3 As Q2 conducts a negative going signalis coupledthrough T2to the base 01779 2 Section IV of Q3 This causes Q3 to cut off completely At the same time a positive going signal is coupled to the base of Q2 causing it to conduct more While Q2 is conducting a negative output will be coupled to the neon circuit 4 41 When T2becomes saturated the positive signal is removed from the base of Q2 and it cuts off At the same time the negative signal is removed from the base of Q3 allowing it to startconducting As conducts a negative going signal is applied tothe base of Q2 holding it cut off and a positive going signal is appliedto the base of Q3 Q3 continuesto conduct causing a positive output tobe coupled the neon cir cuit This will continue until T2 becomes saturated and starts the cycle over again 4 42 The output of the oscillator is coupled through T2 to the neon circuit When an input is applied to the circuit due to inherent resistance characteristics either DS1 or DS2 willlight depending upon which has the least resistance 4 43 Assume that DS1 lights whenthe input is applied to T2 Capacitor charges until the oscillator switches the input and DS1 goes off Whenthe os cillator switches again the ch
67. leakage 104194 Assume the leakage between 2 points and B in a standards laboratory oil bath is to be measured A 100 V power supply and the 419A are connected as shown in Figure 3 2 01779 2 HP 419A Null Voltmeter max Model 419A hp 419A BATTERY OPERATION POWER SUPPLY 100V OIL BATH 419A B 0993 Figure 3 2 Leakage Measurement Assume the 419A indicates 10 pA The leakage of the oil can then be calculated E power supply R leakage 419A _ 100 V leakage 10 pA 21013 FR aeakage Hr 23101 F eakage 70 0 Section 3 21 Calibrating A Voltage Source 3 22 The Model 419A can serve as a very sensitive and accurate null detector These features can be especially useful when matching the output of an ad justable voltage source to a reference standard The adjustable voltage source and the reference standard are connected in series opposition with the Model 419A inserieswithone of the leads The adjustable voltage source is then adjusted for a null indication on the Model 419A Example Assume the output of a dc standard hp Model 7418 is tobe matchedtothe output of a 1 Vtrans fer standard hp Model 735A These instru ments and the Model 419A are connected as shown in Figure 3 3 The reference standard and the adjustable voltage source are both set for a 1 V output The Model 419A indicates any deviations between the two out puts By
68. lif Elgeel Optical Co Inc Rochester N Y Tinsoiite insuiated Wire Co Tarrytown N Y Sylvania Electric Prod Inc Semiconductor Div Robbins and Myers Inc Stevens Mfg Co Inc Howard J Smith Inc Woburn Mass New York N Y Mansfield Ohio Port Monmouth J 00015 39 Revised February 1965 Code No 93929 93983 94137 94144 94145 94148 94154 94197 94222 94310 94330 94682 35023 95236 95238 95263 95264 95265 95275 95348 95354 95712 95987 96067 96095 96256 96296 96330 96341 96501 97464 97539 97966 97979 98141 98159 Manufacturer Address G V Controls Livingston N J Insuline Van Norman Ind Inc Electronic Division Manchester N H General Cable Corp Bayonne N J Raytheon Mfg Co Industrial Components Div Receiving Tube Operation Quincy Mass Raytheon Mfg Co Semiconductor Div California Street Plant Newton Mass Scientific Radio Products Inc Loveland Colo Tung Sol Electric Inc Newark N J Curtiss Wright Corp Electronics Div East Paterson J Southco Div of S Chester Corp Lester Pa Tru Ohm Prod Div of Model Engineering and Mfg Co Chicago Ill Wire Cloth Products Inc Chicago Ill Worcester Pressed Aluminum Corp Worcester Mass Boston Mass Miami Fla Woodside N Y New York N Y Burbank Calif Sheridan Wyo Bridgeport Conn Philbrick Researchers Inc Allies Products Corp Continental Connecto
69. lin W 30 Tel 24 86 36 Hewlett Packard Vertriebs GmbH Achenbachstrasse 15 4 Dusseldorf 1 Tel 68 52 58 GREECE K Karayannis Klaftmonos Square Athens 124 Tel 230 301 INDIA The Scientific Instrument Co Ld 6 Tej Bahadur Sapru Road Allahabad 1 Tel 2451 The Scientific Instrument Co Ld 240 Or Dadabhai Naoroji Road Bombay 1 Tel 26 2642 The Scientific Instrument Co Ld il Esplanade East Calcutta 1 Tel 23 4129 The Scientific Instrument Co Ld 30 Mount Road Madras 1 Tel 86339 The Scientific Instrument Co Ld 8 7 Ajmeri Gate Extn New Delhi 1 Tel 271053 IRAN Telecom Ltd Box 1812 Teheran Tel 43850 48111 ISRAEL Electronics amp Engineering Ltd Division of Motorola Israel Ltd 16 Kremenetski Street Tel Aviv Tel 35021 ITALY Hewlett Packard Italiana 5 Viale Lunigiana 46 Milan Tel 69 15 84 Hewlett Packard Ital iana S p A Palazzo Italia Piazza Marconi 25 Rome Eur Tei 591 2544 JAPAN Yokogawa Hewlett Packard Ltd 59 chome Yoyogi Shibuya ku Tokyo Tel 370 2281 Yokogawa Hewlett Packard Ltd 8 Umeda Kita ku Osaka City Tel 313 0091 INTERNATIONAL Electronic Equipment Yokogawa Hewlett Packard L td 4 3 chome Himeikedori Chigusa ku Nagoya City Tel 751 8545 KOREA American Trading Co Korea Ltd Seoul Box 1103 112 35 Sokong Dong Jung ku Seoul Tel 3 7049 3 7613 LEBANON Constantin E Macridis Clem
70. ltages and currents to be measured are applied to the input attenuator which is a resistive divider consisting of S1R20 to S1R25 and R3 The attenuation factor depends upon the position of the RANGE switch The attenuator is divided into two separate networks to provide the proper impedance levels for filter capacitors A3C2and A3C3 Table 4 1 lists the attenuation factors for all ranges 4 17 INPUT FILTER 4 18 L1 and L2 and A3C2 and A3C3 filter superim posed ac noise from the input signal 4 19 MODULATOR DEMODULATOR 4 20 Themodulator demodulator is a photo conductive chopper Itconsistsofaneon oscillator with two neon bulbs and four photocells mounted in one assembly The photocells have an extremely high resistance when not illuminated and a very low resistance when il luminated 4 21 Assume that A3V1 is illuminated and A3V2 is not The resistance of A3V2 willbe many times greater thanthe resistance of A3V1 The voltage across A3V2 input voltage willbe applied through A3C4 tothe base of Q1 The oscillator willthen switch off the bulb il luminating 1 and switch ona bulb which illuminates A3V2 1 now has the greatest resistance and A8V2 is a virtual short to the feedback which is coupled to Ql The modulator provides a square wave output proportionalto the differencebetween the dc input and I 9 asa dc feedback signals The square wave frequency will depend upon the switching fr
71. making internaladjustments affecting the output of the voltage source until null is reached on the Model 419A s 3 uV range the output of the adjustable voltage source is very accurately matched to the reference standard 3 23 Measuring and Recording Drift 3 24 The rear panel OUTPUT terminals provide adc voltage 0to 1 V proportional to meter deflection This output can be used to record the drift of a dc voltage source whenthat source is compared to a very stable reference voltage Example Assume that the drift of a 10 V power supply is to be observedand recorded The power supply Model 419A stable voltage source hp Model 740B and astripchart recorder hp Sanborn Model 7701A are connected as shown in Figure 3 4 NULL DETECTOR REFERENCE STANDARD hp 419A DC TRANSFER STANDARD hp 735A 000000 OUTPUT 2 419 0994 ADJUSTABLE VOLTAGE SOURCE AC DC AVM DC STANDARD hp Soa aod ooo Figure 3 3 Calibrating A DC Standard 01779 2 3 3 HP 419A DC Null Voltmeter max Section III 3 4 Model 419A STRIP CHART RECORDER hp 7701A SANBORN DRIFT DETECTOR hp 419A POWER SUPPLY 10 OUTPUT TERMINALS ON REAR PANEL 419A B 0992 TO REAR PANEL INPUT STABLE VOLTAGE SOURCE DC STANDARD OVM hp 7408 BL 7759 gt 2 OUTPUT Figure 3 4 Measuring Power S
72. mplifier consisting of Q12 13 CR13 and 14 The diodesbias the transistors at a constant idling state with no input signal applied When an input isapplied the transistor responds im mediately with an output The input does not have to reach a certain amplitude to cause conduction in the transistors since they are already at an idling con dition 4 29 The output of the dc amplifier will be 1 V for end scale input on all ranges output is also ap plied to the and OUTPUT terminals J5 and J6 Adjustable resistor R2 provides control of the recorder output from 0 to 1 volt end scale Diode network CR5 to CR12 protects the amplifier circuit from an overload 4 30 METER CIRCUIT 4 31 The meter is a current driven device which utilizes a taut band movement 1 volt output of the dc amplifier provides end scale needle deflection on all ranges During FAST CHARGE and off positions 1 and 2 of Function Switch S2 the meteris protected from transient voltages by a short across it During the BATTERY TEST mode position 3 of Function Switch S2 resistor S2R1 providesthe amplifier load because the meter is disconnected from theamplifier circuit DA e 1 the meter The are connected in parallel with the meter as a function of the RANGE switch setting 4 99 ES t DAA n vino for 491 A raw U 12123 4 33 FEEDBAC
73. n eight digit serial number 000 00000 If the first three digits of the serial number on your instrument do not agree with those on the title page of this manual change sheets supplied with the manual will define differences between your instrument and the Model 419A described in this manual 01779 2 INFORMATION 1 11 ACCESSORY EQUIPMENT SUPPLIED 1 12 The accessory equipment supplied with each Model 419A is listed and described in Table 1 2 Table 1 2 Accessory Equipment Supplied IDENTIFICATION NUMBER QUANTITY DESCRIPTION 8120 0078 1 Power Cord 00419 90002 1 Operating and Service Manual 1 13 ACCESSORY EQUIPMENT AVAILABLE 1 14 The accessory equipment available is listed in Table 1 3 For further information contact your local hp Sales and ServiceOffice See Appendix B for office locations Table 1 3 Accessory Equipment Available uu e DESCRIPTION 11003A Dual Banana Plugs to Probe and Alligator Clip 60 1 1 HP 419A DC Null Voltmeter max Model 419A Section II SECTION INSTALLATION 2 1 INTRODUCTION 2 2 This section contains information and instruc tions necessary for the installation and shipping of the Model 419A DC Null Voltmeter Included are ini tial inspection procedures power and grounding re quirements installation information and instructions for repackaging for shipment 2 3 INITIAL INSPEC
74. nals Ground terminal OFF FAST CHG BAT TEST ZERO VM AM SET NULL READ NULL ZERO control NULL control RANGE switch LEVEL control and OUTPUT terminals Line Voltage Switch FUSE 1 8 A AC Power Connector 9 OOOO OO CO Figure 3 1 3 0 19 0270 07 8 FUNCTION Indicates value of applied voltage or current in conjunction with RANGE switch and function pushbuttons Lights to indicate application of ac line voltage to power supply circuits Accepts leads for application of dc voltage or current input Accepts lead for grounding of instrument case When depressed all functions are turned off When depressed enables batteries to charge at a fast rate When depressed enables meter to indicate battery voltage When depressed internally disconnects voltmeter from terminal and shorts to terminal When depressed enables meter to indicate value of input voltage or current When depressed places null supply in series opposition to input voltage When depressed enables meter to indicate value of null supply Provides continuously variable control of zero offset to 15 pV Provides continuously variable control for nulling of input voltages below 300 mV when SET NULL pushbutton is depressed Selects one of full scale voltage or current ranges Provides variable control 0 to 1 V full scale of and recorder OUTPUT Provide for connect
75. ng the defective neons a Remove the top and side cover on the meter side of the instrument b Disconnect the neon subassembly leads from pins on A2 board Note location for recon necting the new leads Maneuver subassembly cablethrough the grommet inner shield c Removethe tw o photochopper assembly mount ing screws and remove neon subassembly d Install new neon subassembly Note that the rubber grommet on the subassembly is offset toward the top of the instrument e Route the neonsubassembly cable through the inner shield and reconnect the cable to the A2 board f Replace the side cover and recalibrate the Model 419A as outlined in Paragraph 5 29 5 29 ADJUSTMENT AND CALIBRATION 5 30 Thefollowing isa completeadjustment andcali bration procedure for the Model419A These proce 9 4 Model 419A dures should be conducted only if been previously established by Performance Tests Paragraphs 5 5 to 5 20 that the Model 419A is out of adjustment 5 31 MECHANICAL ZERO ADJUSTMENT 9 32 The mechanical zero adjustment is located on the instrument front panel If the meter pointer does not indicate zero when the instrument power hasbeen off for at least one minute mechanically zero the meter following the procedure outlined below a Turn instrument power off disconnect input signal remove output cable and allow one minute for meter pointer to stabilize b Rotate zero adjustment CW
76. nput At tenuator 5 51 Replacement of Factory Selected Components Section VI CIRCUIT DIAGRAMS 6 1 Introduction 6 3 Schematic Diagrams 6 5 Component Location Diagrams Section VII REPLACEABLE PARTS 7 1 Introduction 1 4 Ordering Information 7 6 Non Listed Parts Appendix A CODE LIST OF MANUFACTURERS Appendix B SALES AND SERVICE OFFICES Appendix C MANUAL BACKDATING CHANGES LIST OF TABLES Number 5 1 Equipment Required 5 2 Accuracy Performance Test Sup plemental Data 5 3 Ammeter Accuracy Test 7 1 Replaceable Parts HP 419A DC Null Voltmeter max 1 O Co Co PO Page 7 1 Page 9 0 111 List of Illustrations Model 419A LIST OF ILLUSTRATIONS Number Page Number Page 1 1 Model 419A DC Null Voltmeter 1 0 5 4 Neon Drive Waveform A2TP2 5 4 3 1 Front and Rear Panel Controls Indi and Connectors 3 0 6 1 Model 419A Component Location 3 2 Leakage Measurement e 3 3 Diagram 6 2 3 3 Calibrating DC Standard 3 3 6 2 Range Switch S1 Component Location 3 4 Measuring Power Supply Drift 3 4 6 2 4 1 Model 419A Block Diagram 4 0 6 3 Amplifier and Ampl
77. o Philadelphia Steel and Wire Corp Philadelphia Pa Potter and Brumfield Div of American Machine and Foundry Princeton Ind Radio Condenser Co Camden N J Radio Receptor Co Inc Brooklyn N Y Resistance Products Co Harrisburg Pa Rubbercraft Corp of Calif Torrance Calif Shakeproof Division of Illinois Tool Works Signal Indicator Corp Struthers Dunn lac San Francisco Calif Brooklyn N Y Malden Mass Los Angeles Calil San Leandro Calif Cleveland Ohio Crystal Lake IIl No Hollywood Calif San Francisco Calif South Pasadena Calif Chicago 111 Elgin III New York N Y Pitman J Thompson Bremer amp Co Chicago 11 Tilley Co San Francisco Calif Stackpole Carbon Co St Marys Standard Thomson Corp Tinnerman Products Inc Transformer Engineers Ucinite Co Veeder Root Inc Wenco Mfg Co Continental Wirt Electronics Corp Philadelphia Pa New Rochelle N Y Waltham Mass Cleveland Ohio Pasadena Calil Newtonville Mass Hartlord Conn Chicago 111 Zierick Mfg Corp Division of Sessions Clock Co Morristown N J Schnitzer Alloy Products Elizabeth N J Times Facsimile Corp New York Electronic Industries Association Any brand tube meeting EIA standards Washington D C Unimax Switch Div of W L Maxson Corp United Transformer Corp Oxford Electric Corp Bourns Laboratories Inc Acro Div of Robertshaw Fulton
78. odel 419A SALES AND SERVICE OFFICES ARGENTINA Mauricio A Suarez Telecommunicaciones Carlos Calvo 224 Buenos Aires Tel 30 6312 34 9087 AUSTRALIA Sample Electronics Vic Pty Ltd 9 1 Cremorne Street Richmond E 1 Victoria Tel 42 4757 Sample Electronics N S W Pty Lid 4 Grose Street Glebe New South Wales Tel 69 6338 AUSTRIA Unilabor H m b H Wissenschaftliche Instrumente Rummelhardtgasse 6 3 Box 33 Vienna IX 71 Tel 426 181 BELGIUM Hewlett Packard Benelux S A 20 24 rue de Hopital Brussels Tel 11 22 20 BRAZIL Ciental Importacao e Comercio Ltda Rua des Eliseu Guilherme 62 Sao 8 Tel 70 2318 CHILE Hector Cal cagni Casilla 13942 Santiago Tel 6 42 26 DENMARK Tage Olsen A S Ronnegade 1 Copenhagen 0 Tel 29 48 00 FINLAND INTO 0 Y Meritullinkatu 11 Box 153 Helsinki Tel 6 11 33 FRANCE Hewlett Packard France 150 Boulevard Massena Paris 13 Tel 707 97 19 Hewlett Packard France 2 rue Tete d Or Lyon 6 Rhone Tel 52 35 66 GERMANY Hewlett Packard Vertriebs GmbH Kurhessenstrasse 95 Frankfurt a Main Tel 52 00 36 Hewlett Packard Vertriebs GmbH Reginfriedstrasse 13 Munich 9 Tel 495121 Hewlett Packard Vertriebs GmbH Beim Strohhause 26 28 Hamburg 1 Tel 240551 Hewlett Packard Vertriebs GmbH Technisches Buro Herrenberger Strasse 110 B blingen Wurttemberg Tel 6971 Hewlett Packard Vertriebs GmbH Lietzenburger Strasse 30 Ber
79. oducts Dept Syracuse N Y Apex Machine amp Tool Co Dayton Ohio Eldema Corp El Monte Calif Transitron Electronic Corp Wakefield Mass Pyrofilm Resistor Co Morristown N J AirMarine Motors Inc Los Angeles Calif Arrow Hart and Hegeman Elect Co Hartlord Conn Lambertville N J New York N Y Myrtle Beach S C Marion Los Angeles Calif Los Angeles Calif Milwaukee Wis Beverly Hills Calif Lawndale Calif Dallas Texas Alliance Ohio Indianapolis Ind Van Nuys Calil Rocklord ill Santa Clara Calif Saugerties N Y Taurus Corp Elmenco Products Co Hi Q Division of Aerovox Elgin National Watch Co Electronics Division Burbank Calif Precision Paper Tube Co Chicago Ill Dymec Division of Hewlett Packard Co Palo Alto Calil Sylvania Electric Prods Inc Electronic Tube Div Mountain View Calif Motorola inc Semiconductor Prod Div Phoenix Arizona Filtron Co Inc Western Div Culver City Calif Automatic Electric Co Northlake 111 Automatic Electric Sales Corp Northlake Ill Sequoia Wire amp Cable Redwood City Calif Precision Coif Spring Co Monte Calif P M Motor Company Chicago 44 Ill Twentieth Century Plastics Inc Los Angeles Calif Westinghouse Electric Corp Semi Conductor Dept Ultronix Inc Engineering Co Cosmo Plaslic c o Electrical Spec Co Barber Colman Co Tilfen Optical Co Roslyn Heights Long I
80. older turret OUTPUT Binding Post black with solder turret Insulator binding post dual Insulator binding post triple Inductor input Meter var prec ww 10 turn 100 5 2 W var lin 20 20 1 3 W fxd prec c flm 90 1 2 W R var comp 2 sect lin tandem ganged 1500 2 and 5000 9 20 fxd comp 2200 Q 10 1 2 W fxd comp 100 kQ 10 1 2 W fxd comp 2700 Q 10 1 2 W HP 419A DC Null Voltmeter max MFR 01121 01121 01121 01121 01121 01121 01121 01121 71450 71450 01121 01121 01121 01121 01121 61637 09569 28480 159 15 000017 28480 28480 28480 28480 28480 28480 28480 28480 28480 28480 28480 28480 28480 ATOU 28480 28480 28480 12697 71450 03888 12697 01121 01121 01121 Model 419A MFR PART NO 2221 4741 2241 EB2221 EB1041 EB3951 EB1031 EB 1011 QS 200 XQS 200 obd EB3941 EB6831 EB2221 1031 EB2221 Y 5201 316469 2140 0008 312 125 H 1061 2 5080 1278 0340 0159 0340 0100 00419 21701 5080 1277 0340 0159 0340 0100 00419 21701 1510 0011 0340 0099 1510 0010 1510 0011 1510 0011 0340 0086 0340 0091 9100 1318 1120 0312 Series 62 CM 33147 Series 45 HV2000 obd Series 53M EB2221 EB1041 EB2721 01779 2 Model 419A Table 7 1 Replaceable Parts Cont d REFERENCE hp DESIGNATOR PART N
81. or hp Part No 0811 0473 are required for this test a Connect test setup illustrated in Figure 5 1 b Make control settings indicated in step 1 of Table 5 2 if Model 419A reading is not within tolerances listed perform Full Scale Cali bration procedure Paragraph 5 37 c Repeatstepb for remaining steps in Table 5 2 9 9 BUCKING VOLTAGE TEST 9 10 No external test equipment is required for the bucking voltage performance test a Depress 419A READ NULL pushbutton set RANGE to 300 mV b Rotate NULL control fully clockwise and then full counterclockwise if 419A meter does not peg in negative and positive direction respectively replace BT 5 Table 5 2 Accuracy Performance Test Supplemental Data VOLTMETER POINT OF 419A 419A STEP CALIBRATOR MEASUREMENT RANGE READING DC OUTPUT FIGURE 5 1 1 A 3 uV 2 84 3 16 2 10 uV 9 7 to 10 3 3 A 30 uV 29 3 to 30 7 4 100 uV 97 9 to 102 1 5 B 300 uV 293 9 to 306 1 6 B 1mV 0 98 to 1 02 7 B 3mV 2 94to 3 06 8 B 10 mV 9 8to 10 2 9 B 30 mV 29 4to 30 6 10 100 mV B 100 mV 98 to 102 11 300 mV B Atten 300 mV 294to 306 12 1 v pj 05 1 v 0 98 to 1 02 13 3 V B 3 V 2 94 to 3 06 14 10 V B 10 V 9 8 to 10 2 15 30 V B 30 V 29 4to 30 6 16 100 V B 100 V 98 to 102 17 300 V B 300 V 294to 306 18 300 V B 1000 280to 320 01779 2 5 1 HP 419A Null Voltmeter max Section V VOLTMETER CALIBRATOR hp 7 38BR e aQ Model 419 hp 419A
82. pring Rd S W 205 881 4591 TWX 510 579 2204 ALASKA Bellevue Wash 98004 11656 N E 8th Street 206 454 3971 TWX 910 443 2303 ARIZONA Scottsdale 85251 3009 No Scottsdale Rd 602 945 7601 TWX 602 949 0111 Tucson 85716 232 So Tucson Blvd 602 623 2564 TWX 602 792 2759 CALIFORNIA North Hollywood 91604 3939 Lankershim Blvd 213 877 1282 and 766 3811 TWX 910 499 2170 Sacramento 95821 259 Carlsbad Ave 916 482 1463 TWX 916 444 8683 San Diego 92106 1055 Shafter Street 714 223 8103 TWX 714 276 4263 Palo Alto 94303 1101 Embarcadero Rd 415 327 6500 TWX 910 373 1280 COLORADO Englewood 80110 7965 East Prentice 303 771 3455 TWX 910 935 0705 CONNECTICUT E 0 Middletown 06457 589 Saybrook Rd 203 346 6611 TWX 710 428 2036 LORIDA Miami 33125 2907 Northwest 7th St 305 635 6461 Orlando 32803 621 Commonwealth Ave 305 425 5541 TWX 305 841 2568 St Petersburg 33708 410 150th Ave Madeira Beach 813 391 0211 and 391 1829 TWX 313 391 0666 GEORGIA 5 66 Atlanta 30305 3110 Maple Drive N E 404 233 1141 TWX 810 751 3283 North Hollywood Calif 91604 3939 Lankershim Blvd 213 877 1282 TWX 910 499 2170 ILLINOIS Skokie 60076 5500 Howard Street 312 677 0400 TWX 910 223 3613 INDIANA Indianapolis 46205 3919 Meadows Dr 317 546 4891 TWX 317 635 4300 LOUISI ANA New Orleans 504
83. r fuly charged state however the batteries may be trickle charged indefinitely without damage 3 15 Thebatteries may be fast charged by connecting the Model 419A to an ac powerline and depressing the FAST CHG pushbutton The instrument cannot be used to make measurements while fast charging thebatteries The batteries should reachfullcharge inapproximately 15 hours 3 16 To obtain maximum battery life the following points should be observed a Do not allow the batteries to discharge below the BAT limits on the meter scale b Use fast charge only when necessary c Chargethebatteries in moderate temperatures 80 F 10 F 27 5 69C whenever possible d Do not store the instrument at temperatures above 1229F 509C or below 409F 209C 3 17 APPLICATIONS 3 18 In addition to straightforward dc voltage and current measurements the Model 419A has a number of applications Several of these are presented the following paragraphs 3 19 Measuring Leakage 3 20 By using the Model 419A as a sensitive dc am meter very high resistanceleakage paths in insulating materials be detected and measured Leakage is observed by connecting the output of a dc power supply across the insulating material and placing the Model 419A in series with one of the power supply leads By noting the current flow on the Model 419A the leakage resistance can be calculated from the formula E power supply R
84. r Corp Leecraft Mfg Co Inc Lerco Electronics Inc National Coil Co Vitramon Inc Gordas Corp Bloomfield N J Methode Mfg Co Chicago Ill Dage Electric Co Inc Franklin Ind Weckesser Co Chicago 111 Huggins Laboratories Sunnyvale Calif Hi Q Division of Aerovox Olean Thordarson Meissner Div of Maguire Industries Inc Mt Carmel Ill Solar Manufacturing Co Los Angeles Calif Carlton Screw Co Chicago Ill Microwave Associates Inc Excel Transformer Co Industrial Retaining Ring Co Aulomatic and Precision Mfg Co Yonkers N Y Burlington Mass Oakland Calif Irvington N J CBS Electronics Div of C B S Inc Reon Resistor Corp Axel Brothers Inc Rubber Teck Inc Danvers Mass Yonkers N Y Jamaica N Y Gardena Calif HP 419A DC Null Voltmeter max Code No 98220 98278 98291 98405 98731 98821 98925 98978 99109 99313 99515 99707 99800 99848 99934 99942 99957 Model 419A Manufacturer Address Francis L Mosley Microdot Inc Sealectro Corp Carad Corp General Mills North Hills Electric Co Clevile Transistor Prod Div of Clevite Corp Inlernational Electronic Research Corp Columbia Technical Corp Varian Associales Marshall Industries Electron Products Division Pasadena Calif Control Switch Division Controls Co of America El Segundo Calif Delevan Electronics Corp East Aurora N Y Wilco Corporation Indiana polis Ind Renbrandt
85. results when the 419A is operated on its internal battery supply 3 7 TURN ON PROCEDURE BATTERY OPERATION NOTE Disconnect the power cable from the power receptacle for battery operation a Depress BAT TEST pushbutton if meter does notindicate within BAT limits perform battery charging procedure Paragraph 3 13 NOTE When the 419A is received or after a period of storage es pecially at high temperatures the batteries may require changing Erratic and inaccurate operation may result if the instrument is operated on weak batteries b Set RANGE switch to 1 V 01779 2 Section III Depress ZERO pushbutton If meter does not indicate zero perform the meter zeroadjust ments Paragraphs 5 31 thru 5 36 d Zero meteron 3 uV range with ZERO control Periodically recheck setting of ZERO control on the 3 uV range 3 8 TURN ON PROCEDURE AC LINE OPERATION a Set line voltage two position slide switch rear panel to correct position for available line voltage DAMAGE TOINSTRUMENT MAY RESULT IF LINE VOLTAGE SWITCH IS SETINCORRECTLY b Connect ac power connector to the line using the ac power cable supplied c Set RANGE switch to 1 V d Depress ZERO pushbutton meter does not indicate zero perform meter zero adjustments Paragraphs 5 31 thru 5 36 e Zero meter on 3 pV range with ZERO control Periodically recheck setting of zero control the 3 uV range 3 9 DC VOLTA
86. s in Figures 6 1 and 6 3 Table 7 1 Change all A4 reference designators to 1 Change hp Part No of A1 to 00419 66504 Change A1C13 to hp Part No 0180 0022 fxd elect 3 9 JF 35 vdew Delete A1C 14 thru A1C 17 Change 1 1 thru A1CR16 to AICRI thru AICR14 Change A1R38 to hp Part No 0686 3055 fxd comp 3 5 1 2 W Change A1R41 thru A1R44 to hp Part No 2100 1410 var lin 20 KQ 30 1 8 W Change A1R48 to hp Part 0687 6821 fxd comp 6 8 10 1 2 W Delete A1R50 and A1R51 Add hp Part No 0180 0283 C fxd Al elect 60 15 10 10 vdew CHANGE 2 Table 7 1 Change J2 to hp Part No 1510 0010 Change to hp Part 1510 0011 Change J5to hp Part No 1510 0026 Change J6 to hp Part No 1510 0027 CHANGE 3 Figure 6 3 Change A1R26 10 K to A1R26 22 K Move A1R26 between A1CR3 and 4 and Q8 Base Delete C10 3 7 emitter of Q12 and 013 Add C10 20 between A1 13 and Short R40 100 9 in base of A1Q10 Add R40 39 kQ between A1C13 and A1R39 Table 7 1 Change A1C10 to C fxd Al elect 20 uF 75 10 25 vdew hp Part No 0180 0045 Change A1R26 to R fxd 22 K 10 1 2 W hp Part No 0687 1031 Change A1R40 to fxd 39 10 1 2 W hp Part No 0687 3931 01779 2 C 1 HP 419A DC Null Voltmeter max Appendix C CHANGE 4 MANUAL BACKDATING CHANGES Change Paragraph 5 34 steps d and e as follows
87. seconds 01779 2 HP 419A Null Voltmeter max Model 419A A4R26 should be increased A4R26 should be between 8 kQ and 15 kQ with a typical value of 10 A4R26 is an Allen Bradley com position 1 4 watt 10 resistor L Y Figure 5 4 Neon Drive Waveform A2TP2 grum 9 35 ELECTRICAL ZERO ADJUSTMENT 5 36 The electrical zero adjustment should be per formed when the meter pointer does not indicate zero on the 1 volt range when instrument power hasbeen on forat least one minute No external equipment is re quired for this adjustment a Set 419A controls as follows RANGE 1V ZERO pushbutton Depressed b Remove top cover adjust A4R14 1V ZERO for zero deflection on 419A meter 5 37 FULL SCALE CALIBRATION 5 38 Thefull scale calibration consists of performing the 3 uV 10 LV 1 mV and 1 V adjustments Volt meter Calibrator hp Model 738BR 100 9 Resistor hp Part No 0811 0398 and a 1 MQ Resistor hp Part No 0811 0473 are required for this test a Connect test setup illustrated in Figure 5 1 b Remove 419A top cover depress VM AMpush button c Set Voltmeter Calibrator for 30 mV output connect 419A to Point A adjust A4R41 3 LV for full scale deflection on 3 uV range d Set Voltmeter Calibrator for 100 mV output connect 419A to Point A adjust A4R42 10 LV for full scale deflection on 10 uV range
88. selected When used as a dc null voltmeter end scale ranges from to 300 mV are provided with infinite input re sistance End scale ranges from 30 to 30nA are provided in the ammeter function with a constant 100 kQ input resistance 4 5 When used as an ammeter circuit operation is identicalto the voltmeter mode of operation Current values are derived from the voltage drop across the constant 100 kQ input resistance on the 30 pA 3 to 30 nA 3 mV ranges 4 6 Adcvoltagebeing measured with the Model 419A is applied to the Input Attenuator through the and INPUT terminals locatedonthefrontpanel In the dc voltmeter and ammeter modes the input is applied to the input attenuatorthroughS1R26 Inthe dc null volt meter mode the output of the Bucking Supply is applied to S1R26 in series opposition to the input dc voltage The difference between the Bucking Supply output and the input dc voltage is applied to the Input Attenuator Table 4 1 liststhe attenuationfactors provided by the Input Attenuator for all ranges 4 7 Thedcoutput of the Input Attenuator is modulated by the Modulator The Modulator is comprised of two photocells which are alternately illuminated by two neon lamps The output of the modulator is a square wave whose amplitude is proportional to the difference between theamplitudes of the input dc voltage and the feedback 4 8 Thesquarewave output of themodulator is amp lified by the AC Amplifier Th
89. sland N Y Metropolitan Telecommunications Corp Metro Cap Division Brooklyn N Y Stewart Engineering Co Santa Cruz Calif Wakelield Engineering Inc Wakefield Mass The Bassick Co Bridgeport Conn Bausch and Lomb Optical Co Rochester N Y E T A Products Co of America Chicago 111 Western Devices Inc Inglewood Calif Amatom Electronic Hardware Co Inc New Rochelle N Y Beede Electrical Instrument Co Inc Penacook N H U S Semcor Division of Nuclear Corp of Phoenix Arizona Torrington Mfg Co West Div Van Nuys Calif Kelvin Electric Van Nuys Calif Youngwood Pa Sunnyvale Calif Cleveland Ohio Rockford San Mateo Calif Code No 07115 07126 07137 07138 07149 07233 07261 07263 07322 07387 07700 07910 07933 07966 07980 08145 08289 08358 08717 08718 08792 08984 09026 09134 09145 09250 09569 09664 10214 10411 10646 11236 11237 11312 11534 11711 11717 11870 12136 12697 12859 12930 13103 13396 13835 14099 14193 14298 14655 14960 15203 15291 15772 15909 16037 16352 16688 16758 17109 17474 18486 18583 18873 19315 19500 19701 20183 21226 21520 21335 21964 24446 24455 Manvfacturer Address Corning Glass Works Electronic Components Dept Digitran Co Transistor Electronics Corp Westinghouse Electric Corp Electronic Tube Div Filmohm Corp Cinch Graphik Co Avnet Corp
90. until pointer is to left of zero moving upscale Continueuntil pointer isatzero If pointer overshoots zero repeat operation c When the pointer is exactly at zero rotate zero adjustment slightly CCW to free it If the meter pointer moves tothe left during this step repeat steps b and c 5 33 CHOPPER ADJUSTMENT 5 34 An Oscilloscope hp Model 130C and Elec tronic Counter hp Model 5211A are required for the chopper adjustment NOTE If Serial Prefix of instrument is 514 refer to Appendix C for chopper ad justment information a Remove 419A top cover and shield b Connect Oscilloscope and Electronic Counter to A2TP2 c SetOscilloscope for2 ms cm horizontal sen sitivity and 50 mV cm vertical sensitivity d Adjust A2R9 FREQ for Electronic Counter indication of 320 to 340 This corresponds to chopper rate of 160 170 pps as Electronic Counter also counts smaller pulses Adjust A2R5 NEON CURRENT for waveform amp litude of 140 to 160 mV Figure 5 4 shows the chopper waveform NOTE If the Neon Waveform is unstable intermittent neon bulb is indicated See Paragraph 5 2 for replacement information e If correct waveform is obtained andresponse time is still not within limits of Paragraph 5 13 A4R26will have tobe reselected If response 3 range is longer than 3 seconds the value of A4R26 should be decreased re sponse on 3 range is less than 2
91. upply Drift The output of the stable voltage source orthe power supply is adjusted until the Model 419A indicates null The voltage range used on the Model 419A depends on how much drift is anticipated from the power supply Ifthe power supply output drifts 8 mV over a period oftime the Model 419A willindicate this variation onthe 10 mV range and supply the strip chart recorder with a voltage that changes from 0 to 0 8 Voverthesame period Inthiscase the drift is amplified by a factor of 100 Gains as high as 333 000 the uV range are available when the Model 419A is used on the lower ranges 01779 2 HP 419A Null Voltmeter max 0 7 AI uonoes 1 1 JINN Od V6LV dH 8 5 LOUT R2 AND E lt P O SI BUCKING SUPPLY INPUT SIR26 P O SI P O A3 INPUT DE ATTENUATOR U AMPLIFIER MODULATOR METER input P O SI FEEDBACK EH SIRI 4I9A RO 6 6LLTO Figure 4 1 Model 419A Block Dia 2815 V6I T POWN Model 419A Section IV SECTION IV THEORY OF OPERATION 4 1 INTRODUCTION 4 2 This section contains the theory of operation of the Model 419A DC Null Voltmeter 4 3 GENERAL DESCRIPTION 4 4 The Model 419A functions as a dc voltmeter a dc null voltmeter and a dcammeter When used as a dc voltmeter the Model 419A provides end scale ranges from uVto 1000 V with an input resistance of 100 kQ to 100 MQ depending on the range
92. y a layer of metal plated through the component holes When working on these boards observe the following general rules 5 3 HP 419A DC Null Voltmeter max Section V a To avoid contamination wear clean lint free cotton or rubber gloves b Usealow heat 25 to 50 watts small tip sol dering iron and a small diameter rosin core solder c Circuit components canbe removed by placing the soldering iron on the component lead on either side ofthe boardand pulling up on lead Ifa component is obviously damaged clipleads as close to component as possible and then remove Excess heat can cause the circuit and board to separate or cause damage to the component d Component lead hole shouldbe cleaned before inserting new lead e To replace components shape new leads and insert them in holes Reheat with iron and add solder as required to insurea good elec trical connection f Cleanexcess flux from the connection and ad joining area g Toavoid surface contamination of the printed circuit clean with weak solution of warm water and mild detergent after repair Rinse thor oughly with clean water When completely dry spray lightly with Krylon 1302 or equi valent 5 27 INSTALLATION OF REPLACEMENT SUBASSEMBLY hp Part No 1990 0214 5 28 Physical alignment and neon selection are cri tical When trouble is isolated to the neon subassembly the complete subassembly should be changed rather than replaci

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