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Fluke 341a User's Manual

1. PEU Mic 15 VOLT REFERENCE SUPPLY M 9 4 uv 04 cj O REFERENCE diari 5 6K n lt 043026 STRING as 9 2 4 6 8 10 0 1 e 9 14 7 N 51 9 1007 R98 9 14 5 A PATER PIR BD 22 975 99 975 re 4 875 99 975 o j 200 A Toor BOV BV IN YN AiNEARLTY MNEARITY UNEARITY UNFARITY UNEARTY uNeAnty m x4 RU ALB Ce VOLT AUXILIARY SUR PLY ry S 343A 400 SAMPLE STRING 9 2 4 6 8 10 on AS 2414 4001 SAMPLE STRING KERANA ae SENSE NOTES ALL RESISTANCES IN OHMS UNLESS OTHERWISE 5 NOTED ALL GAPACITANCES IN MICROFARADS UNLESS OTRERWISE AS NOTED gt seio wma WI DENOTES FACTORY SELECTED COMPONENT DENOTES SENSE DENOTES CIRCUIT GROUND DENOTES INTERNAL ADJUSTMENT DENOTES ASSEMBLY MODEL 341 343A DC VOLTAGE CALIBRATOR KCHEMATIC NO 2 JOHN FLUKE INC PO Bor 7428
2. CODE REF DESIG INDEX NO DESCRIPTION plstc 0 47 ut 42075 250v Fig 8 5 Cap elect 250 uf 50 10 40v Fig 5 4 Cap elect 250 uf 50 10 40v Fig 5 4 Cap elect 250 uf 450 1000 40v Fig 5 4 Cap elect 400 uf 50 10 25v Fig 5 4 Cap mica 220 pf 5 500v Fig 5 5 Cap mica 68 pf 4595 500v Fig 5 5 Cap elect 10 uf 50 1095 25v Fig 5 5 Cap elect 10 uf 450 1005 25v Fig 5 5 plstc 0 1 uf 20 250v Fig 5 5 Cap elect 250 uf 50 10 16 Fig 5 5 Cap plste 0 33 uf 10 200v Fig 5 5 Cap elect 15 uf 75 10 6v Fig 5 5 Cap elect 15 uf 75 10 6v Fig 5 5 Cap elect 30 uf 75 10 15v Fig 5 5 Cap elect 30 uf 75 10 15v Fig 5 5 Cap elect 5 uf 75 10 25v Fig 5 5 Cap mica 5 pf 10 500v Fig 5 5 Cap mica 220 25 500v Fig 5 5 STOCK NO 1507 184366 1502 178616 1502 178616 1502 178616 1502 168153 1504 170423 1504 148510 1502 170266 1502 170266 1507 161992 1502 187765 1507 106047 1502 105700 1502 105700 1502 106492 1502 106492 1502 152009 1504 148577 1504 170423 PART C280AE C437ARG250 C437ARG250 C437ARG250 C437AR F400 CDISF 221d CD15F680J C426ARF10 C426ARF10 C280AE P100K C437ARE250 35
3. 36K 8127 CHOPPER AMPLIFIER cas is 130 i 8170 k 169K 15 7 56 V 15v R151 CY 180K 17 em CRI 0 015 47K 150 au Q us zx 22K V V V 4003 MAINBOARD e 2 5 SENSE NOTES ALL RESISTANCES IN OHMS UNLESS OTHERWISE NOTED ALL CAPACITANCES IN MICROFARAOS UNLESS OTHERWISE NOTED DENOTES SENSE DENOTES CIRCUIT GROUND CHOPPER AMPLIFIER th DENOTES CHASSIS GROUND DENOTES INTERNAL ADJUSTMENT DENOTES ASSEMBLY 077577 DENOTES COMPONENTS NOT MOUNTED ON ASSEMBLY pom STRING 4002 4 j REFERENCE BOARD 1 4 22K SPIKE ca COMPENSATION 4pf 0 047 341A ONLY r 0 1 343A ONLY MODEL 341A MODEL DC VOLTAGE CALIBRATOR SER NO 123 amp ON SENSE FLLIKE JOHN FLUKE MFG CO ING 7428 Seattle Worhindton 98112 gt n BEA STRING 02 476 8 10 0 2 amp 6 amp 10 13 579 19 99 19 991 DEKA DEXA i DECK SEX
4. VOLTAGE DIAL TESTED 895A 341A 343A RANGE NULL 60 0000 09 0000 00 0000 00 000 00 0000 00 0009 00 00000 03 000006 00000 00 00000 00 00000 00 00000 00 00000 Figure 4 9 BETA STRING SWITCHING REQUIREMENTS FAULT ANALYSIS If the beta string switching is incorrect it is likely that one or more beta string resistors has changed value Check for defective resis tors and perform the zero output adjustments and beta string calibration paragraphs 4 65 and 4 66 paragraphs 4 74 4 75 4 79 and 4 80 for the Model 343A 4 59 PANEL METER 4 60 The following test verifies proper operation of the meter circuit by comparing full scale meter readings to instrument output voltages a Set the FUNCTION switch to METER VOLTAGE b Set RANGE switch to 10 and voltage dials to 10 00000 10 000000 on Model 343A The instru ment meter should indicate 10 volts 5 Set RANGE switch to 100 and voltage dials to 100 0000 100 00000 on Model 343A The instru ment meter should indicate 100 volts 5 d Set RANGE switch to 1000 and voltage dials to 1000 000 1000 0000 on Model 343A The instru ment meter should indicate 1000 volts 3 596 Set RANGE switch to 10 and voltage dials to 10 00000 10 000000 on Model 343A f Set CURRENT LIMIT control maximum clockwise and connect the 400 ohm 1 1 watt resistor to the OUTPUT terminals 4 13 341A 343A
5. 341A DC Voltage Calibrator Sheet 2 0 2 Front Panel Assembly 54 ene Rear Panel Assembly 341 Main Assembly Left Hand Side ees Main Assembly Right Hand 4 Reference Assembly 341A Sample String Assembly DC Voltage Calibrator Sheet 1 of 2 343A DC Voltage Calibrator Sheet 2 of 2 Front Panel Assembly 343 Rear Panel Assembly 343A Reference Assembly dae esee s 4 Eee bw Sample String Page 447 4 18 4 18 4 19 4 20 5 4 5 5 5 7 542 5 13 5 29 5 32 5 35 5 36 5 37 5 38 5 40 5 43 341A 343A 341A 343A DC VOLTAGE CALIBRATORS MODEL 341A MODEL 343A 341A SECTION INTRODUCTION AND SPECIFICATIONS 1 1 INTRODUCTION 12 The Fluke Model 341A and Model Voltage Calibrators provide dc voltages of 0 to 1100 volts in three ranges Voltages are selected by eleven position decade switches which provide in line digital readout of the instrument output voltage The Model 341A employs six dial reado
6. 1501 105668 1507 261073 5101 109272 5101 109322 5101 163030 4811 190710 6005 226027 2102 160846 3156 240432 3156 240309 37 4 places Figure 5 10 XF1 XF2 F1 71400 71400 04713 89536 89536 REAR PANEL ASSEMBLY 343A PARTNO 29C9B5 Type 663UW Type MDL Type MDL 1 Type MDL 1 2N3739 4 6005 226027 1 342004 3156 240432 4 3156 240309 341A 343A DESCRIPTION PART NO QTY REFERENCE P C ASSEMBLY 3158 252437 3158 252437 REF Figure 5 11 NOTE The Reference P C Assembly A4 the Sample String P C Assembly A5 and their inter matched resistors can be ordered under one part number 3158 265314 Cap plste 0 1 uf 10 1 200 1507 233718 JF15 Cap plstc 0 1 uf 10 1 200v 1507 233718 JF15 Res var cermet 1k 20 3 4w 4713 190538 Type 78P Res ww 1 4995M matched Res var cermet 1009 5209 3 4w 4713 159889 Type 78P Res ww 149 95k matched Res cermet 1009 420 3 4w 4713 159889 Type 78P REF Res ilm 2009 0 5 1 2w 4705 246248 Type MF7C 1 Res flm 2000 1 1 2w 4705 151480 1 Res 14 9286k matched Res ww 99 955k matched VVV Res ww 99 955k matched Res var cermet 2002 20 3 4w Type 78P Res ww 99 955k matched VY Res ww 99 955k
7. 1 Type MF7C 1 GB4711 REF Type MF8C 1 Type MF5C 1 REC USE QTY CODE 341A 343A REF INDEX STOCK MFR Res comp 2400 5 1w 4704 190587 GB2415 Fig 5 4 Res comp 2402 505 1w 4704 190587 GB2415 Fig 5 4 Res comp 2409 45 1w 4704 190587 GB2415 Fig 5 5 Cover thermal not illustrated 3155 240390 3155 240390 Heat sink transistor 4841 104646 NF207 Q14 R21 and R24 are a factory selected and matched Reference Amplifier set For Model 341A replace the entire set part number 4842 264044 For Model 343A replace the entire set part number 4842 264051 R22 and R23 are a factory matched set For replacement in the Model 341A order part number 4707 265116 For replacement in the Model 343A order part number 4707 265348 5 27 341A 343A DESIG 2 Ri R2 R3 R4 R5 R6 RT R8 R9 R10 R11 R12 R13 R14 R15 R16 R18 R19 R20 R21 R22 5 28 NO C2 R4 C2 Q5 F3 T1 F3 Q5 G2 R5 G1 Q5 E4 S1 E3 Q5 E1 Q5 E5 Q5 K1 Q5 K1 R5 K1 T1 J1 Q5 J3 Q5 J2 S1 13 Q5 13 R5 I3 T1 H3 Q5 H5 Q5 5 51 G5 Q5 H1 S1 DESCRIPTION REFERENCE P C ASSEMBLY Figure 5 6 NOTE The Reference P C Assembly A4 the Sample String P C Assembly A5 and their intermatched resistors can be ordered under one part number 3158 252312 Cap piste 0 1 uf 510
8. 5125 REF 4104 109108 01121 EB5125 REF 4105 261487 19701 Type 1 4104 193342 01121 CB5125 2 4704 148064 01121 CB3925 1 4704 246751 01121 CB82G5 1 4704 160796 01121 CB8225 2 4104 148072 01121 CB4725 1 4704 193342 01121 CB5125 4704 202879 01121 CB2025 REF 4704 148148 01121 CB2735 4104 246728 01121 CB2005 1 4704 202879 01121 CB2025 REF 4104 246801 01121 HB3941 6 E EN 55 K3 M5 K4 P3 K3 R1 K4 R2 K4 S5 14 R2 K1 U2 I4 R3 Ci P2 2 1 C3 N5 DESCRIPTION Res comp 390k 10 2w Fig 5 4 Res ww lk 45 5w Fig 5 4 Res comp 390k 10 2w Fig 5 4 Res comp 390k 10 2w Fig 5 4 Res comp 150k 595 1w Fig 5 5 Res comp 6209 45 1 4w Fig 5 5 Res comp 150k 565 1 Fig 5 5 Res comp 150k 595 1w Fig 5 5 Res comp 6200 2595 1 4w Fig 5 5 Res comp 6200 45 1 4w Fig 5 5 Res comp 150k 5 lw Fig 5 5 Res comp 6209 45 1 4w Fig 5 5 Res comp 7 5k 1 2w Fig 5 5 Res comp 6 8k 45 1 4w Fig 5 5 Res comp 150k 5 1 2w Fig 5 5 Res met flm 56 20 1 1 2w Fig 5 5 Res met flm 46 4k 195 1 2w Fig 5 4 Res met flm 536k 1 1 2w Fig 5 4 Res met flm 2 26M 215 1 2w Fig 5 4 Res met flm 2
9. 0 01 of setting or 0 0002 of range 1000 V 0 01 of setting or 0 0002 of range Model 343A Range Accuracy whichever is greater 10y 0 003 of setting or 0 0003 of range 100 V 0 003 of setting or 0 0001 of range 1000 V 0 003 of setting or 0 0001 of range TEMPERATURE COEFFICIENT OF OUTPUT Model 341A Less than 5 ppm of setting 0 1 ppm range 2 uv per C from 15 to 35 C Less than 8 ppm of setting 0 1 ppm of range 2 uv per from 0 to 509 1 1 341A 343A Model 343A Less than 3 ppm of setting 0 1 ppm of range 2 uv per 9C from 15 to 359C Less than 5 ppm of setting 0 1 ppm of range 2 uv per from 0 to 50 C STABILITY OF OUTPUT The following stability specifications apply at the standard reference conditions noted under ACCURACY OF OUT PUT Model 341A 10V range whichever is greater 30 000746 of setting or 5 uv per hour 0 003 of setting or 15 uv per month 100V range whichever is greater 0 0007 of setting or 10 uv per hour 0 003 of setting or 25 uv per month 1000V range whichever is greater 0 0007 of setting or 20 uv per hour 0 003 of setting or 50 uv per month Model 343A 10V range whichever is greater 0 0005 of setting or 5 uv per hour 30 001546 of setting or 15 uv per month 100V range whichever is greater 0 0005 of setting or 10 uv per hour 0 0015 of setting or 25 uv per month 1000V range whichever is greater 0 0005
10. 1 MSEC CM Figure 4 6 MULTIVIBRATOR SIGNAL TP9 Connect the oscilloscope 10 1 attenuator probe to TP10 using SENSE as common NOTE Ensure that the bottom cover is in place on the instrument when observing the signal at TP10 The top cover should be slid back just far enough to admit the probe Set the oscilloscope input to ac vertical sensitivity to 0 02 volts per centimeter and sweep speed to 1 milli second per centimeter Compare display with the waveform shown in Figure 4 7 which indicates proper adjustment of spike compensation control R162 The signal is acceptable if the positive and negative spike amplitudes are less than 0 3 volts 1 MSEC CM Figure 4 7 CHOPPER AMPLIFIER SIGNAL TP10 If the signal obtained in step g is not acceptable it will be necessary to adjust R160 and R162 Proceed as follows 1 Set chopper drive control R160 fully clockwise 2 Adjust R162 for minimum spike amplitude A point should be found where the positive and negative spike amplitudes are approximately equal and nulled 3 Rotate chopper drive control R160 counter clockwise until noise spikes begin to appear in the formerly quiet regions 4 Reverse the adjustment of R160 just far enough to restore the quiet region 5 Repeat step g NOTE Adjustment of R160 and R162 affects the out put zero on the 10 volt range therefore it will 341A 343A be necessary to perform the 10 volt zero a
11. 0 015 0 03 0 05 0 07 0 09 0 15 the Model 341A 343A is equipped with remote sensing which maintains regulation at the load independent of lead length 2 17 Remote Sensing If the voltage developed in the load connecting leads is found to be excessive proceed as follows a With the FUNCTION switch set to OFF or to STANDBY RESET remove the front panel shorting links between the SENSE and OUTPUT terminals b Using a twisted pair of insulated wires connect the SENSE terminal to the positive side of the load and connect the SENSE terminal to the negative side of the load CAUTION Ensure that the SENSE terminals are connected to the load in the proper polarity Incorrect connections will result in loss of regulation and possible damage to the instrument When re mote sensing is not used the SENSE terminals must be connected to the OUTPUT terminals with the front panel shorting links 2 18 CURRENT LIMIT OPERATION 2 19 The CURRENT LIMIT control sets the operating point of the controlled current limiter which limits the instrument output current to any value between and 25 milliamps The approximate value of limiting current is indicated by to 25 scale circumscribed about the CURRENT LIMIT control on the front panel If no cur rent limiting is desired set the CURRENT LIMIT control fully clockwise 25 In this position maximum instru ment output current is available at all voltage settings If
12. 1 200v Cap piste 0 1 uf 10 1 200v Res var ww 1k 20 1 1 4w Res ww 1 4995M matched Res var ww 1000 2109 1 1 4w Res ww 149 95k matched Res var ww 1009 10 1 1 4w Res Res met flm 2000 195 1 2w Res ww 14 9286k matched Res ww 99 975k matched Res ww 99 975k matched Res Res ww 99 975k matched Res ww 99 975k matched Res Res ww 99 975 matched Res ww 99 975k matched Res Res ww 99 975k matched Res ww 99 975k matched Res Res ww 99 975k matched ww 99 975 matched 3158 240101 1507 233718 1507 233718 4102 113266 gt 4102 208185 4702 208785 71450 Type 110 REF met flm 1002 20 5 1 2w 4705 256248 19701 Type MF7C 1 4705 151480 19701 Type 1 var ww 1009 2109 1 1 4w 4702 208785 71450 Type 110 var ww 1000 gt 10 1 1 4w 4702 208785 71450 Type 110 EF var ww 1000 2109 1 1 4w 4702 208785 71450 Type 110 EF var ww 1002 410 1 1 4w 4702 208785 71450 Type 110 EF var ww 1009 410 1 1 4w 4702 208785 71450 Type 110 ker ail piles 5c MER PARTNO 3158 240101 84411 JF 15 2 84411 JF 15 REF 71450 Type 110 1 71450 Type 110 7 341A 343A Figure 5 6 REFERENCE P C ASSEMBLY 341A 5 29 341A 343A REF INDEX STOCK MFR USE DESCRIPHON MER PARTN
13. 34 3 29 Sink Supply and 34 3 34 Controb Circulb eR e Eo eO I 8 3 5 3 38 High Voltage Power 3 6 340 Meter Circuit deed nU eer Edd EUR 3 6 242 gs ERN cate Capo dre 3 6 continued on page 341A 343A TABLE OF CONTENTS continued Section Title Page IV MAINTENANCE 41 4 1 Introduction 4 1 4 3 Service Information 4 1 4 6 Test Equipment 4 1 4 8 General Maintenance 4 1 4 9 4 4 13 4 3 4 15 g 4 4 4 18 115 230 Volt Conversion 4 5 4 20 Fuse 4 5 422 Lamp Replacement cease es ee e ew 4 5 424 Performance Teste osc dad ba bea 4 6 426 Line Regulation tu be eee RP REOS qu s 4 6 4 28 Load Regulation nm RUE Deer wr 4 6 430 Rippen i idend ecu ee ee qct doge o x Rar 4 7 4 32 Output Voltage Accuracy 4 8 4 36 Troubleshooting 4 405 eu bg Ras 4 8 4 39 Test Point Resistance 4 8 441 Standby Test s s pe ble 4 8 4 43 Auxiliary Supply Voltages 4 9 445 Power On Test 4 10 447 Chopper Amplifier 4 11 4 49 Series Regulator 4 11
14. 897 R98 R99 R100 R101 R102 R103 R104 R105 R106 R107 R108 R109 R110 R112 R113 R114 R115 R116 INDEX NO K1 T1 Di Q2 5 E2 N5 5 Di Pi F3 R5 F2 R5 D5 R5 E1 R5 F4 R5 F5 R5 5 C4 R5 D3 S1 D1 R5 G4 U2 H3 T5 n Ti H4 T2 DESCRIPTION Res ww 200k 45 10w Fig 5 4 Res comp 1M 100 lw Fig 5 4 Res comp 8202 595 1 4w Fig 5 4 Res comp 519 45 19 Fig 5 4 Res comp 15k 259 1 4w Fig 5 4 Res comp 3 3k 5 1 4w Fig 5 4 Res comp lk 595 1 4w Fig 5 4 Res comp 10k 565 1 4w Fig 5 4 Res comp 2 7k 5 1 4w Fig 5 4 Res comp 15k 5 1 4w Fig 5 4 Res comp 8 2k 575 1 4w Fig 5 4 Res comp 22k 575 1 4w Fig 5 4 Res comp 2 7k 595 1 4w Fig 5 4 Res comp 5 6k 5 2w Fig 5 4 Res comp 62k 45 1 2w Fig 5 4 Res comp 15k 10 2w Fig 5 4 Res comp 5102 5 1 4w Fig 5 5 Res comp 6 2k 45 1 4w Fig 5 5 Res 5602 595 1 4w Fig 5 5 Res comp 5600 45 1 4w Fig 5 5 4706 246850 4704 109793 4704 148015 4704 157586 4704 148114 4704 148056 4704 148023 4704 148106 4104 170720 4104 148114 4704 160796 4704 148130 4704 170720 4704 218842 4704 108522 4704 110080 4704 218032 4704 221911 4704 147991 4704 147991 MFR MFR TOT PA
15. Cap elect 200 uf 50 10 250v Fig 5 4 Cap cer luf gmv 3v Fig 5 4 Cap elect 250 uf 50 10 16v Fig 5 4 Cap elect 10 uf 50 10 25v Fig 5 5 Cap mica 4 pf 505 500v Fig 5 5 Cap plste 0 1 uf 42095 250v Fig 5 5 plstc 0 015 uf 2 100v Fig 5 5 Cap plstc 0 015 uf 2 100v Fig 5 5 Cap 0 47 uf 20 250v Fig 5 5 Cap plstc 0 22 uf 20 250v Fig 5 5 Cap elect 100 uf 75 10 25v Fig 5 5 Cap elect 100 uf 75 10 25v Fig 5 5 Cap elect 5 uf 75 10 25v Fig 5 5 Cap elect 10 uf 50 10 25v Fig 5 5 Cap plste 0 47uf 20 250v Fig 5 5 1702 240143 1702 265322 1502 246819 1502 246819 1502 246827 1501 106567 1502 187765 1502 170266 1504 190397 1507 161992 1507 233577 1507 233577 1507 184366 1507 194803 1502 106518 1502 106518 1502 152009 1502 170266 1507 184366 89536 89536 56289 56289 56289 14655 73445 73445 14655 73445 02799 02799 73445 13445 80183 80183 80183 13445 13445 1702 240143 REF 1702 265322 REF Type 68D 6 Type 68D REF Type 68D 1 HCC3105P 50 2 C426ARF10 4 CD15C040K 1 C280AE 3 P100K 1PC153G 2 1PC153G REF C280AE 3 P470K C230AE 1 P220K 1211 2 1211 REF TE1202 3 C426ARF10 C230AE P470K REF
16. FUNCTION OFF RANGE 10 Voltage dials 10 00000 Model 341A 10 000000 Model 343A CURRENT LIMIT Fully clockwise b Connect the instrument through the wattmeter to a 115 volt 1 60 Hz source Set FUNCTION switch to STANDBY RESET The wattmeter should indicate approximately 10 watts and the LIMIT ON lamp should illuminate FAULT ANALYSIS 1 If the LIMIT ON lamp does not light in STANDBY check the following lamp DS3 for continuity test point 2 TP2 and TP3 for proper 15 and 15 volt outputs 013 for proper operation and controlled current limiter for proper operation 341A 343A 443 AUXILIARY SUPPLY VOLTAGES 4 44 In the following test the auxiliary supplies are tested by measuring their respective output voltages Set Model 3414 3434 controls as follows FUNCTION STANDBY RESET RANGE 10 Voltage Dials 10 00000 Model 341A 10 000000 Model 343A CURRENT LIMIT Fully clockwise b Connect the 895A common to the SENSE terminal and measure the following test point voltages Vol tages should be as indicated TEST POINT DC VOLTS 21 to 24 TP2 14 999 to 15 001 TP3 14 5 to 15 5 4 540 to 600 TPS 690 to 760 FAULT ANALYSIS If the auxiliary supply voltages are not correct check for possible defective components as follows TEST POINT POSSIBLE TROUBLE Defective diode CR19 CR20 Defective transistor 023 or Q24 2 Defective transistor 019 020 or 014
17. To eliminate shock hazard leave the ground terminals of the Model 341A 343A and null detector disconnected b Set the null detector voltage range and Model 341A 343A voltage dials to approximately the voltage being measured If the voltage being measured is not known set the null detector to the 1000 volt range initially c Set the Model 341 A 343A FUNCTION switch to ON and set the CURRENT LIMIT control as desired d Set the Model 341A 343A RANGE switch and vol tage dials to the approximate voltage indicated by the null detector The null detector should then indicate a null e Set the null detector for increased sensitivity and adjust the voltage dials for zero deflection on the null detector f The value of the voltage being measured is indicated by the Model 341A 343A voltage dial setting at zero deflection of the null detector g measure a negative voltage reverse the connec tions at the Model 341A 343A OUTPUT terminals 2 31 OPERATION AS A 10 PPM SOURCE 2 32 The Model 3414 3434 together with a reference divider such as the Fluke Model 750A can provide voltages of 0 1 0 5 1 1 1 5 10 50 100 500 1000 and 1100 volts dc which have an accuracy of 10 ppm and are trace able to the National Bureau of Standards Equipment connection is shown in Figure 2 4 Proceed as follows a Set the Model 750A input switch to RESET Adjust the Model 341A 343A CURRENT LIMIT control for 2 milliamps using the
18. 01121 01121 01121 01121 01121 19701 19701 19701 01121 19701 19701 01121 19701 01121 19701 01121 01121 19701 PART CB6815 CB3035 135 CB1325 CB1835 CB1815 CB1815 Type Type Type EB3635 Type MF7C Type EB1045 Type EB1045 Type MF7C EB2435 CB6235 Type MF7C R138 R139 R140 R141 R142 R143 R144 R145 R146 R147 R148 R149 R150 R151 R152 R153 R154 R155 R156 F3 Q4 E2 Q5 D1 Q3 D4 R5 E1 R5 E1 S1 E4 R4 D5 S2 F2 U2 E5 S4 F3 S1 E4 M4 E4 M5 1 2 E3 M3 12 5 DESCRIPTION Res met flm 8 06k 41 1 2w Fig 5 5 Res met flm 34k 1 1 2w Fig 5 5 Res met flm 1620 41 1 2w Fig 5 5 Res met flm 34k 19 1 2w Fig 5 5 Res comp 1 5k 5 1 4w Fig 5 5 Res comp 2209 45 1 4w Fig 5 5 Res comp 13k 5 1 4w Fig 5 5 Res comp 2000 x595 1 4w Fig 5 5 Res comp 22k 45 1 4w Fig 5 5 Res comp 3 3M 5 1 4w Fig 5 5 Res met flm 9 09k 1 1 2w Fig 5 5 Res met flm 249k 41 1 2w Fig 5 5 Res met flm 383k 19 1 2w Fig 5 5 Res comp 47k 2595 1 2w Fig 5 5 Res comp 180k 10 1 2w Fig 5 5 Res comp 22k 595 1 4w Fig
19. 1 3 static awareness x A Message From John Fluke Mfg Co Inc Some semiconductors and custom IC s can be damaged by electrostatic discharge during handling This notice explains how you can minimize the chances of destroying such devices by 1 Knowing that there is a problem 2 Learning the guidelines for handling them 3 Using the procedures and packaging and bench techniques that are recommended The Static Sensitive S S devices are identified in the Fluke technical manual parts list with the symbol The following practices should be followed to minimize damage to S S devices 3 DISCHARGE PERSONAL STATIC BEFORE HANDLING DEVICES 1 MINIMIZE HANDLING 2 KEEP PARTS IN ORIGINAL CONTAINERS UNTIL READY FOR USE 4 HANDLE S S DEVICES BY THE BODY Page 1 of 2 5 USE ANTI STATIC CONTAINERS FOR HANDLING AND TRANSPORT 6 DO NOT SLIDE S S DEVICES OVER ANY SURFACE ud 7 AVOID PLASTIC VINYL AND STYROFOAM IN WORK AREA PORTIONS REPRINTED WITH PERMISSION FROM TEKTRONIX INC AND GENERAL DYNAMICS POMONA DIV Dow Chemical Page 2 of 2 WHEN REMOVING PLUG IN ASSEMBLIES HANDLE ONLY BY NON CONDUCTIVE CONNECTOR EXCEPT AT STATIC FREE WORK STATION PLACING SHORTING STRIPS ON EDGE CONNECTOR USUALLY PROVIDES COMPLETE PROTECTION TO INSTALLED SS DEVICES HANDLE S S DEVICES ONLY ATA STATIC FREE WORK STATION ONLY ANTI STATIC TYPE SOLDER SUCKERS SHOULD B
20. 5 115 230 Volt Conversion Ripple Specifications aunt pees asa MAS eee Ge Vue Multivibrator Signal 9 Chopper Amplifier Signal 0 High Voltage Power Supply Output Beta String Switching Requirements 341A Linearity 341A Output Voltage Requirements Model 343A Preliminary Linearity Adjustments Sheet 1 of 2 Model 343A Preliminary Linearity Adjustments Sheet 2 of 2 DE 1 3 Tp 22 2 3 2 4 2 6 TEE 2 7 Tess wae eS 3 1 mr 3 2 Sheree hts 4 2 4 3 Ee 44 Vx dos SES NS 4 5 ORE 4 7 4 10 d 4 11 MES 4 13 em 4 13 415 4 15 REA 4 16 4 17 continued on page v LIST OF ILLUSTRATIONS continued Figure 4 13 414 4 15 416 417 5 1 5 1 5 3 5 4 5 5 5 7 5 8 5 8 5 9 5 10 5 11 Beta String Linearity Test Setup Linearity Adjustments Deck Linearity Adjustments Deck Range Adjustment and Calibration Verification Test Model 343A Output Voltage 5 341A DC Voltage Calibrator Sheet 1 of 2
21. 525 uv 10 w 100 00000 343A 40k 4 5 1000 1000 000 341 4 5 50 w 1000 0000 343A AS M FAULT ANALYSIS If the line regulation is not within limits it is likely that the chopper amplifier or preampli fier gain is too low Check chopper amplifier performance as described in paragraph 4 47 Check test point 8 TP8 voltages in the pre amplifier as described in paragraph 4 45 428 LOAD REGULATION 4 29 The load regulation test determines if the instru ment output voltage will remain constant within specified limits under no load to full load conditions a Connect the autotransformer to the line and connect the Model 341A 343A to the autotransformer Ad just the autotransformer for 115 volts output b Set the Model 341A 343A controls as follows FUNCTION STANDBY RESET RANGE 10 Voltage dials 1 00000 Model 341A 1 000000 Model 343A CURRENT LIMIT Fully clockwise Jumper the SENSE terminals to the output terminals Connect the 895A differential voltmeter to the SENSE terminals and set the FUNCTION switch to ON Record the voltage indicated by the 895A Connect 40 ohm 5 1 2 watt resistor to the OUTPUT terminals The voltmeter should indicate a voltage change of less than 30 microvolts Remove the 40 ohm resistor and set the voltage dials to 10 00000 10 000000 for the Model 343A Record the voltage indicated by the 895A Connect a 400 ohm 5 1 watt resistor to the OUTPUT terminals
22. 8 Set FUNCTION switch to METER CURRENT The Mode 3414 3434 meter should indicate between 23 7 and 26 3 milliamps oS T FAULT ANALYSIS EDEN 1 H voltage readings are incorrect on one range only check corresponding range resistor R71 R72 R73 or R74 vol tage readings are incorrect on all ranges check meter Mi and resistors R44 and 45 2 If current readings are incorrect check current sensing resistor R70 and asso ciated components 461 MODEL 341A CALIBRATION 4 62 Calibration of the Model 341A consists of five ordered steps 1 reference voltage adjustment 2 zero output adjustment 3 beta string linearity adjustments 4 range adjustments and 5 verification of calibration Before attempting calibration instrument performance should be examined according to the performance tests in paragraph 4 24 to ensure that no malfunctions exist 463 PRELIMINARY OPERATIONS a Connect the Model 341A to the autotransformer and adjust the autotransformer for 115 volts output b Set Model 341A controls as follows FUNCTION ON RANGE 10 Voltage Dials 10 00000 Attach all covers and allowinstrument to operate for at least 1 hour 464 REFERENCE VOLTAGE ADJUSTMENT Unfasten the top cover and slide back just far enough to expose REF ADJUST control R26 and test point TP2 b Connect the 895A differential voltmeter to TP2 using SENSE as common 4 14 4 65 e 4 66 b
23. 80 uf 50 10 450v 1502 246819 56289 Type 68D REF Fig 5 4 E3 U3 Cap elect 80 uf 50 10 450v 1502 246819 56289 Type 68D REF Fig 5 4 D3 T1 Cap elect 80 uf 50 10 450v 1502 246819 56289 Type 68D REF Fig 5 4 E4 R5 Cap mica 100 pf 5 500v 1504 148494 14655 CDI5F101J REF Fig 5 4 C4 V2 Cap 1 uf gmv 3v Fig 5 5 1501 106567 14655 HCC3105P REF J2 T4 Cap cer 0 01 uf 80 10 500v 1501 105668 56289 29C9B5 Fig 5 4 5 10 341A 343A REF INDEX STOCK MFR ToT DL DESCRIPTION NO MER PART NO Cap cer 0 01 uf 1 6 ky 1501 106930 DD16 103 Fig 5 4 Cap 500 pf 10 1 kv 1501 105692 2DDH60N501K 1 Fig 5 5 Diode silicon 1 amp 600 piv 4802 112383 1N4822 12 Fig 5 4 Diode silicon 1 amp 600 piv 4802 112383 1N4822 Fig 5 4 Diode silicon amp 600 piv 4802 112383 1N4822 Fig 5 4 Diode silicon 1 amp 600 piv 4802 112383 1N4822 Fig 5 4 Diode silicon amp 600 piv 4802 112383 1N4822 Fig 5 4 Diode silicon 150 ma 4805 203323 DHD1105 Fig 5 4 Diode silicon 150 ma 4805 203323 DHD1105 Fig 5 5 Diode silicon 150 ma 4805 203323 DHD1105 Fig 5 4 Diode silicon 150 ma 4805 203323 DHD1105 Fig 5 5 Diode silicon 150 ma 4805 203323 DHD1105 Fig 5 5 Diode silicon 150 ma 4805 203323 DHD1105 Fig 5 5 Diode silicon 150 ma 4
24. Switch rotary Decade 1 Switch section decks A amp B Switch section decks C amp D Switch rotary FUNCTION Switch rotary RANGE Switch section decks amp B Switch section decks C amp D Transformer power Bail tilt down not illustrated Cover bottom not illustrated Cover top not illustrated Detent switch S1 Detent switch S2 thru S7 Detent switch S9 Foot not illustrated Shaft extension S2 thru 57 1702 265322 3158 252437 3158 252429 1505 247023 1501 106567 4802 116111 2901 246942 4701 247031 4704 218693 5105 257238 5105 257246 5105 25726 5105 257212 5105 257220 5602 240465 3154 231407 3156 240382 3156 240374 5105 257287 5105 257295 5105 257279 3155 230037 3155 240457 PART NO QTY 1702 265322 3158 252437 3158 252429 264P70 HCC3105P 1N4817 2901 246942 3215502 EB10G5 5105 257238 5105 257246 5105 257261 5105 257212 5105 257220 5602 240465 3154 231407 3156 240382 3156 240374 5105 257287 5105 257295 5105 257279 3155 230037 3155 240457 341A 343A 24 6 places Figure 5 8 343A DC VOLTAGE CALIBRATOR Sheet 1 of 2 5 35 341A 343A M1 A5 81 27 C62 CROS 6 places Latasha a Figure 5 8 343A DC VOLTAGE CALIBRATOR Sheet 2 of 2 5 36 Figure 5 9 Lamp incandescent 28v Binding post red Binding
25. TP3 Defective 15 volt supply Defective transistor Q21 or Q22 Defective diode CR21 Defective diode CR2 CR4 or CRS TPS Defective diode CR3 49 341A 343A 4 45 POWER ON TEST 4 46 This test determines instrument power consump tion under power on conditions and verifies proper opera tion of the chopper stabilized amplifier a Set Model 341A 343A control as follows FUNCTION OFF RANGE 10 Voltage dials 10 00000 Model 341A 10 000000 Model 343A CURRENT LIMIT Fully clockwise b Connect the instrument through the wattmeter to a 115 volt 1 60 Hz source Set FUNCTION switch to STANDBY RESET d Measure the voltage at TP8 with the 895A using SENSE as common The voltmeter should indicate between 1 7 and 2 1 volts Set FUNCTION switch to ON The wattmeter should indicate approximately 15 watts and the LIMIT ON lamp should extinguish f Repeat step d The 895A should indicate between 2 3 and 2 7 volts g Connect the 895A to the OUTPUT terminals The 895A should indicate between 9 999 and 10 001 volts dc 9 9997 to 10 0003 volts dc for the Model 343A p FAULT ANALYSIS 1 the ON lamp does not light in the FUNCTION ON position check for possible de fective lamp DS4 and for proper operation of the control circuit 2 If the TP8 voltages are not within limits the trouble is probably in the negative voltage limiter It may also be due
26. Voltages hazardous to life will be present Use extreme caution When troubleshooting it is recommended that the OUTPUT terminal be jumpered to the chassis ground terminal to reduce shock hazard 439 TEST POINT RESISTANCE CHECK 4 40 This test consists of a resistance check of all power supply outputs within the instrument Set Model 341A 343A controls as follows FUNCTION OFF RANGE 10 Voltage Dials 10 00000 Model 341A 10 000000 Model 343A CURRENT LIMIT Fully clockwise b Connect 853A common to SENSE Measure the resistance between the following points and the SENSE terminal Resistance should be as indicated TEST POINT APPROXIMATE RESISTANCE IN OHMS TP2 2500 3700 5 gt 100k TP6 340 7 gt 100k SENSE 58 FAULT ANALYSIS n I there are errors in test point resistance read ings check the following components TEST POINT POSSIBLE TROUBLE TP2 Defective diode CR17 Defective transistor Q6 or 011 TP3 Defective transistor Q9 011 or 018 5 Defective diode CR1 CR2 CR3 CR4 or CRS TP6 Defective diode CR26 or CR27 Defective lamp DS5 DS6 or DS7 TP7 Defective capacitor C54 Shorted relay K2A and K3A SENSE Resistor R169 changed value 441 STANDBY TEST 4 42 This test determines instrument power consump tion and verifies proper operation of the controlled current limiter under standby conditions a Set Model 341A 343A controls as follows
27. l 107 5 Ci CRI list ou L R53 tl css 390K 80 R54 390K S 4 298 p 99 gt CONTROL CIRCUIT i hov 1 10v 5 o 1 H 1 1 1 b c da 2 y NE 2E ost 2 u CRO R102 14948 INGMA 3 3K Res OTP 54 R92 cs 18K 1 250 RIO BK RIH 62K 106 15K t SINK SUPPLY RT KN R95 R89 9 09K 3 7 0 01 ME TA 7 Tus REGULATOR Ys 243739 283739 Ret 1K A2 r L 750 R80 2K Al 21 K3A d 7 0 005 R84 2K IN4148 5 n 5 62K 106 15K r SINK SUPPLY 34 y CR m5 0 01 50 14961 R89 9 09K Ac 200 0 01 Ln CROWBAR DRIVER R55 1K css 50 la 2 9 3 0 10K nge 80 V 2N3906 ROS R39 1N964 5 ik 620 f 2N3904 Q TPS 52 L n CONTROLLED CURRENT LIMITER ae NEGATIVE VOLTAGE LIWIER a 15V DN476 5120 18K aK c2 9 10 F 34K 128 3 gi 129 28 7K
28. other equip ment which meets the required specifications may be used 48 GENERAL MAINTENANCE 4 9 MAINTENANCE ACCESS 4 10 Main circuit board components are accessible from the top of the instrument after removing the top cover which is held in place with six Dzus fasteners 4 11 The reference board and sample string assemblies are located in the compartment just forward of the main circuit board The compartment covers are each held in place with two machine screws To replace components on the reference board assembly sample string assembly or front panel assembly proceed as follows a Remove top and bottom instrument covers b Remove the reference and sample string assembly compartment covers c Remove the narrow front covers just above and below the meter d Remove the front panel and first bulkhead assem blies as a unit by removing the eight screws which hold the assemblies to the side rails disconnecting the leads to pin 1 and 6 of the sample string assem bly and sliding the assemblies carefully forward away from the main unit as far as the wiring harness will permit NOTE The shafts of the RANGE and first decade switches will disengage from the switch rotors as the front panel is removed To ensure proper shaft orientation when replacing the front panel be sure to note the switch positions before disassembly 44 341A 343A RECOMMENDED EQUIPMENT SPECIFICATIONS
29. 100 volt ranges in the 1000 volt range the error will be equal to 1 milliamp Terminal strip Provides output sense and ground connections for rack mount in stallations Standard on the Model 343A and option only on the Model 341A Fuse high voltage High voltage power supply output fuse rated at 1 16 amp slow blow Fuse line Power line fuse 1 amp slow blow for 115 volts ac operation and 1 2 amp slow blow for 230 volts ac operation Figure 2 1 CONTROLS TERMINALS AND INDICATORS Sheet 2 of 2 No 28 wires each 3 ft long are used to connect a load approximately 1 65 millivolts per foot Therefore the requiring 25 milliamps to the OUTPUT terminals of the connecting wires develop a total voltage of 12 millivolts Model 341A 343A With a straight edge connect the 2 x 3ft x 1 65 mv ft 9 9 mv which is more than one known current on scale 1 25 ma and the wire size on and one half times the published load regulation of the scale 2 28 The resulting IR drop on scale 3 is instrument at 1000 voits output To compensate for this 2 3 341A 343A 2 4 1 OPERATING CURRENT MILLIAMPERES 0 4 0 3 1 5 1 0 0 0 8 0 7 0 0 5 2 AMERICAN WIRE GAUGE NO i 3 IR DROP IN CONDUCTOR MV FOOT t 1 i 0 2 0 01 0 02 0 04 0 06 0 08 0 1 pe 0 6 0 8 1 0 2 0 4 0 Figure 2 2 NOMOGRAPH OF VOLTAGE DROP IN LOAD WIRES
30. 13 15 10 7 16 054 053 3 pl XDS4 XD 3 Figure 5 2 FRONT PANEL ASSEMBLY 341A 341A 343A REF INDEX STOCK MFR REAR PANEL ASSEMBLY 341A Figure 5 3 1501 105668 29C9B5 Cap cer 0 01 uf 80 20 500v 5101 109272 Fuse slow blow 1 amp 250v Type MDL for 115v operation 5101 109322 Fuse slow blow 1 2 amp 250v tor 230v operation Type MDL 5101 163030 Fuse slow blow 1 16 amp 250v Type MDL 4811 190710 2N3739 Tstr silicon NPN behind heat sinks Line cord 6005 226027 6005 226027 Holder Fuse 2102 160846 342004 3156 240432 3156 240432 Heat sink 3156 240309 3156 240309 Panel rear XF2 W1 C59 C60 XH F2 044 042 18 4 places Figure 5 3 REAR PANEL ASSEMBLY 341A 5 7 341A 343A 2 C3 C4 C5 C8 C9 C10 Cii C14 C15 C16 C17 C18 C19 C20 5 8 INDEX NO U3 K3 U3 H3 T1 H1 Q5 1 1 G4 M5 81 G3 R3 H3 M3 F3 N3 G4 Q1 H1 N3 1 53 G2 N5 B5 S4 J1 P3 B4 Q3 DESCRIPTION STOCK NO MER PARTNO MAIN P C ASSEMBLY Figure 5 4 amp 5 5 Model 341A only Model 343A only Cap elect 80 4 50 10 450v Fig 5 4 Cap elect 80 uf 50 10 450v Fig 5 4
31. 144817 1N964B 1N4817 1N4822 TOT QTY RE REF REF REF REF IREF REF REF REF REF REF REF REF REF REF REF REF REF REF REF REF REC USE CODE 341A 343A REF INDEX MFR TOT DESIG NO DESCRIPTION PART NO QTY CR52 H2 R5 Diode silicon 1 amp 600 piv 4802 112383 05277 1N4822 Fig 5 4 CR53 D3 U4 Diode silicon 350 ma 3000 piv 4801 246652 17545 35ST3 Fig 5 4 CR54 D1 U4 Diode silicon 350 ma 3000 piv 4801 246652 17545 35ST3 Fig 5 4 CR55 G3 R5 Diode zener 10v Fig 5 4 4809 246611 07910 1N961B CR56 D3 M4 Diode silicon 150 ma Fig 5 5 4805 203323 03508 DHD1105 CR57 D2 M4 Diode silicon 150 ma Fig 5 5 4805 203323 03508 DHD1105 CR59 D1 V4 Diode silicon 1 amp 100 piv 4802 116111 05277 1N4817 Fig 5 5 CR60 G4 N2 Diode silicon 1 amp 600 piv 4802 112383 05277 1N4822 Fig 5 4 CR61 F5 N2 Diode silicon 1 amp 600 piv 4802 112383 05277 1N4822 Fig 5 4 CR64 H4 R3 Diode zener 6 2v Fig 5 5 4809 180497 07910 1N753 1 CR65 HM R4 Diode silicon amp 100 piv 4802 116111 05277 1N4817 REF Fig 5 5 CR66 D1 P2 Diode zener 10v Fig 5 4 4809 246611 07910 1N961B CR67 4 01 Diode silicon 150 Fig 5 4 4805 203323 03508 DHD1105 CR68 IC3 Q2 Diode silicon 1 amp 100 piv 4802 116111 05277 1N4817 IREF Fig 5 4 CR
32. 2 16 Using The Nomograph With a straight edge connect the point representing output current on scale 1 to the point representing the gauge of the connecting wires on scale 2 The voltage developed in the connecting wires expressed in millivolts per foot is read on scale 3 To determine the total voltage developed in the connecting leads multiply the total length in feet by the value ob tained from scale 3 For example assume that two AWG 21 2 2 Mechanical zero adjust RANGE switch Power ON indicator FUNCTION switch FUNCTION Sets the meter mechanical zero Adjust only after instrument has been turned off for at least 3 minutes Selects one of three full scale voltage ranges 10 100 or 1000 volts de illuminates when instrument is fully operable Controls instrument input power and output monitoring functions In STANDBY RESET position all circuitry except the high voltage power supply is energized In power ON position the instrument is fully operable When instrument is ON output voltage is moni tored in METER VOLTAGE position nd output current in METER CURRENT position LIMIT ON indicator Hluminates when the controlled current limiter is activated When lit output current is limited to a preset value Figure 2 1 CONTROLS TERMINALS AND INDICATORS Sheet 1 of 2 341A 343A FUNCTION CURRENT LIMIT Sets operating point of controlled current limiter which limits max con
33. 257253 5105 257253 5105 257253 5105 257253 5105 257253 REF REF REF REF REF REF REF REF REF REF REF REF REF REF REF REC USE CODE R1 R4 R R8 R9 and R12 thru R25 part of an intermatched resistor The resistors may be replaced individually by giving model serial number full reference set part number 4710 265330 See gt gt page 5 41 designation and all markings on the old resistor be ordered and replaced as a pair However R12 R13 must 5 9 SERIAL NUMBER EFFECTIVITY 5 10 Use Code column is provided to identify certain parts that have been added deleted or modified during production of the Model 341A and 343A Each part for which a use code has been assigned may be identified with a particular instrument serial number by consulting the Use Code Effectivity List below All parts with no code are used on all instruments with serial numbers above 123 USE CODE EFFECTIVITY NO Model 341A serial number 123 and on CODE Model 343A serial number 123 and on 341A 343A 545 REV 4 1 80 Section 7 General Information 7 l This section of the manual contains generalized user information as well as supplemental information to the List of Replaceable Parts contained in Section 5 The following information is presented in this section List of Abbreviations Federal Supply Codes for Manufacturers Fluke Technical Serv
34. 26M 19 1 24 Fig 5 4 4704 246801 4706 246835 4704 246801 4704 246801 4704 153122 4704 221903 4704 153122 4704 153122 4704 221903 4704 221903 47104 153122 4704 221903 4704 108910 4704 148098 4704 150177 4705 150938 47105 247767 4705 233874 4705 221564 4705 221564 01121 91637 01121 01121 01121 01121 01121 01121 01121 01121 01121 01121 01121 01121 01121 19701 19701 19701 19701 19701 PART NO HB3941 Type CW10 HB3941 HB3941 GB1545 CB6215 GB1545 GB1545 CB6215 CB6215 GB1545 CB6215 1525 6825 1545 MF7C MF7C MF7C MF7C Type REC QTY QTY REF REF REF REF REF REF REF REF REF REF 341A 343A USE CODE 5 21 341A 343A REF DESIG R78 R79 R81 R82 R83 R84 R85 R86 R87 R88 R89 R90 R91 R92 R93 R94 R95 R96 5 22 INDEX NO B5 Pi J5 V2 42 05 43 55 Ci V2 B3 V1 B3 R5 D3 P3 G4 Q1 E5 Q4 D5 Qi H1 R5 G4 R5 F5 R1 D4 Q1 H1 Q5 43 03 J4 V1 H3 R5 1 84 DESCRIPTION Res met flm 1M 219 1 2w Fig 5 4 Res comp 6202 45 1 4w Fig 5 5 Res comp 6209 595 1 4w Fig 5 5 Res comp 2k 595 1 2w Fig 5 5 Res ww 1k 45 5w Fig 5 4
35. 4 51 Controlled Current Limiter 4 12 45 gota sae ie seme eee ewe ue 4 4 12 4 55 High Voltage Power 4 12 457 Stine y y a ipie s 4 13 4 59 ERO Ne a 4 13 4 61 Model 341A 4 14 4 63 Preliminary 4 14 4 64 Reference Voltage 4 14 4 65 Zero Output 4 14 4 66 Beta String Linearity 4 14 4 67 Range Adjustments 4 14 4 68 Calibration Verification 4 15 continued on page iii 341A 343A TABLE OF CONTENTS continued Section Title Page 4 70 Model 343A Preliminary 4 15 4 72 Preliminary Operations 4 15 4 73 Reference Voltage Adjustment 4 16 4 74 Output 5 4 16 4 75 Beta String Linearity 4 16 476 Temperature 4 17 4 77 Model 343A Final Calibration 4 17 4 79 Zero Output 447 4 80 Beta String Linearity
36. 5 4 17 4 83 Range Adjustments 4 19 4 84 Calibration Verifications 4 20 LIST OF REPLACEABLE PARTS 5 1 5 1 l troducti n T c 5 1 5 3 Column Description 501 Eee et Bolte ated 5 1 5 5 How To Obtain Pate l ence wp aia xA Rene Kee es 5 2 5 8 List of Abbreviations 5 2 5 9 Serial Number Effectivity 5 45 7 GENERAL INFORMATION 7 1 8 SCHEMATIC DIAGRAMS 8 1 ili 341A 343A Figure Frontispiece 46 47 48 49 4 10 441 442 412 LIST OF ILLUSTRATIONS Title Model 341A and Model 343A DC Voltage Calibrators Model 341A 343A Outline Drawing Controls Terminals and Indicators Sheet 1 of 2 Controls Terminals and Indicators Sheet 20f 2 Nomograph of Voltage Drop in Load Wires Differential Voltmeter Operation asa 10 ppm Source Model 341A 343A Block Diagram Basic Instrument Test and Calibration Equipment Model 341A Adjustment 5 Model 343A Adjustment
37. 5 4 amp 5 5 Figure 5 6 See Figure 5 7 Cap 1 uf 3v Diode silicon 1 amp 100 piv 4802 116111 Meter 0 1 0v 0 30 ma 2901 246942 Res var comp 5k 10 3w 4701 247031 Res comp 12 595 1 2w 4704 218693 Switch rotary Decade 1 Switch rotary FUNCTION 5105 257261 Switch rotary RANGE Switch section decks amp 5105 257212 Transformer power 5602 240465 Bail tilt down not illustrated 3154 231407 Cover bottom not illustrated 3156 240382 Cover top not illustrated 3156 240374 Detent switch 51 5105 257287 Detent switch 52 thru 56 5105 257295 Detent switch 59 5105 257279 Foot not illustrated 3155 230037 Shaft extension S2 thru S6 3155 240457 1501 106567 REF INDEX STOCK MFR Main P C Assembly See Figures 1702 240143 89536 1702 240143 Reference P C Assembly See 3158 240101 89536 3158 240101 Sample String P C Assembly 3158 263012 89536 3158 263012 Cap oil 1 uf 10 1500v 1505 247023 56289 264P70 HCC3105P Cap piste 0 047 uf 20 1600v 1507 246694 84411 Type 663 UW 05277 4817 2901 246942 71450 3215502 01121 EB10G5 Switch section decks A amp B 5105 257238 89536 5105 257238 Switch section decks C amp D 5105 257246 89536 5105 257246 5105 257261 89536 5105 257212 Switch section decks C amp D 5105 257220 89536 5
38. 5 5 Res comp 22k 25 1 2w Fig 5 5 Res met fim 253k 21 1 2w Fig 5 5 Res met fim 243k 41 1 2w Fig 5 5 Res comp 22k 45 1 2w Fig 5 5 4705 159467 4705 151241 4705 151175 4705 151241 4704 148031 4704 147959 4704 221598 4704 193482 4704 148130 4104 208389 4705 151258 4705 218685 4105 176388 4704 108738 4704 108431 4704 148130 4704 186064 4705 247452 4705 247452 4704 186064 L WERE oL I TERRE EER OEA 19701 19701 19701 19701 01121 01121 01121 01121 19701 19701 01121 19701 01121 01121 01121 01121 01121 01121 19701 Type Type Type Type MF7C CB1525 CB2215 CB1335 CB2015 CB2235 CB3355 Type Type MF7C Type MF7C EB4735 841 CB2235 EB2235 Type Type MF7C EB2235 Euer PART NO QTY 341A 343A 5 25 341A 343A REF INDEX DESIG NO R157 13 N2 R158 I3 N1 R159 J3 M3 R160 J4 M5 R161 01 82 R162 H1 St R163 G2 R2 R164 F4 R2 R165 G3 M4 R166 D5 T5 R167 E1 T5 R168 G4 M5 R169 F2 M5 R170 E3 T1 E2 T2 E1 T2 R173 F2 S5 03 85 R178 C4 U2 R179 c4 U1 5 26 DESCRIPTION Res comp 22k 5 1 2w Fig 5 5 Res comp 8 2k 5 1 2w Fig 5 5 Res comp 15k 5 1 4w Fig 5 5
39. Res comp 7502 5 1 4w Fig 5 4 Res comp 7500 559 1 4w Fig 5 4 Res ww 2k 45 10 Fig 5 4 Res comp 5 10 5 lw 5 4 Res comp 12k 5 1 4w Fig 5 4 Res comp 2 2k 10 1w Fig 5 4 Res met flm 169k 1 1 2w Fig 5 4 Res met ilm 9 09k 41 1 2w Fig 5 4 Res comp 15k 5 1 4w Fig 5 4 Res comp 1 8k 10 2w Fig 5 4 Res comp 18k 5 1 4w Fig 5 4 Res comp 390k 10 2w Fig 5 4 Res comp 390k 41005 2w Fig 5 4 Res comp 339 45 1 4w Fig 5 4 Res ww 200k 45 10 Fig 5 4 STOCK NO 4705 161075 4704 221903 4704 221903 4704 169854 4106 246835 4704 218024 4704 218024 4 106 246843 4704 219071 4704 159731 4704 109843 4705 176206 4705 151258 4704 148114 4704 185983 47104 148122 4704 246801 4704 246801 4704 175034 4706 246850 MFR 19701 01121 01121 01121 91637 01121 01121 91637 01121 01121 01121 19701 19701 01121 01121 01121 01121 01121 01121 91637 MFR Type MF7C 1 CB6215 REF CB6215 REF EB2025 1 CB7515 2 CB7515 REF Type CW10 1 GB51G5 1 CB1235 1 GB2221 1 Type 2 Type 2 CB1535 4 HB1821 1 CB1835 2 HB3941 REF HB3941 REF CB3305 1 Type CW10 2 USE PART QTY QTY CODE REF DESIG
40. STEP 4 VOLTAGE DIAL RANGE POSITION OPERATION 100 40 00000 Adjust DECK A 4 to within 30 uv of step s 100 5X 00000 Record voltage indication within 30 uv Adjust DECK A 6 to within 40 uv of step u 100 60 00000 100 7X 00000 Record voltage indication within 40 uv Adjust DECK A 8 to within 40 uv of step w 100 80 00000 100 9X 00000 Record voltage indication within 60 uv Adjust DECK A 10 to within 60 uv of step y 100 100 00000 Figure 4 12 MODEL 343A PRELIMINARY LINEARITY ADJUSTMENTS Sheet 2 of 2 4 76 TEMPERATURE STABILIZATION a Install all instrument covers b Set RANGE to 100 and voltage dials to 100 00000 Operate the instrument continuously for at least 2 hours in an ambient temperature of 23 C 10 prior to beginning final calibration 477 MODEL 343A FINAL CALIBRATION 4 78 Final calibration of the Model 343A consists of the tests and adjustments of paragraphs 4 79 through 4 84 Calibration should be completed without interruption and control positions should be maintained from step to step unless otherwise instructed 4 79 NOTE Ensure that the ambient temperature condi tions specified in paragraph 4 76 are maintained throughout the remainder of the Model 343A calibration ZERO OUTPUT ADJUSTMENTS Unfasten the top cover and slide back just far enough to expose the beta string calibration controls 4 80 4 81 341A 343A C
41. STRING LINEARITY ADJUSTMENTS Set RANGE switch to 1000 and connect the 895A to the Model 343A OUTPUT terminals with the Model 343A negative OUTPUT terminal connected to chassis ground b STEP Qe Set the Model 343A controls as shown in Figure 4 12 and perform the indicated operations VOLTAGE DIAL RANGE OPERATION POSITION 00X 0000 Record voltage indication within 10 uv Adjust DECK B 1 to within 10 uv of step c Record voltage indication within 30 uv Adjust DECK B 2 to within 30 uv of step e 1000 010 0000 1000 01X 0000 1000 020 0000 1000 03X 0000 Record voltage indication within 30 uv Adjust DECK B 4 to within 30 uv of step g Record voltage indication within 30 uv Adjust DECK B 6 to within 40 uv of step i 1000 040 0000 1000 05X 0000 1000 060 0000 1000 07X 0000 Record voltage indication within 40 uv Adjust DECK B 8 to within 40 uv of step k 1000 080 0000 1000 09 0000 Record voltage indication within 60 uv 0X0 0000 Adjust DECK B X to within 60 uv of step m 100 0X 00000 Record voltage indication within 10 uv Adjust DECK A 1 to within 10 uv of step o 100 10 00000 100 1X 00000 Record vottage indication within 30 uv Adjust DECK A 2 to within 30 uv of step q Record voltage indication within 30 uv Figure 4 12 MODEL 343A PRELIMINARY LINEARITY ADJUSTMENTS Sheet 1 of 2 100 20 00000 100 3X 00000
42. The 895A should indicate a voltage change of less than 75 microvolts Remove the 400 ohm resistor Set the RANGE switch to 100 and the voltage dials to 100 0000 100 00000 on Model 343A Record the voltage indicated by the 895A Connect a 4k 5 10 watt resistor to the OUTPUT terminals The 895A should indicate a voltage change of less than 525 microvolts Remove the 4 k resistor Set the RANGE switch to 1000 and the voltage dials to 1000 000 1000 0000 on the Model 343A Record the voltage indicated by the 895A VOLTAGE DIALS 10 00000 341A 10 000000 343A 100 0000 341A 100 00000 343A 1000 000 341A 1000 0000 343A 10 100 1000 341A 343A Connect a 40k 595 50 watt resistor to the OUTPUT terminals The 895A should indicate a voltage change of less than 5 millivolts Repeat steps a through m for line voltages of 103 5 volts ac and 126 5 volts ac FAULT ANALYSIS If load regulation is poor check for proper operation of the preamplifier and chopper amplifier as described in paragraph 4 45 and 4 47 Also ensure that SENSE terminals are connected properly See paragraph 2 14 4 30 4 31 RIPPLE The ripple test determines if the ac ripple present on the instrument dc output is within specified limits a 115 VAC 50 60 HZ LINE Install top and bottom instrument covers and con nect OUTPUT to chassis ground Connect the preamplifier to the OUTPUT terminals and connect
43. and is normally supplied with connections for 115 volt use Dual primary windings in the power trans former permit ready conversion from one operating voltage to the other The conversion procedure is described in sec tion IV paragraph 4 18 2 10 PRELIMINARY OPERATION 211 The following paragraphs describe preliminary connections control settings adjustments and safety pre cautions which should be observed before operating the instrument 2 12 AC LINE CONNECTIONS 2 13 Connect the Model 341 343 line plug to a 115 volt ac or to 230 volts ac if the instrument is so wired 50 to 440 Hz single phase three wire outlet WARNING The round pin on the polarized three prong plug connects the instrument case to power system ground Verify that the ac outlet is pro vided with the earth ground wire normally found in a three wire single phase connector If the third wire is not present in the outlet or if a three to two wire adapter is used ensure that the instrument ground wire is connected to a high quality earth ground 2 14 SENSE CONNECTIONS 2 15 When a load is connected to the Model 341A 343A there may be an appreciable voltage drop between the instrument and the load due to the resistance of the connecting leads The nomograph shown in Figure 2 2 can be used to determine the approximate voltage de veloped in the leads If the voltage drop is excessive the instrument can then be connected for remote sensing
44. matched Res var cermet 2000 22005 3 4w Res ww 99 955k matched ww 99 955k matched VV var cermet 2002 420 3 4w Type 78P ww 99 955k matched VV ww 99 955k matched var cermet 2009 20 3 4w ww 99 955k matched VV ww 99 955k matched 5 39 341A 343A Figure 5 11 REFERENCE P C ASSEMBLY 343A 5 40 REF DESIG INDEX NO Res Res Res Res Res Res Res DESCRIPTION var var var var ww var cermet 2009 420 3 4w ww 10k 10 1 1 4w ww 10k 510 1 1 4w ww 10k 510 1 1 4w 99 955k matched cermet 1000 420 3 4w comp 330k 595 lw 4713 186213 4702 162115 4702 162115 4702 162115 4113 159889 4104 109777 71450 71450 71450 73138 01121 Type 78P Type 110 Type 110 Type 110 Type 78P GB3345 L PART NO 341A 343A number 4710 265330 serial number full reference designation However R9 R10 R12 R13 R15 R16 R18 R19 and R21 R22 must be ordered and replaced in pairs R2 R4 R8 R9 R10 R12 R13 R15 R16 R18 R19 R21 R22 R27 and A5R1 ASR4 A5R5 A5R8 5 9 and A5R12 thru A5R25 an intermatched resistor set part The resistors may be replaced individually by giving model and all marki
45. rotary Dec de 2 Switch rotary Decade 3 Switch rotary Decade 4 Switch rotary Decade 5 Switch rotary Decade 6 STOCK NO 4107 248724 4707 248757 4707 248740 4707 248740 4707 248740 4707 248740 4707 248740 4705 187781 47105 148890 5105 257253 5105 257253 5105 257253 5105 257253 5105 257253 MFR 01686 01686 01686 01686 01686 01686 01686 19701 19701 89536 89536 89536 89536 89536 MFR TOT PART NO QTY Type T2 Type T2 Type T2 Type T2 Type T2 Type T2 Type T2 Type MF7C Type MF7C 5105 257253 5105 257253 5105 257253 5105 257253 5105 257253 REF REF REF REF REF 1 1 5 REF REF REF REF DE Thru R12 are part an intermatched resistor set part number 4710 252445 Gee REC 5 30 The resistors may be replaced individually by giving model serial number full reference designation and all markings on the old resistor when ordering 341A 343A USE CODE 5 33 341A 343A 5 34 DESCRIPTION DC VOLTAGE CALIBRATOR Figure 5 8 Front Panel Assembly See Figure 5 9 Rear Panel Assembly See Figure 5 10 Main P C Assembly See Figures 5 4 amp 5 5 Reference P C Assembly See Figure 5 11 Sample String P C Assembly See Figure 5 12 Cap oil luf 10 1500v Cap cer Luf gmv 3v Diode silicon 1 amp 100 piv Meter 0 1 Ov 0 30 ma Res var comp 5k 10 3w Res comp 19 5 1 2w
46. the 931B true rms voltmeter to the output of the preamplifier Set the FUNCTION switch to on and set the RANGE switch and voltage dials as shown in Figure 4 5 The rms ripple should not exceed the values shown MAXIMUM RIPPLE 115 VAC 400 HZ LINE 50 uv 50 uv Figure 4 5 RIPPLE SPECIFICATIONS 47 341A 343A d Remove the 931B from the output of the preampli fier and connect the oscilloscope in its place e Repeat step c The p p ripple should not exceed the values shown FAULT ANALYSIS 4 If ripple is excessive check for ground loops in equipment connections and check for proper operation of the preamplifier and chopper amplifier paragraphs 4 45 and 4 47 4 32 OUTPUT VOLTAGE ACCURACY 4 33 the instrument has successfully passed the line load and ripple tests it can be assumed to be operating correctly The output voltage accuracy test compares the instrument output voltage to the accuracy specifica tions given in Section I 434 Model 341A Output Voltage Test a Connect the 895A to the Model 341A OUTPUT terminals with the negative OUTPUT terminal con nected to chassis ground b Set the Model 341A controls as shown in Figure 4 11 The output voltages should be as indicated in column 2 FAULT ANALYSIS If output voltages are incorrect check the 15 volt reference adjustment paragraph 4 64 the zero output adjustments paragraph 4 65 the r
47. the voltage across 34 CR48 exceeds 8 volts When the voltage across CR48 drops below 8 volts Q13 conducts cutoff bias is applied to O12 and the current limiter is activated The purpose of Q13 is covered in the control circuit discussion paragraph 3 36 3 26 The current limit lamp driver turns on the current limit light whenever the controlled current limiter is activa ted When the current through Q12 is reduced at the be ginning of the current limit operation the current in Q11 increases The current change in O11 is amplified by Q9 which turns on switch Q7 lighting the current limit lamp DSI 3 27 NEGATIVE VOLTAGE LIMITER 3 28 negative voltage limiter consists of a two stage inverting amplifier O5 Q6 and a coupling diode Q4 The limiter is connected between the output and input of the chopper stabilized amplifier When the output of the chopper stabilized araplifier attempts to go more negative than approximately 2 5 volts transistor Q6 conducts hard enough to turn on Q5 and current flows from the 15 volt supply through Q5 through the coupling diode 04 and into the summing junction at the input to the amplifier This limiting current balances the input refer ence and beta string currents thereby limiting the output of the amplifier to approximately 2 5 volts Coupling diode Q4 and resistor R52 are used to limit the effects of leakage current Q5 Resistor R51 and capacitor C14 control the frequenc
48. to STANDBY RESET voltage is applied to the control circuit to the 15 volt reference supply and to the auxiliary power supplies At this time the high voltage is disabled by contacts KIA of the high voltage relay and the instrument output terminals are shorted by contacts K1B of the high voltage relay which prevents any uncontrolled voltage from appearing on the output terminals while the amplifiers are stabilizing Rectified voltage for the control circuit is provided by CR26 CR27 and CR24 This voltage is applied to the base of 51 through a time constant circuit consisting of R86 and C25 thus delaying turn on of 051 for to 5 seconds This delay ensures that the auxiliary power supplies will be on and stabilized before high voltage is applied The delayed voltage then turns on Q51 and Q27 The other input to the AND gate is controlled by the FUNCTION switch and is not present until the FUNCTION switch is set to ON A positive voltage is then applied through R87 to the base of 026 turning it on The high voltage relay then operates high voltage is applied to the main rectifier and filter and normal operation ensues The purpose of diode CR68 is to discharge C25 quickly in the event of power failure or other interruption of main power thus assuring a full 3 to 5 second delay cycle 3 36 In the STANDBY RESET condition the series regulator is cut off to ensure that the main control ampli fier is within its linear operating range
49. 000 VOLTAGE DIAL POSITION OPERATION Record voltage indication within 10 uv Adjust 10V LINEARITY to within 50 uv of step c Record voltage indication within 40 uv Adjust 20V LINEARITY to within 70 uv of step e Record voltage indication within 40 uv Adjust 40V LINEARITY to within 70 uv of step g Record voltage indication within 40 uv Adjust 60V LINEARITY to within 70 uv of step i Record voltage indication within 40 uv Adjust 80V LINEARITY to within 70 uv of step Record voltage indication within 40 uv Adjust 100V LINEARITY to within 70 uv of step m 0000 10 0000 1X 0000 20 0000 3X 0000 40 0000 5X 0000 60 0000 7X 0000 80 0000 9X 0000 100 0000 Figure 4 10 341A LINEARITY ADJUSTMENTS c Adjust 10 RANGE ADJUST for 10 0 00003 volts indication on the 895A d Set RANGE switch to 100 and adjust 100V RANGE ADJUST for 100 0 0004 volts indication on the 895A Set RANGE switch to 1000 and adjust 1000V RANGE ADJUST for 1000 40 004 volts indication on the 895A 4 68 CALIBRATION VERIFICATION 4 69 following measurements should be made immediately following the range adjustments paragraph 4 67 3 Connect the 895A to the OUTPUT terminals with the Model 341A negative OUTPUT terminal con nected to chassis ground NOTE Use the same 895A that was used for the range adjustme
50. 105 257220 5602 240465 89536 3154 231407 89536 3156 240382 89536 3156 240374 5105 257287 5105 257295 89536 5105 257279 3155 230037 3155 240457 Y 341A 343A QTY 5 3 341A 343A 5 4 Figure 5 1 341A DC VOL TAGE CALIBRATOR Sheet 1 of 2 341A 343A 8 AB R177 C862 5 places C66 CRES 341A 343A REF INDEX STOCK MFR TOT REC USE DESIG DESCRIPTION PARTNO FRONT PANEL ASSEMBLY 341A Figure 5 2 Lamp incandescent 28v 3901 246686 08806 7387 5 2 Binding post red 2811 226308 58474 DF21RC 2 Binding post black 2811 226282 58474 DF2iBC 2 Binding post white 2811 261156 58474 DF21WTC 1 Holder lamp 3155 252411 89536 3155 252411 5 Handle 2404 246306 89536 2404 246306 2 Knob CURRENT LIMIT 2405 190249 89536 2405 190249 1 Knob DIGIT 0 X 3155 252353 89536 3155 252353 5 Knob DIGIT 0 10 3155 252361 89536 3155 252361 1 Knob FUNCTION RANGE 2405 158956 89536 2405 158956 2 Lens lamp clear 3155 222596 89536 3155 222596 3 Lens lamp red 3155 228056 89536 3155 228056 2 Link Shorting 2811 101220 24655 0938 9712 3 Panel Front 1406 240267 89536 1406 240267 1 XDS6 XDS7 DS6 DS7 9 14 11 11 11 11 2 9 13 15
51. 19 218396 04713 Fig 5 5 Tstr silicon NPN 4819 218396 04713 Fig 5 5 Tstr silicon NPN 4819 150359 95303 Fig 5 4 Tstr silicon NPN 4819 150359 95303 Fig 5 4 Tstr silicon NPN 4819 218396 04713 Fig 5 4 Tstr silicon NPN 4819 218396 04713 Fig 5 4 Tstr silicon NPN 4819 218511 95303 Fig 5 4 Tstr silicon NPN 4819 218511 95303 Fig 5 4 Tstr silicon NPN 4819 218396 04713 Fig 5 5 Tstr silicon PNP 4818 195974 04713 Fig 5 5 Tstr silicon PNP 4818 195974 04713 Fig 5 5 Tstr Dual FET N channel 4828 248005 05397 Fig 5 5 Tstr silicon PNP 4818 225599 07263 Fig 5 5 Tstr silicon PNP 4818 195974 04713 Fig 5 5 Tstr FET N channel 4826 257121 07263 Fig 5 5 Tstr MOS FET P channel 4831 226043 07263 Fig 5 5 2N3904 SM4144 2N3906 CDQ10656 2N3904 2N3904 2N3053 2N3053 2N3904 2N3904 40327 40321 2N3904 2N3906 2N3906 2N3958 5 22650 253906 FE0654C FT704 341A 343A 341A 343A INDEX NO DESCRIPTION STOCK NO MFR K3 V1 K3 U3 K3 T4 K3 S1 K3 Q2 K3 N3 Tstr silicon NPN Fig 5 5 Tstr silicon NPN Fig 5 5 Tstr silicon NPN Fig 5 5 Tstr silicon NPN Fig 5 5 Tstr silicon NPN Fig 5 5 Tstr silicon NPN Fig 5
52. 332B dials for zero 40 uv on the 845AR Adiust DECK A 8 for an 845AR indication within 40 uv of step k Adjust the 3328 dials for zero 40 uv on the 845AR Adjust DECK A10 for indication within 40 uv of step m d 10 00000 10 0000 e 20 00000 1x 0000 f 20 00000 20 0000 9 40 00000 3X 0000 h 40 00000 40 0000 i 60 00000 5X 0000 j 60 00000 60 0000 k 80 00000 7X 0000 80 00000 80 0000 m 100 00000 9X 0000 100 00000 Figure 4 15 LINEARITY ADJUSTMENTS DECK A 4 83 Set Model 343A and 332B voltage controls for zero volts output RANGE ADJUSTMENTS Connect equipment as shown in Figure 4 16 Set the Model 343A controls as follows RANGE 10 Voltage dials 10 000000 CURRENT LIMIT Approximately 5 ma Set the 750A input and output switches to 10 341A 343A Adjust the 332B controls for 10 volts output Set the 750A standard cell circuit switch to MOMEN TARY and adjust the 332B controls for zero t1 microvolt on 845AR No 1 Adjust the 10V RANGE ADJUST control for zero 10 microvolts on 845AR No 2 Set the Model 343A RANGE to 100 and voltage dials to 100 00000 Set the 750A input and output switches to 100 Adjust the 332B controls for 100 volts output MODEL 750A t MODEL 3328 SIMPLIFIED MODEL 343A 5555555 MODEL 845 NO 2 MODEL 343A MODEL 3328 Figure 4 16 RANGE ADJUSTMENT AND CALIBRATION
53. 5 Tstr silicon NPN 5 5 Tstr silicon NPN Fig 5 4 Res comp 100 45 1 4w Fig 5 4 Res comp 109 259 1 4w Fig 5 4 Res comp 3900 45 1 2w Fig 5 5 Res comp 27k 595 1 4w Fig 5 5 Res comp 5 6k 5 1 2w Fig 5 5 Res comp 229 259 1 2w Fig 5 5 Res comp 75k 5 1 2w Fig 5 5 Res comp 7 5k 5 1 2w Fig 5 5 Res comp 33k 45 1 4w Fig 5 5 Res met flm 15k 10 1 2w Fig 5 5 Res met flm 15k 1 1 2w Fig 5 5 Res comp 2k 5 1 4w Fig 5 5 4819 203489 4819 203489 4819 218511 4819 218511 4819 218511 4819 218511 4819 218396 4819 218396 4704 147868 4704 147868 4 104 109082 4704 148148 4704 187880 4704 169847 4704 108928 4704 108910 4704 148155 4705 151498 4705 151498 4704 202879 07910 07910 95303 95303 95303 95303 04713 04713 01121 01121 01121 01121 01121 01121 01121 01121 01121 19701 19701 01121 MFR PART NO CDQ10656 CDQ10656 40327 40327 40321 40327 2N3904 2N3904 CB1005 1005 EB3915 CB2735 EB5625 EB2205 535 EB7525 CB3335 Type Type MF7C CB2025 REF IREF EF EF R13 R14 R15 R16 R17 R18 R19 R20 R21 R22 R23 R24 R25 R26 R28 R29 C1 R4 C1 Q4 B4 R2 B4
54. 5 1 CB 535 i Type 1 Type MF7C 1 Type MF7C 1 CB1035 3 Type 1 Type MF7C 1 Type 110 1 Type 1 CB27G5 1 EB8225 2 CB1035 REF 2 5125 4 341A 343A USE CODE 341A 343A DESCRIPTION 5 20 Res comp 16k 45 1 2w Fig 5 5 Res comp 5 1k 25 1 2w Fig 5 5 Res comp 15k 10 1 2w Fig 5 5 Res comp 752 559 1 2w Fig 5 5 Res comp 750 25 1 2w Fig 5 5 Res met flm lik 51 1 2w Fig 5 5 Res comp 5 1k 595 1 2w Fig 5 5 Res comp 5 1k 595 1 2w Fig 5 5 Res met flm 34 8k 1 1 8w Fig 5 5 Res comp 5 1k 595 1 4w Fig 5 5 Res comp 3 9k 595 1 4w Fig 5 5 Res comp 8 20 595 1 4w Fig 5 5 Res comp 8 2k 595 1 4w Fig 5 5 Res comp 4 7k 45 1 4w Fig 5 5 Res comp 5 1k 5 1 4w Fig 5 5 Res comp 2k 5 1 4w 5 5 Res comp 27k 5 1 4w Fig 5 5 Res comp 202 45 1 4w Fig 5 5 Res comp 2k 5 1 4w Fig 5 5 Res comp 390k 10 2w Fig 5 4 ND MFR QTY 4104 159632 01121 EB1635 1 4704 109108 01121 5125 REF 4104 108530 01121 EB1531 1 4704 108753 01121 EB7505 2 4104 108753 01121 505 REF 4705 222216 19701 Type REF 4104 109108 01121
55. 5274 341 A 343A DC Voltage Calibrators Instruction Manual WARRANTY Notwithstanding any provision of any agreement the following warranty is exclusive The JOHN FLUKE MFG CO INC warrants each instrument it manufactures to be free from defects in material and workmanship under normal use and service for the period of 1 year from date of purchase This warranty extends only to the original purchaser This warranty shail not apply to fuses disposable batteries rechargeable type batteries are warranted for 90 days or any product or parts which have been subject to misuse neglect accident or abnormal conditions of operations In the event of failure of a product covered by this warranty John Fluke Mfg Co Inc will repair and calibrate an instrument returned to an authorized Service Facility within 1 year of the original purchase provided the warrantor s examination discloses to its satisfaction that the product was defective The warrantor may at its option replace the product in lieu of repair With regard to any instrument returned within 1 year of the original purchase said repairs or replacement will be made without charge If the failure has been caused by misuse neglect accident or abnormal conditions of operations repairs will be billed at a nominal cost In such case an estimate will be submitted before work is started if requested THE FOREGOING WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES EXPRESS OR IMPLI
56. 5C334K TE1089 TE1089 TE1158 TE1158 TE1202 CD15C050K CD15F221J REF REF REF REF REF REF 341A 343A 341A 343A TOTI REC USE F PESCRIPTION MER PART QTYIQTY CODE Cap mica 100 pf 45 500v 1504 148494 14655 CD15F101J 2 Fig 5 5 mica 620 pf 5 500v 1504 215244 14655 CD19F621J 1 Fig 5 5 Cap elect 5 uf 75 10 25v 1502 152009 80183 1202 REF Fig 5 5 Cap elect 100 uf 75 10 3v 1502 106534 80183 TE1059 5 2 Fig 5 5 F1 R1 Cap elect 50 uf 50 10 25v 1502 168823 73445 C426ARF50 1 Fig 5 5 E4 R5 Cap elect 100 uf 75 10 3v 1502 106534 80183 TE1059 5 REF Fig 5 5 D5 S3 Cap plste 0 047 uf 20 200v 1507 162008 73445 C280AE L Fig 5 5 P4TK E2 U3 Cap plstc 0 1 uf 20 250v 1507 161992 73445 C280AE REF Fig 5 5 P100K G2 M5 Cap cer 0 01 uf gmv 1 6 kv 1501 106930 71590 DD16 103 4 Fig 5 4 J5 U2 Cap cer 0 0012 uf 1095 500v 1501 106732 71590 CF 22 1 Fig 5 5 B4 U3 Cap 0 01 uf gmv 1 6kv 1501 106930 71590 DD16 103 REF Fig 5 4 A5 V1 Cap cer 0 01 uf 1 6kv 1501 106930 71590 DD16 103 REF Fig 5 4 H3 V1 Cap 0 005 uf 20 3kv 1501 188003 71590 2DDH6R502M 1 Fig 5 4 G3 U3 Cap elect 80 uf 50 10 450v 1502 246819 56289 Type 68D REF Fig 5 4 F3 T1 Cap elect
57. 69 K1 V3 Diode silicon 1 amp 100 piv 4802 116111 05277 1N4817 IREF Fig 5 5 CR70 jCi T3 Diode silicon 150 ma 6 piv 4805 113308 07910 CD13161 Fig 5 5 251 1 5 Lamp neon Figure 5 4 3902 100347 71744 NE2E DS2 C5 P5 Lamp neon Figure 5 4 3902 100347 71744 NE2E D5 Q1 IC operational amplifier 3140 246603 04713 MC1709CG Fig 5 5 E1 N2 Relay dpdt 115v 15 amp 4504 246678 73949 245U2C24D Fig 5 4 K2 Relay Fig 5 4 Switch dry reed 5103 184440 DRVT1 Coil reed switch 24v 1802 186155 SP24P Relay Fig 5 4 Switch dry reed 5103 184440 DRVT1 Coil reed switch 24v 1802 186155 SP24P 5 15 341A 343A REF INDEX STOCK MER REC USE DESCRIPTION MER DESIG NO SCRIPTS NO PART NO QTY CODE EH G5 Q4 Choke RF 1 000 uh 140 ma 1801 147819 72259 WEE1000 Fig 5 4 Qi G2 S1 Tstr silicon NPN 4819 218396 04713 2N3904 14 3 Fig 5 5 92 F5 M3 Tstr silicon NPN 4819 218396 04713 2N3904 EF Fig 5 5 F1 M3 Tstr silicon NPN 4819 218396 04713 2N3904 REF Fig 5 5 Q4 E3 U2 Tstr silicon NPN 4819 179374 04713 2N2218 2 Fig 5 5 95 G4 Q3 Tstr silicon PNP 4818 195974 04713 2N3906 10 Fig 5 5 Q6 G4 R1 Tstr silicon NPN 4819 218396 04713 2N3904 REF Fig 5 5 97 21 52 Tstr silicon PNP 4818 190389 04713 SM4144 2 Fig 5 5 Q8 E3 T4 Tstr silic
58. 805 203323 DHD1105 Fig 5 5 Diode zener 18y 4809 113365 1N3026A Fig 5 5 Diode zener 12v 4809 249052 1N963B Fig 5 5 Diode zener 12v 4809 249052 1N963B Fig 5 5 Diode zener 6 8v 4809 166199 1754 Fig 5 5 Diode silicon 1 amp 100 piv 4802 116111 1N4817 Fig 5 4 Diode silicon 1 amp 100 piv 4802 116111 1N4817 Fig 5 4 5 11 341A 343A Figure 5 4 MAIN P C ASSEMBLY Left Hand Side 5 12 341A 343A Q N M 213 415 11212 415 1 212 415 1 2 3 4 5 1 23 5 13 MAIN P C ASSEMBLY Right Hand Side Figure 5 5 1 x 341A 343A REF INDEX ESCRIPTION DESIG NO p CR24 2 Diode silicon 1 amp 100 piv Fig 5 4 CR25 H2 P1 Diode silicon 1 amp 100 piv Fig 5 4 CR26 H2 Q1 Diode silicon 1 amp 100 piv Fig 5 4 CR27 H2 Q2 Diode silicon 1 amp 100 piv Fig 5 4 CR28 F2 R1 Diode zener 10v Fig 5 4 CR29 G4 R2 Diode thyristor Fig 5 4 CR30 F1 Q3 Diode silicon 1 amp 100 piv Fig 5 4 CR31 F1 Q5 Diode silicon 1 amp 100 piv Fig 5 4 CR32 C5 T5 Diode silicon 1 amp 600 piv Fig 5 4 CR33 C4 U4 Diode silicon 1 amp 600 piv Fig 5 4 CR34 2 51 Diode zener 16v Fig 5 4 CR35 C2 S1 Diode silicon 1 amp 600 piv Fig 5 4 D4 T1 Diode silicon 1 amp 100 piv Fig 5 5 CR38 D5 T1 Diode s
59. 845AR on the 1 microvolt range Set the Model 343A RANGE to 10 and voltage dials to zero The 845AR should indicate zero 5 micro volts Set the Model 343A RANGE to 100 The 845AR should indicate zero 5 microvolts Set the Model 343A RANGE to 1000 The 845AR should indicate zero 20 microvolts Calibration of the Model 343A is complete Set the FUNCTION switch to OFF and disconnect equip ment 343A 845AR NO 2 NULL TOLERANCE 1 000000 5 000000 10 000000 0X 00000 50 00000 100 00000 100 0000 500 0000 1000 0000 Figure 4 17 MODEL 343A OUTPUT VOLTAGE REQUIREMENTS 341A 343A SECTION LIST OF REPLACEABLE PARTS 5 1 INTRODUCTION 5 2 This section of the manual contains listing of replaceable components for this instrument The first listing contains a complete breakdown of all the major assemblies followed by subsequent listings that itemize the components on each major assembly illus tration accompanies each major assembly listing to aid in locating the listed components 5 3 Assemblies and subassemblies are identified by a reference designation beginning with the letter A fol lowed by a number e g Al Electrical components appearing on the schematic diagram are identified by their schematic diagram reference designation Compo nents not appearing on the schematic diagram are con secutively numbered throughout the parts list These components are identified with whole number
60. Adjust R26 for an 895A indication of 15 0 0001 volts dc Disconnect the 895A and position the top cover so that only the beta string calibration controls are ex posed ZERO OUTPUT ADJUSTMENTS Set Model 341A voltage dials to zero and connect the negative OUTPUT terminal to chassis ground Zero the 895A on the 1 volt range with null sensi tivity set to 100 microvolts then connect the 895A to the Model 341A OUTPUT terminals using low thermal copper leads Set RANGE switch to 10 and adjust the 10V ZERO ADJUST control for zero 5 microvolts indication on the 895A WARNING Use only an insulated tool for all adjustments within the beta string compartment Set RANGE switch to 100 and adjust the 100V ZERO ADJUST control for zero 10 microvolts indication on the 895A Set RANGE switch to 1000 and adjust the 1000V ZERO ADJUST control for zero 10 microvolts indication on the 895A BETA STRING LINEARITY ADJUSTMENTS Set RANGE switch to 100 and connect the 895A to the Model 341A OUTPUT terminals with the Model 341A negative OUTPUT terminal connected to chassis ground Set the Model 341A controls as shown in Figure 4 10 and perform the indicated operations step c through step n RANGE ADJUSTMENTS Connect the 895A to the OUTPUT terminals with the Model 341A negative OUTPUT terminal con nected to chassis ground Set the Model 341A controls as follows FUNCTION ON RANGE 10 Voltage dials 10 00
61. C2 Q4 Res ww 20k matched C5 Q4 Res ww 20k matched gt D2 Q4 Res ww 20k matched gt D4 Q4 Res ww 20k matched gt E5 Q4 Res ww 1k matched E1 Q4 Res ww 2k matched E4 Q4 Res ww 2k matched gt F1 Q4 Res ww 2k matched gt F3 Q4 Res ww 2k matched gt F3 Q4 Res ww 2k matched gt H4 Q4 Res ww 1009 0 03 1 2w 4707 155846 89536 4707 155846 1 G1 Q4 Res ww 2002 0 01 1 2w 4707 178988 89536 4707 178988 5 G3 Q4 Res ww 2009 0 01 1 2w 4707 178988 89536 4707 178988 REF G5 Q4 Res ww 2002 0 01 1 2w 4707 178988 89536 4707 178988 REF H1 Q4 Res ww 2002 0 01 1 2w 4707 178988 89536 4707 178988 REF H3 Q4 Res ww 2002 0 01 1 2w 4107 178988 89536 4707 178988 REF J3 Q5 Res ww 109 40 5 0 Tw 4707 248732 01686 Type T2 1 5 05 Res ww 209 40 5 0 7w 4707 248724 01686 Type T2 5 12 Q5 Res ww 200 0 5 0 7w 4701 248724 01686 Type T2 REF 14 Q5 Res ww 202 40 5 0 4707 248724 01686 Type 2 REF 15 Q5 Res ww 202 20 59 0 71 4707 248724 01686 Type T2 REF 5 31 341A 343A 5 32 Figure 5 7 R SAMPLE STRING P C ASSEMBLY 341A REF INDEX DESIG NO Res Res Res DESCRIPTION ww 202 20 59 0 7w ww 12 53 0 7w ww 22 43 0 71 ww 29 43 0 ww 20 43 0 ww 20 395 0 7w ww 22 43 0 Tw met flm 3 16k 51 1 2w met flm 4 99k 1 1 2w Switch
62. E USED ONLY GROUNDED TIP SOLDERING IRONS SHOULD BE USED Anti static bags for storing S S devices or pcbs with these devices on them can be ordered from the John Fluke Mfg Co Inc See section 5 any Fluke technical manual for ordering instructions Use the following part numbers when ordering these special bags John Fluke Part No Description 453522 6 X 8 Bag 453530 8 X 12 Bag 453548 16 X 24 Bag 454025 12 X 15 Bag Pink Poly Sheet Wrist Strap 30 x60 x60 Mil P N TL6 60 P N RC AS 1200 7 00 20 00 J00898 07U7810 SE EN Litho in U S A 341A 343A SECTION H OPERATING INSTRUCTIONS 2 1 INTRODUCTION 22 This section contains operating instructions and applications infromation for the Model 341A and Model 343A Voltage Calibrators Unless otherwise specified all instructions apply to both instruments 2 3 If any problem is encountered in operating the instrument contact the nearest John Fluke Sales Repre sentative or write directly to the John Fluke Manufactur ing Company Please include the instrument serial number when writing 24 OPERATING FEATURES 2 5 The following paragraphs describe instrument con trols and power requirements 2 6 CONTROLS TERMINALS AND INDICATORS 2 7 The name and function of the front and rear panel controls terminals and indicators are shown in Figure 2 1 2 8 INPUT POWER REQUIREMENTS 2 9 The instrument operates on either 115 or 230 volt ac power
63. ED INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY OF MERCHANTABILITY FITNESS OR ADEQUACY FOR ANY PARTICULAR PURPOSE OR USE JOHN FLUKE MFG CO INC SHALL NOT BE LIABLE FOR ANY SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES WHETHER IN CONTRACT TORT OR OTHERWISE any failure occurs the following steps should be taken 1 Notify the JOHN FLUKE MFG CO INC or nearest Service facility giving full details of the difficulty and include the model number type number and serial number On receipt of this information service data or shipping instructions will be forwarded to you 2 On receipt of the shipping instructions forward the instrument transportation prepaid Repairs will be made at the Service Facility and the instrument returned transportation prepaid SHIPPING TO MANUFACTURER FOR REPAIR OR ADJUSTMENT All shipments of JOHN FLUKE MFG INC instruments should be made via United Parcel Service or Best Way prepaid The instrument should be shipped in the original packing carton or if it is not available use any suitable container that is rigid and of adequate size If a substitute container is used the instrument should be wrapped in paper and surrounded with at least four inches of excelsior or similar shock absorbing material CLAIM FOR DAMAGE IN SHIPMENT TO ORIGINAL PURCHASER The instrument should be thoroughly inspected immediately upon original delivery to purchaser All material in the container sh
64. O o DESCRIPTION STOCK MER Res ww 1000 matched Res ww 209 0 25 0 7w 4707 255620 01686 Res ww 200 0 25 0 Tw 4707 255620 01686 Res ww 202 0 25 0 4707 255620 01686 Res ww 202 0 25 0 7w 4707 255620 01686 Res ww 200 0 25 0 4707 255620 01686 Res ww 109 0 25 0 7w 4707 255638 01686 Res ww 20 1 0 7w 4707 255646 01686 Res ww 20 41 0 7w 4707 255646 01686 Res ww 29 1 0 7w 4707 255646 01686 Res ww 20 41 0 7w 4707 255646 01686 Res ww 22 51 0 7w 4107 255646 01686 Res ww 10 1 0 4707 255653 01686 Res ww 0 20 43 0 7w 4707 255661 01686 Res ww 0 20 43 0 7w 4707 255661 01686 Res ww 0 20 396 0 7w 4707 255661 01686 Res ww 0 2243 0 7 4707 255661 01686 Res ww 0 29 43 0 Tw 4707 255661 01686 Res ww 0 10 43 0 4707 255679 01686 Res met flm 4 99k 41 1 2w 4705 148890 19701 Res met flm 3 16k 1 1 2w 4705 187781 19701 Switch rotary Decade 2 5105 257253 89536 Switch rotary Decade 3 5105 257253 89536 Switch rotary Decade 4 5105 257253 89536 Switch rotary Decade 5 5105 257253 89536 Switch rotary Decade 6 5105 257253 89536 Switch rotary Decade 7 5105 257253 89536 MER PART NO Type T2 Type T2 Type T2 Type T2 Type T2 Type T2 Type T2 Type T2 Type T2 Type T2 Type T2 Type T2 Type T2 Type T2 Type T2 Type T2 Type T2 Type T2 Type MF7C Type MF7C 5105 257253 5105
65. O j QTYIQTY CODE R24 3 1 Res var ww 10k 10 1 1 4w 4702 162115 71450 Type 110 3 R25 3 Res var ww 10k 10 1 1 4w 4702 162115 71450 Type 110 REF 1826 D4 TI1 Res var ww 10k 10 1 1 4w 4702 162115 71450 Type 110 REF R27 K4 Q5 Res ww 99 975k matched B R28 4 51 Res var ww 502 410 1 1 4w 4702 144782 71450 Type 110 1 R29 B1 S3 Res comp 330k 5 lw 4704 109777 01121 GB3345 1 gt R8 R9 R10 R12 R13 R15 R16 R18 R19 R21 R22 R27 and A5R1 through A5R12 are an intermatched resistor set part number 4710 252445 The resistors may be replaced individually by giving model serial number full reference designa tion and all markings on the old resistor However R9 R10 R12 R13 R15 R16 R18 R19 and R21 R22 must be ordered and replaced in pairs 5 30 341A 343A REF INDEX STOCK MER TOT REC USE NO DESCRIPTION NO MER PART NO SAMPLE STRING P C ASSEMBLY 3158 263012 89536 3158 263012 REF Figure 5 7 NOTE The Reference P C Assembly A4 the Sample String P C Assembly A5 and their intermatched resistors can be ordered under one part number 3158 252312 B3 T2 Diode silicon 200 ma 25 piv 4805 190272 93332 1N456A 2 A5 T2 Diode silicon 200 ma 25 piv 4805 190272 93332 1 456 REF E2 Q4 Res ww 10k matched gt B4 Q2 Res ww 20k matched
66. R5 B4 S2 C3 R5 C4 S4 C3 T2 C3 S5 C3 T3 B5 T4 C2 T5 C1 U3 C1 V2 1 01 D2 T2 1 5 H2 Q1 12 01 I2 P1 DESCRIPTION Res met flm 75k 1 2w Fig 5 5 Res comp 1 52 45 1 2w Fig 5 5 Res comp 75k 45 1 4w Fig 5 5 Res met flm 8 25k 21 1 2w Fig 5 5 Res met flm 57 6k 1 1 2w Fig 5 5 Res met flm 6 04k 1 1 2w Fig 5 5 Res comp 10k 59 1 4w Fig 5 5 Res met flm 2 74k 41 1 2w Fig 5 5 Res met fim factory matched Fig 5 5 Res ww factory matched Fig 5 5 Res ww factory matched Fig 5 5 Res factory matched Fig 5 5 Res met flm 4990 41 1 2w Fig 5 5 Res var ww 1000 20 1 1 4w Fig 5 5 Res met flm 1782 50 596 1 2w Fig 5 5 Res comp 2 79 45 1 4w Fig 5 5 Res comp 8 2k 595 1 2w Fig 5 5 Res comp 10k 5 1 4w Fig 5 5 Res met flm 11k 1 1 2w Fig 5 5 Res comp 5 1k 595 1 2w Fig 5 5 4705 193961 4704 246793 4704 220525 4705 192492 4705 246777 4105 162586 4704 148106 4705 240614 4105 151514 4702 112797 4 105 256255 4704 246744 4704 147777 4704 148106 4105 222216 4704 109108 19701 01121 01121 19701 19701 19701 01121 19701 19701 71450 19701 01121 01121 01121 19701 01121 MFR TOT PART NO Type 1 EB15G
67. REQUIRED EQUIPMENT NOMENCLATURE Fluke Model 895A DC Differential Voltmeter Range 0 to 1100 vdc Accuracy 10 002596 of input Oscilloscope Sensitivity 20 mv cm Tektronix Model 541 Sweep 1 msec cm True RMS Voltmeter Range 10 to 100 mv Fluke Model 9318 Accuracy 0 05 1000 5 Hz to 100 kHz Preamplifier Gain Bandpass Genera Radio Model WSMT3AW Voltage 0 to 130 vac Autotransformer Current 3 amp Multimeter Accuracy 2 dc 3 396 11 megohms de Fluke Model 853A Input Impedance 1 megohm ac Load Resistors 40 ohms x 596 1 2w Ctarostat Model 240C 400 ohms 5 1w 4k 5 10w 40k 5 50w Null Detector Model 343A only Sensitivity 1uv Fluke Model 845AR or 845AB Standard Cell Model 343A only Accuracy 0 0005 Guildline Instruments Model 9152 P4 DC Voltage Calibration System 343A only Range 0 1 to 1100 vde Accuracy 10 ppm Fluke Model 71008 consisting of the following equipment Fluke Model 750A Fluke Model 3328 Fluke Model 845AR Reference Divider DC Voltage Source Null Detector Figure 4 1 TEST AND CALIBRATION EQUIPMENT 4 2 Remove the nine screws which hold the sample string assembly in place on the rear of the first bulkhead The reference board assembly is held in place on the fro
68. RTNO Type CW10 GB1051 CB8215 GB5105 CB1535 CB3325 CB1025 CB1035 CB2725 CB1535 CB8225 CB2235 CB2725 HB5625 EB6235 1531 5115 CB6225 CB5615 CB5615 341A 343A 5 23 341A 343A 5 24 12 3 13 01 DESCRIPTION Res comp 6802 45 1 4w Fig 5 5 Res comp 30k 5 1 4w Fig 5 5 Res comp 11k 565 1 4w Fig 5 5 Res comp 1 3k 595 1 4w Fig 5 5 Res comp 18k 45 l 4w Fig 5 5 Res comp 1800 45 1 4w Fig 5 5 Res comp 1802 5 1 4w Fig 5 5 Res met flm 20k 1 1 2w Fig 5 5 Res met flm 20k 175 1 2w Fig 5 5 Res met flm 2M 1 1 2w Fig 5 5 Res comp 36k 5 1 2w Fig 5 5 Res met flm 34k 19 1 2w Fig 5 5 Res met flm 28 7k 1 1 2w Fig 5 5 Res comp 100k 5 1 2w Fig 5 5 Res met flm 10k 41 1 2w Fig 5 5 Res comp 100k 5 1 2w Fig 5 5 Res met flm 10k 519 1 2w Fig 5 5 Res comp 24k 45 1 2w Fig 5 5 Res comp 62k 565 1 4w Fig 5 5 Res met flm 68 1k 1 1 2w Fig 5 5 4704 148007 4704 193417 4704 221580 47104 234252 4704 148122 4704 147942 4704 147942 47105 162438 4705 162438 4705 217760 4704 185991 4705 151241 4705 193987 4704 168054 4705 151274 4704 168054 4705 151274 4704 108654 4704 220053 4705 161083 01121 01121
69. Res var ww 10k 20 1 1 4w Fig 5 5 Res met flm 24 3k 1 1 2w Fig 5 5 Res var ww 5k 5 2w Fig 5 5 Res met flm 4 226 1 1 2w Fig 5 5 Res comp 10M 410 1 2w Fig 5 5 Res comp 2000 5 1 4w Fig 5 5 Res comp 4700 10 lw Fig 5 5 Res met flm 10k 41 1 2w Fig 5 5 Res comp 2009 5 1 4w Fig 5 4 Res comp 560 21095 2w Fig 5 4 Res met flm 169k 41 1 2w Fig 5 5 Res met flm 51 1k 41 1 2w Fig 5 8 Res met flm 2k 1 1 2w Fig 5 5 met flm 109 4195 1 2w Fig 5 5 Res comp 4702 10 1 Fig 5 5 Res met flm 2 ik 41 1 8w Fig 5 5 Res met flm 4 02k 1 1 8w Fig 5 5 STOCK NO 4704 186064 4704 147777 4704 148114 4702 112862 4705 217430 4702 111609 4705 223396 4704 108142 4704 193482 4704 109710 4705 151274 4704 193482 4704 110221 4705 176206 4705 159665 4705 151266 4705 151043 4704 109710 4705 168237 4705 235325 MFR 01121 01121 01121 71450 19701 71450 19701 01121 01121 01121 19701 01121 01121 19701 19701 19701 19701 01121 19701 19701 MER TOT PART NO QTY REF EB2235 EB8225 REF CB1535 REF Type 110 1 Type 1 Type E115 1 Type MF7C 1 EB1061 1 CB2015 REF GB4711 2 MF7C CB2015 REF HB5601 1 Type MF7C REF Type 1 Type
70. VE VOLTAGE LIMITER RANGE 3 3 BLOCK DIAGRAM ANALYSIS 34 The instrument circuitry is basically that of a high gain operational amplifier as shown in Figure 3 2 The driving signal is generated in a precision voltage reference and applied through a range control network to the am plifier input The series regulator which is the output stage of the amplifier provides the high voltage capability ra CONTROLLED 15 VOLT 5 CURRENT REFERENCE AUXILIARY LIMITER SUPPLY SUPPLY on R70 CONTROL SIGNAL CHOPPER STABILIZED AMPLIFIER PREAMP ee Y FEEDBACK MODEL 341A 343A BLOCK DIAGRAM 3 1 341A 343A BETA STRING REFERENCE pak UNREGULATED pc OUTPUT SERIES REGULATOR Figure 3 2 BASIC INSTRUMENT CIRCUITRY Amplifier output is controlled by the range and beta string resistors which control the input signal and the negative feedback 3 5 The signal source is the 15 volt reference supply A reference amplifier within the supply assures high sta bility with respect to time and temperature An output current of 10 microamps 100 microamps or 1 milliamp for the 10 volt 100 volts and 1000 volt ranges respectively is selected by the range control switch The resulting volt age at the summing junction S is applied to the input of the chopper stabilized amplifier The function of this amplifier is to control conduct
71. VERIFICATION TEST SETUP 4 19 484 4 85 Repeat step e Adjust the 100V RANGE ADJUST control for zero 100 microvolts on 845AR No 2 Set the 343A RANGE to 1000 and voltage dials to 1000 0000 Set the 750A input and output switches to 1000 Adjust the 332B controls for 1000 volts output Repeat step e Adjust the 1000V RANGE ADJUST control for zero 1 millivolt on 845AR No 1 NOTE Allow the Model 343A to stabilize approxi mately 5 minutes before making the 1000 volt range adjustment CALIBRATION VERIFICATION The following test should be performed imme diately following Model 343A calibration Leave equipment connected as shown in Figure 4 16 Perform the 750A standardization paragraph 4 83 step e Set the equipment controls as shown in Figure 4 17 The null indication obtained in each step should be within the indicated tolerance 750A 3328 OUTPUT INPUT OUTPUT NOTE The null tolerances listed in column 1 Figure 4 17 apply to those instruments which have just been calibrated in no case should the out put error exceed the tolerances given in column 2 which are derived from instrument specifica tions found in Section I of the manual Set the Model 343A voltage dials to zero Disconnect the 750A from the Model 343A OUTPUT terminals and connect the 845AR directly to the Model 343A OUTPUT terminals Ensure that the negative OUTPUT terminal is connected to chassis ground Zero the
72. ack to ON 3 38 HIGH VOLTAGE POWER SUPPLY 3 39 Diodes CR53 and CR54 and capacitors C55 through C58 comprise a full wave voltage doubler The voltage supplied to the doubler depends on the setting of the range switch and the most significant decade switch On the 10 and 100 volt ranges the high voltage output is fixed at about 500 volts On the 1000 volt range the eleven position decade switch selects a voltage ranging from 500 to 1500 volts 3 6 3 40 _ METER CIRCUIT 3 41 The meter circuit is connected between and SENSE for voltage readings and is connected in shunt with R70 for output current readings In current measure ment mode the meter current includes beta string current This introduces a small error which is negligible on the 10 and 100 volt ranges On the 1000 volt range the error will be equal to 1 milliamp 3 42 STRING 3 43 The beta string is a six decade resistive network seven decades on the 343A which provides precise con trol of feedback to the chopper stablized amplifier there by controlling instrument output The first decade of the 341A and the first and second decades of the 343A incor porate linearity adjustments which are adjusted during calibration to ensure exact resistance ratios The resistors and switches which comprise the beta string are located on reference board and sample string assemblies 341A 343A SECTION IV MAINTENANCE 4 1 INTRODUCTION 4 2 This
73. al passes through IC1 an operational amplifier having a gain of approximately 420 and a frequency response of 20 Hz to 10 kHz The output of IC1 is inverted in Q37 and appears with approxi mately equal amplitude at both collector and emitter of Q37 The collector signal is synchronously demodulated by shunt switch Q36 The resulting voltage is filtered by R129 and C31 leaving only the amplified de and low frequency signals The Q37 emitter signal is applied through a filter network to C31 to assist in reducing chopper ripple and to cancel any base band signal that is present The purpose of 57 is to assist in stabilization and quick recovery of the amplifier by providing a quick charge path for C36 Diode CR56 clamps the voltage at the emitter of Q36 to a safe value 3 18 The source of the 215 Hz chopper drive signal is multivibrator Q2 Q3 and driver Q1 The signal at the collector of Q1 is coupled to the drain of Q39 to compen sate for the dc error introduced by the gate to drain capacitance of Q39 and is adjusted by R162 3 19 The preamplifier consists of two differential impli fiers and an output emitter follower The signal passes through the input FET amplifier Q35 through a second differential pair Q33 Q34 and out the emitter of Q32 to the series regulator The purpose of C1 and C2 on the ref erence board assembly is to reduce noise principally 60 Hz ripple by increasing the ac feedback at the undesired frequenc
74. ange adjustments paragraph 4 67 and the beta string paragraph 4 57 4 35 Model 343A Output Voltage Test To check the Model 343A output voltage accuracy perform the Model 3434 calibration verification procedure paragraph 4 84 steps a through h The output voltages should be as indicated in Figure 4 17 column 2 FAULT ANALYSIS If output voltages are incorrect check the 15 volt reference adjustment paragraph 4 73 the zero output adjustmen s paragraphs 4 74 and 4 79 the range adjustments paragraph 4 82 and the beta string paragraph 4 57 4 8 4 36 TROUBLESHOOTING 437 In the following checks paragraphs 4 39 through 4 59 the performance of the major functional circuitry is examined by an appropriate test These tests together with specific troubleshooting information are intended to aid in locating instrument malfunctions The tests begin with power off resistance checks proceed to standby and power on checks and conclude with specific functional circuit checks The tests should be performed in the order given unless the general trouble location is suspected beforehand 4 38 When measuring voltages on the circuit boards it is recommended that the major portion of the voltage probe be wrapped with insulating tape This will reduce the possibility of damaging a transistor due to an accidental short circuit For component locations refer to the illus trated parts breakdown in Section V WARNING
75. are shorted at voltage settings of 300 or above on the 1000 volt range The control circuit consists of an AND gate which maintains the high voltage relay in an energized condition as long as both the delay and trip inputs are present 3 11 The high voltage power supply is a conventional full wave voltage doubler Output voltage is determined by the range switch and most significant decade control switch which select one of six voltage taps at the power transformer secondary 3 12 CIRCUIT ANALYSIS 3 13 15 VOLT REFERENCE AND AUXILIARY SUPPLIES 3 14 The 15 volt reference supply is a conventional series regulated power supply employing a reference amplifier and an error amplifier to provide a stable well regulated output Filtered unregulated de voltage for the 15 volt supply is provided by CR22 CR25 and 23 Darlington amplifier 015 023 together with zener diodes 19 and CR20 form a simple preregulator The pre regulator improves line regulation and reduces noise due to power line transients Reference amplifier 014 is a single device containing matched zener reference and amplifier elements thereby providing a voltage reference that is extremely stable with respect to temperature variations Output voltage variations are sensed at the input of differential amplifier Q15 Q17 The amplified output of the differential amplifier is applied to the input of the Darlington amplifier pair Q20 Q19 which varies the conduction
76. ches and through special attention to component layout In addition all circuit boards are coated with a moisture sealant 4 17 To clean the instrument proceed as follows CAUTION Avoid touching the polyethelene grommets contamination can cause excessive electrical leakage 44 Remove loose contamination from the instrument with low pressure clean dry air Pay particular attention to the front panel binding posts binding post wiring switches and polyethelene grommets Clean the polyethelene binding posts and the front panel with anhydrous ethyl alcohol or an aerosol can of Freon TF Degreaser Miller Stephenson Chemical Inc When necessary clean the exposed dielec tric surfaces of switches with anhydrous alcohol using a small stiff bristled brush which has been wrapped with a clean cloth to prevent saturating the switch contacts After cleaning recoat the ex posed dielectric surfaces with silicon fluid This will prevent leakage along these surfaces due to moisture CAUTION Do not use Metriclene acetone lacquer thin ner Freon TF Degreaser or any ketone on the Lexan switch shafts and spacers because they will react with the Lexan do not saturate the switch contacts which have been perma nently lubricated Printed circuit boards have been coated with epocast a polyurethane resin to inhibit fungus growth and moisture absorption When soldering to a printed circuit land the heat f
77. crowbar discharges the high voltage filter capacitors and the clamping function of the sink supply ceases 3 32 crowbar circuit consists of Schmitt trigger 928 029 relay driver 030 series regulator Q31 crowbar relays K2A and and associated components Under normal conditions Q28 is cutoff and Q29 is conducting Thus Q30 is also off and the crowbar relays are de ener gized Assume the instrument is downranged The output capacitor C49 begins to discharge and the voltage across the series regulator begins to rise As this voltage rises current flow increases through CRS1 CR52 R88 and R89 thereby increasing the positive voltage at the base of Q28 When the voltage across the series regulator rises to within 40 volts of the sink supply voltage Q28 is biased on and the Schmitt trigger changes state This turns on the relay driver Q30 which activates the crowbar relays The crowbar relays place R81 and R84 directly across filter capacitors C55 through C58 and the capacitors quickly begin to discharge When the voltage across the filter capacitors has decreased by approximately 80 volts the decreased voltage at the base of Q28 resets the Schmitt trigger and the crowbar relays deenergize The continued discharge of C49 however causes the voltage across the series regulator to rise again When the voltage rises to within 40 volts of the sink supply voltage the crowbar circuit is again activated and the filter capacitor
78. cting wires WARM UP TIME Model 341A Within 50 ppm of final output at turn on Within 15 ppm of final output in 30 minutes Model 343A Within 25 ppm of final output at turn on Within 5 ppm of final output in 30 minutes INPUT POWER 115 230 volts 10 50 to 440 Hz single phase Approximately 70 volt amperes fully loaded 1 6 ENVIRONMENTAL SPECIFICATIONS TEMPERATURE RANGE Operating 00 to 4509 Storage 409 to 65 C RELATIVE HUMIDITY 0 to 70 SHOCK Withstands 15 g 11 millisecond half sine wave shock per MIL T 21 200 VIBRATION Withstands 10 Hz to 55 Hz 4 5 g maximum per MIL T 21200 ALTITUDE Up to 10 000 feet operating and 50 000 feet non operating per MIL T 21200 1 7 MECHANICAL SPECIFICATIONS SIZE 3 inches high by 17 inches wide by 18 inches deep MOUNTING Mounting brackets provided for standard EIA 19 inch rack mount and resilient feet provided for bench use Tapped 341A 343A holes also provided for attaching chassis slides The instru ment outline drawing is shown in Figure 1 1 WEIGHT 23 pounds 1 8 GENERAL SPECIFICATIONS DESIGN Solid state throughout FUSES Single fused ac line and high voltage METER Monitors output voliage and current 3 00 a BAIL STAND Removable NO 8 32 TAPPED MTG HOLE 5 each side Figure 1 1 MODEL 341A 343A OUTLINE DRAWING
79. dly as de scribed in step f check for defective com ponents in the gate circuit of CR29 Lo 4 55 HIGH VOLTAGE POWER SUPPLY 4 56 This test verifies proper operations of the high voltage power supply by measuring rectifier output voltages for all instrument voltage ranges a Connect the 895A to TP7 using OUTPUT as common b Set FUNCTION switch to ON and RANGE switch to 1000 Set the voltage dials as shown in Figure 4 8 and verify the voltages are as indicated VOLTAGE DIALS VOLTS 341A 343A 300 to 360 360 to 420 410 to 480 450 to 520 450 to 520 470 to 540 Figure 4 8 HIGH VOLTAGE POWER SUPPLY OUTPUT VOLTAGES FAULT ANALYSIS If the high voltage power supply voltages are not correct check diodes CR53 and CRS4 capacitors C55 through C58 and transformer Ti 457 STRING 4 58 The following sequence of tests is intended to detect gross errors in the beta string resistors or their switching patterns a Connect the 895A to the OUTPUT terminals Set the 895A to TVM mode with readout dials at zero b Set the Model 341A 343A controls as follows FUNCTION ON RANGE 100 Voltage dials Zero CURRENT LIMIT Fully clockwise c the 895A on the 100 uV range d Set the Model 341 343 and 895A controls as Shown in Figure 4 9 The voltage increments should correspond to the values shown 341A 343A OUTPUT VOLTAGE NCREMENT
80. e item to the original manufacturer is listed in the MFR PART NO column If a component must be ordered by description the type number is listed The TOT QTY column lists the total quantity of the items used in the instrument and reflects the latest Use Code Second and subsequent listings of the same item are referenced to the first listing with the abbreviation REF In the case of optional subassem blies plug ins etc that are not always part of the instrument or are deviations from the basic instru ment model the TOT QTY column lists the total quantity of the item in that particular assembly Entries in the REC QTY column indicate the recom mended number of spare parts necessary to support one to five instruments for a period of two years This list presumes an availability of common elec tronic parts at the maintenance site For mainten ance for one year or more at an isolated site it is recommended that at least one of every part in the instrument be stocked In the case of optional sub assemblies plug ins etc that are not always part of the instrument or are deviations from the basic instrument model the REC QTY column lists the recommended quantity of the item in that particular assembly The USE CODE column identifies certain parts which have been added deleted or modified during the production of the instrument Fach part for which a Use Code has been assigned may be iden tified with a particular instrument ser
81. er and adjust the autotransformer for 115 volts output b Set the Model 343A controls as follows FUNCTION ON RANGE 10 Voltage dials 10 000000 CURRENT LIMIT Fully clockwise 4 15 341A 343A 4 73 4 74 4 75 4 16 Attach ali covers and allow instrument to operate for at least 1 hour REFERENCE VOLTAGE ADJUSTMENT Unfasten the top cover and slide back just far enough to expose REF ADJUST control R26 and test point TP2 Connect the 895A differential voltmeter to TP2 using SENSE as common Adjust R26 for an 895A indications of 15 0 0001 volts de Disconnect the 895A and position the top cover so that only the beta string calibration controls are exposed ZERO OUTPUT ADJUSTMENTS Set Model 343A voltage dials to zero and connect the negative OUTPUT terminal to chassis ground Zero the 895A on the 1 volt range with null sensi tivity set to 100 microvolts then connect the 895A to the Model 343A OUTPUT terminals using low thermal copper leads Set RANGE switch to 10 and adjust the 10V ZERO ADJUST control for zero 4 microvolts indication on the 895A WARNING Use only an insulated tool for all adjustments within the beta string compartment Set RANGE switch to 100 and adjust the 100V ZERO ADJUST control for zero 10 microvolts indication on the 895A Set RANGE switch to 1000 and adjust the 1000V ZERO ADJUST control for zero 10 microvolts indication on the 895A BETA
82. f crowbar relays which discharge the high vol tage filter capacitors in a series of steps The action of the crowbar relays is very rapid and is audible to the user When downranging from the 1000 volt range 500 to 1000 volt dial settings to the 100 or 10 volt ranges crow bar operation can be heard as a rattle as the switch position is changed The crowbar circuit provides continuous pro tection as long as downranging is not excessive however if downranging occurs consistently at intervals less than 5 seconds the instrument will automatically trip to STANDBY 2 23 MECHANICAL ZERO ADJUSTMENT 2 24 When necessary mechanically zero the meter with the adjustment screw on the front panel If the instrument has been operating it must be turned off for at least 3 minutes prior to this adjustment 2 25 OPERATION AS A VOLTAGE CALI BRATOR 2 26 use the Model 341 A 3434 as a voltage source proceed as follows Set the FUNCTION switch to STANDBY RESET Allow at least a 10 minute warm up period if the instrument has just been energized b Connect the SENSE terminals to the OUTPUT ter minals with the shorting links provided and connect the load If remote sensing is desired connect the SENSE terminals to the load as described in para graph 2 17 2 5 341A 343A c Set the CURRENT LIMIT contro fully clockwise 25 or to a predetermined value using the proce dure of paragraph 2 17 d Set the RANGE switch and
83. for a change in value of resistors R58 R60 R61 or R64 4 11 341A 343A 451 CONTROLLED CURRENT LIMITER 4 52 This test verifies proper limiter operation and determines the current control range a Set Model 341A 343A controls as follows FUNCTION ON RANGE 10 10 00000 Model 341A 10 000000 Model 343A Voltage dials CURRENT LIMIT b Connect the 853A set to the 100 milliamp range to the OUTPUT terminals The LIMIT ON lamp should illuminate and the 853A should indicate between 25 and 36 milliamps c Set the CURRENT LIMIT control fully counter clockwise The range of adjustment should be approximately 30 milliamps d Set Model 3414 3434 controls as follows FUNCTION ON RANGE 1000 Voltage dials 100 0000 Model 341A 100 00000 Model 343A Adjust the CURRENT LIMIT control through its range while observing the 853A The range of adjustment should be approximately 34 milliamps Fully clockwise FAULT ANALYSIS controlled current range is not sufficient check 15 and 15 volt supply output voltages and check transistors 011 and Q12 4 53 CROWBAR 4 54 In the following test crowbar circuitry is exer cised by short circuiting the output and by down ranging the instrument excessively a Set Model 3414 3434 controls as follows FUNCTION METER VOLTAGE RANGE 1000 Voltage dials 100 000 Model 341A 100 0000 Model 343A CURRENT LIMIT Fully clockwise 442 b Sho
84. i 1075 milliampere s maximum metal film megahertz minimum millimeter millisecond most significant bit most significant digit mean time between failures mean time to repair millivolt s multivibrator megohrn s nano 1079 not applicable normally closed negative normally open nanosecond operational amplifier pico 107 paragraph printed circuit board picofarad part number pos pot ppm PROM psi RAM rf rms ROM or sec scope SH Si serno uht us of us uut v var vco vhf vif w ww xfmr xstr xtal xtlo positive potentiometer peak to peak parts per million programmablle read only memory pound force per square inch random access memory radio frequency root mean square read only memory second time oscilloscope shield silicon serial number shift register tantalum terminal board temperature coefficient or temperature compensating temperature compensated crystal oscillator test point micro 1075 ultra high frequency microsecond s 10 5 unit under test volt voltage variable voltage controlled oscillator very high frequency very low frequency watt s wire wound transformer transistor crystal crystal oscillator ohm s micro 10 5 7 2 47 m n R96 200K CR53 5135573 CR54 5135573 115 230 50 TO 440 CRS 20 46
85. ial number 51 341A 343A by consulting the Serial Number Effectivity List at the end of the parts list Sometimes when a part is changed the new part can and should be used as a replacement for the original part In this event a parenthetical note is added in the DESCRIPTION column 55 HOW TO OBTAIN PARTS 5 6 Standard components have been used wherever possible Standard components may be ordered directly from the manufacturer by using the manufacturer s part number or parts may be ordered from the John Fluke Mfg Co factory or authorized representative by using the Fluke part number In the event the part you order has been replaced by a new or improved part the re placement will be accompanied by an explanatory note and installation instructions if necessary 5 7 You can insure prompt and efficient handling of your order to the John Fluke Mfg Co if you include the following information a Quantity b FLUKE Stock Number c Description d Reference Designation e Instrument model and serial number 2 each 4805 177105 Transistors 2N3565 Q107 108 for 845AR s n 168 Example If you must order structural parts not listed in the parts list describe the part as completely as possible A sketch of the part showing its location to other parts of the instrument is usually most helpful V n a qaaaarsasraas 58 LIST OF ABBREVIATIONS ac alternating current MHz megahertz rf radio frequency Al A
86. ials for zero 20 uv on the 845AR Adiust DECK B 6 for an 845AR indication within 010 0000 e 10 00000 20 00000 9 20 00000 h 40 00000 i 40 00000 j 60 00000 k 60 00000 20 uv of step j Adjust the 332B dials for zero 40 uv on the 845AR Adjust DECK B 8 for an 845AR indication within 40 uv of step Adjust the 332B dials for zero 40 uv on the 845AR Adjust DECK B X for 845AR indication within 46 uv of step n 80 00000 80 00000 n 100 00000 o 100 00000 Figure 4 14 343A LINEARITY ADJUSTMENTS DECK B 4 18 4 82 Deck Adjustments a Set the Model 343A and 3328 RANGE to 100 b Set the Model 343A and 332B voltage dials as shown in Figure 4 15 and perform the indicated operations 332B VOLTAGE DIALS 343A VOLTAGE DIALS OPERATION 4 EN 10 00000 0000 Adjust the 3328 dials for zero 10 on the 845AR Adjust DECK A 1 for an 845AR indication within 10 uv of step c Adjust the 332B dials for zero 10 uv on the 845AR Adjust DECK 2 for an 845AR indication within 10 uv of step e Adjust the 332B dials for zero 20 uv on the 845AR Adjust DECK A 4 for an 845AR indication within 20 uv of step g Adjust the 332B dials for zero 20 uv on the 845AR Adjust DECK A 6 for an 845AR indication within 20 uv of step i Adjust the
87. ice Centers U S and Canada Fluke Technical Service Centers International Sales Representatives U S and Canada Sales Representatives International List of Abbreviations and Symbols Aor amp ac af assy AWG bed cow cer cermet ckt cm cmrr comp cont crt d a dac dc dmm dvm elect ext F FET ff freq FSN GHz ampere alternating current audio frequency analog to digital assembly american wire gauge bel binary coded decimal Celsius capacitor counterclockwise ceramic ceramic to metal seal circuit centimeter common mode rejection ratio composition continue cathode ray tube clockwise digital to analog digital to analog converter decibel direct current digital multimeter digital voltmeter electrolytic external farad Fahrenheit Field effect transistor flip flop frequency federal stock number gram giga 10 guard germanium gigahertz guaranteed minimum value ground henry heavy duty LED 158 LSD mA max mt MHz min mm ms MSB MSD MTBF MTTR MO n na NC or neg NO ns opni ampi para peb pF pn high frequency hertz integrated circuit intermediate frequency inch es internal input output kilo 10 kilohertz kilohm s kilovolt s low frequency light emitting diode least significant bit least signiticant digit mega 105 mill
88. ilicon 1 amp 100 piv Fig 5 5 CR39 D4 U1 Diode silicon i amp 100 piv Fig 5 5 CR40 D3 U1 Diode silicon 1 amp 100 piv Fig 5 5 CR41 J5 R4 Diode silicon 1 amp 100 piv Fig 5 5 CR42 J4 R4 Diode silicon 1 amp 100 piv Fig 5 5 CR43 J3 R4 Diode silicon 1 amp 100 piv Fig 5 5 CR44 Ji U2 Diode silicon amp 100 piv Fig 5 5 CR45 J1 Vi Diode silicon 1 amp 100 piv Fig 5 5 CR47 K4 U1 Diode silicon 1 amp 100 piv Fig 5 5 CR48 I3 R1 Diode zener i3v Fig 5 5 CR50 J3 U4 Diode silicon 1 amp 100 piv Fig 5 5 CR51 13 Diode silicon 1 amp 600 piv Fig 5 4 STOCK NO 4802 116111 4802 116111 4802 116111 4802 116111 4809 246611 4837 192567 4802 116111 4802 116111 4802 112383 4802 112383 4809 113332 4802 112383 4802 116111 4802 116111 4802 116111 4802 116111 4802 116111 4802 116111 4802 116111 4802 116111 4802 116111 4802 116111 4809 110726 4802 116111 4802 112383 MFR 05277 05277 05277 05277 07910 03508 05277 05277 05277 05277 07910 05277 05277 05277 05277 05277 05277 05277 05277 05277 05277 05277 07910 05277 05277 PART NO 1N4817 1N4817 1N4817 1N4817 1N961B C 6F 1N4817 1N4817 1N4822 1N4822 1N966A 1N4822 1N4817 1N4817 1N4817 1N4817 1N4817 1N4817 1N4817 1N4817 1 4817
89. ion of the series regulator so that the resulting voltage at S approaches zero As shown on the sig nal flow line signal current from the series regulator passes through the rectifier and filter and through the volt age control network into the summing junction thereby completing the servo loop 3 6 The chopper stabilized amplifier consists of a chopper amplifier and a preamplifier The chopper ampli fier amplifies all frequencies from dc to approximately 30 Hz the preamplifier is used principally for frequencies from 30 to approximately 500 kHz 37 The controlled current limiter together with the chopper stabilized amplifier and series regulator comprise a second servo loop which operates under abnormal load ing conditions such as short circuited output to ensure linear operation of the amplifier The controlled current limiter continuously monitors output current and compares it to the setting of the current limit control When the vol tage across current sensing resistor 70 exceeds the refer 32 ence voltage set by the current limit control the limiter generates a current which subtracts from the 15 volt reference current Thus the output is limited or clamped to the preset value 3 8 The function of the negative voltage limiter is to ensure linear operation of the shopper stabilized amplifier during periods such as downranging when the series regu lator is cut off and the main servo loop is opened The nega
90. ith reference to the troubleshooting section should help to locate the trouble NOTE Unless otherwise specified the following tests apply to both Model 341A and Model 343A instruments 4 26 LINE REGULATION 4 27 The line regulation test determines whether the output voltage of the instrument will remain constant within specified limits for low and high line voltages Connect the autotransformer to the line and connect the Model 341A to the autotransformer Adjust the autotransformer for 115 volts output b Set the Model 341A 343A controls as follows FUNCTION STANDBY RESET RANGE 10 Voltage Dials 1 00000 Model 341A 1 000000 Model 343A CURRENT LIMIT Fally clockwise Connect 40 ohm 459 1 2 watt resistor to the Model 341A 343A OUTPUT terminals d Connect the 895A differential voltmeter to the OUTPUT terminals and set the FUNCTION switch to ON 46 Vary the line voltage from 115 volts to 103 5 volts The 895A should indicate a voltage change of less than 30 microvolts f Vary the line voltage from 115 volts to 126 5 volts The 895A should indicate a voltage change of less than 30 microvolts Repeat steps c through f with loads and instrument settings as follows The maximum voltage changes should be as indicated a MAXIMUM VOLTAGE LOAD RANGE VOLTAGE DIALS CHANGE 400 ohms 5 10 10 00000 341A 75 10 000000 343A 5 100 100 0000 341A
91. luminum M megohm rfi radio frequency interference amp ampere met flm film resistor assy assembly ua microampere rms root mean square cap capacitor uf microfarad rtry rotary car flm carbon film uh microhenry sec second centigrade usec microsecond sect section cer uv T icrovolt S N serial number comp composition ma millampere Si silicon conn connector mh millihenry scr silicon controlled rectifier db decibel m milliohms spdt single pole double throw dc direct current millisecond spst single pole single throw dpdt double pole double throw iv millivolt sw switch dpst double pole single throw Ta tantalum elect electrolytic mw milliwatt tstr transistor F fahrenheit na tvm transistor voltmeter Ge germanium nger nanosecond uhf ultra high frequency gmv guaranteed minimum value nanovolt vivm vacuum tube voltmeter h henry 9 ohm var variable Hz hertz ppm parts per million vhf very high frequency hf high frequency piv peak inverse voltage vif very low frequency Ic integrated circuit p p peak to peak v volt if intermediate frequency pf picofarad va voltampere k kilohm plstc plastic vac volts alternating current kHz kilohertz p pole vde volts direct current kv kilovolt pos position w watt if low frequency P C printed circuit ww wire wound 5 2 DC VOLTAGE CALIBRATOR Figure 5 1 Front Panel Assembly See Figure 5 2 Rear Panel Assembly See Figure 5 3
92. ment fuses are contained in bayonet type fuse holders located at the rear of the instrument Correct values for the fuses are as follows REFERENCE DESIGNATION FUNCTION RATING Line fuse 115 volt connections lamp slow blow 230 volt connections 1 2 amp slow blow F2 High voltage 1 16 amp slow blow fuse 422 LAMP REPLACEMENT 4 23 RANGE LIMIT ON and power ON lamps are lo cated immediately behind the front panel They are accessible from the top of the instrument after removing the top instrument cover and the narrow front cover just 230 VOLT OPERATION Figure 4 4 115 230 VOLT CONVERSION 45 341A 343A above the meter The lamps are easily removeable without special tools The two control circuit lamps DS and DS2 are located on the main circuit board and are accessible after removing the top cover 4 24 PERFORMANCE TESTS 4 25 Performance tests consist of line regulation load regulation ripple and output voltage accuracy tests and are designed to compare instrument performance to speci fications The tests may be used during maintenance or for receiving inspection Test should be performed under standard test conditions ambient temperature 23 1 C relative humidity less than 70 Allow instrument to warm up for at least 1 hour before testing An instrument that fails any of the performance tests may require corrective maintenance or calibration In case of trouble analysis of the tests results w
93. n X AN 2 1 2 4 Operating Features 2 1 2 6 Controls Terminals and Indicators 2 1 2 8 Input Power Requirements 2 1 2 10 Preliminary Operation 2 1 2 12 AC Line 2 1 2 14 Sense 5 2 1 2 18 Current Limit 25 2 20 Overload 2 5 2 23 Mechanical Zero 2 5 2 25 Operation a Voltage 2 5 2 21 Applications sien nu e SM ete 2 6 2 29 Operation as a Differential 2 6 2 31 Operation as a 10 ppm 2 6 HI THEORY OF 3 1 3 1 Introduction nig oe AR Bees 3 1 3 3 Block Diagram Analysis 3 1 3 12 Analysis cse ree Wd eee 3 3 3 13 15 Volt Reference and Auxiliary 3 3 3 16 Chopper Stabilized 3 3 3 220 Series 3 3 3 23 Controlled Current 3 4 3 27 Negative Voltage
94. nd range adjustments paragraphs 4 65 and 4 67 paragraphs 4 74 4 79 and 4 83 for the Model 343A FAULT ANALYSIS 1 HE signal at is not correct check for square wave signal at the collector of Q2 Transistor Q39 Q1 Q2 or Q3 may be defective 2 E the signal at is not correct inte grated circuit IC1 or MOS FET transistor Q38 or 039 may be defective 4 49 SERIES REGULATOR 4 50 This test verifies proper operating voltages for the control transistor and preregulator transistors a co FAULT ANALYSIS Set Model 341A 343A controls as follows FUNCTION ON RANGE 10 Voltage dials 10 00000 Model 341A 10 000000 Model 343A CURRENT LIMIT Fully clockwise Connect the 895A between the metal case collector of Q40 and the OUTPUT terminal The voltmeter should indicate between 10 and 13 5 volts Connect a 400 ohm 5 1 watt resistor to the OUTPUT terminals and connect the positive OUT PUT terminal to chassis ground Using the 853A multimeter measure and record the collector to emitter voltages of each series regulator transistor 048 046 044 and 042 The voltages should differ by less than 25 volts dc 1 the collector voltage of 040 is not within limits zener diode CR48 is prob ably defective Also check transistors Q40 Q42 and Q43 2 H the voltage division across the preregu lator is not equal within 25 volts check transistors 042 through 049 and check
95. ngs on the old resistor 5 41 341A 343A REF INDEX DESIG NO DESCRIPTION PARTNO SAMPLE STRING P C ASSEMBLY 3158 252429 3158 252429 REF Figure 5 12 NOTE The Reference P C Assembly A4 the Sample String P C Assembly A5 and their intermatched re sistors can be ordered under one part number 3158 265314 Diode silicon 200 ma 25 piv 4805 190272 IN456A Diode silicon 200 ma 25 piv 4805 190272 IN456A Res ww 19 991k matched gt Res var cermet 209 43095 3 4w 4713 186197 Res var cermet 209 30 3 4w 4713 186197 Res ww 19 991k matched VV Res ww 19 991k matched Res cermet 209 30 4713 186197 Res cermet 209 2309 4 13 1 6197 Res 19 991k matched 19 991k matched cermet 200 30 2 cermet 109 430 Ll 19 991k matched 19 991k matched 2k matched 2k matched 2k matched 2k matched 2k matched lk matched 2002 matched 7 7 2002 matched or 2009 matched 2002 matched 2000 matched 5 42 341A 343A Figure 5 12 SAMPLE STRING P C ASSEMBLY 343A 5 43 341A 343A REF DESIG R25 R26 R27 R28 R29 R30 R32 R33 R34 R35 R36 R37 R38 R39 R40 R41 R42 R43 R44 R45 52 S3 54 85 56 87 5 44 INDEX N
96. nt of the second bulkhead by six screws Separate the front panel from the first bulkhead by removing the RANGE FUNCTION CURRENT LIMIT and voltage control knobs and unsoldering the wires which connect to the output terminals 4 12 To gain access to rear panel mounted components proceed as follows Remove the top and bottom covers b Remove the narrow covers located immediately above and below the rear panel 341A 343A c Remove the eight screws which hold the rear panel to the side rails d Remove the four transformer screws which are located on the rear panel e Remove the two screws which hold the rear panel to the center bulkhead f Separate the rear panel from the main unit to the extent permitted by the wiring 413 ADJUSTMENT LOCATIONS 444 All controls required for calibration and trouble shooting are accessible from the top of the instrument after removing the top cover See Figure 4 2 for Model 341A adjustment locations and Figure 4 3 for Model 343A ad justment locations Figure 4 2 MODEL 341A ADJUSTMENT LOCATIONS 341A Figure 4 3 MODEL 343A ADJUSTMENT LOCATIONS 415 CLEANING 4 16 The instrument should be cleaned periodically to remove dust grease and other contamination Since the instrument is completely enclosed having no fans the need for cleaning is reduced Care has been taken to prevent leakage through the use of high quality insuiating materials in all swit
97. nts 341A 343A b Set the Model 341A voltage dials as shown in Figure 4 11 The output voltages should be as indicated in column for an instrument that has just been cali brated In no case should the output error exceed the tolerances given in column 2 which are derived from instrument specifications found in Section I of the manual VOLTAGE DIAL OUTPUT VDC 0 00000 00 0000 000 000 10 00000 0 0 00001 0 0 00002 0 0 00006 10 10 0002 5 0 0002 100 40 002 50 0 002 10 10 0005 5 0 0003 1000 0 02 500 0 02 100 0 005 50 10 003 0 0 00002 0 40 0001 00 001 10 0 001 5 10 0005 100 20 01 50 0 005 10 0 001 5 10 0005 1000 0 1 500 0 05 100 0 01 50 0 005 5 00000 100 0000 50 0000 10 0000 05 0000 1000 000 500 000 100 000 050 000 Figure 4 11 341A OUTPUT VOLTAGE REQUIREMENTS c Calibration of the Model 341A is complete Set the FUNCTION switch to OFF and disconnect equip ment 4 70 MODEL 343A PRELIMINARY CALIBRA TION 4 71 Preliminary calibration of the Model 343A consists of three main steps ordered as follows 1 reference vol tage adjustment 2 preliminary zero output and beta string adjustments and 3 temperature stabilization Be fore attempting calibration instrument performance should be examined according to the performance tests of para graph 4 24 to ensure that no malfunctions exist 472 PRELIMINARY OPERATIONS a Connect the Model 343A to the autotransform
98. of Q19 to maintain a constant output voltage Frequency response for the overall servo loop is controlled by R14 and C20 3 15 Filtered dc voltage for the 15 volt auxiliary supply is provided by CR23 CR24 and C22 The voltage reference for this supply is the 15 volt reference supply output The error amplifier consists of differential ampli fier Q16 Q18 Series control of the output is provided by Darlington amplifier 022 021 Transistor 024 and associated components comprise a constant current source for Q16 thus achieving a high overall loop gain Capacitor C21 and resistor R6 control the frequency for this servo loop 341A 343A 3 16 CHOPPER STABILIZED AMPLIFIER 3 17 The chopper amplifier consists of an input modu lator a high gain amplifier a synchronous demodulator and an output filter network Input signals are restricted to less than 30 Hz by a low pass filter consisting of R172 R171 and C47 The resulting baseband signal dc to 30 Hz is applied through R170 to the drain of MOS FET chopper Q39 Q39 is switched off and on at a 215 Hz rate by a squarewave signal applied to its gate thus modulating the input signal and producing a squarewave output signal having an amplitude proportional to the amplitude of the baseband signal The resulting signal is coupled to the in put of JFET amplifier Q38 Use of the JFET as an input amplifier provides high input impedance and assures low noise operation From Q39 the sign
99. of setting or 20 uv per hour 0 0015 of setting or 50 uv per month OUTPUT CURRENT 0 to 25 milliamps at any output voltage OVERCURRENT PROTECTION Automatically limits output current at any present level between 1 and 25 milliamps via continuously variable front panel control Panel lamp illuminates during limiting SHORT CIRCUIT PROTECTION At output voltage dial settings of 299 99X 299 999 the Model 343A or less normal operation is restored upon removal of overload At output voltage dial settings of 300 000 300 0000 on the Model 343A or above the instrument trips to STANDBY when the output is short circuited 1 2 RIPPLE AND NOISE all frequencies Model 341A 60 Hz Line Less than 100 uv rms or mv p p 400 Hz Line Less than 100 uv rms or 2 mv Model 343A 60 Hz Line Less than 50 uv rms or 400 uv p p 400 Hz Line Less than 100 uv rms or 2 mv p p SETTLING TIME Model 341A Within 50 ppm of final output in 5 seconds Model 343A Within 25 ppm of final output in 5 seconds LINE REGULATION 0 0005 of setting 25 uv for a 10 line voltage change from nominal LOAD REGULATION 0 0005 of setting 25 uv for a full load change ISOLATION Either output terminal may be floated up to 500 volts dc from chassis ground REMOTE SENSE Separate terminals are provided for sensing the output vol tage directly at the load thereby eliminating errors due to voltage drop in the instrument to load conne
100. on NPN 4819 179374 04713 2N2218 REF Fig 5 5 Q9 12 P4 Tstr silicon NPN 4819 218396 04713 2N3904 REF Fig 5 5 910 5 3 Tstr silicon NPN 4819 218396 04713 2N3904 REF Fig 5 5 Qui 5 2 Tstr silicon PNP 4818 195974 04713 2N3906 REF Fig 5 5 912 H5 P4 Tstr silicon PNP 4818 195974 04713 2N3906 EF Fig 5 5 913 03 Tstr silicon PNP 4818 195974 04713 2N3906 EF Fig 5 5 Qi4 B5 T2 Tstr Factory matched Fig 5 5 915 c2 s2 Tstr silicon NPN 4819 168708 03508 2N3391 2 Fig 5 5 5 916 J5 P4 Tstr silicon PNP 4818 195974 04713 2N3906 EF Fig 5 5 017 85 51 Tstr silicon NPN 4819 168708 03508 2N3391 EF Fig 5 5 Q18 52 21 Tstr silicon PNP 4818 195974 04713 2N3906 EF Fig 5 5 919 Ic2 Q5 Tstr silicon NPN 4819 203489 07910 CDQ10656 4 2 Fig 5 5 pa ah a i 5 16 Q20 Q21 Q22 Q23 Q24 925 926 Q27 Q28 Q29 Q30 931 932 933 934 935 B4 R1 42 03 25 02 C2 P4 J5 P1 B4 P5 G4 Q5 F3 Q4 G2 S1 5 51 C5 R1 D3 R2 H T4 H4 S5 G2 T4 MFR PART NO STOCK DESCRIPTION No MER Tstr silicon NPN 4819 218396 04713 Fig 5 5 Tstr silicon PNP 4818 190389 04713 Fig 5 5 Tstr silicon PNP 4818 195974 04713 Fig 5 5 Tstr silicon NPN 4819 203489 07910 Fig 5 5 Tstr silicon NPN 48
101. onnect the 845AR to the Model 343A output ter minals with the Model 343A negative OUTPUT terminal connected to chassis ground Set the Model 343A RANGE to 10 and voltage dials to zero Zero the 845AR on the 1 microvolt range Adjust the 10V ZERO ADJUST control for a null indication 2 microvolts on the 845 Set the Model 343A RANGE to 100 and adjust the 100V ZERO ADJUST control for a null indication 2 microvolts on the 845 AR Set the Model 343A RANGE to 1000 and adjust the 1000V ZERO ADJUST control for a null indication 10 microvolts on the 845AR BETA STRING LINEARITY ADJUSTMENTS Deck Adjustments Connect the equipment as shown in Figure 4 13 SIMPLIFIED MODEL 845 MODEL 343A MODEL 3328 MODEL B45AR Figure 4 13 BETA STRING LINEARITY TEST SETUP 4317 341A 343A b Set the 3328 VOLTAGE RANGE to 100 C Set the Model 343A and 332B voltage dials as shown in Figure 4 14 and perform the indicated operations STEP 332B VOLTAGE 343A VOLTAGE OPERATION 10 00000 Adjust the 3328 dials for zero 10 uv on the BASAR Adjust DECK B 1 for an 845AR indication within 10 uv of step d Adjust the 332B dials for zero 10 uv on the 845AR Adjust DECK B2 for an 845AR indication within 10 uv of step f Adjust the 3328 dials for zero 20 uv on the 845AR Adjust DECK B 4 for indication within 20 uv of step h Adjust the 332B d
102. ould be checked against the enclosed packing list The manufacturer will not be responsible for shortages against the packing sheet unless notified immediately if the instrument damaged in any way a claim should be filed with the carrier immediately To obtain a quotation to repair shipment damage contact the nearest Fluke Technical Center Final claim and negotiations with the carrier must be completed by the customer The JOHN FLUKE MFG CO INC will be happy to answer all applications or use questions which will enhance your use of this instrument Please address your requests or correspondence to JOHN FLUKE MFG CO iNC P O BOX 43210 MOUNTLAKE TERRACE WASHINGTON 98043 ATTN Sales Dept For European Customers Fluke Holland B V P O Box 5053 5004 EB Tilburg The Netherlands European customers Air Freight prepaid John Fluke Co Inc Box 43210 Mountlake Terrace Washington 98043 Rev 4 80 TABLE OF CONTENTS Section Title Page I INTRODUCTION AND SPECIFICATIONS 1 1 1 1 Introduction nece ibo v des ree es 1 1 1 5 Electrical Specifications u rc IRR 1 1 1 6 Environmental 5 1 2 1 7 Mechanical 1 3 1 8 General Specifications 2 1 3 H OPERATING INSTRUCTIONS 2 1 2 1 Introductio
103. post black Binding post white Holder lamp Handle Knob CURRENT LIMIT Knob DIGIT 0 Knob DIGIT 0 10 Lens lamp clear Lens lamp red Link shorting Panel front XDS6 DS6 33 XDS5 055 30 31 Knob FUNCTION RANGE 3901 246686 2811 226308 2811 226282 2811 261156 3155 252411 2404 246306 2405 190249 3155 252353 3155 252361 2405 158956 3155 222596 3155 228056 2811 101220 1406 252403 XDS7 057 30 30 30 34 XDS3 pr STOCK FRONT PANEL ASSEMBLY 343A 89536 24655 29 Figure 5 9 FRONT PANEL ASSEMBLY 343A 341A MER PART NO QTY DF21RC DF21BC DF21WTC 3155 252411 2404 246306 2405 190249 3155 252353 3155 252361 2405 158956 3155 222596 3155 228056 0938 9712 1406 252403 42 28 35 3 places 5 37 341A 343A 5 38 DESCRIPTION REAR PANEL ASSEMBLY 343A Figure 5 10 Cap cer 0 01 uf 80 20 500v Cap 0 1 uf 420 1600v Fuse slow blow 1 amp 250v for 115v operation Fuse slow blow 1 2 amp 250v for 230v operation Fuse slow blow 1 16 amp 250v Tstr silicon NPN behind heat sinks Line cord Holder Fuse Heat sink Panel rear
104. procedure of paragraph 2 18 b Set the Model 341A 343A FUNCTION switch to STANDBY RESET Set the Model 750A standard cell voltage dials to the voltage of the standard cell MODEL SIMPLIFIED 341A 343A MODEL 750A a Figure 2 4 OPERATION AS A 10 PPM SOURCE Set the input voltage switch of the Model 750A as desired Set the Model 341A 343A output to the same voltage Set the Model 341A 343A FUNCTION switch to ON and set the Model 845AB for 100 microvolts sensi tivity e Adjust the voltage dials of the Model 341A 343A and the coarse and fine dials of the Model 750A for a null on successively more sensitive null ranges of the Model 845AB Final null should be the 10 microvolt range The output voltage of the Model 750A corresponds to the output voltage switch setting 2 7 341A 343A SECTION Hi THEORY OF OPERATION 3 1 INTRODUCTION 32 The following paragraphs describe the theory of operation of the Model 341A and 343A Voltage Calibra tors For the block diagram analysis refer to the block diagram shown in Figure 3 1 and for the detailed circuit analysis refer to the detailed circuit schematic at the end of Section V w QUTPUT CROWBAR DRIVER SINK SUPPLY SERIES REGULATOR HIGH VOLTAGE POWER SUPPLY 1 auxit l lany ciacuirs i MAIN POWER CONTROL CIRCUIT Figure 3 1 NEGATI
105. rom the soldering iron decom poses the epocast resin leaving a charred residue Upon completion of soldering this residue should be removed with a solvent such as toluol CAUTION The following precautions should be adhered to when using toluol Avoid inhaling the vapors avoid excessive contact with the skin and keep away from open flames Ensure that plastic components do not come into contact with toluol since it will dissolve most types of plastic d After removal of the epocast residue the affected area should be recoated with a sealant A spray can of Circuit Coat Furane Plastic Inc 4516 Brazil Street Los Angeles California or 16 Spielman Road Fairfield New Jersey may be used for recoating 4 18 115 230 VOLT CONVERSION 4 19 Model 341A 343A may be operated from either a 115 or 230 volt ac power line depending upon the connection of the power transformer primary winding Convert the instrument from one type of power line operation to the other by the following procedure 115 VOLT OPERATION 341A 343A Disconnect the instrument from the power line b Remove the top cover The power transformer is located in the rear of the instrument near the point of line cord entry Orient the instrument and perform the appropriate electrical connections as shown in Figure 4 4 d Use the proper fuse for the selected voltage as specified in paragraph 4 20 4 20 FUSE REPLACEMENT 4 21 Instru
106. rt circuit the OUTPUT terminals and set the voltage dials to 300 000 300 0000 on the Model 343A The LIMIT ON lamp should illuminate and the instrument should trip to STANDBY c Remove the short from the OUTPUT terminals and reset the instrument The LIMIT ON lamp should extinguish and the ON lamp should illuminate d Set the voltage dials to 1000 000 1000 0000 on Model 343A and then downrange the instrument by setting the RANGE switch to 100 The crowbar relays K2A and K3A should operate several times very rapidly or rattle as the RANGE switch is changed Repeat step d several times allowing at least 5 seconds between range changes f Repeat step several times allowing only 2 seconds or less between range changes The instrument should trip to standby 2525225 FAULT ANALYSIS If instrument does not trip to STANDBY when the OUTPUT terminals are shorted at 300 volts output check the Schmitt trigger input voltage across R89 This voltage should be at least 6 volts to trig ger the Schmitt circuit If input is cor rect check other Schmitt trigger compo nents especially transistor Q31 zener diode CR55 and relays K2B and K3B Also check diodes CR6 CR8 CR29 CR66 and CR67 2 the crowbar relays do not rattle when the instrument is downranged from 1000 volts check for proper operation of the Schmitt trigger circuit 3 If instrument does not trip to STANDBY when it is downranged repeate
107. s are dis charged another 80 volt step This action continues until C49 and C55 through C58 have stabilized at the selected downrange voltage The step discharge of the filter capaci tors is a function of the hysterisis exhibited by the Schmitt trigger that is the Schmitt trigger is activated by a much higher voltage than is required to deactivate it Thus the crowbar relays are energized for a finite time period which contributes greatly to minimum arcing at the contacts and consequently long contact life Transistor Q31 is a series regulator for the Schmitt trigger and relay driver stages 3 33 second function of the crowbar circuit is to pro vide a trip signal to the control circuit whenever crowbar relay closure time becomes excessive This will occur if the instrument output is short circuited at voltage settings above 300 on the 1000 volt range It will also occur if the instrument is downranged excessively Closure of the crow bar relays applies a voltage to the RC time constant circuit 341A 343A consisting of R101 R102 and C5 which determines the crowbar relay closure limits excceds this limit a positive trip voltage is coupled through CR67 the control circuit When crowbar operation 3 34 CONTROL CIRCUIT 3 35 The control circuit consists of AND gate Q26 027 high voltage relay silicon controlled rectifier CR29 and associated components When the instrument FUNCTION switch is set from OFF
108. s on the arrow call out illustrations and by index numbers on the grid illustrations Flagnotes are used throughout the parts list and refer to special ordering explanations that are lo cated in close proximity to the flagnotes 5 4 COLUMN DESCRIPTION a The REF DESIG column indexes the item descrip tion to the associated illustration In general the reference designations are listed under each assembly in alpha numeric order Subassemblies of minor proportions are sometimes listed with the assembly of which they are a part In this case the reference designations for the components of the subassembly may appear out of order b The INDEX NO column lists coordinates which locate the designated part on the associated grid illustrations c The DESCRIPTION column describes the salient characteristics of the component Indention of the description indicates the relationship to other assem blies components etc In many cases it is necessary to abbreviate in this column For abbreviations and symbols used see the following page The ten digit part number by which the item is identified at the John Fluke Mfg Co is listed in the STOCK NO column Use this number when order ing parts from the factory or authorized representa tives The Federal Supply Code for the item manufacturer is listed in the MFR column An abbreviated list of Federal Supply Codes is included in the Appendix The part number which uniquely identifies th
109. section contains information concerning pre ventive and remedial maintenance for the Model 341A 3434 Voltage Calibrators Preventive maintenance consists primarily of cleaning the instrument which is performed periodically to sustain the instrument in peak operating condition Remedial maintenance consists of trouble Shooting calibration and performance test procedures which are designed to aid in maintaining instrument opera tion within specifications Section III of the instruction manual is an important supplement to the troubleshooting section since a thorough knowledge of instrument theory is indispensible in troubleshooting 43 SERVICE INFORMATION 4 4 Each instrument manufactured by the John Fluke Manufacturing Company is warranted for a period of one year upon delivery to the original purchaser Complete warranty information is contained in the Warranty page located at the rear of this manual 4 5 Factory authorized calibration and repair service for all Fluke Instruments is available at various world wide locations A complete list of factory authorized service centers is located at the rear of the manual If requested an estimate will be provided to the customer before any re pair work is begun on instruments which are beyond the warranty period 46 TEST EQUIPMENT 4 7 Figure 4 1 lists the equipment recommended for performance testing troubleshooting and calibration If the recommended equipment is not available
110. some degree of current limiting is desired proceed as fol lows Set the Model 341A 343A control follows FUNCTION STANDBY RESET RANGE 10 Voltage dials 1 00000 Model 341A 1 000000 Model 343A CURRENT LIMIT Fully clockwise b Piace a short across the and OUTPUT terminals c Set the FUNCTION switch to METER CURRENT d Set the output current limit by rotating the RENT LIMIT control counterclockwise until the panel meter indicates the desired limiting current 341A 343A e Set the FUNCTION switch to STANDBY RESET and remove the short from across the OUTPUT ter minals 2 20 OVERLOAD PROTECTION 2 21 The Model 3414 3434 is automatically protected against current overload and a continuous short circuit will in no way harm the unit At output voltage dial settings of 299 99 299 999 on the Model 343A or less the output voltage will return quickly upon removal of the overload At voltage dial settings of 300 000 300 0000 on the Mod el 343A and above a short circuit at the output will trip the instrument to STANDBY Trip is evidenced by illu mination of the CURRENT LIMIT lamp and extinction of the ON lamp After the overload condition is corrected the instrument may be reset by setting the FUNCTION switch to the STANDBY RESET position momentarily and then back to ON 2 22 Output voltages are fully controlled when down ranging or switching to STANDBY This is accomplished by a pair o
111. tive voltage limiter is activated when the amplifier output attempts to go below 2 5 volts The limiter then generates a current into the summing junction which balances the input reference and beta string currents thereby limiting the negative output of the amplifier The action of the limiter thus assures fast recovery and settling time for the amplifier 3 9 The primary function of the sink supply and crowbar circuitry is to quickly discharge the output capacitor and the high voltage filter capacitors when downranging the instrument These circuits also provide protection for the instrument during abnormal load con ditions such as short circuited output The sink supply serves two purposes It discharges the output capacitor and it protects the series regulator transistors by tempor clamping the voltage across them to a safe value The crowbar circuit protects the series regulator transistors by discharging the high voltage filter capacitors It also generates a signal for the control circuit which under certain conditions is used to trip the instrument to standby 3 10 The control circuit provides a fixed delay of 3 to 5 seconds following initial turn on before ac is connected to the high voltage power supply This allows the auxilliary power supplies time to stabilize and reach equillibrium before high voltage is applied Secondly the control circuit acts to trip the instrument to STANDBY when the output terminals
112. to preamplifier imbalance or improper chopper amplifier oper ation Check the input voltage to the con trolled current limiter in STANDBY it should be approximately zero volts Check Q35 for balance with C31 shorted the drain voltages of Q35 should be equal within 0 5 volts Check the chopper amplifier as described in paragraph 4 47 4 10 3 If the LIMIT ON lamp does not extinguish in FUNCTION ON position check the high voltage fuse F2 check for proper control circuit operation and check controlled current limiter operation paragraph 4 51 4 H the output voltage is not within limits check as described in paragraph 4 34 paragraph 4 35 for the Model 343A 447 CHOPPER AMPLIFIER 2X 4 48 This test verifies proper chopper amplifier opera tion by examining multivibrator and chopper amplifier signal characteristics a Set Model 3414 3434 controls as follows FUNCTION ON RANGE 10 10 00000 Model 341A 10 000000 Model 343A Voltage dials CURRENT LIMIT Fully clockwise b Connect the oscilloscope 10 1 attenuator probe to test point TP9 using SENSE as common c Set the oscilloscope input to dc vertical sensitivity to 0 2 volts per centimeter and sweep speed to 1 millisecond per centimeter d Compare the oscilloscope display with the waveform shown in Figure 4 6 for amplitude period and symmetry The observed signal parameters should be equal to those of the given signal within 10
113. trol imum output current to any value from zero to about 25 milliamps Ground Terminal Connection for grounding either positive or negative OUTPUT term inal to power line ground OUTPUT terminals Output voltage connections with both terminal isolated from instru ment case and power line ground Terminals may be fioated up to 500 volts dc from chassis SENSE terminals Direct connection to instrument regulating circuitry Connected to OUTPUT terminals or remote load to provide optimum load regu lation Decimal lamps Indicate location of decimal point for voltage dial readout and are controlled by the RANGE switch Voltage dials Six voltage dials seven dials on the 343A set output voltage and pro vide in line digital readout from 0 to 1111 110 volts de 0 to 1111 1110 volts dc for the Model 343A dial set to X 10 repre sents 0 with a carry of 1 to the left thus 11 11110 would be dialed as 10 XXXXX NOTE In dial readout notation the underscore 10 denotes a single dial that is displaying two significant digits Indicates OUTPUT voltage or load current depending on setting of FUNCTION switch The meter voltage range corresponds to the setting of the RANGE switch Voltage is indicated on a 0 to 10 scale with 10 over ranging The meter current range is fixed at O to 30 milliamps NOTE Meter current includes beta string current This introduces a small error which is negligible on the 10 and
114. ts drawing current away from the base of Q41 thereby limiting output current to 60 ma The purpose of diode CR50 is to permit the preamplifier output voltage to swing below zero volts 3 23 CONTROLLED CURRENT LIMITER 3 24 controlled current limiter utilizes differ ential amplifier 011 O12 a voltage amplifier and a diode connected transistor Q8 to accomplish the current limit function The voltage developed across current sensing resistor R70 is applied to the base of Q12 The base of Q11 which is tbe other input to the differential amplifier is connected to the current control potentio meter R41 When the voltage developed across R70 exceeds the voltage set by R41 transistor Q12 ceases conduction When Q12 stops conducting a shunt current path is offered to the reference current flowing into the summing junction This path is through Q8 and 10 and into the 15 volt supply The main amplifier input current is reduced accordingly and the instrument output current is thus limited to the preset value Resistor R44 and transistor Q8 form a coupling network which prevents the leakage current of 010 from affecting the summing junction current Transistor Q8 is used as a diode because of its inherently low leakage 3 25 Transistor Q13 is used to activate the controlled current limiter during instrument warmup and STANDBY conditions The base of 013 is connected to CR48 and cutoff bias is applied to Q13 as long as
115. ut with 1 ppm resolution and the Model employs seven dial readout with 0 1 ppm resolution 1 3 A controlled current limiter a fixed current limit er and an electronic crowbar circuit provide protection against instrument malfunction and operator error Output current or voltage depending on function desired are con tinuously monitored by a front panel meter 1 4 The instruments are designed for rack mount installation using the mounting brackets supplied and are equipped with resilient feet and tilt down bail for field or bench use 1 5 ELECTRICAL SPECIFICATIONS OUTPUT VOLTAGE Model 341A Model 343A 0 to 1111 110 volts de to 1111 1110 volts dc VOLTAGE RANGES Model 341A Range volts Output volts 10 0 to 11 11110 10 uv steps 100 0 to 111 11 10 100 uv steps 1000 O to 1111 110 1 mv steps 343A Model 343A Range volts Output volts 10 O to 11 111110 1 uv steps 100 Oto 111 11 110 10 uv steps 1000 010 1111 1110 100 uv steps RESOLUTION Model 341A 1 ppm of range 10 uv maximum Model 343A 0 1 ppm of range 1 uv maximum ACCURACY OF OUTPUT NOTE The following accuracy specifications apply after 1 hour warmup at standard reference conditions of 23 C 50 for the Model 341A and 23 C 1 C for the Model 343A up to 70 relative humidity constant line voltage and constant load Model 341A Range Accuracy whichever is greater 10V 0 01 of setting or 0 0003 of range 100
116. voltage dials to the value of the desired output voltage Set the FUNCTION switch to ON f The output voltage delivered to the load will corres pond to the voltage indicated on the voltage dials To monitor output voltage or current place the FUNCTION switch in either the METER VOLTAGE or METER CURRENT position 2 27 APPLICATIONS 2 28 he Model 341A 343A Voltage Calibrators pro vide parameters of stability accuracy temperature co efficient and response required by a broad range of labora tory and production applications The following para graphs describe a method of using the instrument as a differential voltmeter and in conjunction with a reference divider as a precision voltage source with traceability to the National Bureau of Standards 2 29 OPERATION AS A DIFFERENTIAL VOLTMETER 2 30 The Model 3414 3434 can be used in combina tion with a null detector such as the Fluke Model 845AB as a differential voltmeter Connection of the equipment for measurement of a positive voltage is shown in Figure 2 3 Proceed as follows MODEL 341A 343A VOLTAGE BEING MEASURED Figure 2 3 DIFFERENTIAL VOLTMETER 2 6 a Connect the null detector INPUT terminal to the positive terminal of the voltage to be measured and connect the null detector COMMON terminal to the Model 341A 343A OUTPUT terminal Connect the Model 341A 343A OUTPUT terminal to the negative side of the voltage being measured WARNING
117. when the high voltage is applied This is accomplished by Q13 which activates the controlled current limiter as described in paragraph 3 25 When the high voltage is off there is no zener current for CR48 Consequently transistor Q13 will be on and the controlled current limiter will be activated The main feedback loop at this time is provided by the negative limiter which clamps the output of the differential amplifier to 2 5 volts 3 37 The trip function of the control circuit is accom plished by silicon controlled rectifier CR29 CR29 receives an enabling trigger under two conditions When the crow bar relay closure is excessively long a trigger voltage is developed as described in paragraph 3 33 A second means of triggering CR29 is provided by the circuit consisting of 3 5 341A 343A neon lamps 051 and DS2 and resistor R98 This circuit is activated if the instrument output voltage becomes exces sively high on the 10 or 190 volt ranges for example if the main amplifier opened and the series regulator were driven fully on Under these conditions DS1 and DS2 would fire and a positive trigger voltage would be developed at the anode of CR67 When the voltage at the gate of CR29 is sufficiently high CR29 conducts and removes one input to the AND gate This de energizes the high voltage relay and places the instrument in STANDBY To reset the relay it is necessary to momentarily set the FUNCTION switch to STANDBY RESET and b
118. y 3 20 SERIES REGULATOR 3 21 series regulator is composed of a preregulator a control transistor and a fixed current limiter The pre regulator consists of four Darlington amplifiers in series 042 through Q49 Resistors R58 R60 R61 and R64 divide the high voltage equally among the four amplifiers 33 344A 343A so that each preregulator control transistor feels one fourth of the high voltage The base of the final preregulator control transistor Q42 is held at 12 4 volts by zener diode CR48 Consequently the emitter of Q42 will be constant at approximately 11 6 volts and the main control transis tor O40 will see no more than 11 6 voits for any value of high voltage output The control transistor 040 together with Q41 form a Darlington pair The purpose of diode CR65 is twofold It prevents breakdown of Q42 when 040 is suddenly cut off and it clamps the voltage at the collector of Q40 to a safe value Diodes CR41 through CRAS prevent excessive voltage drops across current sens ing resistor R70 which could occur under certain output load conditions such as short circuited output 3 22 Fixed current limiting is provided by 050 and associated components and is designed to protect the series regulator against catastrophic failure 050 is con nected as a shunt regulator across the base of Q41 and limits control transistor current to a maximum of 60 ma When the current through R70 exceeds 60 ma transistor 050 conduc
119. y response of this servo loop Again transistor Q4 is used as a diode because of its inherently low leakage 3 29 SINK SUPPLY AND CROWBAR 3 30 730 volt sink supply is composed of two power supplies connected in series The 570 volt supply is a full wave voltage doubler consisting of diodes CR2 5 and capacitors Cl and C2 The 160 volt supply is a half wave rectifier consisting of diode CR3 and capacitor C3 load resistors for the sink supply R96 and R97 The sink supply is connected through R96 and R97 across output capacitor C49 When the instru ment is downranged current flows through the sink supply and its load resistors to quickly discharge C49 to the selected downrange voltage 3 31 When the instrument is downranged or the output is short circuited the voltage across the series regulator will attempt to rise because of the charge on the high voltage filter capacitors The charge on these capacitors can be as high as 1500 volts The sink supply clamps the voltage across the series regulator to a safe value until the crowbar circuit is activated which occurs in less than 100 mili seconds The sink supply is connected across the series regulator through diodes CR32 and CR33 When the vol tage across the series regulator approaches 730 volts CR32 and CR33 conduct and the sink supply clamps the voltage across the regulator to 730 volts As soon as the crowbar circuit is activated the

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