______________T.0. 33A1 -1 2-933-1 1

TECHNICAL MANUALOPERATION AND MAINTENANCE INSTRUCTIONS

MULTIMETERAN/PSM-37

PART NUMBER 4D-3573NSN 6625-00-224-2252

FOURDEE DIVISIONEMERSON ELECTRIC CO.CASSELBERRY, FLORIDACONTRACT NUMBER

F41606-76-D-0106F4160887-DA288

BASIC AND ALL CHANGES HAVE BEEN MERGEDTO MAKE THIS A COMPLETE PUBLICATION.

DISTRIBUTION STATEMENT Authorized to the U.S. Government agencies and theircontractors only for Administrative and Operational Use, 1 December 1987. Other requestsfor this document shall be referred to SA-ALC/TIRT, Kelly AFB, TX 78241-5000.

HANDLING AND DESTRUCTION NOTICE For unclassified, limited documents, destroy byany method that will prevent disclosure of the contents or reconstruction of the document.

1 SEPTEMBER 1979DOODAPS 300ct98 50 REPRINT CHANGE 4 MAY l’W

T.O. 33A1-12-933-11

vertical line in the outer margins of the page. Changes to illus-trations are indicated by miniature pointing hands. Changes towiring diagrams are indicated by shaded areas.

Dates of issue tor original and changed pages are:

Original...0... .1 Sep 79Change. 1.. 30 Oct 84Change.....2...15 Dec 85Change. 3... 1 Jun 86Change.....4....1 May 87

TOTAL NUMBER OF PAGES IN THIS PUBLICATION IS 52 CONSISTING OF THE FOLLOWING:

Page ’Change Page ’Change Page ’ChangeNo. No. No. No. No. No.

Title... ........4A. ..........4i.................0ii............ ....1iii... ............0iv Blank..........01-1 1-5....... ..01-6 Blank.........02-1.. ..02-2 Blank.. .......03-1. ..............03-2 Blank.. .....04-1 4-13.. ......04-14..............24-15 4-17.. ..04-18 Blank.. .05-1.. .......45-2....... .05-2A............. .15-2B Blank........!5-3 5-5.........05-6 5-7... ......35-8 5-10.. ...06-1. ...06-2 Blank.. .......06-3..... ...06-4 Blank.. ...0

6-5.. ..06-6 Blank.........0

* Zero in this column indicates an original page.

A Change 4

T.0. 33A1-12-933-11

TABLE OF CONTENTS

Section/Para Page Section/Para Page

I. INTRODUCTION AND GENERAL 4-11. Ac Voltage 1,000 Ohms-INFORMATION. 1-1 Per-Volt. 4-5

4-12. Ac Voltage 10 Megohms 4-51-1. INTRODUCTION. 1-1 4-13. Amperes Milliamperes 4-51-3. Purpose. 1-1 4-14. Special. 4-51-4. GENERAL INFORMATION. 1-1 4-15. Ohms. 4-51-5. Description 1-1 4-16. Overload Protection 4-121-8. Related Publications. 1-4 4-17. Metering Circuits. 4-121-9. DEFINITIONS 1-4 4-18. Batteries 4-121-1 1. Warnings, Cautions, and Notes 1-4 4-19. Controls 4-121-12. LIST OF TIME COMPLIANCE 4-20. Range Switch A3. 4-12

TECHNICAL ORDERS. 1-4 4-21. Function Switch S2. 4-121-14. IMPROVEMENT REPORTS. 1-4 4-22. Polarity Switch S3. 4-14

4-23. OPERATING CONTROLS 4-14II. SPECIAL TOOLS AND TEST 4-24. Function Switch 4-14

EQUIPMENT 2-1 4-25. Range Switch 4-144-26. Polarity Switch 4-14

2-1. GENERAL REQUIREMENTS 2-1 4-27. OhmsAdj 4-142-2. General 2-1 4-28. Safe Switch. 4-14

4-29. OPERATING PROCEDURES. 4-14III. PREPARATION FOR USE AND 4-30. Voltage Measurements. 4-14

SHIPMENT. 3-1 4-31. High Voltage or High ImpedanceVoltage Measurements. 4-16

3-1. PREPARATION FOR USE. 3-1 4-32. High Voltage or High Impedance3-2. General 3-1 Ac Voltage Measurements. 4-163-3. Unpacking. 3-1 4-33. Current Measurements. 4-173-4. Battery Installation. 3-1 4-34. Resistance Measurements 4-173-5. Operational Check. 3-1 4-35. Crystal Current Measurements. 4-173-6. PREPARATION FOR 4-36. Turning Multimeter Off. 4-17

SHIPMENT. 3-1V. MAINTENANCE. 5-1

IV. OPERATION INSTRUCTIONS 4-15-1. MINIMUM PERFORMANCE

4-1. GENERAL 4-1 STANDARDS. 5-14-3. THEORY OF OPERATION 4-1 5-3. INSPECTION AND PRE-4-4. Introduction 4-1 VENTIVE MAINTENANCE. 5-14-5. FUNCTIONAL OPERATION. 4-1 5-5. BATTERY TESTING AND4-6. DC Voltage 20,000 Ohms- REPLACEMENT. 5-1

Per-Volt. 4-1 5-6. Mechanical Zero 5-24-7. DC Voltage 1,000 Ohms- 5-7. Test Lead Set 5-2

Per-Volt. 4-1 5-8. Exterior Cleaning 5-34-8. DC Voltage 10 Megohms 4-1 5-9. Inspection. 5-34-9. Meter Amplifier U3. 4-1 5-10. TROUBLE ANALYSIS. 5-34-10. Ac Voltage 20,000 Ohms- 5-11. General 5-3

Per-Volt. 4-5 5-12. Procedure 5-3

T.0. 33A1-12-933-11

TABLE OF CONTENTS Continued

Section/ Para Page Section/Para Page

5-13. Operational Checks. 5-3 5-30. DC Volts IKn/V Cali-5-14. REPAIR 5-6 bration Procedure 5-85-15. General 5-6 5-31. DC Volts 10 MEGf2 Cali-5-16. Repair Techniques. 5-6 bration Procedure 5-95-17. Disassembly. 5-6 5-32. Ac Volts 10 MEGn Cali-5-18. Interior Cleaning. 5-7 bration Procedure 5-95-19. Interior Inspection 5-7 5-33. Ac Volts 1K n/V Cali-5-20. Assembly. 5-7 bration Procedure 5-95-21. CALIBRATION 5-7 5-34. Ac Volts 20K n/V Cali-5-22. Frequency. 5-7 bration Procedure 5-95-23. General 5-7 5-35. Ac Milliamperes Calibration5-24. Test Equipment Procedure 5-9

Required 5-7 5-36. Ac Millivolts Special5-25. PROCEDURES. 5-7 Calibration Procedure 5-105-26. DC Microamperes Special 5-37. Ac Microamperes Special

Calibration Procedure 5-7 Calibration Procedure 5-105-27. DC Millivolts Special 5-38. Ohms LP Calibration

Calibration Procedure 5-8 Procedure 5-105-28. DC Milliamperes Calibration 5-39. Ohms Std Calibration

Procedure 5-8 Procedure 5-105-29. DC Volts 20K n/V Cali-

bration Procedure 5-8 VI. DIAGRAMS 6-1

LIST OF ILLUSTRATIONS

Figure Title Page Figure Title Page

1-1. AN/PSM-37 Multimeter. 1-2 4-5. Simplified Circuit, AC Volts,1-2. AN/PSM-37 Multimeter. 1-3 1K Ohms/V. 4-71-3. AN/PSM-37 Multimeter 4-6. Simplified Circuit, AC Volts

Accessory Set 1-5 10 Megohms 4-84-1. Simplified Circuit, DC Volts 4-7. Simplified Circuit, Amps-mA 4-9

20K ohms/V 4-2 4-8. Simplified Circuit, 100 VA/100 mV 4-104-2. Simplified Circuit, DC Volts 4-9. Simplified Circuit, Ohms. 4-11

1K Ohms/V 4-3 4-10. Simplified Diagram, Voltage4-3. Simplified Circuit, DC Voltage Protection. 4-13

10 Megohm 4-4 4-11. AN/PSM-37 Multimeter Controls 4-154-4. Simplified Circuit, AC Volts, 5.1. AN/PSM-37 Multimeter Handle. .5-2A |

20K Ohms/V. 4-6 g., ^^g Diagram, AN/PSM-37. 6-36-2. Schematic Diagram, AN/PSM-37. 6-5

ii Change 1

T.0. 33A1-12-933-11

LIST OF TABLES

Number Title Page Number Title Page

1-1. Equipment Supplied 1-1 5-2. Overload Limits. 5-22-1. Test Equipment Required for 5-3. Multimeter Input Impedance Checks. 5-4

Servicing 2-1 5-4. Test Equipment Required for5-1. Multimeter Basic Accuracies 5-1 Calibration 5-8

iii/(iv blank)

T.0. 33A1-12-933-11

SECTION I

INTRODUCTION AND GENERAL INFORMATION

1-1. INTRODUCTION, b. Current ampere; 10 amperes withMX-9127/PSM-37

1-2. This manual contains operation and mainte-nance instructions for the AN/PSM-37 Multimeter, c. Resistance 100 Megohmspart number 4D-3573. This section providesdescription, purpose, leading particulars, equip-ment supplied, identification data, related tech- e

nical manuals, and reference documents for theAN/PSM-37 Multimeter (hereafter referred to as All measurements are made with testthe Multimeter). See figure 1-1. leads connected to two jacks at the

bottom center of the panel, with1-3. PURPOSE. The Multimeter is a general RANGE, FUNCTION, and POLARITYpurpose, ruggedized instrument designed for switches in appropriate positions. (Seetroubleshooting electrical and electronic circuits, section IV for operation procedures.)The Multimeter is used for measuring resistance,ac and dc voltage, and ac and dc current. Acces-sories supplied with the Multimeter extend the 1-4. GENERAL INFORMATION.useable range of the basic meter (see table 1-1).The maximum indications that can be obtained 1-5. DESCRIPTION. The Multimeter and acces-are as follows: series are contained in a durable plastic case (see

figure 1-2). The Multimeter is watertight with thea. Voltage 1000 volts; 5000 volts dc with cover on or off. The overall size of the Multimeter

MX-1410/V is 8-1/2 inches high, 7 inches wide, 5 inches deep

Table l-l. Equipment Supplied

Nomenclature Manufacturer’s part number

Multimeter, AN/PSM-37 4D-3573

Test Lead Set, CX-2104A/U 4D-3563

Test Prod, MX-1410/U 4D-3566

Shunt, MX-9127/PSM-37 4D-3565

Test Adapter. MX-9128/PSM-37 4D-3564

Alligator Clips (Part of test lead set) 4D-3592-1 (Red) 4D-3592-2 (Black)

Needle Tip 4D-2674

Adapter, Phone Tip 4D-2887

1-1

T.0. 33A1-12-933-11

(( ^^^________nnn________^^/^_ ^I ( /^MULTIMETER ^^ ^^ FOURDEE ^^\ \

^y AN/PSM 37 ^ ,^--^-^^yP/N 4D-3573 (M 1US ^^^ Q ^^^^F41508-76-D-0106

y^ ^< SER. NO.

n ^ ) ) >OHMS /-=-\

+-- Nj\ /L//^^^ Dc T^JI^^

5 (C) ^Ji^ ^1’ ^/ ^fc-(C) ga AMPS /Y IY^20^^ SAFE "’V / fl v^50 D

PULSE M^( n ^yll j1K" v

2.5 ^^j j 500

SPECIAL^4^-^K ""/^\ /^^N"5 ^ ^-^^ ^000. ^v ^^^(^(^ ^ s)

^v ^J}Figure 1-1. AN/PSM-37 multimeter

4 DM-3

1-2

T.O. 33A1-12-933-11

r~\- :-^^ u ~i( n

(C)\ G, ^_

’-L^J^ L-’4DM-17

Figure 1.2. AN/PSM-37 multimeter

1-3

T.0. 33A1-12-933-11

and weighs 7.5 pounds. The Multimeter requires 1-1 1. WARNINGS, CAUTIONS, AND NOTES.six AA size 1.5-volt cells (batteries) for proper Warnings, cautions, and notes which appear in thisoperation. The basic meter movement is a manual are defined as follows:50-microampere meter mounted on a plastic caseand connected via three selector switches to |-------^precision measuring and metering circuits. The WARNIH6 jMultimeter handle serves multiple functions. It can ^--^^be used to carry or suspend the Multimeter. The An operating procedure, practice, etc.,handle may be stowed in a collapsed position, or which if not correctly followed, couldbe pivoted in its extended position to form a fixed result in personal injury or loss of life.easel. This is accomplished by sliding the handle

tfrjfjjjjjjjjjj.

ends into notches in the case lip (see figure 1-2). CAUTIONfig-^^i^---*-----’

.; T,, ,.. An operating procedure, practice, etc.,1-6. The Multimeter cover is mounted on front or

^^ ^ ^ ^^ observed, could re-rear of Multimeter case.

^ ^ ^^ ^ ^ destruction of,equipment.

1-7. The data plate in the cover opens to provideaccess to the accessories in the stowage space Notebehind the data plate. To open, slide data platetowards hinged side so that it moves out of slotted An operating procedure, condition, etc.,catch. The data plate will hold in the open position which it is essential to highlight.until pushed closed. Accessories contained in coverare listed in table 1-2 (see figure 1-3). 1-12. LIST OF TIME COMPLIANCE TECHNI-

CAL ORDERS.

1-8. RELATED PUBLICATIONS. T.O. 33A1-12- 1-13. This technical order includes all changes,933-14, Technical Manual, Illustrated Parts additions, and deletions required by the followingBreakdown, time compliance technical orders:

1-9. DEFINITIONS. T-0- No- DATE TITLE

1-10. The words SHALL or WILL are used in this 1-14. IMPROVEMENT REPORTS.manual to indicate mandatory requirements. Theword SHOULD indicates a nonmandatory desire or 1-15. Suggestions for improvements to this manuala preferred method of accomplishment. The word shall be forwarded to OOAMA (MMST), Hill AirMAY indicates an acceptable or suggested means of Force Base, Utah 84406 in accordance with

accomplishment. T.O. 00-5-1.

\A

T.0.33A1-12-933-11

esZ^I^I

CLIP, ADAPTER SET ’3 0^SHUNT

BAG, PLASTIC INSTRUMENTMULTIRANGE

MX-9127/PSM-37

PROD. TEST MX-1410/UD-5000 VDC VOLTAGE RANGE MULTIPLIER

TEST LEAD SET

S A c B "ng g_^-ADAPTER. NEEDLE TIP ADAPTER TESTPHONE TIP MX-9128/PSM-37

4DM-2

Figure 1-3. AN/PSM-37 multimeter accessory set

1-5/( 1-6 blank)

T.0. 33A1-12-933-11

SECTION II

SPECIAL TOOLS AND TEST EQUIPMENT

2-1. GENERAL REQUIREMENTS.

2-2. GENERAL. Table 1-2 lists test equipmentrequired for repairing and maintaining theAN/PSM-37 Multimeter.

Table 2-1. Test Equipment Required for Servicing

Equipment Use andnumber Nomenclature application

FLUKE 5205 CALIBRATOR High ac voltageor Equivalent POWER AMPLIFIER calibration

FLUKE 5101A METER Ac and dcor Equivalent CALIBRATOR voltages, ac and dc

amperes, and resistancechecks

AN/PSM-37 MULTIMETER Impedance checksor Equivalent

2-1/(2-2 blank)

T.0. 33A1-12-933-11

SECTION III

PREPARATION FOR USE AND SHIPMENT

3-1. PREPARATION FOR USE. 3-5. OPERATIONAL CHECK. After completingbattery installation, remove test leads from stor-

3-2. GENERAL. The AN/PSM-3 7 is packaged in a age compartment in cover. Connect test leads toone unit container. The accessories are stowed in Multimeter. Rotate FUNCTION switch to OHMS/the compartment behind the data plate in Multim- ^P, RANGE switch to RX 10, and AC/DC +-/OFFeter cover. The batteries and a copy of this manual switch to DC +. Short test leads together andare packaged in the unit container but external to vg^y n^er indicates up-scale. Using ZERO OHMSMultimeter case. ^nob, adjust meter indication for 0 OHMS. When

0 ohm indication is obtained, check that meter

CAUTION continues to indicate approximately full scale,’..^..rrrrrr, with DC position and FUNCTION switch in

< i+- ^ OHMS/STD. If the preceding indications cannotWhen removing Multimeter, do not cut -be obtained, check batteries for proper installa-deeper than carton closure, or damage tobatteries or manual may result. lon’

3-3. UNPACKING. Open unit container and re-^^,^

move batteries, which are located just inside carton CAUTIONtop closure. Remove the manual which is between w^ow****^the cushioning and the carton wall. Remove Mul- p^r to using the Multimeter to measuretimeter from carton and, remove Multimeter voltage or current, read the operatingcover. Open data plate and check that listed acces- instructions contained in section IV.series are all included.

3-4. BATTERY INSTALLATION. Use instruc- 3-6. PREPARATION FOR SHIPMENT.tions on the data plate and install batteries. Thebattery compartment has raised markings showingthe proper battery polarities. The Multimeter is 3-7- Retnove the battenes and P^ the Multlm-

not protected against accidental reverse battery eter in accordance with current packing and ship-

installation and will not function properly unless P"^ directions.

all batteries are properly installed.

3-1 /(3-2 blank)

T.0. 33A1-12-933-11

SECTION IV

OPERATION INSTRUCTIONS

4-1. GENERAL, switch (S2) in the IKn/V position, and RANGEswitch in any position, resistors A3A3R1 through

4-2. This section contains the theory of operation A3A3R7 provide the series resistance values forand operating procedures for the Multimeter, the required ranges of the Multimeter. The series

resistors and resistors contained in the meter4-3. THEORY OF OPERATION, amplifier circuit comprise the required resistance

for IKn/V operation. The meter amplifier (U3)4-4. INTRODUCTION. The Multimeter is a pre- provides an output current proportional to thecision general-purpose test instrument which corn- input voltage. Due to the large open-loop gain ofbines the functions of an ac and dc voltmeter (with the operational amplifier, this current is inde-both 20,000 ohms-per-volt and 1,000 ohms-per- pendent of the meter resistance (Rm) but isvolt meter sensitivities), an ammeter, an ohmmeter, directly proportional to the very stable senseand a 10-megohm function. The settings of the resistance (Rs) A1R20.FUNCTION, RANGE, and POLARITY switchescontrol the characteristics and range of the meter 4-8. DC VOLTAGE 10 MEGOHMS. Thecircuit, and the discussion of the theory of opera- simplified circuit is shown in figure 4-3, with thetion will therefore be divided into the individual FUNCTION switch in the 10 MEG S2 position.circuits resulting from each combination of switch The resistors for the 10 MEGn function aresettings. The complete schematic diagram is located on PWB A3A5, and are labeled A3A5R1shown in Section VI, figure 6-2. through A3A5R14. The combination of resistors

A3A5R1 through A3A5R14 provide the resist-4-5. FUNCTIONAL OPERATION, ance for the required ranges of the Multimeter

using the 10 MEGO function. The resistors of4-6. DC VOLTAGE 20,000 OHMS-PER-VOLT. RANGE switch A3A2 and resistors contained inThe following paragraphs describe the operation the meter amplifier circuit comprise the requiredof the Multimeter for measuring dc voltages using resistance for 10 MEGn operation. The meterthe 2OKI2/V function. Refer to figure 4-1 for the amplifier (U3) provides an output current pro-following discussion. With the FUNCTION switch portional to the input voltage. Due to the large(S2) in the 20Kn/V position, and RANGE switch open-loop gain of U3 this current is independentin any position, resistors A3A4R1 through of the meter resistance (Rm), but is directlyA3A4R6 provide the series resistance values for proportional to the very stable sense resistancethe required ranges of the Multimeter. The series (Rs) A1R20.resistors and resistors incorporated in the meteramplifier circuit comprise the required resistance 4-9. METER AMPLIFIER U3. All ac measure-for 20KI2/V operation. The meter amplifier (U3) ments and the dc measurements on OHMS andprovides an output current proportional to the 10-megohm input impedance functions use ampli-input voltage. Due to the large open-loop gain of fier U3. U3 is a high-input impedance integratedthe operational amplifier, this current is inde- operational amplifier selected for low-input biaspendent of the meter resistance (Rm) but is and offset currents. It features low power con-directly proportional to the very stable sense sumption, low harmonic distortion and internalresistance (Rs) A 1R20. frequency compensation. The high-input imped-

ance of U3 does not load the input circuits and4-7. DC VOLTAGE 1,000 OHMS-PER-VOLT. thus does not affect the accuracy of meter read-The following paragraphs describe the operation ings. The low power consumption of U3 pro-of the Multimeter for measuring DC voltages longs the life of the batteries used in theusing the 1KO/V function. Refer to figure 4-2 Multimeter. The internal frequency compensationfor the following discussion. With the FUNCTION features allows accurate ac voltage measurements.

4-1

T.0. 33A1-12-933-11

i 8cc 5

@ < c$ I.--- --l --WSr-ljl

": A u-

i /\ sI / s \sUJ /_________\

T[-__^ CO

g f il ^> o 510 a

.------------------^-- --w^-y^-1|, oS ^ 8 ^5 ^ (E (0 (E 0

> < N ^0 ^ ^in <2 o < N

M < ^ j2CM 0a. &

3 ^ <j

^ i s ^|-------- s Ii i i> $

s _s i5 s

o <> o^-------- I" Y ^ i^ ^- / ^

g 3 5 ^/ ? T > ^ -1/ i ^ sy a < -

> A <D^ 0 CC

IS^. I j i l

r4"g \,S^ Y< wA /\

Q ^Ui U

5CD

4-2

T.0. 33A1-12-933-11

5 8^ ’CC ^

(R) < ^ s

I--- ---f-^WSr-ll. S

’ A1 /\a. / q \ "-

\t- / \ ln

^ T T ^^---- ^5 <’< 8 gs ^ ^----I ^------------------"----- --WSr-i-^A/^(--||l tS

in v ’-<

^ SS S______s ^ < < j I-> 5 ^ .t:1 3 ?

fc

-S^< q-

5 3 0 :?(j) 8 < " |S J \ 0< $

"L-^ ^ << t P 3y^ ^< S < M </ ^---------------- ?/r T . ? ! . -’. ( i-^-FCa j | $ E

^ vi g E E ^ "

j^". V1 1/\ <t OT ^\

0Ua: 5CD

4-3

T.0.33A1-12-933-11

4D3666 4D3627

S1 S2E

BLACK \--0^ 0-. RED \-----------ff---0----.= 10Mf2

ri^ |---WS----WSr^ HR8 R7

^I--I-----^ 1 /------W^\ rf R6

-0 D--^U R5

9 0------WSr-\ Cl R4 R11

\ ^------VNAr^\ R3

\ R12

’----------^AAr^p2 LF351N

A1R18 S^

1---------------W\r- -^A^-^AA^-( >-|-^AAr< ^s.R1 R14 R13 U3 ^%---i

------------^-----------~l^ ^S

4D3628 {^) M1

S3 V--’

R20

^ 2K I2

4DM-7

Figure 4-3. Simplified circuit, dc voltage 10 Megohm

4-4

T.0. 33A1-12-933-11

4-10. AC VOLTAGE-20,000OHMS-PER-VOLT. and the RANGE switch at any position. TheThe simplified circuit is shown in figure 4-4, with resistors for the current-range switch are locatedthe POLARITY switch (S3) at AC and the FUNC- on A3A1 switch and A4 (encapsulated module)TION switch at VOLTS-20Kn/V. Resistors located on the PWB Al. Current measurementsA3A4R1 through A3A4R6 provide the series are accomplished through the use of a commutatedresistance values for the required ranges of the shunt resistance and the voltage sensitive meterMultimeter. The series resistors and resistors amplifier (U3). Due to the very high input imped-contained in the meter amplifier circuit comprise ance of the meter amplifier, there is no significantthe required resistance values for 20KO/V opera- loading error. The high-input impedance of U3tion. A diode bridge circuit consisting of CR3 also eliminates the contact potential errors of thethrough CR6 provides an absolute value function current-range switch. This is accomplished bywhich converts ac inputs to a rectified dc current allowing the shunt resistance to be in parallelthrough the meter (Ml). The large gain of U3 with U3 and switching only the entry point ofeliminates diode voltage drop errors. At higher the current load. The sense resistors (Rs) for thefrequencies, the high slew rate of U3 keeps the highest current ranges have built in sense taps toerrors low. Mechanical inertia in the meter move- obtain the required accuracy. The voltage sensi-ment averages the waveforms to a stable reading, tivity of the ampere function is 50 millivolts, full

scale. The current protection circuit provides a4-11. AC VOLTAGE 1,000 OHMS-PER-VOLT. shunt for large over-scale currents. Four high-The simplified circuit is shown in figure 4-5, with current diodes are incorporated in opposing polar-the POLARITY switch at AC and the FUNCTION ity parallel paths of two series diodes each. Dualswitch at VOLTS-1K.S2/V. This circuit is essen- series diodes are used to meet the peak voltagetially the same as the 20KS2/V function, except requirements for the integral pulse mode. Pro-that the 1KS2/V resistance string of A3A3R1 tection is required to prevent shunt bum-out forthrough A3A3R7 has been switched in. These ten ampere overloads on all scales.series resistors and resistors in the meter ampli-fier circuit of U3 provide for 1KO/V, ac operation. 4-14. SPECIAL. With the FUNCTION switch at

SPECIAL and the RANGE switch at any position,4-12. AC VOLTAGE 10 MEGOHMS. The the simplified circuit is shown in figure 4-8. Theresimplified circuit is shown in figure 4-6, with the is no RANGE switch in the SPECIAL configura-POLARITY switch in AC position and FUNCTION tion. The positive lead is connected to the meterswitch in VOLTS 10 MEG position. The amplifier via the S2E portion of the FUNCTIONresistors for the 10-MEGn function are located on switch. This function is used for measuring veryPWB A3A5. Resistors A3A5R1 through A3A5R14 low currents.comprise the input impedance voltage divider.RANGE switch A3A2 switches in the resistors 4-15. OHMS. With the FUNCTION switch atlocated on PWB A3A5. The combination of OHMS, the simplified circuit is shown in figure 4-9.these resistors and resistors located in the meter The basic operation of the ohmmeter circuit isamplifier circuit comprise the required resistance derived from a constant current source. Two volt-for 10-MEGn operation. The diode bridge circuit ampere sensitives exist and both are at 20 ohmsconsisting of CR3 through CR6 provide an abso- center scale. The STANDARD scale is 1.34 voltslute value function which converts ac inputs to a and the LP (Low Power) scale is at 0.094 volt. Therectified dc current through the meter (Ml), sensitivity of Ul is changed by the FUNCTIONThe large gain of U3 eliminates diode voltage switch (LP f2 or STD S2) and the gain of the meterdrop errors. At higher frequencies, the high slew amplifier is changed by the OHMS RANGE selec-rate of U3 keeps the errors low. Mechanical tor switch (A3A1). Protection on the ohm’s func-inertia in the meter movement averages the wave- tion is provided at the voltage source. The voltageforms to a stable reading, source for the ohm’s function is a unipolar voltage.

When the voltage source is overloaded, it becomes4-13. AMPERES MILLIAMPERES. The simpli- a constant current source. The high voltage tran-fied circuit is shown in figure 4-7, with the FUNC- sistor bears the brunt of the overload voltage forTION switch at AMPS-MA/PULSE MA position positive swings. The 1N4007 diode blocks the

4-5

T.0. 33A1-12-933-11

^ jIL ^./]\^ g ^rK Qy^T^^T111x ^C u^

/ 3 \ S* S

^I T < 8

$ "*3------4-^^-4^a- S "v T T^c t^

> ’---i <^> > ^i------------------^---AA/Sr--W\---1|1 1----\(---’ IS ^ g ^ 1\

s ^ ^ g S a ^^ ^ S 5 2 5 ^ ^ ^N 4 4 5 ^oc o

I I I S.-------------i .^s

n aSC. J

S l ^g 5 ^s 8 <L o^ s I^-- ^ > ^l t’-o y> Q s 5 5 co

/ ^-----^--- ^/ Q s ’^f

/ ? T >5 ! ^^ g 38

$5 (R)(D flr

" 111 i; SS S 8 | J0 <

. \^"I YJL ^XQ ^HI U

5CD

4-6

T.0. 33A1-12-933-11

01

oc .^^^. ^ ^0 X \ 0 Q

r\ \~0 y^ -^^"t^11/ ^s \ CC

^I T 5 8

^^ ------------< ^-NAA^i

^^{___ |h: |

I------------------"~---T---WSr^-WSr-^ll ^---|(--1 0

E SG SG v ^> 5 S g E a aS 5 ^ < < 3 | |

" ^ ^^ 3’0 ci ?

________________^ < .iS(^

s Is^.

/.

g 5 I3 0 ---------- .5

3 I \ ^ S’3

5 9 \_ > ^ ^’--0 P Q, S ^/ V < M S

/ Q ? S i|/ S P^ in < ?M

1 to(M cc .^ c

i s / a 5 ^5 a s 5 5 ^ 5 5

A""<o o(6 f"0V W t

/\ /\Q ^ui <-)

5m

4-7

T.0.33A1-12-933-11

4D3666 4D3627

Vs1 ^ \ J2!BLACK )---OT O-l RED >-------------0---0----i

-L- WMSl

A3A2 ____. .____AA-A

4D3684 |----W^---W^R8 R7

^|--|----< /----^/^Ar^[ \ 0 y Re

-0 D--K7 R5

0 0-----WSr^\ ^. R4 R11

\ ^------^AAr-\ R3

\ R12

^-------------WS^R2 A1R18 LF351N

R14 R13 200K ’S.

-----------B-^0---------------- CR3 ^^ N>t cR4

CR5 ^^ if^\ M1 X (;R6

A1R23

_^\^_| i,-----------A

^ A1R24 ^ A1R20A1C23 ^"^ ^ ^

4DM-10

Fuw 4-6. Simplified circuit, ac volts 10 Megohms

4-8

T.0. 33A1-12-933-11

2 G 7

(R) s ^ s

I--- -^ ^SAAHl. s

s? A

^ito

I(E ’IS

I2 ^SjS.,__E: 1 I

I Si ^ ^0 ^^ Q (’’’

/ Q>s--------i---- - 1"< / ? ? . ?

I ts 3!>i i > |n I- d

^-^ I. H.[" 5

A A ^U1-

4-9

T.0. 33A1-12-933-11

A1R18200K S^

RED ^-----------------\\\------ ^^^A1R30 $__

^^^11^ ^ ^^^^ ^^K .^ ^.BLACK ^>-- ] f ^+/- -F w1

A1R20

i"4DM-12

Figure 4.8. Simplified circuit, 100 VAllOOmV

4-10

T.0. 33A1-12-933-11

+4.5V

Constant / ^Current V /

^r MJ205 IN4007

t-r-^^ (TT""--" ^ ^" -^*

T ^^o^6 (!) TL066CP /\|\

FUNCTION \ 2N2222 ( J-)---SWITCH y^ \ l’ 1^/

!CURRENTSENSE

-4.5V

-------f^,------------------( i-(x--.OPERATIONALAMPLIFIER [PROTECTON

UNKNOWN $

METERAMPLIFIER >^\ A"’18

^ b-----------^AA(---------(X-1(--< "3 L l

-^^ P-- ^(f RANGE

^SJ ^> SWITCH

/^ "^N LF351N

\^y STDA1R22LPA1R39

1------- -w^-i

4DM-13

Figure 4-9. Simplified circuit, ohms

4-11

T.0. 33A1-12-933-11

overload potentials for a negative voltage swing, a. A3A1 is the range selector switch for OHMS.High performance for this unit is derived from the It connects metering neutral through resistances ofoperational amplifier (Ul) and the constant cur- 1.78K, 17.8K, 178K and 1.78M ohms and tworent source of (Ql). resistors (R37 and R25) located on the Al PWB.

FUNCTION switch S2C in STD OHMS position4-16. OVERLOAD PROTECTION. The following also connects resistor R23 (26.7K) of Al PWBparagraphs describe the functional operation of the into the metering circuit. In LP OHMS positionvoltage protection circuit of the Multimeter. R39 of Al PWB is connected into the meteringFigure 4-10 is a simplified circuit diagram of the circuit. The other portion of A3A1 is the RANGEvoltage protection circuit. The operational ampli- selector switch for AMP. Three resistors Rlfier (U2) is located on the OHM SOURCE/METER (80.6 ^) R2 (15 n), and R3 (4.0 n) are physicallyAMPLIFIER PWB (Al). The SPARK-GAP, pro- located on the RANGE switch. Four other resist-tection circuit (A4) is electrically located in the ance values of the AMP RANGE switch are locatedinput circuit of the Multimeter. The VOLTAGE in encapsulated module A4, located on the AlPROTECTION BRIDGE circuit is contained on PWB. The RANGE switch will allow currentthe A2 PWB. On the 1000-volt range, the voltage measurements from 0.1 mA to amp.protection circuit (PWB A2) protects the meteragainst overload voltages. For voltages above b. A3A2 is the 10 MEGn input-impedance1500 V rms, a spark-gap (A4) cuts in to pro- range selector switch. It connects the input totect against internal arcing. Refer to Section the meter amplifier (U3), via S2E, to the appro-VI, schematic diagram (figure 6-2), for protec- priate tap on the 10 MEGO voltage divider. Thetion circuits of the Multimeter, resistors of the 10 MEGn selector switch are

located on PWB A3A5.

4-17. METERING CIRCUITS. All functions of c. A3A3 is the 1K n/V RANGE selectorthe multimeter are connected through meter switch. It connects the positive input terminal toamplifier U3 and to meter Ml through FUNCTION range resistances of 500SI, 2K, 7.5K, 40.2Kswitch S2B. Ml has a sensitivity of 50 jua (+/-1%) 200K, 249K and two parallel resistors of meg-full scale with a resistance of 2Ki2 +/-1%. ohm each. The output of the RANGE selector

switch is applied to the meter amplifier circuit via4-18. BATTERIES. The multimeter requires six switch S2D.1.5-volt alkaline batteries for proper operation.The batteries are located in the battery compart- d. A3A4 is the 20K S2/V RANGE selectorment on the back of the multimeter. The correct switch. It connects the positive input to resist-polarity for battery placement is marked in the ances of 10K, 40.2K, 150K, 806K, 4.02M, 4.99Mbattery compartment and should be strictly and 10M ohms. The output from the 20K n/Vadhered to. RANGE selector switch is fed to the meter ampli-

fier via switch S2D. Switch S2C connects themeter amplifier to ground through resistor R20 on

4-19. CONTROLS, the meter amplifier PWB.

4-20. RANGE SWITCH A3. A3 is the RANGE 4-21. FUNCTION SWITCH S2. S2 is the FUNC-selector switch and is used to select the correct TION selector switch and interconnects the input,measurement range. The proper range for voltage meter amplifier, overload, and metering circuits toor current is normally that which gives the great- obtain the proper circuit for proper operationest scale deflection without going overscale. The for each function.proper ohms range is normally that which producesa reading within the wide-band part of the green a. S2E is the input selector switch and connectsarc on meter Ml. the positive Multimeter terminal to the appropriate

4-12

T.0. 33A1-12-933-11

+4.5

iWNff jll -0 "ED

^ ^ ^ INPUT

---------^ + W^ l X \

"3 ^------- 1N6263 J-f---0 BLACK

LF351N ^< Y^

-4.5

-----^/^/^,--------------------------OPERATIONAL AMPLIFIER

INPUT PROTECTION

4DM-14

Figure 4-10. Simplified diagram, voltage protection circuit

4-13

T.0. 33A1-12-933-11

input circuit according to the function selected. 4-25. RANGE SWITCH. The RANGE switchThe switch is constructed so that the high voltages (see figure 4-11) is located on the lower rightor currents applied to one function will not break side of the Multimeter front panel. Once thedown to other input circuits incapable of tolerating FUNCTION switch has been set, the RANGEsuch overloads, switch should be set to the proper range to pro-

vide an accurate indication on the meter.b. S2C is connected to the negative input termi-

nal and provides a ground path for the particular 4-26. POLARITY SWITCH. The polarity switch isfunction selected. A ground path for the meter located centrally on the right side of the Multim-amplifier is also accomplished through the selected eter front panel, but is not marked as such.function of the FUNCTION switch (S2C). This switch turns the Multimeter on and off and

selects the nature of the measurement to be made,c. S2D provides a ground path for the LPS2 DC +, DC -, or AC. The + and polarity indi-

function and for the AMP function when measur- cates the polarity applied to the red jack whening an ac current, the meter reads upscale on dc measurements,

and the output polarity of the red jack whend. S2A connects the proper battery voltages making ohms measurements.

to the electronic components incorporated in themultimeter circuitry according to the function 4-27. OHMS ADJ. The OHMS ADJUST con-selected. trol is located centrally on the left side of the

Multimeter front panel. The OHMS ADJUSTe. S2B connects meter Ml to the meter ampli- is used only to set full-scale deflection with the

fier circuits. The path for current flow through test leads shorted prior to making resistancethe meter depends on the function selected for use. measurements. This control adjusts for varia-

tions due to battery condition, temperature,4-22. POLARITY SWITCH S3. The POLARITY range and function settings.switch is used to cut the meter on and off, and toselect DC or DC + and the ac mode. 4-28. SAFE SWITCH. The SAFE switch is a

make-and-break switch and is normally closeda. S3A is the amplifier feedback selector switch. (NC). The switch is pressed to open the negative

In dc polarities, it connects the meter amplifier input of the Multimeter while connecting thecircuit to the meter via meter FUNCTION switch Multimeter leads to a circuit for measurement.S2B. For ac operation, S3A provides a groundpath for the meter amplifier through the network 4-29. OPERATING PROCEDURES.of R23, R24 and C23. S3A also connects thebridge rectifier circuit of the meter amplifier in x********x^the ac position. CAUTION

rjjjjjijujjj-jjj^

Prior to making any measurements, readb. S3B connects the proper battery vol ages and

^ ^^ ^ ^ ^ OPERATINGpolarities to the proper electronic circuits of the PROCEDURES. Failure to follow themultimeter.

operating procedures could cause dam-

c. S3C provides the path for current flow whenthe Multimeter FUNCTION switch is in the 10- a- General. Check that the meter is mechanical-MEG position. ^ zeroed, if not, adjust in accordance with para-

graph 5-6.4-23. OPERATING CONTROLS. 4-30. VOLTAGE MEASUREMENTS. Ac and dc

voltages may be measured directly on the ME-418/4-24. FUNCTION SWITCH. The FUNCTION PSM-37 in the range of 0 to 1000 volts at inputswitch (see figure 4-11) is located on the lower impedances of 1000 ohms/volt, 20,000 ohms/left of the Multimeter front panel and provides volt, or at a fixed 10 megohms. These impedancethe means for selecting the particular electrical functions are marked on the front panel of thefunction to be measured. Multimeter under the VOLTS caption around the

4-14 Change 2 15 December 1985

T.0.33A1-12-933-11

(f ==^\

^=^__________BBS__________^^^_ "^// /^kMULTIMETER ^ ^^ FOURDEE ^^?\ U

^^ef AN/PSM 37 ^y .^---^--^^^^1^ 40-3573 (S/ IJUS .^^^ (C) ^^^s.^F41508-76-D-0106 |f

/^ "^SKSl^P0 \@\ y^/r-^

OHMS y-^ +-N^\|^/

5 ^ LP STD ^^ ^0) ’ffjTOO OFF ^ 50: ^F i^-7+t^ ,., ^^ / RxlO ^Jft^ RxIK ^S^ Da AMPS / / | \\ SAFE "107 7 H \N^50 ]D

SPECIAL^<L--^ ^ ^"/ ^^N / ^^ \~5^.L_-J ^ "1000100MV ^--^ f (0) ) f (0) 1 ^--^^

/ ^^ FUNCTION ^^ v vy / v ^y y^^ RANGE .tf^ s.

\ ^____0^-^ ^-^^____Q^ ^Figure 4-11. ANfPSM-37 multimeter controls

4-15

T.0. 33A1-12-933-11

FUNCTION switch. Measurements of small signals 4-31. HIGH VOLTAGE OR HIGH IMPEDANCEup to 100 millivolts at 1000 ohms (10,000 ohms/ VOLTAGE MEASUREMENTS. The use of testvolt) is available under the SPECIAL function prod MX-1410/U permits dc voltage measurementsmarked on the panel under the AMPS function, up to 5,000 volts at an input impedance of 100To measure voltages in the range of 0 to 1000 megohms. When used with the 500-volt range ofvolts, the procedure is as follows: the 20K n/V function, a full-scale value of 5000

volts is obtained. When used with the 10 MEGfZa. Set FUNCTION switch to 20K n/V, 1K function, it becomes a 10 times voltage divider and

n/V, or 10 MEGf2 as desired, will produce full-scale deflection from 5 to 10,000volts. Do not make measurements over 5000 volts.To make high voltage or high impedance measure-

**ote ments, the procedure is as follows.

The 10 MEGS2 function is inherently a. Set FUNCTION switch to 20K n/V orprotected against overload and is recom- MEGS2 as desired.mended for initial measurements.

b. Set RANGE switch to desired full scale WARNING fe

CAUTION j Make sure equipment is turned off when.****> connecting or disconnecting where high

Whenever taking an unknown voltage voltages may be present. Do not changemeasurement, always set RANGE switch FUNCTION switch while equipmentto the highest range and decrease until under test is energized, or damage tothe proper range is reached. Multimeter may occur.

c. Turn POLARITY switch to DC +, DC -, or b. Set RANGE switch to 500 for 5000-volt full-AC as desired, scale indication. Other full-scale values may be

selected only on the 10 MEGO function, and willd. Connect test leads to meter jacks red lead have a full-scale value equal to 10 times the switch

to red (+) jack, black lead to black (-) jack. setting.

e. Connect test lead tips to circuit being meas- c. Set POLARITY switch to DC +.ured, with black lead to ground or lower voltagepoint (if known). If meter indicates in reverse d. Plug red test lead tip into MX-1410/U.direction on dc measurements, change POLARITYswitch to opposite polarity, e. Connect MX-1410/U clip to high voltage or

high impedance test point. Connect black testf. If a voltage below 100 millivolts is indi- lead to low side or ground. Turn on high voltage.

cated, the FUNCTION switch may be set to If meter indicates in the reverse direction, changeSPECIAL and measurements taken. The position POLARITY switch to DC-.of the RANGE switch does not affect full-scalevalue of the special function. 4-32. HIGH VOLTAGE OR HIGH IMPEDANCE

AC VOLTAGE MEASUREMENTS. The proce-dure of paragraph 4-30 may be used for making

Not(R) ac measurements up to 5000 volts peak with thePOLARITY switch set to AC. The very high

The 10-MEGS2 function employs a impedance of the MX-1410 may be affected byblocking capacitor when set to AC shunting capacitance of the test leads, powerpolarity and permits the reading of low line, etc. Measurements are not recommendedlevel ac signals present on higher level above power line frequencies except for thedc voltages, purpose of monitoring changes or fluctuations.

4-16

T.0. 33A1-12-933-11

4-33. CURRENT MEASUREMENTS. Ac and dc c. Set RANGE switch at proper multiplier socurrents (including pulsed dc) from 0 to ampere that the resistance measured falls in the centermay be measured directly on the Multimeter, and portion of the green OHMS scale on the meter.currents up to 10 amperes may be measuredwith the use of the multirange instrument shunt, d. Plug test leads into meter jacks, short circuitMX-9127/PSM-37. The procedure is as follows, the free ends of the test leads and adjust OHMS

ADJ until full-scale deflection (0 ohms) isa. Set FUNCTION switch to MA/PULSE MA. obtained.

b. For measurements up to ampere, set e. Clip the test leads across the item to beRANGE switch to desired range, measured. Read resistance on the OHMS scale

and multiply by the range setting.c. Set POLARITY switch to DC +, DC -, or

AC as desired, f. If resistance in the opposite direction is alsodesired, change POLARITY switch to DC and

d. Plug test leads into meter jacks. Connect read. The polarity of the red jack matches theother end of leads in series with circuit under setting of the POLARITY switch. An internaltest while the power is off. Turn on power and regulator circuit precludes resetting zero forread meter, routine range-to-range, function-to-function, or

battery discharge effects. This permits rapid in-e. For measurements above ampere, con- circuit measurements at LP and STD, forward and

nect test lead tips to pin jacks in shunt MX-9127/ reverse polarity, without disconnecting the leadsPSM-37. Connect circuit under test to appro- during test to rezero. Different forward andpriate load circuit binding posts. Set the RANGE reverse readings will be obtained on a known pas-switch to 2.5 or 10 to correspond with the shunt sive device only if outside power is passing throughsection used. the device.

f. Turn on power and read meter. For a 2.5- 4-35. CRYSTAL CURRENT MEASUREMENTS.ampere shunt section, the meter is set for 2.5 and To make standard measurements of crystal cur-reads a 2.5 amperes full-scale. Use of the 10- rent, test adapter MX-9128/PSM-37 is used asampere shunt section results in a full-scale value follows.of 10 amperes.

a. Set FUNCTION switch to MA.g. If a current below 100 microamperes is ^r^r: * i, ’-> c

TpTTMrvri^xr i, i, b. Set RANGE switch to 2.5.indicated, the FUNCTION switch may be set toSPECIAL and a full-scale value of 100 micro- c. Set POLARITY TO DC+.amperes obtained. This function is also usefulfor standard external shunts, d. Plug test leads into meter jacks and connect

test lead tips to pin jacks on adapter.4-34. RESISTANCE MEASUREMENTS. Tomeasure resistance from 0 to 100 megohms, the e. Connect phone plug to test circuit and readprocedure is as follows, meter.

a. Set FUNCTION switch to OHMS LP or 4-36. TURNING MULTIMETER OFF. UponOHMS STD depending on whether 100-millivolt or completion of measurements turn POLARITY1.4-volt output is desired. OHMS LP is generally switch to OFF position. The internal amplifiersused to measure in-circuit resistance where semi- draw battery current whenever the POLARITYconductor junctions will block out the effect of switch is not OFF. The batteries when fresh willother components. OHMS STD is best to check operate the Multimeter for at least 500 hours withsemiconductors for forward and reverse conduc- test leads open on the LP OHMS functions and fortion and to minimize the effects of thermal, 250 hours on OHMS STD. The Multimeter mustchemical, or leakage voltage, be off before the cover will fit properly, due to a

mechanical interference interlock incorporatedb. Set POLARITY switch to DC +. into the POLARITY switch knob.

4-17/(4-18 blank)

T.O. 33A1.12-933.11

SECTION V

MAINTENANCE

5-1. MINIMUM PERFORMANCE STANDARDS. 5-4A. Repair of AN/PSM-37 Multimeter handle, re-

fer to figure 5-1.5-2. The accuracies which this instrument is de-signed to meet are marked on the inside cover lidof the Multimeter and in tables 5-1 and 5-2. These 5-5. BATTERY TESTING AND REPLACEMENT.measurement accuracies constitute the minimumperformance standards and may be checked by a. Remove mounting screws from the battery covercomparing the readings of the Multimeter against on the rear of the case and lift off the cover and gas-another AN/PSM-37 or other standard multimeter ket.with accuracies as good or better than the AN/PSM-37 under test. Overload limits are given in table 5-2. b. Remove batteries.

5-3. INSPECTION AND PREVENTIVE MAINTE- c- Use another AN/PSM-37 or equivalent to measure

NANCE eac^ battery for 1.5 volts.

5-4. No periodic maintenance is required beyond Notereplacement of the batteries, adjustment of themechanical zero, oiling the handle hinge pivots. Fully charged batteries will read aboveand visual inspection and cleaning of the Multim- 1.4 volts each. Although proper metereter exterior and accessories. The high voltage readings may be obtained with batteriestest prod, current shunt, and test adapter are pre- reading above 1.1 volts each, batteriescision components which cannot be repaired in the under 1.25 volts have little remainingfield but must be replaced in their entirety if de- service life and should not be retainedfective. except in special circumstances.

Table 5-1. Multimeter Basic Accuracies

Function 77 (25C) 131F (55C) -40F(-40C)

DC volts or amps’- +/-3% +/-5% +/-6%Ac volts or amps +/-4% +/-6% +/-7%Ohms +/-3% +/-5% +/-6%

Note: 100 microamp special: Accurate at 77F (25C) only, resistance 1000 ohms

Ac frequency response: 20 Hz to 30 KHz

(Accuracies expressed in percentage of scale length)

Change 4 5-1

T.0. 33A1-12-933-11

Table 5-2. Overload Limits

Ranges Overload limits

All voltage ranges except 1000 volt ranges 1000 volts ac

1000 volts dc, either polarity

1000 volt ranges 5000 volts ac

5000 volts dc, either polarity

All current ranges 10 amperes dc, either polarity

1000 volts dc, either polarity

1000 volts ac

All ohms ranges 1000 volts ac

1000 volts dc, either polarity

220 volts ac, 30 amperes

300 volts dc, 30 amperes, either polarity

NOTE: Limits apply within the frequency range of 20 Hz to 30 KHz.

d. Replace weak or defective cells with new AA 2. Unscrew the two cap screws and removesize alkaline cells, observing proper polarity as the pin and pin holder from the test lead.marked on battery compartment.

3. Strip approximately 1/2 inch of insulatione. Replace battery cover and gasket and tighten from the lead end.

the eight mounting screws.4. Insert the test lead wire into the pin hold-

5-6. MECHANICAL ZERO. The mechanical zero er, through the hole, and crimp it around the hole.adjustment screw is located at the bottom centerof the meter panel just above the mounting screw. 5. Insert the pin into the pin holder andAdjust the meter for mechanical zero by turning screw the two cap screws onto the pin holder.the screw with a small standard screwdriver.

6. Slide the test lead holder firmly back onto5-7. TEST LEAD SET. In the event that a test the serrated pin holder.lead or pin breaks or a banana plug becomes de-fective, a replacement plug or pin may be attached b. Banana plug.as follows.

1. Unscrew the threaded plastic holder froma. Test Pin. the banana plug.

1. Grip the two plastic cap screws firmly and 2. Pull the threaded holder away from thepull the test lead holder straight back and away metal portion of "banana plug and remove test leadfrom the serrated pin holder, from the eyelet.

5-2

T.0. 33A1-12 933-11

(( ==^ c==^AN/PSM-37PART NO. 4D-357340 HANDLE

SAME AS

SEE DETAIL A DETAIL A

V -. /- -y> n \ / \/ r\ \ \\ 1 ; \ /\ / \ /\ ^u, ^ \ u^ ^

/^O Co ) ./ ^^y ^NSN 9505-00-062-4175 /

0.020 IN. SAFETY WIRE /.

fl I I---Dq

DETAIL ANOTE

INSERT WIRE ON RETAINER RING PRIOR TO SNAPPING IN PLACE. AFTERATTAINING PROPER TENSION ON WIRE, BEND SHARP END UNDER.

Figure 5-1. AN/PSM-37 Multimeter Handle

Chanae 1 5-2A//5-2B blank^

T.0. 33A1-12-933-11

3. Strip approximately 1/2 inch of insulation of performance of the AN/PSM-37 in afrom the test lead. given situation be made when it is

known that the equipment being4. Insert the stripped portion of test lead checked by the AN/PSM-37 is operating

wire into the eyelet and crimp it around the hole. correctly.

5. Slide the threaded holder back over theeyelet and wire. 5-12. PROCEDURE. Measure the input impe-

dance as prescribed in table 5-3 using an operational6. Screw the threaded holder back onto the AN/PSM-37 connected to the test jacks of the unit

metal portion of banana plug and tighten, under test/repair. Place the RANGE, FUNCTION,and POLARITY switches in the positions required

5-8. EXTERIOR CLEANING. The Multimeter is for each step in figure 5-3 on the unit under testcompletely watertight and airtight. It is only and the operational AN/PSM-37. Complete allnecessary to clean the exterior, using a cloth steps and determine that range of any given func-moistened with mild soap and water, and rinse, tion which reads off value by the largest percentage

from the listed reading. If all impedances are cor-5-9. INSPECTION. Under conditions of normal rect or within the allowed tolerances, perform theuse, only periodic routine visual inspection is operational checks listed in paragraph 5-13.necessary to determine mechanical condition,evidence of corrosion, etc. 5-13. OPERATIONAL CHECKS.

5-10. TROUBLE ANALYSIS, a. Set meter to zero with POLARITY switch toOFF.

5-11. GENERAL. The particular circuit or com-ponent causing the trouble may be isolated by b. Set meter to 10 MEGS2, 0.5 Volt, + POLAR-following the procedures in the following para- ITY. Short test leads together. Meter should readgraphs and be referring to the wiring diagram within one division of zero.(figure 6-1) and the schematic diagram (figure6-2). Repair or replacement of components lo- 1. If meter reads correctly, proceed to step c.cated on the printed wiring boards (PWB’s) isdiscouraged. When a component on a particular 2. If meter reads in excess of one divisionPWB is determined to be defective, the PWB will from zero, open Multimeter case and adjust A 1R19be replaced. Problems with the Multimeter will (offset adjust) on the A PWB for zero.normally occur during normal use. A note shouldbe made as to the particular function which does (a) If meter now operates correctly,not operate properly. This should give an indica- proceed to step c.tion as to which section of the meter is not func-tioning properly. Example: Meter operates on (b) If meter continues to read incor-all functions except 10 MEG OHM function, rectly, check resistors R7 and R8 located on(Refer to figure 6-2 in Section VI.) A resistor A3A5 PWB, and resistor R20 on the Al PWB.(or resistors) on PWB A3A5 or wire W17, W15,W5, W64, W29 or W92 through W98 could be (c) If A3A5R7 or A3A5R8 are defec-defective. tive, replace PWB A3A5. If A1R20 is defective

replace the Al PWB.

**01(R) (d) If the resistors are good, the meteramplifier U3 is defective and PWB Al should be

The AN/PSM-37 is unshielded and pick- replaced.up from adjacent high voltage lines ontothe test leads or into the Multimeter may c. Set the FUNCTION switch to STD OHMS,degrade performance under some cir- RANGE switch to any position (except .5), andcumstances. It is suggested that a record POLARITY switch to DC +.

5-3

T.0.33A1-12-933-11

?^ ?^ ?^ 0 0 0 00 iu 2 S S O ’u ^ u ^ u ’^i iu ^j iuS .S S ^ ^r ^i- <^ .S tt; .5 CK; .s oi .>; ff; .s

’S S ^ fc <; < < <: <; <; ^ ^ -^ V ^ -3 ^ ^ ^ ^M i i ! s s 5 i i i ii st i i ^1 ^i3 -5 -g ^ ^; 2 2 2 o o " ^ S ^ S ^ S ^ S^

^ ^ ^ S ^ ^ 5 2 5 s s s ^ 5 ^) 5 ^ S D 5^.O D 0 ^ 1? ’"; ’o "o ’a o^ h h ’s h fc’rt -o c S o < <; <: < ^ ^ S o < o <t; o <^; o <: oO tt-i t>0 ^< IU " <" ’" ’3 "S ..fl U tt lU IU lU

2 o.S 5 o ^.3 ^\3 ^\3 2 " I " 2 " < ^ ^ ^ 2 r^^ ^ S&< a o g oo os; g i2; g a; g ^ > ^ > a .^ co’’c Q< 5 D!; 5 o^ ^ o^ g

’a f^ > ;> > C1’*^ &]’^ ^-’S r^ ’t 5* Tfr 5"

^ > <4- >S tti i-L, a; ^ < tt- <; fc < y- S u S u 3 (u a; [i- < IA. <: [i- < h- < tt.

U- rri IX, (D U., pri fc c ^ C ’S C ^3 ^1- ro ll. f^ U- ro h- m IX.< 0 < S <C O < 0 <: 0 [ri -S W-S u - <C O < 0 < 0 <: 0 <: 0

3 S S o 2 ^y) S C ^ ^.s l o o^ ^ s s i | |

l ^ ^ s s s ^ - ^ ^ 0 0 ^ ^0 rn

g

^ s >>^ ^- ’G6^ ^ 03

S. < 755 ^

&- + + + + + + + + + + + + +

^ ^ ^ ^g -a o ^ o og- ca o o ^i ^ o o o’^ (U BO

^ Cli C X X X X X X X X X X X X X

S O (S c(; a; ff; tt; a; K; 0!; tt; oi oS Qi c^ Q;

C; c/l en co c/a en’3 &O c^ orl l^l &cl &n &o &n S S S S SS c S S S S S S S S E E S S E

-S a a ^ ^ ^ s E E o o o o o^ "S O Q O O O O O O Q Q Q Q Q

^ CL. Cl. O- &- &- &< 0- Cl- ^-l ^-’ ^-’ ^- ^-l

^ ^ >-) _l ^-l i-! >-l i-l i-l ^ co ai co co &n

5

^ ’CC8

(2 + + + + + + + + + + + + +

t >-S cS ^ ^ - o o ^ S g

^ - o o ^^1-C. <; >^ ^ ^ ^ ^ ^ (-^ l^ (^|

ac3

’5 | ^ ^ ^ ^ ^ ^^ ’^ G G G G G G5 [J-1 <C <: <C <: <C <: <: ^ ^ ^ ^ ^s e^ ^ ^ ^ ^ ^ ^ ^ o o o o o[-^ &r> 2 2 2 S 2 2 2 <^i M r^ r^ r^i

Q.<u

0 r^ mi-o o^ m -’^’ i^ ^o r-’ oo c^

S^t

T.0. 33A1-12-933-11

0 0 o o o o ^ r\(^ lu ^ lu o ’u ^ ’u ’^i ’u ^ r ’^i ’y oo’’ ^ ^o^ >; a; >; c^ .: tt; ., a; .>; a; .>; oi .2; S m "2 $ Q

rt S -S eyi S Q S G S ;-’ u-i a m ,",5 ^ " ^’ " " ^ " -f’ ^ .rf’ " ^ " 02 1-1 m > <g <l: (U <; lU l> <, <U <I lU <t,l> <c l> ; t-i

01 3 <*-’ ’*-’ .<f ’*-’ ’*- t-’ -<< S O-i M-i

|^ 5 S ^ S ^ ^ -g S ^ S ^ S ^ S ^ ^ ^ ^ < ^3 ^ ’ 00

^O M " ^ s ^ S ^ S ^ S ^ ^ ^ 5) o

^ ^ 5 ^ 5 ^ 2 ^ S ? 2 ^ 5 ^ 5 ^ 2 ? ^ ^ ^ | ^g ^ g ^ S ^ 5 ^ 5 ^ 5 ^ S ^ 5 ^ 5 ^ ^ a^ | g ^I ’s S’ ^ ^ < S ^| S| ^| ^1 ^S . ^ < ^ n h i( ’0 o; 3 0i; 3 ^’a ff; 5 0e; 5 ai 5 0i S CK o .S o^ oo ’a oi g U ^:

ca <t > ^ > r^ > m r^ m m m rN -S ro rn m < ai

2 <; u- < u- ai ^ < [i. < fc < [i. < [i- < a; .u < a; ^) <; ^ D-ro ll. m l-]- li- ro IJ- m il. m IJ-< m lJ< m ~3 m m il- < m< 0 < 0 <0 <0 < 0 < 0 < 0 <: < -a <: < o < 0 U c^i

o’ o’ 2"e ^

0S (N o ,,j

BB CI U ^ S S’’^ 1^ O fc

j I I I j g ^ S i i I ^<J l> 0 0 0 u-l 0 0 >^ 0 0 2;Q^ (N m r^ i/-i r^ ir>

>, f?S SI ^5 z it < ’o -;S o^ + + + + + + + +____j^____+ + c

"S ^ ^! ^ ^i; ^; 0

Q. -^ 0 0 0 0 ^! 0 0 0 -c^

^ ^ O O O O ^ ^ O 0 O O g,

^ 1> GO ^Q. C X X X X X X X X X X ^S. O ^ ^ ^ aS oi aS ttS ^ S o; os o;; ^^ ^(./i M Gn oo &n c/i cn GO c/3 (/i c/i

^ 2 S S S S S S S S S S g

^ c K K E E E S K E S X; K ^5 .2 0 0 0 0 0 0 0 0 0 0 0 g

^ ’S Q Q Q Q Q Q Q Q Q Q Q 3a c ^. (_ ^, p, ^, ^, ^ ^_ ^ p, ^, c;?! ai iyi &o &^ &o iyi co &o Gfi GCI QO ^c^^ y

^ > 5A c ^2 UK (2 + + + + + + + + + + < <u

rt

ID

-l a^ i

| | 8 8^ - o o ^ 8 | | |

^ ^ M ^ r^ t^) < < rt

"0Q"

c c

^ cG G -S

g .2 ^ ^- > > > > > > > g g tg ^ S ^ G’ ^ G ^ ^ G S S -S3 0 0 ^! ^ ^ ^ ^! ^; ^! o o SS

^ I2 -<^- in <0 (~~ oo o\ 0 r^ m -^t-oQ r^ r-i r< M r^ *

5-5

T.0. 33A1-12-933-11

d. Connect test leads to Multimeter and short 5-15. GENERAL. Field repair primarily consiststhem together, of replacing components such as resistors, capaci-

tors, switches and PWB boards. PWB Al, A2,e. Using the OHMS ZERO adjust, zero the A3A5, Ml and the case (except for the handle) are

meter, not repairable and must be replaced. The accuracyof measurement depends completely upon the pre-

1. If the meter adjusts to zero on the range cision of the component parts; therefore it isselected, repeat the check for all ranges, necessary that each defective part be replaced by

its exact equivalent, both in nominal value and in2. If the meter will adjust to zero on all tolerance. Refer to the Illustrated Parts Break-

ranges, the Meter Amplifier (U3), Operational down for part numbers and nomenclatures.Amplifier (Ul), and the batteries are assumed tobe good. Proceed to step f. 5-16. REPAIR TECHNIQUES.

3. If the meter will not adjust to zero on the a. Do not use a soldering iron which does notlower ranges but will adjust to zero on the higher have automatic temperature control when remov-ranges (RX1K and above), the batteries are weak ing or replacing any PWB Al or PWB A2. Tem-and should be replaced, perature setting of soldering equipment should not

exceed 750’^.4. If the meter will not zero on range posi-

tion (RX100 through RX100K), check the resis- b. Use only 60/40 or 63/37 solder with resin ortors A3A1R4 through A3A1R7 on the A3A1 organic flux. Never use acid flux on electricalswitch for the range affected. (Refer to schematic connections.diagram, -figure 6-2.) Replace defective resistor.

c. If a part is known to be defective it is recom-5. If the meter will not zero on range posi- mended that the lead be cut at one end of the part

tion RX1 or RX10, check resistor A1R37 and to facilitate removal.A1R25 located on the Al PWB. If either of the re-sistors are defective, the Al PWB should be re- d. Ensure that all replacement parts have aplaced, stress-relief bend similar to that of the part re-

placed.6. If the meter will not zero in any range

position, check resistor A1R22 located on the e. Mount parts with the markings showingmeter amplifier PWB (Al). If this resistor is de- where possible.fective replace the A PWB. i---------i

WARNINGf. Place the FUNCTION switch in LPO post- I---------I

tion and repeat steps b. through c, (5). rpi r \ rpj^g ygg QJ^ rnetal screws tor mounting

1. If meter does not read zero on any range, switch, knobs wm create a hazard lf the

check resistor A1R39 on the Al PWB. If this re- ^^ or low slde 01 the potential beingsistor is defective, replace the Al PWB. measured is removed. This hazard could

result in serious injury or death if the po-2. If resistor A1R39 is good and the meter tential being measured is great enough.

still will not adjust to zero, A1U3, A1U1, orA1Q1 are defective, f. Use only plastic screws when mounting

switch knobs, since the switch shafts are elec-W0*0 trically connected to the negative Multimeter

terminal.Upon determining any component onthe OHM SOURCE/METER AMPLI- 5-17. DISASSEMBLY. The following procedureFIER (Al PWB) to be defective the Al is to be used to gain access to various parts of thePWB should be replaced. Multimeter.

5-14. REPAIR, a The meter may be removed without remov-ing the case from the chassis as follows:

5-6 Change 3

T.0. 33A1-12-933-11

1. Remove the six round head machinescrews from the meter panel.

3 Inspect front panel and case interior to en-sure that labeling and the schematic diagram are

2. Lift the meter and gasket off the front legiblepanel.

3. Unsolder the two leads from the meter. b,. ^P^ for cleanliness to ensure that no dustor dirt is present that could deteriorate compo-

C nents, connections, and grounding.

1. Remove the 14 round head machine c Inspect all wiring for charring strength, and

screws from the front panel of the meter. unlform b0"^ of soldered connections.

2. Place the meter face down and lift the d- ^ct an components for physical tightness

bottom case and gasket from the chassis. and evldence of charrlng or burnlng-

c. Circuit boards, g Inspect the circuit boards for charring, burn-ing, cracks, or warping. Inspect all soldered connec-

1. Remove the four screws with lockwashers, ^g ^ bonding.from the circuit board mounting brackets.

f. Inspect rubber gaskets for deterioration and2. Gently lift the circuit board straight up nrooer fit

and off the brackets.

d. The front panel controls (FUNCTION, 5-20. ASSEMBLY. Assembly is in the reverseRANGE and POLARITY switches and the OHMS order of disassembly.ADJUST potentiometer) may be removed asfollows: 5-21. CALIBRATION.

1. Remove knob retaining screw. 5.22. FREQUENCY. This equipment shall bescheduled for calibration as required.

2. Pull knob off shaft..5-23. GENERAL. Verification of calibration Con-

3, Remove shaft nut. 5^5 yC full-scale accuracy checks on each range ofeach function of current or voltage, and mid-scale

4. Gently push switch out from panel, being accuracy checks on each range of the ohms func-careful not to disturb attached or adjacent wiring, ^s. Ac accuracy at 60 Hz is +/-4 percent of full-

5-18. INTERIOR CLEANING. If it becomes scale deflection on all ranges and functions and

necessary to clean the interior, a hot, deionized or wlth a11 ^cessones.

distilled water rinse followed by a thorough drying 5^ ^^ EQUIPMENT REQUIRED. The testis recommended. Drying temperatures shall not ex-

equipment listed in table 5-4. or equivalents, areceed l6U K required to calibrate the AN/PSM-37. Less sophis-

"^AuflON" ticated equipments may be used, provided a basic

ttittsssftssffs3ic or dc accuracy of 0.5 percent or better is ob-tained. The equipment listed provides the entire

Solvents particularly keytones shall not spectrum of calibration requirements. Responsebe used for cleaning because of possible be checked from 50 Hz to 30 kHz. Voltage atdamage to the dielectric materials in the

^^ ^ove is limited to 600 V rms.multimeter.

5.25. PROCEDURES.CAUTION

^""""""^ 5-26. DC MICROAMPERES SPECIAL CALI-Always remove batteries before cleaning BRATION PROCEDURE.to avoid shorting components.

a. Connect test leads from test jacks of Multim-5-19. INTERIOR INSPECTION. The following eter AN/PSM-37 to appropriate jacks of testinspection will be performed to evaluate the physi- instrument.cal condition of the multimeter.

Change 3 5-7

T.0.33A1-12-933-11

Table 5-4. Test Equipment Required for Calibration

Part number Nomenclature Application

FLUKE 5101A METER CALIBRATOR Check ac and dc voltageor Equivalent Check ac and dc current

Resistance checks

FLUKE 5205 METER CALIBRATOR High ac voltage calibrationor Equivalent

b. Set FUNCTION switch of Multimeter to c. Apply full-scale value of current from test in-SPECIAL, POLARITY switch to DC +, and strument and compare with Multimeter reading.RANGE switch to any position.

d. Repeat step c for the 2.5, 10, 50, 250, 500c. Apply 100 microamperes from test instru- and 1000 ranges.

ment and compare with Multimeter reading.e. If Multimeter indications are not within +/-3

d. If Multimeter does not indicate within +/-3 percent of test instrument readings, refer to table

percent of test instrument reading, refer to table 5-3 for probable cause of defect.

5-4 for probable cause of defect.

^ ^ ^^ ^^ CALIBRATION

5-27. DC MILLIVOLTS SPECIAL CALIBRA- PROCEDURE.

TION PROCEDURE.^ Connect test leads from test jacks of Multim-

eter AN/PSM-37 to appropriate jacks of testa. Connect test leads from test jacks of Multim-

eter AN/PSM-37 to appropriate jacks of testmsirumeni.

instrument, b. Set FUNCTION switch of Multimeter toVOLTS 20Kn/V, POLARITY switch to DC +,

b. Set FUNCTION switch of Multimeter to and RANGE switch to 5SPECIAL, POLARITY switch to DC +, andRANGE switch to any position, c. Apply full-scale value of voltage from test in-

strument and compare with Multimeter reading.c. Apply 100 millivolts from test instrument

and compare with Multimeter reading, d. Repeat step c for the 2.5, 10, 50, 250, 500and 1000 ranges.

d. If Multimeter does not indicate within+/-3 percent of test instrument reading, refer to e- ^ Multimeter indications are not within +/-3

table 5-3 for probable cause of defect, percent of test instrument readings, refer to table5-4 for probable cause of defect.

^TT^ MILLIAMPERES CALIBRATION PRO-^ ^ ^^ IK^/V CALIBRATION

CfcUUKb. PROCEDURE.

a. Connect test leads from test jacks of Multim- a Connect test leads from test jacks of Multim-eter AN/PSM-37 to appropriate jacks of test g^r AN/PSM-37 to appropriate jacks of testinstrument, instrument.

b. Set FUNCTION switch of Multimeter to b. Set FUNCTION switch of Multimeter toAMPS-MA, POLARITY switch to DC +, and VOLTS IKn/V, POLARITY switch to DC +,RANGE switch to .5. and RANGE switch to .5.

5-8

T.0. 33A1-12-933-11

c. Apply full-scale value of voltage from test in- 5-33. AC VOLTS 1K n/V CALIBRATIONstrument and compare with Multimeter reading. PROCEDURE.

d. Repeat step c for the 2.5, 10, 50, 250, 500 a. Connect test leads from test jacks of Multim-and 1000 ranges, eter AN/PSM-37 to appropriate jacks of test

instrument.e. If Multimeter indications are not within +/-3

percent of test instrument readings, refer to table b. Set FUNCTION switch of Multimeter to5-3 for probable cause of defect. VOLTS 1K n/V, POLARITY switch to AC, and

RANGE switch to .5.5-31. DC VOLTS 10 MEGn CALIBRATIONPROCEDURE, c. Apply full-scale value of voltage from test in-

strument and compare with Multimeter reading.a. Connect test leads from test jacks of Multim-

eter instrument and compare with Multimeter d- Repeat step c for the 2.5, 10, 50, 250, 500

readings, and 1000 ranges.

b. Set FUNCTION switch of Multimeter to e- If Multimeter indications are not within +/-4

VOLTS 10 MEGS2, POLARITY switch to DC +, P^^"1 of test instrument readings, refer to table

and the RANGE switch to .5. 5-3 for Probable cause of defect.

,, ,, ,, 5-34. AC VOLTS 20K n/V CALIBRATIONc. Apply lull-scale value ot voltage trom the no^^crMTocrKUt-.r’.UUKr’..

test instrument and compare with Multimeterreadings.

^ Connect test leads from test jacks of Multim-eter AN/PSM-37 to appropriate jacks of test

d. Repeat step c for the 2.5, 10, 50, 250, 500 instrument.and 1000 ranges.

b. Set FUNCTION switch of Multimeter toe. If Multimeter indications are not within +/-3 VOLTS 20K S2/V, POLARITY switch to AC, and

percent of test instrument readings, refer to table RANGE switch to .5.5-3 for probable cause of defect.

c. Apply full-scale value of voltage from test in-5-32. AC VOLTS 10 MEGn CALIBRATION strument and compare with Multimeter reading.PROCEDURE.

d. Repeat step c for the 2.5, 10, 50, 250, 500a. Connect test leads from test jacks of Multim- md 1000 ranges.

eter AN/PSM-37 to appropriate jacks of testinstrument e- ^ Multimeter indications are not within +/-4

percent of test instrument readings, refer to table

b. Set FUNCTION switch of Multimeter to 5-3 for Probable cause of defect.

^NCE0^ POLARITY switch to Ac’ 5-35. AC MILLIAMPERES CALIBRATION PRO-and RANGc switch to .5.

LbDUKb.

c. Apply full-scale value of voltage from test3 Connect test leads from test jacks of Multim-

mstrument and compare with Multimeter read- ^er AN/PSM-37 to appropriate jacks of testln^’ instrument.

d. Repeat step c for the 2.5, 10, 50, 250, 500 b. Set FUNCTION switch of Multimeter toand 1000 ranges. AMPS-MA, POLARITY switch to AC, and RANGE

switch to .5.e. If Multimeter indications are not within +4

percent of test instrument readings, refer to table c. Apply full-scale value of current from test5-4 for probable cause of defect, instrument and compare with Multimeter reading.

5-9

T.0.33A1-12-933-11

d. Repeat step c for the 2.5, 10, 50, 250, 500 5-38. OHMS LP CALIBRATION PROCEDURE.and 1000 ranges.

a. Plug test leads into Multimeter AN/PSM-37e. If Multimeter indications are not within +/-4 ^est jacks and short the test lead tips together.

percent of test instrument readings, refer to table5-3 for probable cause of defect,

i- o ci TM^TirtXT * i, r i*-b. Set FUNCTION switch of Multimeter to

5-36. AC MILLIVOLTS SPECIAL CALIBRA- OHMS Lp’ POLARITY switch to DC +, andTION PROCEDURE. RANGE switch to Rx 1.

a. Connect test leads from test jacks of Multim- c. Adjust OHMS ADJUST knob until Multim-eter AN/PSM-37 to appropriate jacks of test eter reads zero.instrument.

d. Repeat step c for the RxlO, RxlOO, RxlK,b. Set FUNCTION switch of Multimeter SPE- RxlOK and Rx OOK ranges

CIAL, POLARITY switch to AC, and RANGEswitch to any position.

c. Apply 100 millivolts from test instrument Noteand compare with Multimeter reading. ^ p^^ ^^ be adjusted on all

.p ranges, the battery voltage is low.d. If Multimeter does not indicate within +/-4 r i, <: < ? uRefer to paragraph 5-5 for battery

percent ot test instrument readings, refer to tabletesting and replacement instructions.

5-3 for probable cause of defect.

5-37. AC MICROAMPERES SPECIAL CALI- e- Connect test leads from Multimeter to appro-BRATION PROCEDURE. Pi^e Jacks of test instrument.

a. Connect test leads from test jacks of Multim- f. Set mid-scale reading on Multimeter with testeter AN/PSM-37 to appropriate jacks of test instrument.instrument.

u c mm--ri/-^T * i, e ^ ^- 8- Repeat step f for the RxlO, RxlOO, RxlK,b. Set FUNCTION switch of Multimeter to r ,ny i v inny

coc^iAi n<->r AnTTvr D M/^ Rx OK, and Rx OOK ranges.SPECIAL, POLARITY switch to AC, and RANGEswitch to any position.

h. If Multimeter readings are not within +/-3 per-

c. Apply 100 microamperes from test instru- cent of test instrument reading, refer to table 5-3ment and compare with Multimeter reading, for probable cause of defect(s).

d. If Multimeter does not indicate within +/-4 5-39. OHMS STD CALIBRATION PROCEDURE.percent of test instrument readings, refer to table Repeat the procedure outlined in paragraph 5-38.5-3 for probable cause of defect.

5-10

T.O. 33A1.12-933.11

SECTION VI

DIAGRAMS

The wiring diagram in figure 6-1 and schematic and table 5-3 in Section V for troubleshootingdiagram figure 6-2 may be used in conjunction and/or maintenance.with the individual circuits depicted in Section IV

ftV.S. GOVERNMENT PRINTING OFFICE: Nf3 771411/MZ2S f. llf. Ua-n\r\

T.0. 33A1-12-933-11

Rxl _C 9^9 wTT A2W2 ________n"25 DC- |-----------------------A,v3 ____<,E30 RxlO 0 0 ill V I------------------------------------------------------------------------------------------------------------------------------ ------~5Q 0)0 SPEC Q 0 LP" OFF Q o DC< /\. W61______________________________________________________________________. __________-_________________________ p6’

"S. < "< IN3491 ^ V. IN3491R W47 W46 |----------------------------------------------~--"--------->0 O^"100 \) OSTO \) OAC /h ’\ ,-A --0-6----o-0-^>-- ..r^------------------------------------------------i5" / < E35 E2 E15 E17 1-18 E9 47 J. V62___ 403628

lSS Qv^ OMEG0

0;’OK"/V S3-PR6SELECT <----------~7 -V f S3B

"^ ’K"/VPOSmON LAYOUT ,N349,R\ ^,N349, S2A 403627 S2A _/

A3 HANGESELECT S2 FUNCTION SELECT ’^’l’9

Q---- 0 6^-ttO^-l 0 O^-BO-- f>POSITION LAYOUT POSITION LAYOUT " "A 0 0- 0

W19 "^? 0 0 ’^^ 0 0 ^ ^*E8 v51 E8 EW" ll0 ’----’ o S38 S:

I-- --! -v W50 ?E-4 ---*--------*--------------- V^M i^ "RED ------0 _16

v ~6 +/-:OVERLOAD " r---------"S5-----, "C^05------, 4036" fo-----1 J’ W52 T^LACK PROTECT Y r ^6

Rl OHMS .___4 O’8 ^--------^Y W65 *( 7./-----------1 11-^-t-l ADJ e"1 ^ I~SW ________^_______"_________,I. ^" T 0< / $ R2 "’ R2 ’ En 0_______I A4WI________I______________S2E J. !! / S VA VA-1 *^-0-0 ____________0 -_______ S3C 0F "-----^- ^r~" s/^4 J / .^T^,- ,^ "y o

666 -^ 9 T’6-L "y ^ " t ^ ?" EM?--------------2 o

/NC ^P T A3A1 E?9 0-T,______+/- I-----( o---- A3A4 I- -0 0-------I-------0 611’ f --- ^i----

ONO Q j^3684 6 0^------, ?~ W25 S2B I \, W24

0 ^3\ f O ?,, 403664 [’" S:1A / O-4-^’7] ’\v-t ’3

E28 ^ ^p---^!’"------------i\ ^R5 ’-------- (M.) ^ s0 A3

\ \_^’ r&-----| _____________0 VOLTAGE

1--W, > Al [- s, Q PROTECT

R6 OHM SOURCE METER AMPLIFIER ^ \ MODULE

r---y-’^-i I-------o"7 w26-^v ~~. ’"^r w87

Fl 1 o^^^"""! ^>^O2 4036" S-3A O

T ----1 W5 E26 / O74 o--n v8’ w3 ^---------------& -^0------------------- ----io--1 _!S------^ .S W6 ^___,

ii-w^--i t

_wio

?T17 |--------)|-------> ^74 P2 E26 __J._ 33 ^ l <^-" ?’-1---i--l " ^ / f l^684 ---? -Egf--W3---,03627-----6 6---------------------------------- w’7 / 1 ’’"’____________W7 ---0-------------- Oil

rA^AT’E^- ---i^-^^- ---! ^y ^" " ^’e f"2 ’59 ^l S3A

r~----- -O"6 L-__4 .---4A3A3 __-0 0^------.-----l^"’^ H-^--) />J^ F684 " ^n ^^"7 ^. r:=^i_ _-_J -4^ 0

W93 I.E23 9 ’S.^ X 1 9 -\2 f -i 1240 /------0 17\ Y-A \-- |__1 65 W41_____________3684 / \ E40 0A3A2 / W94 \ >

R5 ^^--*^-’ f-0\ \/ >------- \- 1</ / -^^--f L- -----------I __________|

^ L.9 A3A5 R6_____ ’----------------------- |E32 "0-------w56-----------------------------------Il-6 -------- RESISTOR i--^----I -6"’ d NETWORK S38 P

" ’^ ^K *6 ^17 ________6_J -----~\, E39 E43 E31 E;4 E23 E21 622 620 0---|

V^L-OE’5 ""r---I 403628

" I T -^------^^l’ ,--------0------^’ "^ O ^28 W37 ---’ f6, ’4|----------’ ’-^^ p^3 6 ^8 """"___, s2^ ^ "" /’O--- I____ -0- -J

0^,, 0-’ ^ ^ r" <n L--_/ iL3.3 ^___ ^0

w57 i w30 r W 0^-----1 p---------------I___________________J J_W64 I---------------------------------------------------------------------------------------------------1 0

S3C p E18 E10 E25

--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------.---------1---------- _9/ T 71 W69 W66

1 ^^ 4DM -1

Fi^fire 6-l. Wiring diagram. AN/PSM.37

6-3/(6-4 blank)

T.0. 33AM 2-933-11

_C E9 w7S A2W2 1"^25 AMP DC 1------------------------------------------------------------------------------------------------------:-----------------------------------------00 RxlO 0 0 A *V A2"3__________________________________________________________________________________________________________________ _______0

SQ OlO SPEC 0 0 OFF 0 DC’ /\ Wfil tl

\, RxlOO \, \, IN3491 .(C ^ IN3491R W47I -IW46 f-------------------------------------------------------^^Rx’OOKo R^K OSTD OAC / \ P’^EM"T^TEir’ET^’ETs’J^t’’’-’ , W\ W62 :,03^8Z o ^0 OMEG

0020K"<V S3 PRESELECT ^- -^ ? ^ -V *V P S3B

""^ 1K./VPOSITION LAYOUT ,N349,R\ ^N349, V 3^ OHM SOURCE/

^ ,o3627 32* _A <?^s s=- y .jL2^^^^---""""^"-"u ,^ ^n ,^ ^ v ..

^wis --------------l

LF35’i| --| Wo o o weT’O o 0 " -X-*

--------------------------------------"E8 WS’ pM L _____________________________^ JlO ’----J p "B S:

-" WSO E14 -’v R’6 f --------"--------------- / 9 I -<> E2r~ ^ RED -SS’--oL. ’OK I--------I ,.,1G -V-<< :L

^OVERLOAD " ,--------WK----- ----------------^

W,

0, I------T--------------------------T-------^------------ww-----I 4D3627 f "^FTI ./ WS2 fPROTECT Rl 01 17 18 0s--------0

Y ^ L7/----w8----, .^V^-, AD^ 2NM67D ^"I.K tv B33J W34 J-S20"’ 0 "4D3627 t"o< / ? R? "’ R2 "’ E13 1 G/? 1 [""^-------I 0 ^--------------------------------I. , A4V>1 I,____________S2E j, Q11 , / f --^^-^^-, ^-<><>----i--------U, ,^^1------& R14 ^ B31 ^ _________0 S3CT^ -W^B ^13 T / ^-i / /---* f lE12.________ ^

v

^ Rg ’9K ? ’6.2K f _^^^^^^^_ 4D3628<L -J <?^---------| <’ // ^ ’it// ^R3^---------I TL06t 68UF?^ Q2 :;499K l L<>ji’M-----=======----------------i3666 ^-- ? -L- C/9 ?R3 f << ^ ~I ’N.7 w^ ’"3 $ E34!f>HC ^ Wl, 09___f A3A1 1^,9 A4 r--$10K I----^< .pA C-i ;. ^_____

0

/ -^ ’----o o--* A3A4 l- -6 o----i----o----i ui >-v^-i >-H iM’x.7 c,, ro--i o---i

9’* ^ SR^03684 ’6 0^------’ Li-s [---^< R4 ^vbY ’--------T^--------n W25 S2B I ^ W2,

P ^’Yj 9 ?,, 403664 8 ’99K1 /FSQ3 ^ |------* <--------| "A f ^_^

’7I ’5\ "-t ’3.E28 +---H- )MJ206 Jl* .^^__^^’23____________/ 0

\ r5 ^-- ^" n (C) ^S_ ^ ?\ 1---ii ;’"o T f"----| I------o(-~v f 249K S2B S W27 8

W20 R6_________________E27 04 /^n I-------6 6--J---.__-------------|i A2

rr--^ ^" s^n ^^ w26 ^^---^i L" ^^n, 05 r ^ .OOK ^ ,03627 0^

1 ’’-6-1 ^, W13 I-------------w-----^----, ’---------*----*-^ Egl ] ^1-6 0---II 1--------------I I----------------I RB R)1 R)2 I------0-----------------------------------I I------rfo--1

R’05 ________________________10 249K____249K w31

^__M p

n17 i-)i-i ^yi" - -.^-j ,_____^^33-_^i T " i-?----*-- ____________________________i W17 / -1 A3A1__________^7 Jh-- -’ i| ^A E36p W32 4D3627

^A3A^<>EM --E?2<?-’>E3--RES^TOR~~1 5(0 9/ ^3 ^"e E42

R37 R25 ^OK R18 | ’5? T^l S3A

1----------’ 17aMll 1--" NETWORK ""B------------1 ^41 178 200K -I ,,9 ----TT ^._______w42 Q^6 y,. ^ 1-_---11> 0---*A3A3 .--6 O8------.-^A/^-i-O^W^------^V^ W-, L ,OK U--""- 0

? "^^T R91

Q’3 l4D3684 ’8 o^ I R4,,-

J- J ------v |------^-----^W43 /

^3 E23 E,2"8M" 4^ 267M"

P ^K f4 9 c^ ^ l-^-------^---------------------’ ___A I-------------S2^--------^2-----------_----J ^/ -fc------^^--T "X -t ’4

^ L^1 SK RM ^^ ^^ E5^________"i!___________-____A-, / ^4 L. r^o ^ j4. ^" \ r5 -L? r^--T-- r-L r-^ ^ bT^cjr,. / .^---0----^------^^T’ .^^\4 L---"!----R6------i .02’ R23 L^______v L-< ^263_)l----I

"(^ .^E9 M ^2 P’1R6 I l----------------------l 374I< CR3\^CR4 F----^----------------------------I

w -^, o ^ j^ji.-^18 ^ i, 2^, L^,-I j-o^^------I r^"’---T--T--T- r---o-----w56------------,--i’00 I R30 ,__^1__, R29 C3 J_ ^ R22 < R39 R21 f R20 ~1 S3B .PO^ ’^E7 R3., 1K ^1 ’OMil ;: <70pf ^-p ;;20K 2S.7K 1.87K 1K ? 2K /

0 H \ W96 J^E17 E6402K R12 C5 T 6 J -----\ ----?---~S--------^---T"" 22’"" E39, .1UF E43; E3t ’-----’ E24 E23 E21 E22 1 E20 --------| |-------- -;__\ i^ps R2 -"---"- --* --"--9-->1--’ --9-- w^" --I\ W97 JE16 .U 2K___E-8 ..sol----| T------------ms- ---------, [ 0 5

’---------S:------^---T^1 ’---------| M9 1 4D3628 _________________22L---J ^i" ___0"i^>p, Rl 6 R14 R13 46 6 S3C _______________________W37 I------------I’

w9e j^3_ E2 ^ ^^U^i.,^

.’ ^ ^ I__________________!"!L.::__ ?! o2? ""To--l l__ _-yiL _.

L"1^ I E. E3o J ^1" .301--------- :=H ^ L--------^<^J .^-------------,

II--A-- 0-- --(-’ I--

____________________J JL.W64 -------------------------------------------------------------------------------------------------------------I 0

-----------------’,---------------------------------------------------------_______________________________________

S3C Q E18 E10 E25

9^8 jV71 JW69 lw66

------------------:------------------------------------------------------------------------- 11-i 4- 4- 4-J 1 o 10 ^I---------------------------------------------------------------------------------------------------------------------------------------------i--------I 4DM-4

Figure 6-2., Schematic diagram. AN/PSM-37

6-5/(6-6 blank)