Directed Electronics A1200/4 Especificaciones

TM 11-5820-670-30TECHNICAL MANUALAVIATION INTERMEDIATEMAINTENANCE MANUALRADIO SET AN/ARC-131(NSN 5821-00-937-4686)HEADQUARTERS, DEPARTMENT OF THE ARMY

TM 11-5820-670-30EL1AT231Radio Set AN/ARC-131(iii blank)/1-0

TM 11-5820-670-302-5. AUDIO POWER OUTPUT AND DISTORTION TEST. (CONT)4. Tune signal generator AN/URM-103 to 60.05 MHz as indicated by maximum indicatio

TM 11-5820-670-302-6. AUDIOFREQUENCY RESPONSE AND FRONT PANEL METER TEST. (CONT)INITIAL EQUIPMENT CONTROL SETTINGSSet equipment controls as indicated

TM 11-5820-670-302-6. AUDIOFREQUENCY RESPONSE AND FRONT PANEL METER TEST. (CONT)EQUIPMENTAN/URM-127TS-723A/UTEST PROCEDURE1.2.3.4.CONTROL AND SWITCH S

TM 11-5820-670-302-6. AUDIOFREQUENCY RESPONSE AND FRONT PANEL METER TEST. (CONT)10. Observe audio output change in db from the 1000 Hz reference (step

TM 11-5820-670-302-7. RECEIVER SENSITIVITY, QUIETING, AND LIMITING TEST. (CONT)TEST SETUPConnect equipment as shown in test setup diagram. Turn on all

2-7. RECEIVER SENSITIVITY, QUIETING, AND LIMITING TEST. (CONT)TM 11-5820-670-30EQUIPMENTAN/URM-103TS-723 A/UAN/URM-127CONTROL OR SWITCHBAND SWITCH an

TM 11-5820-670-302-8. MAXIMUM SIGNAL PLUS NOISE-TO-NOISE RATlO TEST.PURPOSEThis test checks the ratio of received audio signal power and noise power

TM 11-5820-670-302-8. MAXIMUM SIGNAL PLUS NOISE-TO-NOISE RATlO TEST. (CONT)INITIAL EQUIPMENT CONTROL SETTlNGSSet equipment controls as indicated in t

TM 11-5820-670-302-9. RECEIVER CARRIER SQUELCH SENSITIVITY TEST.PURPOSEThis test checks the squelch capability when carrier squelch is selected on th

TM 11-5820-670-302.9. RECEIVER CARRIER SQUELCH SENSITIVITY TEST. (CONT)INITIAL EQUIPMENT CONTROL SETTINGSSet equipment controls as indicated in the fo

TM 11-5820-670-30CHAPTER 1INTRODUCTIONSubjectSectionPageGeneral Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-5820-670-302-9. RECEIVER CARRIER SQUELCH SENSITIVITY TEST. (CONT)STANDARD. Audio is present.7. If audio is not present, see troubleshooting char

TM 11-5820-670-302-10. RECEIVER TONE SQUELCH SENSITIVITY TEST.PURPOSEThis test checks the squelch capability when tone squelch is selected on the con

TM 11-5820-670-302-10. RECEIVER TONE SQUELCH SENSITIVITY TEST. (CONT)TEST SETUPConnect equipment as shown in test setup diagram. Turn on both AN/URM-

TM 11-5820-670-302-10. RECEIVER TONE SQUELCH SENSITIVITY TEST. (CONT)EQUIPMENTTS-2575/ARC-131TS-723A/UAN/URM-103TEST PROCEDURECONTROL AND SWITCH SETT

TM 11-5820-670-302-10. RECEIVER TONE SQUELCH SENSITIVITY TEST. (CONT)12. Reduce AN/URM-103 output level until audio output indication disappears, and

TM 11-5820-670-302-11. TRANSMITTER POWER OUTPUT TEST. (CONT)INITIAL EQUIPMENT CONTROL SETTINGSSet equipment controls as indicated in the following ta

TM 11-5820-670-302-12. TRANSMITTER TONE MODULATION TEST.PURPOSEThis test checks the frequency and deviation of the 150 Hz tone signal generated in the

TM 11-5820-670-302-12. TRANSMITTER TONE MODULATION TEST. (CONT)CONTROL AND SWITCH SETTlNGSEQUIPMENTTS-2575/ARC-131ME-57/UC-1611 D/AlCCONTROL OR SWITC

TM 11-5820-670-302-13. TRANSMlllER DEVIATION NARROW BAND TEST.PURPOSEThis test checks the transmitter deviation when the rt is transmitting rf signal

TM 11-5820-670-302-13. TRANSMITTER DEVIATION NARROW BAND TEST. (CONT)INITIAL EQUIPMENT CONTROL SETTINGSSet equipment controls as indicated in the fol

TM 11-5820-670-301-2. MAINTENANCE FORMS, RECORDS, AND REPORTS. (CONT)DISCREPANCY IN SHIPMENT REPORT (DISREP) (SF 361)Fill out forward Discrepancy in S

TM 11-5820-670-302-14. TRANSMITTER DISTORTION NARROW BAND TEST.PURPOSEDistortion will ruin the quality of an audio signal and must, therefore, be kept

TM 11-5820-670-302-14. TRANSMllTER DISTORTION NARROW BAND TEST. (CONT)INITIAL EQUIPMENT CONTROL SETTlNGSSet equipment controls as indicated in the fo

TM 11-5820-670-302-15. TRANSMITTER SIGNAL PLUS NOISE-TO-NOISE RATIO TEST.PURPOSEThis test checks the transmitted power to noise ratio. Transmitted no

TM 11-5820-670-302-15. TRANSMITTER SIGNAL PLUS NOISE-TO-NOISE RATlO TEST. (CONT)INITIAL EQUIPMENT CONTROL SETTINGSSet equipment controls as indicated

TM 11-5820-670-302-16. TRANSMITTER FREQUENCY STABILITY TEST.PURPOSEThis test checks the frequency of the transmitter power at several points on the r

TM 11-5820-670-302-16. TRANSMITTER FREQUENCY STABILITY TEST. (CONT)INITIAL EQUIPMENT CONTROL SETTINGSSet equipment controls as indicated in the follo

TM 11-5820-670-302-17. TRANSMlTTER AUTOMATIC FREQUENCY SELECTION AND CHANNEL CHANGING TONE TEST.PURPOSEThis test checks the rt’s ability to tune to a

TM 11-5820-670-302-17. TRANSMITTER AUTOMATIC FREQUENCY SELECTION AND CHANNEL CHANGING TONETEST. (CONT)TEST PROCEDURE1. Set frequency selectors to 30.

TM 11-5820-670-302-18. TRANSMlTTER SIDETONE TEST. (CONT)TEST SETUPConnect equipment as shown in test setup diagram. Turn on all equipment and allow a

TM 11-5820-670-302-18. TRANSMITTER SIDETONE TEST. (CONT)EQUIPMENTTS-2575/ARC-131C-1611 D/AICAN/URM-127TS-723A/UAN/URM-103TEST PROCEDURECONTROL AND SW

TM 11-5820-670-301-8. SAFETY, CARE, AND HANDLING.Observe all warnings, cautions and notes in this manual. This equipment can be extremely dangerousif

TM 11-5820-670-302-19. HOMING SENSITIVITY TEST.PURPOSEThis test checks homing signals that operate vertical and horizontal needles of homing indicato

2-19. HOMING SENSITIVITY TEST. (CONT)EQUIPMENTTS-2575/ARC-131AN/URM-103CONTROL AND SWITCH SETTINGSCONTROL OR SWITCHMODE SWITCHSQUELCHFREQ selLEFT and

TM 11-5820-670-302-19. HOMING SENSITIVITY TEST. (CONT)TEST PROCEDURE (CONT)12. Adjust AN/URM-103 for zero input to the radio set.STANDARD. Horizontal

TM 11-5820-670-302-20. C-7088/ARC-131 MODE SWITCH SELECTION AND FRONT PANEL ILLUMINATION TEST.(CONT)TEST SETUPConnect equipment as shown in test setu

TM 11-5820-670-302-20. C-7088/ARC-131 MODE SWITCH SELECTION AND FRONT PANEL ILLUMINATION TEST.(CONT)TEST PROCEDURESet C-7088/ARC-131 MODE SWITCH to O

TM 11-5820-670-302-21. SQUELCH SWITCH AND FREQUENCY SELECTION TEST.PURPOSEThis test checks for proper operation of the control unit’s squelch functio

TM 11-5820-670-302-21. SQUELCH SWITCH AND FREQUENCY SELECTION TEST. (CONT)TEST PROCEDURE1. Set control unit SQUELCH switch under test to CARR.2. Rota

TM 11-5820-670-302-21. SQUELCH SWITCH AND FREQUENCY SELECTION TEST. (CONT)14. If kHz indicator on gearbox assembly does not correspond to last two di

TM 11-5820-670-302-22. RETRANSMIT RECEIVE TEST.PURPOSEThis test checks the rt and control unit when the radio set is receiving rf in the retransmit m

TM 11-5820-670-302-22. RETRANSMIT RECEIVE TEST. (CONT)INITIAL EQUIPMENT CONTROL SETTINGSSet equipment controls as indicated in the following table.CO

TM 11-5820-670-301-11. DIFFERENCES BETWEEN MODELS/SILICON VERSIONS. (CONT)INTERCHANGEABILITY OF MODULESGermanium and silicon modules may be used toge

TM 11-5820-670-302-23. RETRANSMIT TRANSMIT TEST.PURPOSEThis test checks the rt and control unit when the radio set is transmitting rf in the retransm

TM 11-5820-670-302-23. RETRANSMIT TRANSMIT TEST. (CONT)INITIAL EQUIPMENT CONTROL SETTINGSSet equipment controls as indicated in the following table.C

TM 11-5820-670-30Section Ill TROUBLESHOOTINGSubjectParaGeneral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-5820-670-302-24. GENERAL. (CONT)OVERALL TROUBLESHOOTING APPROACHWhen a radio set fails to meet a designated standard during a performance test,

TM 11-5820-670-302-24. GENERAL. (CONT)Troubleshooting procedures in this section make use of TMDE and Maintenance Kit, ElectronicEquipment MK-1035/AR

TM 11-5820-670-302-25. HOW TO USE THE TROUBLESHOOTING CHARTS.NOTE1. The following measurement checks distortionat 1020 Hz.The preceding illustration

TM 11-5820-670-302-25. HOW TO USE THE TROUBLESHOOTING CHARTS. (CONT)CORRECTIVE ACTION OR ADDITIONAL INSTRUCTIONA corrective action box or additional

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)PRELIMINARY PROCEDURE. Set up equipment as shown in diagram.NOTE:INDICATES EQUIPMENT MARKINGEL1A

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-1Voltage Distribution Troubleshooting(Sheet 1 of 5)CHECK DISTRIBUTION OF+24 VDC TO RT AS

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-1Voltage Distribution Troubleshooting(Sheet 2 of 5)PERFORMTROUBLE-SHOOTING CHART 2-4.MEA

TM 11-5820-670-30SubjectTRANSMIT MODETransmitter Signal Flow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-5820-670-302-26 TROUBLESHOOTING CHARTS. (CONT)CHART 2-1Voltage Distribution Troubleshooting(Sheet 3 of 5)MEASURE VDC TO GROUNDAT TP9504 ON A9500

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-1Voltage Distribution Troubleshooting(Sheet 4 of 5)CHECK DISTRIBUTION OF+16 VDC. SEE CHA

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-1Voltage Distribution Troubleshooting(Sheet 5 of 5)2-60

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-2+ 27.5 vdc Circuit Troubleshooting(Sheet 1 of 3)NOTES1. P9501 pin locations.EL1AT161REPL

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-2+27.5 vdc Circuit TroubleshootingREPLACE A9700 ASSEMBLY(PARA 2-71). ALINE (PARA2-29).1C

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-2+27.5 vdc Circuit Troubleshooting(Sheet 3 of 3)EL1AT2042-63

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-3+24 vdc Regulated Circuit Troubleshooting(Sheet 1 of 4)REPLACE POWER SUPPLYASSEMBLY A95

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-3+24 vdc Regulated Circuit Troubleshooting(Sheet 2 of 4)EL1AT164REPLACE POWER SUPPLYASSE

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-3+24 vdc Regulated Circuit Troubleshooting(Sheet 3 of 4)REPLACE A9700 ASSEMBLYPARA 2-71)

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-3+24 vdc Regulated Circuit Troubleshooting(Sheet 4 of 4)EL1AT2052-67

TM 11-5820-670-301-12. GENERAL.This section contains information covering principles of operation of major electronic assemblies ofthe receiver-trans

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-4+ 16 vdc Circuit Troubleshooting(Sheet 1 of 4)REPLACE A2100 ASSEMBLY(PARA 2-50).DISCONN

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-4+ 16 vdc Circuit Troubleshooting(Sheet 2 of 4)REPLACE A5500 ASSEMBLY(PARA 2-44).4REPLAC

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-4+ 16 vdc Circuit Troubleshooting(Sheet 3 of 4)DISCONNECT P4001 FROMPINS ON A4000 ASSEMBL

2-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-4+16 vdc Circuit Troubleshooting(Sheet 4 of 4)TM 11-5820-670-302-71

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-5No Audio Output Troubleshooting(Sheet 1 of 8)CONNECT EQUIPMENT ASSHOWN IN AUDIO POWEROUT

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-5No Audio Output Troubleshooting(Sheet 2 of 8)CHECK AC VOLTAGE ATTP5513 ON THE RECEIVERAU

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-5No Audio Output Troubleshooting(Sheet 3 of 8)CHECK CONTINUITY OFREPEAT AUDIO POWERRELAY

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-5No Audio Output Troubleshooting(Sheet 4 of 8)REMOVE A4200 AND INJECTDISCONNECT P4902 FR

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-5No Audio Output Troubleshooting(Sheet 5 of 8)CHECK AC VOLTAGE ATTP4004 ON IF. AMPLIFIER

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-5No Audio Output Troubleshooting(Sheet 6 of 8)REPLACE RECEIVERSQUELCH AMPLIFIERMODULE A5

TM 11-5820-670-301-13. RECEIVER SIGNAL FLOW.A system block diagram showing receiver signal flow can be found on FO-1 in the back of this manual.Refer

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-5No Audio Output Troubleshooting2-78

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-5No Audio Output Troubleshooting(Sheet 8 of 8)2-79

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-6Audio Power TroubleshootingCONNECT EQUIPMENT ASSHOWN IN AUDIO POWEROUTPUT PERFORMANCETES

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-7Audio Distortion Troubleshooting(Sheet 1 of 2)PERFORM AUDIO LEVELADJUSTMENT (PARA 2-30)

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-7Audio Distortion Troubleshooting(Sheet 2 of 2)EL1AT2062-82

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-8Poor Audio Response Troubleshooting(Sheet 1 of 2)CONNECT EQUIPMENT ASSHOWN IN AUDIO-FRE-

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-8Poor Audio Response Troubleshooting(Sheet 2 of 2)2-84EL1AT206EL1AT197

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-9Poor Sensitivity Troubleshooting(Sheet 1 of 2)PERFORM RECEIVERSENSITIVITY ADJUSTMENT(PA

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-9Poor Sensitivity Troubleshooting(Sheet 2 of 2)2-86II

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-10Maximum Signal Plus Noise-to-Noise Ratio TroubleshootingCONNECT EQUIPMENT ASSHOWN IN M

TM 11-5820-670-301-13. RECEIVER SIGNAL FLOW. (CONT)The 11.5 MHz if. output from the fifth if. amplifier is applied to limiter module A4200 (13). The

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-11Carrier Squelch Sensitivity TroubleshootingPERFORM CARRIERSQUELCH ADJUSTMENT(PARA 2-31

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)PER FORM TONE SQUELCHADJUSTMENT (PARA 2-33).CHART 2-12Tone Squelch Sensitivity Troubleshooting(Sh

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-12Tone Squelch Sensitivity Troubleshooting(Sheet 2 of 2)EL1AT2072-90

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CONNECT EQUIPMENT ASSHOWN IN TRANSMITTERPOWER OUTPUT PERFOR-MANCE TEST (PARA 2-11).CHART 2-13Tran

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-13Transmitter Power Output (HI) Troubleshooting(Sheet 2 of 3)REPLACE MODULE A6400ON A6000

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-13Transmitter Power Output (HI) Troubleshooting(Sheet 3 of 3)PERFORM TRANSMITTERPOWER OUT

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-14Transmitter Power Output (LO) TroubleshootingCONNECT EQUIPMENT ASSHOWN IN TRANSMITTERP

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CONNECT EQUIPMENT ASSHOWN IN TRANSMITTERTONE MODULATION PER-FORMANCE TEST (PARA2-12).PERFORM 150

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-15Transmitter Tone Modulation Troubleshooting(Sheet 2 of 2)REPLACE 11.5 MHz MOD-ULATOR MO

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CONNECT EQUIPMENT ASSHOWN IN TRANSMITTERDEVIATION NARROW BANDPERFORMANCE TEST (PARA2-13).PERFORM

TM 11-5820-670-30LOCAL OSCILLATOR AFC/CRYSTAL REFERENCE SYSTEM. (CONT)The heterodyning process in crs second mixer A3300 (6) produces sum and differen

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-16Transmitter Deviation Narrow Band Troubleshooting(Sheet 2 of 2)2-98

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-17Transmitter Distortion Narrow Band Troubleshooting(Sheet 1 of 2)CONNECT EQUIPMENTAS SH

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-17Transmitter Distortion Narrow Band Troubleshooting(Sheet 2 of 2)2-100

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-18Maximum Signal Plus Noise-to-Noise Ratio Troubleshooting(Sheet 1 of 2)CONNECT EQUIPMENT

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-18Maximum Signal Plus Noise-to-Noise Ratio Troubleshooting(Sheet 2 of 2)CHECK WIRE BETWE

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CONNECT EQUIPMENT ASSHOWN IN TRANSMITTERFREQUENCY STABILITYPERFORMANCE TEST (PARA2-16).CHART 2-19

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)DISCONNECT P3002 FROMJ3002 AND APPLY AGROUND TO PIN 2 ON THEVHF TUNER. SEE ILLUS-TRATIONS ON SH 4

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)REPLACE CRYSTAL REF-ERENCE SYSTEM ASSEMBLYA3000 (PARA 2-43).CHART 2-19Transmitter Frequency Stabi

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-19Transmitter Frequency Stability Troubleshooting(Sheet 4 of 5)TABLE BLast twodigits offr

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-19Transmitter Frequency Stability Troubleshooting(Sheet 5 of 5)EL1AT2212-107

TM 11-5820-670-301-15. CRS BALANACED MIXER A3200.The balanced mixer accepts inputs from the following two sources:EL1AT090Local oscillator through hi

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-20Automatic Frequency Selection and Channel Changing Tone TroubleshootingCONNECT EQUIPMEN

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-21Transmitter Sidetone TroubleshootingCONNECT EQUIPMENT ASSHOWN IN TRANSMITTERSIDETONE P

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-22Homing Flag Indication TroubleshootingCONNECT EQUIPMENT ASSHOWN IN HOMING SENSI-TIVITY

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-23Homing Needle Indication Troubleshooting(Sheet 1 of 3)CONNECT EQUIPMENT ASSHOWN IN HOMI

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHECK FOR CONTINUITYBETWEEN TP4809 ANDPIN 9 OF CONNECTOR P4801,SEE ILLUSTRATION, SH 3AND FO-12 FO

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-23Homing Needle Indication Troubleshooting(Sheet 3 of 3)EL1AT225EL1AT2262-113

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-24Control Unit Troubleshooting(Sheet 1 of 12)NOTEUse the troubleshooting table to isolate

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-24Control Unit Troubleshooting(Sheet 2 of 12)MALFUNCTIONTEST OR INSPECTIONCORRECTIVE ACT

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-24Control Unit Troubleshooting(Sheet 3 of 12)MALFUNCTIONTEST OR INSPECTIONCorrective ACTI

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-24Control Unit Troubleshooting(Sheet 4 of 12)CONTROL UNIT RESISTANCE TABLESThe charts in

TM 11-5820-670-301-15. CRS BALANCED MIXER A3200. (CONT)Since the output of the balanced mixer is applied to a 53 MHz filter (FL3003), only two freque

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)MODE SWITCH at T/R, SEQUELCH switch at DIS.CHART 2-24Control Unit Troubleshooting(Sheet 5 of 12)F

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-24Control Unit Troubleshooting(Sheet 6 of 12)MODE SWITCH at RETRAN, SQUELCH switch at DIS

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-24Control Unit Troubleshooting(Sheet 7 of 12)MODE SWITCH at RETRAN, SQUELCH switch at TO

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-24Control Unit Troubleshooting(Sheet 8 of 12)MODE SWITCH at HOME, SQUELCH switch at CARR.

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-24Control Unit Troubleshooting(Sheet 9 of 12)FREQUENCY SELECTION CODE TABLESThe tables i

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-24Control Unit Troubleshooting(Sheet 10 of 12)TABLEResistance Measurements for Antenna Co

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-24Control Unit Troubleshooting(Sheet 11 of 12)TABLE (CONT)RESISTANCE TO GROUND FOR CONN

TM 11-5820-670-302-26. TROUBLESHOOTING CHARTS. (CONT)CHART 2-24Control Unit Troubleshooting(Sheet 12 of 12)FREQUENCYSELECTED(MHz)404142434445464748495

TM 11-5820-670-30Section IV ALINEMENT AND ADJUSTMENT PROCEDURESSubjectParaGeneral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-5820-670-302-28. RF AMPLIFIER ASSEMBLY A6500 ALINEMENT.TEST EQUIPMENT AND MATERIALSMaintenance Kit MK-1035/ARC-131Multimeter AN/USM-223Power Su

TM 11-5820-670-301-16. CRS SECOND MIXER A3300 AND CRYSTAL SWITCH A2000. (CONT)SECOND MIXER A3300The second mixer performs a signal heterodyning funct

TM 11-5820-670-302-28. RF AMPLIFIER ASSEMBLY A6500 ALINEMENT. (CONT)INITIAL EQUIPMENT CONTROL SETTINGSSet equipment controls as indicated in the foll

TM 11-5820-670-302-28. RF AMPLIFIER ASSEMBLY A6500 ALINEMENT. (CONT)1. Place the TRANSMIT switch on test set to ON position.2. Adjust C6512 for min

TM 11-5820-670-302-29. GEARBOX ASSEMBLY A9700 ALINEMENT.TEST EQUIPMENT AND MATERIALSMaintenance Kit MK-1035/ARC-131Power Supply PP-2953/UTEST SETUPCo

TM 11-5820-670-302-29. GEARBOX ASSEMBLY A9700 ALINEMENT. (CONT)7. Using hex wrench, loosen setscrews on all three coupling collars.8. Install coupler

TM 11-5820-670-302-30. AUDIO LEVEL ADJUSTMENT.TEST EQUIPMENT AND MATERIALSMaintenance Kit MK-1035/ARC-131Signal Generator AN/URM-103Signal Generator

TM 11-5820-670-302-30. AUDIO LEVEL ADJUSTMENT. (CONT)CONTROL AND SWITCH SETTINGSEQUIPMENTCONTROL OR SWITCHTS-2575/ARC-131AN/URM-127AN/URM-103ADJUSTME

TM 11-5820-670-302-31. CARRIER SQUELCH ADJUSTMENT.TEST EQUIPMENT AND MATERIALSMaintenance Kit MK-1035/ARC-131Signal Generator AN/URM-103Signal Genera

TM 11-5820-670-302-31. CARRIER SQUELCH ADJUSTMENT. (CONT)ADJUSTMENT PROCEDURE1. On TS-2575/ARC-131, place the +28 VDC ON – OFF switch to ON.2.3.4.5.6

TM 11-5820-670-302-32. 150 Hz TONE MODULATION FREQUENCY AND DEVIATION ADJUSTMENT.TEST EQUIPMENT AND MATERIALSMaintenance Kit MK-1035/ARC-131Electronic

TM 11-5820-670-302-32. 150 Hz TONE MODULATION FREQUENCY AND DEVIATION ADJUSTMENT. (CONT)6. Adjust potentiometer R8609 on module A8600 fully clockwise

TM 11-5820-670-301-16. CRS SECOND MIXER A3300 AND CRYSTAL SWITCH A2000. (CONT)SECOND MIXER AND CRYSTAL SWITCH OPERATING EXAMPLE – Radio Frequency Sel

TM 11-5820-670-302-33. TONE SQUELCH ADJUSTMENT.TEST EQUIPMENT AND MATERIALSMaintenance Kit MK-1035/ARC-131Signal Generator AN/URM-103Signal Generator

TM 11-5820-670-302-33. TONE SQUELCH ADJUSTMENT. (CONT)ADJUSTMENT PROCEDURE1.2.3.4.5.Place +28 VDC ON-OFF switch on test set to ON.Set control unit mo

TM 11-5820-670-302-34. NARROW BAND DEVIATION ADJUSTMENT.TEST EQUIPMENT AND MATERIALSMaintenance Kit MK-1035/ARC-131Modulation Meter ME-57/USignal Gen

TM 11-5820-670-302-34. NARROW BAND DEVIATION ADJUSTMENT. (CONT)INITIAL EQUIPMENT CONTROL SETTINGSSet equipment controls as indicated in the following

TM 11-5820-670-30RECEIVER SENSITIVITY ADJUSTMENTS.TEST EQUIPMENT AND MATERIALSMaintenance Kit MK-1035/ARC-131Signal Generator AN/URM-103Oscilloscope A

TM 11-5820-670-302-35. RECEIVER SENSITIVITY ADJUSTMENTS. (CONT)EL1AT2446. Using board extractor, remove A1100 module from its mount. Inspect A-B boar

TM 11-5820-670-302-35. RECEIVER SENSITIVITY ADJUSTMENTS. (CONT)ADJUSTMENT PROCEDURE (CONT)9. Repeat step 5, and if signal still drops off, run signal

TM 11-5820-670-302-35. RECEIVER SENSITIVITY ADJUSTMENTS. (CONT)13. Change frequency to 75.00 MHz and repeat step 10, tuning 65.00 and 75.00 MHz coils

TM 11-5820-670-302-36. LOCAL OSCILLATOR ALINEMENT.TEST EQUIPMENT AND MATERIALSMaintenance Kit MK-1035/ARC-131Power Supply PP-2953/UFrequency Meter AN

TM 11-5820-670-302-36. LOCAL OSCILLATOR ALINEMENT. (CONT)CONTROL UNITFREQUENCY COUNTERFREQUENCY (MHz)READOUT (MHz)A BANDB BAND30.0053.0041.50 ± 0.002

TM 11-5820-670-301-17. CRS FIRST AND SECOND IF. AMPLIFIER A3400/CRS THIRD IF. AMPLIFIER AND LIMITERA3500.EL1AT093An intermediate frequency from the se

TM 11-5820-670-302-37. HOMING ADJUSTMENT.TEST EQUIPMENT AND MATERIALSMaintenance Kit MK-1035/ARC-131Signal Generator AN/URM-103Power Signal PP-2953/U

TM 11-5820-670-302-37. HOMING ADJUSTMENT. (CONT)EL1AT2494.5.6.7.8.Adjust vertical needle adjust potentiometer R4805, located on homer-detector amplifi

TM 11-5820-670-30Section V REPAIR AND REPLACEMENT PROCEDURESSubjectParaGeneral. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-5820-670-30SubjectControl Unit C-7088/ARC-131Front Panel Knobs Replacement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-5820-670-302-39. RT CASE REPLACEMENT.MATERIALS/PARTS: Case, receiver-transmitter (P/N SMD619940)REMOVAL1. Using screwdriver, loosen two turn-lo

TM 11-5820-670-302-40. HOMING MODULE A4600 REPLACEMENT.MATERIALS/PARTS: Module, homing, A4800 (P/N SMD619582)PRELIMINARY PROCEDURE: Remove case (para

TM 11-5820-670-302-41. A4000 MODULES AND ASSEMBLY REPLACEMENT.MATERIALS/PARTS: Amplifier assembly, if. A4100 (P/N SMC413726)Amplifier assembly, if. A

TM 11-5820-670-302-41. A4000 MODULES AND ASSEMBLY REPLACEMENT. (CONT)NOTEModules FL4001 and FL4002 are secured with locknuts. Steps 4 and 5 are typic

TM 11-5820-670-302-41. A4000 MODULES AND ASSEMBLY REPLACEMENT. (CONT)INSTALLATION (CONT)NOTEBefore installing FL4002 filter, establish whether a 50 k

TM 11-5820-670-302-41. A4000 MODULES AND ASSEMBLY REPLACEMENT. (CONT)3. Position module (1) on board and install IT Iockwashers (2) and locknuts (3)

TM 11-5820-670-301-17. CRS FIRST AND SECOND IF. AMPLIFIER A3400/CRS THIRD IF. AMPLIFIER AND LIMITERA3500. (CONT)The third if. amplifier increases the

TM 11-5820-670-302-41. A4000 MODULES AND ASSEMBLY REPLACEMENT. (CONT)INSTALLATION (CONT)7. Connect blue wire (P4902) (1) to J4902.CAUTIONCare must be

TM 11-5820-670-302-42. A9500 ASSEMBLY REPLACEMENT.MATERIALS/PARTS: Power supply assembly A9500 (P/N SME619765)PRELIMINARY PROCEDURE: Remove case (par

TM 11-5820-670-302-43. A3000 MODULES AND ASSEMBLY REPLACEMENT.MATERIALS/PARTS: Amplifier, interfrequency A3400 (P/N SMB413634)Crystal REF system asse

TM 11-5820-670-302-43. A3000 MODULES AND ASSEMBLY REPLACEMENT. (CONT)NOTEModules A3100 through A3700 are secured with captive screws. Steps 3, 4, and

TM 11-5820-670-302-43. A3000 MODULES AND ASSEMBLY REPLACEMENT. (CONT)REMOVAL (CONT)EL1AT01210. Using screwdriver, loosen two captive screws (1).11. C

TM 11-5820-670-302-43. A3000 MODULES AND ASSEMBLY REPLACEMENT. (CONT)NOTEModules FL3001 through FL3005 are secured with locknuts and are soldered to

TM 11-5820-670-302-43. A3000 MODULES AND ASSEMBLY REPLACEMENT. (CONT)INSTALLATION (CONT)CAUTIONBefore installing modules, ensure pins are not bent. St

2-43. A3000 MODULES AND ASSEMBLY REPLACEMENT. (CONT)CAUTIONExtreme care must be taken when performing next step to prevent damaging pins onassembly.8

TM 11-5820-670-302-44. A5500 MODULES AND ASSEMBLY REPLACEMENT.MATERIALS/PARTS: Amplifier, assembly, radio frequency, A5500 (P/N SMD619527)Amplifier, a

2-44. A5500 MODULES AND ASSEMBLY REPLACE. (CONT)NOTEModules A5200 through A5400 are secured with captive screws. Steps 3 and 4 are typ-ical for all

TM 11-5820-670-301-18. CRS HUNT DISCRIMINATOR A3600, CRS PHASE DISCRIMINATOR A3700, AND REFERENCEOSCILLATOR A2000. (CONT)The hunt discriminator is tu

TM 11-5820-670-302-44. A5500 MODULES AND ASSEMBLY REPLACEMENT. (CONT)NOTERelays K5501 through K5505 are held into sockets by a holddown clamp. Steps 8

TM 11-5820-670-302-44. A5500 MODULES AND ASSEMBLY REPLACEMENT. (CONT)INSTALLATION1. Position assembly (9) in hinge (8).2. Install hinge pin (7) in hi

TM 11-5820-670-302-44. A5500 MODULES AND ASSEMBLY REPLACEMENT. (CONT)INSTALLATION (CONT)CAUTIONBefore installing modules, ensure pins on assembly are

TM 11-5820-670-302-44. A5500 MODULES AND ASSEMBLY REPLACEMENT. (CONT)12. Position P5501 (4) on pins and push into place.13. Using screwdriver, tighte

TM 11-5820-670-302-45. A8700 MODULES AND ASSEMBLY REPLACEMENT.MATERIALS/PARTS: Amplifier, intermediate frequency, A8300 (P/N SMB414197)Amplifier modu

TM 11-5820-670-302-45. A8700 MODULES AND ASSEMBLY REPLACEMENT. (CONT)Modules A8100 through A8400 and A8600 are secured with captive screws. Steps 3 a

TM 11-5820-670-302-45. A8700 MODULES AND ASSEMBLY REPLACEMENT. (CONT)REMOVAL (CONT)8. Remove two C-clips (1) from hinge pins (2).9. Remove two hinge

TM 11-5820-670-302-45. A8700 MODULES AND ASSEMBLY REPLACEMENT. (CONT)6.7.8.9.10.NOTEFilter module is secured with locknuts and is soldered to printed

TM 11-5820-670-302-45. A8700 MODULES AND ASSEMBLY REPLACEMENT. (CONT)INSTALLATION (CONT)11. Connect violet wire connector (1) to A8300 assembly (2).12

TM 11-5820-670-302-46. A6600 ASSEMBLY REPLACEMENT.MATERIALS/PARTS: Amplifier assembly, isolation, A6000 (P/N SMD619913)PRELIMINARY PROCEDURE: Remove

TM 11-5820-670-301-18. CRS HUNT DISCRIMINATOR A3600, CRS PHASE DISCRIMINATOR A3700, AND REFERENCEOSCILLATOR A2000. (CONT)HUNT DISCRIMINATOR, PHASE DI

TM 11-5820-670-302-47. POWER SUPPLY CIRCUIT CARD REPLACEMENT.MATERIALS/PARTS: Circuit card assembly (P/N SMD619800)PRELIMINARY PROCEDURE: Remove case

TM 11-5820-670-302-47. POWER SUPPLY CIRCUIT CARD REPLACEMENT. (CONT)4. Using soldering iron, unsolder wires as shown in circuit card wiring table bel

TM 11-5820-670-302-48. A6300 AND A6400 MODULE REPLACEMENT.MATERIALS/PARTS: Circuit card assembly, A6300 (P/N SMD374993)Circuit card assembly, A6400 (

TM 11-5820-670-302-48. A6300 AND A64Q0 MODULE REPLACEMENT. (CONT)INSTALLATIONCAUTIONBefore installing modules A1100 through A1300, ensure band switch

TM 11-5820-670-302-49. A4500 ASSEMBLY REPLACEMENT.MATERIALS/PARTS: Control, radio frequency, A4500 (P/N SMC619709)PRELIMINARY PROCEDURE: Remove case

TM 11-5820-670-302-49. A4500 ASSEMBLY REPLACEMENT. (CONT)REMOVAL1. Disconnect white wire (P1001) (1) from J1001, violet wire (P1003) (2) from J1003,

TM 11-5820-670-302-50. A2100 ASSEMBLY REPLACEMENT.MATERIALS/PARTS: Regulator assembly, voltage, A2100 (P/N SMD41457)PRELIMINARY PROCEDURE: Remove cas

TM 11-5820-670-302-51. FRONT PANEL REPLACEMENT.MATERIALS/PARTS: Panel, frontPRELIMINARY PROCEDURE: Remove TEST METER, M9601 (para 2-53).Remove SQ DIS

TM 11-5820-670-302-52. A1100 THROUGH A1500 MODULE REPLACEMENT.MATERIALS/PARTS: Circuit card assembly, A1100 (P/N SMD 374983)Circuit card assembly, A12

TM 11-5820-670-302-52. A1100 THROUGH A1500 MODULE REPLACEMENT. (CONT)NOTEA 1000 assembly cover is also used as a module puller to remove all modules.

TM 11-5820-670-301-18. CRS HUNT DISCRIMINATOR A3600, CRS PHASE DISCRIMINATOR A3700, AND REFERENCEOSCILLATOR A2000. (CONT)With the radio set to 30.00

TM 11-5820-670-302-52. A1100 THROUGH A1500 MODULE REPLACEMENT. (CONT)INSTALLATION - CONTINUEDEL1AT0421.Carefully pushNOTEEnsure spring contacts on mod

TM 11-5820-670-302-53. TEST METER M9601 REPLACEMENT.MATERIALS/PARTS: Meter, electrical indicating, dc, M9601 (P/N MS90212-24)PRELIMINARY PROCEDURE: R

TM 11-5820-670-302-54. SQ DIS SWITCH S9602 AND XMTR TEST SWITCH S9603 REPLACEMENT.MATERIALS/PARTS: Switch, push, S9602 and S9603 (P/N SMC 619497)PREL

TM 11-5820-670-302-54. SQ DIS SWITCH S9602 AND XMTR TEST SWITCH S9603 REPLACEMENT. (CONT)INSTALLATION1.2.3.4.5.6.7.8.Position switch (10) in front pa

TM 11-5820-670-302-55. TEST SWITCH S9601 REPLACEMENT.MATERIALS/PARTS: Switch, rotary, S9601 (P/N SMC619495-1)PRELIMINARY PROCEDURE: Remove A8700 asse

TM 11-5820-670-302-55. TEST SWITCH S9801 REPLACEMENT. (CONT)NOTEPlace chassis in upright position.Pull front panel away from chassis slightly and move

TM 11-5820-670-302-56. SQ ADJ SWITCH R9602 REPLACEMENT.MATERIALS/PARTS: Switch, rotary, R9602 (P/N SMC619495-2)PRELIMINARY PROCEDURE: Remove A8700 as

TM 11-5820-670-302-57. XMTR HI-LO SWITCH S9604 REPLACEMENT.MATERIALS/PARTS: Resistor, variable, S9604 (P/N RV6NAYSL253A)PRELIMINARY PROCEDURE: Remove

TM 11-5820-670-302-58. A6500 ASSEMBLY REPLACEMENT.MATERIALS/PARTS: Amplifier, radio frequency, A6500 (P/N SME619596)PRELIMINARY PROCEDURE: Remove cas

TM 11-5820-670-302-58. A6500 ASSEMBLY REPLACEMENT. (CONT)REMOVAL1.2.3.4.5.6.7.8.9.Using screwdriver, loosen two captive screws (1) and lower A4500 as

TM 11-5820-670-301-18. CRS HUNT DISCRIMINATOR A3600, CRS PHASE DISCRIMINATOR A3700, AND REFERENCEOSCILLATOR A2000. (CONT)The two signals entering the

TM 11-5820-670-30RADIO INTERFERENCE FILTER FL9601 REPLACEMENT.MATERIALS/PARTS: Filter, radio interference, FL9601 (P/N SMD619508)PRELIMINARY PROCEDURE

TM 11-5820-670-302-59. RADIO INTERFERENCE FILTER FL9601 REPLACEMENT. (CONT)2. Using screwdriver, loosen one captive screw (3) and raise A3000 assembl

TM 11-5820-670-302-60. TRANSISTOR Q9601 REPLACEMENT.MATERIALS/PARTS: Transistor, Q9601 (P/N JAN 2N1479)Compound, heat sink, Dow Corning, DC-340 (item

TM 11-5820-670-302-60. TRANSISTOR Q9601 REPLACEMENT. (CONT)NOTEDue to inaccessible location of screw, it is advised that it not be removed.4. Remove

TM 11-5820-670-302-61. A4900 ASSEMBLY REPLACEMENT.MATERIALS/PARTS: Attenuator, variable, A4900 (P/N SME619695)PRELIMINARY PROCEDURE: Remove case (par

TM 11-5820-670-302-62. RF ATTENUATOR AND DIODE SWITCH 24501 REPLACEMENT.MATERIALS/PARTS: Attenuator and switch assembly, Z4501 (P/N SMD619719)PRELIMI

TM 11-5820-670-302-63. REFLECTOMETER AND SIDETONE DETECTOR 24502 REPLACEMENT.MATERIALS/PARTS: Control assembly, Z4502 (P/N SMD619733)PRELIMINARY PROC

TM 11-5820-670-302-64. LOW-PASS FILTER FL4501 REPLACEMENT.MATERIALS/PARTS: Filter, low-pass, FL4501 (P/N SMD619747)PRELIMINARY PROCEDURE: Remove case

TM 11-5820-670-302-65. RELAYS K4501 THROUGH K4504 REPLACEMENT.MATERIALS/PARTS: Relay, armature, K4501 (P/N SMD6201 14)Relay, armature, K4502 (P/N SM

TM 11-5820-670-302-66. RELAYS K9601 THROUGH K9606 REPLACEMENT.MAERIALS PARTS: Relay, armature, K9601 through K9605 (P/N SMC41433)Relay, dummy, K9606

TM 11-5820-670-30SAFETY STEPS TO FOLLOW IF SOMEONE IS THEVICTIM OF ELECTRICAL SHOCKDO NOT TRY TO PULL OR GRAB THE INDIVIDUALIF POSSIBLE, TURN OFF THE

TM 11-5820-670-301-20. GEARBOX ASSEMBLY A9700.Refer to FO-3 in the back of this manual while reading the text in this paragraph.The electrical portio

TM 11-5820-670-302-67. A1000, A2000, A6000, AND A9700 ASSEMBLY REPLACEMENT.PRELIMINARY PROCEDURE: Remove A4000 assembly (para 2-41).Remove A4500 assem

TM 11-5820-670-302-67. A1000, A2000, A6000, AND A9700 ASSEMBLY REPLACEMENT. (CONT)7.8.9.Using screwdriver, loosen one captive screw (15) and swing op

TM 11-5820-670-30A1000, A2000, A6000, AND A9700 ASSEMBLY REPLACEMENT. (CONT)REMOVAL (CONT)13. Disconnect brown wire (P6002) (1) from J6002 (2) and yel

TM 11-5820-670-302-67. A1000, A2000, A6000, AND A9700 ASSEMBLY REPLACEMENT. (CONT)15. Using screwdriver, loosen two screws (11) on wire clips (12) an

TM 11-5820-670-302-67. A1000, A2000, A6000, AND A9700 ASSEMBLY REPLACEMENT. (CONT)INSTALLATION (CONT)10.11.12.13.14.15.16.17.18.Install four screws (

TM 11-5820-670-302-67. A1000, A2000, A6000, AND A9700 ASSEMBLY REPLACEMENT. (CONT)19.20.21.22.23.24.25.26.Install two screws (22) and ground strap (2

TM 11-5820-670-302-68. A1000 ASSEMBLY REPLACEMENT.MATERIALS/PARTS: Tuner assembly, vhf, A1000 (P/N SMD416345)PRELIMINARY PROCEDURE: Remove A1000, A20

TM 11-5820-670-302-68. A1000 ASSEMBLY REPLACEMENT. (CONT)REMOVAL1. Using wrench, loosen three captive nuts (1).2. Remove A1000 assembly (2).INSTALLAT

TM 11-5820-670-302-69. A6000 ASSEMBLY REPLACEMENT.MATERIALS/PARTS: Oscillator buffer assembly, A6000 (P/N SMC619909)PRELIMINARY PROCEDURE: Remove A10

TM 11-5820-670-302-69. A6000 ASSEMBLY REPLACEMENT. (CONT)REMOVAL1. Using wrench, loosen three captive nuts (1).2. Remove A6000 assembly (2).INSTALLAT

TM 11-5820-670-301-21. RF CONTROL ASSEMBLY P/O MODULE A4500 (RECEIVE MODE).EL1AT097Frequency modulated rf from the communications antenna is applied

TM 11-5820-670-302-70. A2000 ASSEMBLY REPLACEMENT.MATERIALS/PARTS: Oscillator, radio frequency, A2000 (P/N SMD414430)PRELIMINARY PROCEDURE: Remove A1

TM 11-5820-670-302-71. A9700 ASSEMBLY REPLACEMENT.MATERIALS/PARTS: Gearbox, A9700 (P/N SME619807)PRELIMINARY PROCEDURE: Remove A1000, A2000, A6000, a

TM 11-5820-670-302-72. RELAY K3001 REPLACEMENT.MATERIALS/PARTS: Relay, K3001 (P/N SMD413526)PRELIMINARY PROCEDURE: Remove case (para 2-39).REMOVAL1.

TM 11-5820-670-302-73. A1600 ASSEMBLY REPLACEMENT.MATERIALS/PARTS: Power supply assembly, A1600 (P/N SMC416316)PRELIMINARY PROCEDURE: Remove A6500 as

TM 11-5820-670-302-74. FRONT PANEL KNOBS REPLACEMENT.MATERIALS/PARTS:Knob, frequency selector (P/N SMB620191)Knob, squelch mode and mode control (P/N

TM 11-5820-670-302-74. FRONT PANEL KNOBS REPLACEMENT. (CONT)INSTALLATIONFor frequency selector knobs, do steps 1 and 2. For volume control knobs, do

TM 11-5820-670-302-75. FRONT PANEL DIAL MASK REPLACEMENT.MATERIALS/PARTS: Mask, dial (P/N SMC620195)PRELIMINARY PROCEDURE: Remove frequency selector

TM 11-5820-670-302-76. LIGHT PANEL REPLACEMENT.MATERIALS/PARTS: Panel, light (P/N SMD620232)PRELIMINARY PROCEDURE: Remove dial mask (para 2-75).REMOV

TM 11-5820-670-302-77. SWITCH AND WIRING ASSEMBLY REPLACEMENT.PRELIMINARY PROCEDURE: Remove light panel (para 2-76).REMOVAL1. Using screwdriver, loos

TM 11-5820-670-302-77. SWITCH AND WIRING ASSEMBLY REPLACEMENT. (CONT)5. Using screwdriver and wrench, remove two screws (6), flat washers (7), Iockwas

TM 11-5820-670-301-22. ANTENNA TUNING AND PROTECTION MODULE A1100.Frequency modulated rf signals from transmit/receive relay K4501 are fed through ho

TM 11-5820-670-302-78. SQUELCH SWITCH S9106 REPLACEMENTMATERIALS/PARTS: Switch, rotary, S9106 (P/N SMC 620158)PRELIMINARY PROCEDURE: Remove light pan

TM 11-5820-670-302-78. SQUELCH SWITCH S9106 REPLACEMENT. (CONT)WIRE COLORINDEX NO.GRYJUMPERVlOWHT/YELBLKWHT/YEL7891011124. Remove switch (5).INSTALLA

TM 11-5820-670-302-79. VOLUME CONTROL SWITCH R9103 REPLACEMENT.MATERIALS/PARTS: Resistor, fixed, composition (P/N RC07GF391J)Resistor, variable, R910

TM 11-5820-670-302-79. VOLUME CONTROL SWITCH R 9103 REPLACEMENT. (CONT)NOTEDiscard attached resistor along with defective switch.INSTALLATIONNOTEBefo

TM 11-5820-670-302-80. TENTHS FREQUENCY SELECTOR SWITCH S9103 AND/OR HUNDREDTHS FREQUENCYSELECTOR SWITCH S9104 REPLACEMENT.MATERIALS/PARTS: Switch, r

TM 11-5820-670-302-80. TENTHS FREQUENCY SELECTOR SWlTCH S9103 AND/OR HUNDREDTHS FREQUENCYSELECTOR SWITCH S9104 REPLACEMENT. (CONT)1.2.3.SWITCH S9104WI

TM 11-5820-670-302-81. MODE SWITCH S9105 REPLACEMENT.MATERIALS/PARTS: Diode, semiconductor, device, CR9101 (P/N JANIN645)Resistor, fixed, composition

TM 11-5820-670-302-81. MODE SWITCH S9105 REPLACEMENT. (CONT)REMOVALEL1AT075NOTEView from rear of switch. Position switch locating tab as shown in ill

TM 11-5820-670-302-81. MODE SWITCH S9105 REPLACEMENT. (CONT)INSTALLATIONNOTEView from rear of switch.See FO-21 for complete wiring diagram.Before sol

TM 11-5820-670-302-81. MODE SWITCH S9105 REPLACEMENT. (CONT)WIRE COLORINDEX NO.WHT/RED7WHT/BRN8WHT/BRN9YEL10WHT11WHT/GRY12BLK13WHT/YEL14WHT/BLK15WIRE

TM 11-5820-670-301-23. FIRST RF AMPLIFIER MODULE A1200. (CONT)The A1200 tuning circuits provide additional attenuation of unwanted frequencies by the

M 11-5820-670-302-82. ELECTRICAL CONNECTOR J910I REPLACEMENT.MATERIALS/PARTS: Connector, receptacle, electrical (P/N MS3112E24-61P)PRELIMINARY PROCED

TM 11-5820-670-302-82. ELECTRICAL CONNECTOR J9101 REPLACEMENT. (CONT)REMOVALNOTETag all wires with connector pin letters. See table to verify wire co

TM 11-5820-670-302-83. TENS FREQUENCY SELECTOR SWITCH S910I REPLACEMENT.MATERIALS/PARTS: Switch, rotary, S9101 (P/N SMC620160)PRELIMINARY PROCEDURE: R

TM 11-5820-670-302-83. TENS FREQUENCY SELECTOR SWITCH S9101 REPLACEMENT. (CONT)NOTEView from rear of switch. Position switch locating tab as shown in

TM 11-5820-670-302-83. TENS FREQUENCY SELECTOR SWITCH S9101 REPLACEMENT. (CONT)2-242EL1AT083

TM 11-5820-670-302-83. TENS FREQUENCY SELECTOR SWITCH S9101 REPLACEMENT. (CONT)INSTALLATION1. Position switch (1) in panel (2) with switch locating t

TM 11-5820-670-302-84. UNITS FREQUENCY SELECTOR SWITCH S9102 REPLACEMENT.MATERIALS/PARTS: Switch, rotary, S9102 (P/N SMC-620161)PRELIMINARY PROCEDURE

TM 11-5820-670-302-84. UNITS FREQUENCY SELECTOR SWITCH S9102 REPLACEMENT. (CONT)EL1AT086NOTEView from rear of switch. Position switch locating tab as

TM 11-5820-670-302-84. UNITS FREQUENCY SELECTOR SWITCH S9102 REPLACEMENT. (CONT)REMOVAL (CONT)E L1AT087View from rear of switch. Position switch loca

TM 11-5820-670-30INSTALLATION2-84. UNITS SELECTOR SWITCH S9102 REPLACEMENT. (CONT)1. Position switch stem (1) in hole in panel (2) alining switch lo

TM 11-5820-670-301-15. MIXER AND BUFFER AMPLIFIER A1400 (RECEIVE MODE). (CONT)Mixer V1401 is the last of three vacuum tubes in the receiver section.

TM 11-5820-670-302-84. UNITS FREQUENCY SELECTOR SWITCH S9102 REPLACEMENT. (CONT)INSTALLATION (CONT)EL1AT1372-248

TM 11-5820-670-302-84. UNITS FREQUENCY SELECTOR SWITCH S9102 REPLACEMENT. (CONT)NOTEView from rear of switch. Position switch locating tab as shown i

TM 11-5820-670-302-84. UNITS FREQUENCY SELECTOR SWITCH S9102 REPLACEMENT. (CONT)INSTALLATION (CONT)EL1AT1395. Position switch locating tab in hole in

TM 11-5820-670-30APPENDIX AREFERENCESA-1. SCOPE.This appendix lists all pamphlets, technical bulletins, technical manuals, and miscellaneouspublicatio

TM 11-5820-670-30A-4. TECHNICAL MANUALS. (CONT)Organizational, Direct Support and General Support Repair Parts andSpecial Tools List (Including Depot

TM 11-5820-670-30A-4. TECHNICAL MANUALS. (CONT)Operator and Organizational Maintenance Manual (Including Repair Partsand Special Tool Lists): Generato

TM 11-5820-670-30EXPENDABLESUPPLIES AND MATERIALS LISTB-1. SCOPE.APPENDIX BThis appendix lists expendable supplies and materials you will need to main

TM 11-5820-670-301-26. LOCAL OSCILLATOR MODULE A1500. (CONT)TUNING CIRCUITSThe tuning circuits control the frequency of the oscillator. They contain

TM 11-5820-670-301-27. IF. ATTENUATOR MODULE A4900 (RECEIVE MODE).EL1AT103In receive mode, if. attenuator module A4900 allows if. signals from the mi

TM 11-5820-670-301-29. THIRD, FOURTH, AND FIFTH IF. AMPLIFIER, LIMITER AND DISCRIMINATOR A4200.THIRD, FOURTH, AND FIFTH IF. AMPLIFIERSEL1AT105The thi

TM 11-5820-670-30INDEXSubjectPageAAdministrative storage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-5820-670-30INDEX (CONT)SubjectC (CONT)PageControl, radio set C-7088/ARC-131 functioning. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-5820-670-30INDEX (CONT)SubjectPageD (CONT)Modules and assembly replacement, A8700. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-5820-670-30INDEX (CONT)SubjectPageHHomer-detector amplifier assembly A4800. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-5820-670-30INDEX (CONT)SubjectPageM (CONT)Modulator module A8100, 11.5 MHz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-5820-670-30INDEX (CONT)SubjectP (CONT)PagePrinciples of operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-5820-670-30INDEX (CONT)SubjectPageP (CONT)Hunt cutoff detector p/o module A4200. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-5820-670-30INDEX (CONT)SubjectPageSSafety, care, and handling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-5820-670-30INDEX (CONT)SubjectPageT (CONT)Homing modeHoming flag indication troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-5820-670-301-30. AUDIO AND SQUELCH PREAMPLIFIER MODULE A4300.The discriminator in module A4200 demodulates both the audio intelligence and the

TM 11-5820-670-30afafcagcamcrsfmif.kHzMHzrecrfrtxmitGLOSSARYSection 1 ABBREVIATIONSAudio frequencyAutomatic frequency controlAutomatic gain controlAmp

TM 11-5820-670-301-31. AUDIO AMPLIFIER MODULE A5400 (RECEIVE MODE). (CONT)The 150 Hz signal from output of amplifier Q5401 (1) operates relay K5501,

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TM 11-5820-670-30HIGH VOLTAGEis used in the operation of this equipment.DEATH ON CONTACTmay result if personnel fail to observe safety precautions.Nev

TM 11-5820-670-301-32. RECEIVER SQUELCH AMPLIFIER MODULE A5200 AND SQUELCH FILTER MODULEA5300 (RECEIVE MODE). (CONT)TONE (SQUELCH MODE)The received 1

TM 11-5820-670-301-32. RECEIVER SQUELCH AMPLIFIER MODULE A5200 AND SQUELCH FILTER MODULEA5300 (RECEIVE MODE). (CONT)DIS (SQUELCH MODE)When the squelc

TM 11-5820-670-301-33. TRANSMllTER SIGNAL FLOW. (CONT)Buffer amplifier A6400 also applies audio modulated signals to isolation amplifier A6600 (18) a

TM 11-5820-670-301-34. MASTER OSCILLATOR FREQUENCY CONTROL LOOP.For proper radio transmitter operation, the fm output of the master oscillator must b

TM 11-5820-670-301-34. MASTER OSCILLATOR FREQUENCY CONTROL LOOP. (CONT)Phase DiscriminatorThe phase discriminator performs the following four functio

TM 11-5820-670-301-34. MASTER OSCILLATOR FREQUENCY CONTROL LOOP. (CONT)The hunt cutoff detector is basically a diode clipper and a filter, which clip

TM 11-5820-670-301-35. AUDIO MIXER MODULE A8600.EL1AT108Audio signals from the interphone amplifier are applied through low-pass filter FL8701 whose

TM 11-5820-670-301-36. 11.5 MHz MODULATOR MODULE A8100. (CONT)The combined signal from the audio mixer is applied to the capacitance diodes which cau

TM 11-5820-670-301-38. PHASE DISCRIMINATOR MODULE A8200.Ring modulator in A8200 accepts two different signals.11.5 MHz audio modulated signal from 11

TM 11-5820-670-301-39. HUNT GENERATOR MODULE A8400.EL1AT112The manner in which the hunt generator controls master oscillator frequency drift is discu

TM 11-5820-670-30Adequate ventilation should be provided while using TRICHLOROTRIFLUOROETHANE.Prolonged breathing of vapor should be avoided. The solv

TM 11-5820-670-301-40. MASTER OSCILLATOR MODULE A6300.The capacitance diodes in the A6300 module accept four signals.1. 100 Hz sawtooth voltage from

TM 11-5820-670-301-40. MASTER OSCILLATOR A6300. (CONT)CAPACITANCE DIODESThe capacitance diodes are reverse-biased at 6.3 vdc. Any change in bias caus

TM 11-5820-670-301-41. BUFFER AMPLIFIER MODULE A6400 AND REGULATOR ASSEMBLY. (CONT)BUFFER AMPLIFIERThe output of master oscillator A6300 is applied t

TM 11-5820-670-301-43. MIXER AND BUFFER AMPLIFIER A1400 (TRANSMIT MODE).In transmit mode, mixer V1401 receives two signals:Frequency modulated signal

TM 11-5820-670-301-44. HUNT CUTOFF DETECTOR P/O MODULE A4200.EL1AT117Frequency modulated 11.5 MHz if. from module A4100 enters the hunt cutoff detect

TM 11-5820-670-301-45. AUDIO AMPLIFIER MODULE A5400 (TRANSMIT MODE).Refer to FO-4 while reading the text in this paragraph.Amplified audio signals fr

TM 11-5820-670-301-48. RF AMPLIFIER ASSEMBLY MODULE A6500.RF AMPLIFIERSEL1AT118Frequency modulated signals from the master oscillator are applied thr

TM 11-5820-670-301-48. RF AMPLIFIER ASSEMBLY MODULE A6500. (CONT)The rf detector is a directional coupler circuit that samples the forward and reflec

TM 11-5820-670-301-49. RF CONTROL ASSEMBLY P/O MODULE A4500 (TRANSMIT MODE).Band-pass filter FL4501A filters out harmonics of all transmitted signals

TM 11-5820-670-301-49. RF CONTROL ASSEMBLY P/O MODULE A4500 (TRANSMIT MODE). (CONT)When the push-to-talk button is pressed, transmit/receive relay K4

TM 11-5820-670-301-50. HOMING SIGNAL FLOW.Homing operation is available on any of 920 channels in the frequency range of 30.00 to 75.95 MHz.The homin

TM 11-5820-670-301-50. HOMING SIGNAL FLOW. (CONT)The application of the dc signal to the vertical needle of the homing indicator provides the pilot w

TM 11-5820-670-301-51. RF CONTROL ASSEMBLY P/O MODULE A4500 (HOMING MODE).DIODE SWITCHEL1AT125Rf signals entering the left and right homing antennas

TM 11-5820-670-301-51. RF CONTROL ASSEMBLY P/O MODULE A4500 (HOMING MODE). (CONT)The rf attenuator circuit operates only in homing mode and is contro

TM 11-5820-670-301-53. HOMER-DETECTOR AMPLIFIER ASSEMBLY A4800.100 Hz OSCILLATOREL1AT128Transistors Q4801 and Q4802 form a common base square-wave os

TM 11-5820-670-301-53. HOMER-DETECTOR AMPLIFIER ASSEMBLY A4800. (CONT)The homer if. signal from the hunt cutoff detector in the fourth if. amplifier

TM 11-5820-670-301-53. HOMER-DETECTOR AMPLIFIER ASSEMBLY A4600. (CONT)OFF COURSE SIGNAL AMPLIFIEREL1AT131The homer if.-am signal, isolated by transis

TM 11-5820-670-301-53. HOMER-DETECTOR AMPLIFIER ASSEMBLY A4800. (CONT)The output if.-am signal from amplifier Q4810 is applied to transistors Q4803 a

TM 11-5820-670-301-54. RETRANSMIT OPERATION.NOTEThis paragraph contains a discussion of retransmit operation. Not to duplicate otherareas of the manu

TM 11-5820-670-301-54. RETRANSMIT OPERATION. (CONT)With K5502 energized, the retransmit control ground, which originates in the receiver-transmitterd

Technical ManualNo. 11-5820-670-30*TM 11-5820-670-30HEADQUARTERSDEPARTMENT OF THE ARMYWashington, DC, 13 September 1985AVIATION INTERMEDIATE MAINTENAN

TM 11-5820-670-301-56. VOLTAGE REGULATOR ASSEMBLY A2100.Voltage regulator assembly A2100 provides a regulated output of +16 vdc for circuits in the r

TM 11-5820-670-301-57. POWER SUPPLY ASSEMBLY A9500. (CONT)REGULATOR OPERATIONThe series regulators, connected in parallel, increase the current capab

TM 11-5820-670-301-58. RECEIVER-TRANSMITTER INTRAUNIT CIRCUIT FUNCTIONING. (CONT)In transmit operation, relay K9601 couples regulated +24 vdc through

TM 11-5820-670-301-58. RECEIVER-TRANSMITTER INTRAUNIT CIRCUIT FUNCTIONING (CONT)METERING CIRCUITSee FO-12, receiver-transmitter, Radio RT-823/ARC-131

TM 11-5820-670-301-59. CONTROL, RADIO SET C-7088/ARC-131 FUNCTIONING. (CONT)When mode control switch S9105 is set to T/R position, + 27.5 vdc from th

TM 11-5820-670-301-59. CONTROL, RADIO SET C-7088/ARC-131 FUNCTIONING. (CONT)Resistor R9102 serves as a dropping resistor to establish the proper sign

TM 11-5820-670-301-59. CONTROL, RADIO SET C-7088/ARC-131 FUNCTIONING. (CONT)When SQUELCH switch S9106 is set to TONE, the ground at contact 7 is conn

TM 11-5820-670-301-59. CONTROL, RADIO SET C-7088/ARC-131 FUNCTIONING. (CONT)The homing indicator vertical (course) needle is controlled by the homer

TM 11-5820-670-301-60. RADIO SET AN/ARC-131 INTERUNIT CIRCUIT DETAILS.Interunit functioning is presented to provide an understanding of the interrela

TM 11-5820-670-301-60. RADIO SET AN/ARC-131 INTERUNIT CIRCUIT DETAILS. (CONT)The + 27.5 vdc primary power is supplied to the radio set from the aircr

TM 11-5820-670-30HOW TO USE THIS MANUALThis manual is designed to help you maintain Receiver-Transmitter, Radio RT-823/ARC-131 andControl, Radio Set C

TM 11-5820-670-301-60. RADIO SET AN/ARC-131 INTERUNIT CIRCUIT DETAILS. (CONT)In transmit operation, the control unit control switch is placed in T/R

TM 11-5820-670-301-60. RADIO SET AN/ARC-131 INTERUNIT CIRCUIT DETAILS. (CONT)AUDIO CIRCUITSSee FO-15 while reading this section.Audio signals from th

TM 11-5820-670-301-60. RADIO SET AN/ARC-131 INTERUNIT CIRCUIT DETAILS. (CONT)In T/R mode, primary + 27.5 vdc power is applied from pins C, D, and E o

TM 11-5820-670-301-60. RADIO SET AN/ARC-131 INTERUNIT CIRCUIT DETAILS. (CONT)Retransmit Mode (RETRAN)In RETRAN mode, + 27.5 vdc primary power is appl

TM 11-5820-670-301-60. RADIO SET AN/ARC-131 INTERUNIT CIRCUIT DETAILS. (CONT)Homing Mode (HOME)In homing mode, +27.5 vdc primary power is applied as

TM 11-5820-670-301-60. RADIO SET AN/ARC-131 INTERUNIT CIRCUIT DETAILS. (CONT)SQUELCH CONTROL CIRCUITSSee FO-17 while reading this section.Squelch Dis

TM 11-5820-670-30RADIO SET AN/ARC-131 INTERUNIT CIRCUIT DETAILS. (CONT)SQ ADJ potentiometer R9602 allows front panel adjustment of the carrier squelch

TM 11-5820-670-301-61. TUNING SYSTEM RADIO SET AN/ARC-131.Receiver-Transmitter Radio RT-823/ARC-131 operates on any of 920 channels within range from

TM 11-5820-670-301-61. TUNING SYSTEM RADIO SET AN/ARC-131. (CONT)Correct ground combinations are applied to pins j, K, M, Z, and AA of control unit c

TM 11-5820-670-301-61. TUNING SYSTEM RADIO SET AN/ARC-131. (CONT)These lines are grounded in various combinations at the control unit to provide requ

TM 11-5820-670-301-61. TUNING SYSTEM RADIO SET AN/ARC-131. (CONT)Conduction of Q9702 simultaneously applies a ground signal to the control coil of K9

TM 11-5820-670-301-61. TUNING SYSTEM RADIO SET AN/ARC-131. (CONT)The geneva assembly also drives open-seeking switch S9705 through a 6 to 1 speed-red

TM 11-5820-670-301-61. TUNING SYSTEM RADIO SET AN/ARC-131. (CONT)RF OSCILLATOR ASSEMBLY MECHANICAL TUNINGThe shaft of the 0.05 MHz cam is mechanicall

TM 11-5820-670-30CHAPTER 2MAINTENANCESubjectSectionRepair Parts, Special Tools, and TMDE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-5820-670-30Section II PERFORMANCE TESTSSubjectParaGeneral. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TM 11-5820-670-302-3. GENERAL.This section contains performance test procedures for use with Maintenance Kit MK-1035/ARC-131and discrete test equipmen

TM 11-5820-670-302-4. TEST METER TESTS.PURPOSEThe test meter tests provide an overall performance check of the radio set. Test switch S9801 selectsvar

TM 11-5820-670-302-4. TEST METER TESTS. (CONT)EQUIPMENTCONTROL OR SWITCHPOSITION/SETTINGTS-25751ARC-131FREQ selSQUELCHMODE SWITCHTRANSMIT SWITCHWIDEB

TM 11-5820-670-302-5. AUDIO POWER OUTPUT AND DISTORTION TEST.PURPOSEThis test checks the receiver section of the radio set. Two signal generators sim

TM 11-5820-670-302-5. AUDIO POWER OUTPUT AND DISTORTION TEST. (CONT)INITIAL EQUIPMENT CONTROL SETTINGSSet equipment controls as indicated in the follo