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2. Inspect capacitors for:

a. Loose mounting, deformities or obvious physical damage.
b. Leakage or corrosion around leads.

3. Inspect connectors for:

a. Loose or broken parts, cracked insulation and damaged con

tacts. DO NOT disassemble connectors solely for inspec

tion and cleaning.

4. Inspect potentiometers for:

a. Free rotation. If rotation feels rough, refer to Section

7 for proper test procedure.

5. Inspect circuit boards for:

a. Corrosion or damage to connectors.
b. Damage to any mounted components, including crystals and

IC's.

c. Freedom from all foreign materials.

6. Inspect resistors for:

a. Cracked, broken, charred or blistered bodies.
b. Loose or corroded soldered connections.

7. Inspect semiconductors for:

a. Cracked, broken, charred or discolored bodies.
b. Loose or damaged seals around leads.

8. Inspect switches for:

a. Loose levers, terminals and switch body contact to frame.
b. Bent or loose line switch contacts.

9. Inspect wiring for:

a. Broken or loose ends and connections.
b. Cuts in or charred insulation.

10. It is recommended that all connectors not in use be covered

with a suitable dust cover to prevent tarnishing of connector

contacts.

8-2

Summary of Contents for FM/AM-500

Page 1: ...MAINTENANCE MANUAl FM AM 500 A COMMUNICATIONS SERVICE MONITORS 10200 Wost York Street Wichita Kansas 67215 U S A 316 522 4981 TWX 910 741 6952 1002 5201 100 ...

Page 2: ...hts reserved Printed in the United States of America No part of this publication may be reproduced stored in a retrieval ystem or transmitted in any form or by any means electronic mechanical photocopying recording or otherwise without the prior permission of the publisher ...

Page 3: ...O PULL OR GRAB THE VICTIM 2 IF POSSIBLE TURN OFF THE ELECTRICAL POWER 3 IF YOU CANNOT TURN OFF ELECTRICAL POWER PUSH PULL OR LIFT THE VICTIM TO SAFETY USING A WOODEN POLE A ROPE OR SOME OTHER DRY INSULATING MATERIAL FIRST AID 1 AS SOON AS VICTIM IS FREE OF CONTACT WITH SOURCE OF ELECTRICAL SHOCK MOVE VICTIM A SHORT DISTANCE AWAY FROM SHOCK HAZARD 2 SEND FOR DOCTOR ANO OR AMBULANCE 3 KEEP VICTIM WA...

Page 4: ... INTO NOR REMOVED FROM CIRCUITS WITH POWER ON 5 PC BOARD WHEN TAKEN OUT OF THE SET MUST BE LAID ON A GROUNDED CONDUCTIVE MAT OR STORED IN A CONDUCTIVE STORAGE BAG Remove any built in power source such as a battery before laying PC Boards on conductive mat or storing in con ductive bag 6 PC BOARDS IF BEING SHIPPED TO THE FACTORY FOR REPAIR MUST BE PACKAGED IN A CONDUC TIVE BAG AND PLACED IN A WELL ...

Page 5: ...pyright Page 3 Warning Page 2 Caution Page o A 3 B 3 i thru vi o vii 3 viii thru ix o x thru xvi 3 1 1 thru 1 3 o 1 4 Blank O 1 5 thru 1 6 o 2 1 thru 2 11 o 2 12 Blank o 3 1 thru 3 3 0 3 4 Blank O 3 5 0 3 6 Blank 0 3 7 0 3 8 Blank o 3 9 0 3 10 2 3 11 thru 3 14 2 3 15 thru 3 16 0 A 03 Pg No Change No 3 17 o 3 18 Blank o 3 19 thru 3 20 O 3 21 0 3 22 thru 3 23 0 3 24 thru 3 25 2 3 26 Blank o 3 27 thr...

Page 6: ... 7 11 thru 7 15 0 7 16 Blank 0 7 17 thru 7 45 o 7 46 Blank o 7 47 thru 7 74 0 7 75 thru 7 78 3 7 78a 3 7 78b Blank 3 7 79 thru 7 83 o 7 84 Blank o 7 85 thru 7 86 O B 03 Pg No Change No 8 1 thru 8 2 o 9 1 thru 9 4 3 9 5 1 9 6 thru 9 8 3 9 9 1 9 9a thru 9 9b 3 9 10 thru 9 12 3 9 13 1 9 14 2 9 15 thru 9 16 1 9 7 thru 9 18 3 10 1 thru 10 2 3 10 3 1 10 4 thru 10 5 2 10 6 3 10 7 1 10 8 thru 10 10 3 10 1...

Page 7: ...GANIZATION The contents of this manual are divided into eleven major sections SECTION 1 INTRODUCTION Provides a brief description of the electrical and mechanical con figuration of the FM AM 500A intended to familiarize the technician with the overall structure of the set SECTION 2 THEORY OF OPERATION Describes the FM AM 500A circuit theory on a simplified level based on accompanying block diagram...

Page 8: ... of operation troubleshooting and testing recommendations for all modules within the FM AM 500A deemed to be field repairable I SECTION 8 PREVENTIVF MAINTENANCE Contains routine instructions for cleaning and inspection of the FM AM 500A r SECTION 9 PC BOARD ASSEMBLIES Contains component layout drawings for all PC Board assemblies within the FM AM 500A SECTION 10 CIRCUIT SCHEMATICS Contains FM AM 5...

Page 9: ...ion 1 1 Frequency Selectors 1 1 Meters 1 1 Mode Bandwidth Control 1 1 RF Output Level Control 1 2 FM AM SOOA Power Requirements 1 2 1 4 Frequency Standards 1 2 1 5 FM AM SOOA Mechanical Description 1 2 1 6 Reference Designators 1 2 1 7 Corrective Maintenance Procedures 1 3 SECTION 2 THEORY OF OPERATION 2 1 Introduction 2 1 2 1 1 2 1 2 Simplified Theory of Operation 2 1 Intermodule Systems Theory o...

Page 10: ...y of Operations 2 5 Reference Frequencies 2 5 Frequency Conversion Modules 2 5 Audio System 2 6 Frequency Error Display 2 8 Phase Lock Indicator Circuit 2 10 SECTION 3 PERFORMANCE EVALUATION General 3 1 Test Equipment Requirements 3 2 3 2 Mobile Performance Evaluation Procedures 3 3 3 2 1 3 2 2 3 2 3 3 2 4 3 2 5 3 2 6 1 kHz Tone Generator 3 5 Variable Receiver Tone Gener ator 3 7 3 9 RF Frequency ...

Page 11: ...Meter RF SSB Frequency Error Meter Audio Modulation and Power Meter SINAD Meter Power Meter SECTION 4 CALIBRATION General Safety Precautions Disassembly Requirements Recommended Calibration Sequence Test Equipment Requirements Controls and Calibration Points Calibration Procedures Mechanical Zeroing of Modulation and Frequency Error 3 27 3 31 3 33 3 35 3 39 41 4 1 4 1 4 2 4 2 4 3 4 3 4 7 Meters 4 ...

Page 12: ...y Precautions Test Equipment Requirements Disassembly Reassembly Requirements Index of Troubleshooting Flowcharts 5 1 5 2 5 2 5 3 5 3 Troubleshooting Power Supply 5 5 Incorrect Output Voltages 5 5 Incorrect Battery Charging Rate 5 9 Troubleshooting Receiver 5 11 Sensitivity Low at Certain Frequencies 5 11 Sensitivity Low at All Frequencies 5 13 Improper Demodulation Troubleshooting Generator Incor...

Page 13: ... 2 10 6 2 11 6 2 ll a 6 2 12 6 2 13 6 2 14 Disassembly Reassembly Procedures 6 1 Genera1 6 1 Preliminary Considerations 6 1 Index Of Module Disassembly and Reassembly Procedures 6 2 Removal and Disassembly 6 3 Case 6 3 Battery 6 5 Oven Oscillator 6 5 Frequency Standard PC Power Supply PC Board Boa rd 6 5 6 5 1120 MHz Low Pass Filter 6 6 Speaker 6 6 Motherboard 6 6 Audio PC Boards 6 7 Enclosed Modu...

Page 14: ... Modules Recommended for Factory Repair Disassembly Requirements Test Equipment Requirements Safety Precautions Index of Module Testing Procedures Power Supply Theory of Operation Preparation for Testing Testing Reassembly IF Module Theory of Operation for Testing Preparation Testing Reassembly Dual VCO Theory of Operation Viii Page 6 19 6 25 6 26 6 26 7 1 7 1 7 1 7 1 7 2 7 3 7 5 7 5 7 7 7 8 7 9 7...

Page 15: ...sizer Module 7 23 Theory of Operation 7 23 Preparation for Testing 7 29 Testing Reassemb1 y Low Loop Synthesizer Theory of Operation 7 29 7 32 7 33 7 33 Preparation for Testi_ng 7 35 Testing Reassembly Receiver Generator Theory of Operation 7 35 7 36 7 37 7 37 Preparation for Testing 7 40 Testing Reassembly Frequency Standard Theory of Operation 7 41 7 42 7 43 7 43 Preparation for Testing 7 44 Tes...

Page 16: ...7 56 Receive Audio Module 7 57 Theory of Operation 7 57 Preparation for Testing 7 62 Testing 7 63 Reassembly 7 66 Generate Audio Module 7 67 Theory of Operation 7 67 Preparation for Testing 7 70 Testing 7 71 Reassembly 7 74 Output Amplifier 7 75 Theory of Operation Thru S N 3224 7 75 Theory of Operation S N 3225 On 7 76 Preparation for Testing 7 78 Testing 7 78a Reassembly 7 78a Variable Tone Gene...

Page 17: ...eassembly 7 86 SECTION 8 PREVENTIVE MAINTENANCE Preventive Maintenance 8 1 External Cleaning Internal Cleaning Visual Inspection SECTION 9 PC BOARD ASSEMBLIES 8 1 8 1 8 1 General 9 1 Index of PC Board Assembly Drawings 9 1 SECTION 10 CIRCUIT SCHEMATICS Genera 1 10 1 Index of Schematics 10 1 Specifications Test Equipment APPENDICES A 1 B 1 Special Test Equipment C 1 Abbreviations and Symbols D 1 Re...

Page 18: ...dicator Block Diagram 2 10 Phase Lock Indicator Circuit Block Diagram 2 11 1 kHz Tone Generator Lab Test Set up 3 19 Variable Tone Generator Lab Test Set up 3 21 Receiver Lab Test Set up 3 23 Frequency Error Meter Lab Test Set up RF SSB 3 31 Frequency Error Meter Lab Test Set up Audio 3 33 Modulation Meter Lab Test Set up 3 35 Calibration Points 4 6 Modulation Meter Calibration Set up 4 19 FM AM S...

Page 19: ...7 33 Low Loop Synthesizer Test Set up Receiver Generator Block Diagram Frequency Standard Block Diagram Digital Module Block Diagram Digital Module Input Signals 7 35 7 38 7 44 7 49 7 53 Receive Audio Module Block Diagram 7 59 Generate Audio Module Block Diagram 7 68 Output Amplifier Module Block Diagram SN 1001 thru 3224 7 75 Output Amplifier Module Block Diagram SN 3225 On 7 77 Variable Tone Gen...

Page 20: ...C Board FM AM 500 9 13 9 16 Receive Audio PC Board FM AM 500A 9 13 9 17 Generate Audio PC Board 9 14 9 18 Variable Tone Generator PC Board 9 15 9 19 Digital Reference PC Board 9 16 9 20 Digital Counter PC Board 9 16 9 21 Generate Amplifier PC Board 9 17 9 22 Dual VCO Module 9 18 10 1 Coax Interconnect 10 3 10 2 Electrical Interconnect Prior to SN 2501 10 4 10 3 Electrical Interconnect SN 2501 and ...

Page 21: ...t Amplifier Schematic SN 3225 On 10 12a IF Module Schematic High Loop Schematic Dual VCO Schematic Low Loop Schematic Receiver Generator Schematic 10 13 10 14 10 17 10 18 10 20 Receive Audio Schematic FM AM 500 10 22 Receive Audio Schematic FM AM 500A 10 24 Generate Audio Schematic 10 26 Variable Tone Generator Schematic 10 27 Digital Module Schematic 10 28 Generate Amplifier Schematic 10 32 Circu...

Page 22: ...bration Sequence Page 4 3 Module Replacement and Alignment Requirements 4 5 Frequency Error Meter Calibration 4 18 Power Supply Output Voltages 7 9 RF Frequency BCD Logic Values 7 30 RF Frequency Error Testing 7 55 Audio Frequency Error Testing 7 55 MIC ACC Jack Functions 7 73 xvi 03 ...

Page 23: ...ule Replacement and Alignment Requirements 4 5 4 3 Frequency Error Meter Calibration 4 18 7 1 Power Supply Output Voltages 7 9 7 2 RF Frequency BCD Logic Values 7 30 7 3 RF Frequency Error Testing 7 55 7 4 Audio Frequency Error Testing 7 55 7 5 MIC ACC Jack Functions 7 73 xvii xviii Blank ...

Page 24: ...ncy selected by the thumbwheels or can vary it more than 10 kHz above or below the selected frequency 1 2 2 METERS Two analog de milliammeters provide visual references for analysis The mode and sensitivity of each meter is controlled by its own rotary selector switch The Frequency Error Meter reflects the difference between the frequency of a monitored signal and the frequency produced by either ...

Page 25: ...pprox imately 13 5 14 volts will also recharge the battery 1 4 FREQUENCY STANDARDS A temperature compensated crystal oscillator TCXO generates a 10 MHz reference signal for frequency control The TCXO can be calibrated to WWV or a frequency counter An optional oven oscillator is available but if it is selected the optional battery cannot be installed If desired an external frequency standard can be...

Page 26: ... High Loop Divider PC Board Low Loop PC Board Receiver Generator PC Board Digital Counter PC Board Digital Reference PC Board Chassis Wire Harness Output Amplifer PC Board Power Supply PC Board 1120 MHz Low Pass Filter Generate Amplifier PC Board 1 7 CORRECTIVE MAINTENANCE PROCEDURES In the event a failure is confirmed within the FM AM 500A the tech nician should take appropriate corrective mainte...

Page 27: ...ORM APPROPRIATE CALIBRA TION PROCEDURE S REF CALIBRA TION TABLE PASS TEST RESULT REPEAT PERFORMANCE EVALUATION TEST S FAIL NATURE OF ORIGINAL FAILURE MALFUNCTION GO TO SECTION 5 OF THIS MANUAL AND PERFORM TROUBLE SHOOTING GO TO SECTION 7 OF THIS MANUAL TO REPAIR OR REPLACE DEFECTIVE COMPONENTS GO TO SECTION 4 OF THIS MANUAL __ I AND PERFORM APPROPRIATE CALIBRA TION PROCEDURE S REF CALIBRA TION TAB...

Page 28: ...ctor Switch 16 1 kHz TONE Level Control 17 Power Switch 18 VAR TONE FREQ Thumbwheels KEY ITEM 19 FREQ ERROR Meter Range Switch 20 Freq Error Meter Zero Adjustment 21 FREQ ERROR Meter 22 RF Frequency LOCK Lamp 23 ANTENNA Connector 24 GEN LOCK Control 25 RF FREQUENCY Thumbwheels 26 GEN REC Mode Switch 27 VOLUME Control 28 SQUELCH Control 29 REF Frequency Adjustment 30 AC Power Connector 31 DC Power ...

Page 29: ...lated within the mechanical assemblies for ample shielding and ease of maintenance accessibility yet minimizing space and interconnection requirements Except for AC and DC power connectors and a 10 MHz RF connector on the Rear Panel all controls indicators and connectors are mounted on the Front Panel The main power transformer AC voltage select switch and power fuses are also mounted on the Rear ...

Page 30: ... Output Amplifier Amplifies generated RF signals and attenuates received RF signals coupled through the T R jack on the Front Panel 4 Generate Amplifier Optional A plug in accessory which ampli fies a generated RF signal by 30 dBm 2 3 SIMPLIFIED THEORY OF OPERATION Reference Figure 2 2 2 3 1 OPERATION AS A RECEIVER When a signal is received it first enters the IF Module where it is filtered amplif...

Page 31: ...OP E HIGH LOOP r GENERATE AUDIO ____ RECEIVE AUDIO VARIABLE TONE GENERATOR FRONT PANEL OUTPUT AMPLIFIER IF MOOULE DUAL VCO 1120 MHz LOW PASS FILTER FREQUENCY STANDARD CPTIONAL OVEN OSCILLATOR REAR PANEL POWER SlPPLY Figure 2 1 FM AM 500A Module Identification 2 3 ...

Page 32: ...utput Amp lifier routes the signal through the O to 100 in 10 dB steps RF LEVEL attenuator providing a 127 dBm to 20 dBm signal at the 50 ohm T R jack A power detector in the Output Amplifier provides a signal to a power monitor in the Receive Audio Module corresponding to the RF output level Feedback from the power monitor to the leveler cir cuit in the Generate Audio Module allows the leveler to...

Page 33: ...eference for the High Loop Synthesizer Module and to 1 MHz for the Digital Module The 1 MHz is then divided into frequencies of 10 Hz 100 Hz 1 kHz and 10 kHz to operate the counter timing circuit The 100 Hz is also fed to the Low Loop Synthesizer Module as its reference The 1 kHz is used as a reference for the 21 4 MHz VCO in the Receiver Generator and by the Generate Audio Module to produce the f...

Page 34: ...hen is 10 7 MHz or the IF frequency An RF signal received from the antenna or through the T R jack enters the IF Module where it passes through a 1000 MHz low pass filter It is then mixed with a selected frequency from the first VCO A 1300 MHz bandpass filter allows only a difference frequency of 1298 1300 MHz to pass thus rejecting all RF frequencies other than any within the 2 MHz span which wil...

Page 35: ... LOOP SYNTHESIZER SECOND vco 89 MHz x THIRD vco LOW LOOP SYNTHESIZER 842 I 8421 842 I 8421 842 I 8421 8421 I I I I I 100MHz 10 MHz I MHz 100 KHz 10 KHz I KHz 100 Hz RF FREQUENCY THUMBWHEELS REC GEN AUDIO MODULATION DEMOD AUDIO DEMODULATOR CARRIER Figure 2 4 Frequency Conversion Modules Block Diagram 2 7 ...

Page 36: ... DISPLAY Figure 2 6 When in use the Frequency Error Meter displays the difference between the frequency of a received signal audio or RF carrier and the set ting of the RF FREQUENCY or VAR TONE FREQ Thumbwheels When the fre quency of the received signal differs from the thumbwheel setting a Digital to Analog Converter DAC in the Digital Module produces a more or a less positive voltage This voltag...

Page 37: ...ROR COUNTER L121 il AL 2 t IUB MODULE 7 FREQ ERROR METER Figure 2 5 Audio System Block Diagram B AUDIO FREQUENCY When measuring an audio frequency the counter system is pre loaded with a count of 128 which causes the DAC to produce a null voltage and the meter to read 0 The timing circuit of the Digital Module couples the unknown audio frequency to the counter system which counts upward for a time...

Page 38: ... output decreases linearly to zero volts at 128 then swings positive linearly to 255 When the count exceeds 255 the overflow is passed on to the first overflow counter and the two DAC counters are reset The overflow is added to the statting count set on the overflow counters and their ending value is interpreted by the over under range detector When an over or under range count is detected a posit...

Page 39: ...g logic The grounding logic then grounds that input to the phase lock logic which also grounds that module s LED and allows it to illuminate With either or both inputs low the phase lock logic supplies a high signal to the flasher logic The flasher oscillator provides a continually pulsing signal to one input of the flasher logic at approximately two pulses per second The second input is from the ...

Page 40: ... its own battery power if the optional battery is installed Only a two foot length of 50 ohm coaxial cable with BNC connectors on each end is required to perform these checks B LABORATORY OR BENCH PERFORMANCE CHECKS These procedures are intended for use in a laboratory or bench environment where each test can be supported and verified by using additional test equipment These procedures are more de...

Page 41: ...ndix Bat the back of this manual contains a comprehensive list of test equipment suitable for performing any of the procedures in this manual Any other equipment meeting the specifications listed in the appendix may be substituted for the recommended models ij For cert n procedures in this manual the equipment 1isted in Appendix Bmay exceed the minimum required specifications For this reason minim...

Page 42: ...tion 3 5 3 2 2 Variable Tone Generator Performance Evaluation 3 7 3 2 3 Receiver Performance Evaluation 3 9 3 2 4 RF Frequency Error Meter Performance Evaluation 3 11 3 2 5 Audio Frequency Error Meter Performance Evaluation 3 13 3 2 6 Generate Mode and Modulation Meter Performance Evaluation 3 15 3 3 3 4 Blank ...

Page 43: ...ING 11 SPEAKER11 Fully ccw 11 OFF11 11 OFF11 Fully ccw If any of the following test procedures fails to produce the proper results refer to Correc tive Maintenance Flowchart in Section 1 for appropriate corrective action 1 Set Power Switch 17 in 11 LINE11 position if AC power is avail able or in 11 BATT11 position if external DC or optional bat tery power is to be used 2 Slowly rotate 1 kHz TONE L...

Page 44: ... produce the proper results refer to Correc tive Maintenance Flowchart in Section 1 for appropriate corrective action 1 Set Power Switch 17 in 11 LINE11 or 11 BATT11 position as appli cable 2 Slowly rotate VAR TONE Level Control 13 cw until a tone is audible 3 Rotate the first digit 1000 Hz of the VAR TONE FREQ Thumb wheels 18 through all ten positions Verify a change in tone occurs with each incr...

Page 45: ...umbwheels 26 GEN REC Mode Switch 27 VOLUME Control 28 SQUELCH Control PROCEDURE 2i SETTING SIG FM MID OFFII OFF OFF LOCK Set to local FM Broadcast Station REC Fully ccw Fully ccw If any of the following test procedures fails to produce the proper results refer to Correc tive Maintenance Flowchart in Section 1 for appropriate corrective action 1 Connect accessory antenna to ANTENNA jack 23 2 Set Po...

Page 46: ...udible Steps 9 through 14 apply to the FM AM 500A only 9 Connect coax cable between TONE OUT 10 and EXT MOD SINAD 7 jacks 10 Set 1 kHz TONE Selector Switch 15 in INT MOD position 11 Rotate level control fully ccw 12 Rotate Modulation Meter Range Switch 4 to DIST Modula tion Meter 1 should read less than 3 on the top scale 13 Rotate VAR TONE Thumbwheels 18 to 2400 and set VAR Tone Selector Switch 1...

Page 47: ...IB2 f l SETTING 11 SSB11 11 0FF11 11 0FF11 11 0FF11 11 RF lK11 11 LOCK11 11 010 000 11 REC Fully ccw Fully ccw 0 If any of the following test procedures fails to produce the proper results refer to Correc tive Maintenance Flowchart in Section 1 for appropriate corrective action 1 Connect coax cable to 10 MHz REF and ANTENNA jacks 2 Set Power Switch 17 in 11LINE11 or 11 BATT11 position as appli cab...

Page 48: ...0 Verify FREQ ERROR Meter 21 indicates 3000 Hz 150 Hz 9 Rotate RF FREQUENCY Thumbwheels 25 to 010 003 0 Verify FREQ ERROR Meter 21 indicates 3000 Hz 150 Hz 10 Rotate Frequency Error Meter Range Switch 17 to RF 10K 11 Rotate RF FREQUENCY Thumbwheels 25 to 010 010 0 Verify FREQ ERROR Meter 21 indicates 10 kHz 300 Hz 12 Rotate RF FREQUENCY Thumbwheels 25 to 009 990 0 Verify FREQ ERROR Meter 21 indica...

Page 49: ...tch 27 VOLUME Control 28 SQUELCH Control PROCEDURE SETTING II 2011 11 FM MID 11 0FF11 INT MOD Fully ccw 11 0FF11 11 1000 011 AUDIO 311 II LOCKII 11 001 000 011 11 GEN11 Fully ccw Fully ccw If any of the following test procedures fails to produce the proper results refer to Correc tive Maintenance Flowchart in Section 1 for appropriate corrective action 1 Set Power Switch 17 in LINE or BATT positio...

Page 50: ...970 0 Verify FREQ ERROR Meter 21 indicates 30 Hz 1 8 Hz 7 Rotate VAR TONE FREQ Thumbwheels 18 to 1030 0 Verify FREQ ERROR Meter 21 indicates 30 Hz 1 8 Hz 8 Rotate Frequency Error Meter Range Switch 19 to AUDIO 300 9 Rotate VAR TONE FREQ Thumbwheels 18 to 1300 0 Verify FREQ ERROR Meter 21 indicates 300 Hz 18 Hz 10 Rotate VAR TONE FREQ Thumbwheels 18 to 0700 0 Verify FREQ ERROR Meter 21 indicates 30...

Page 51: ...1 0FF11 INT MOD11 Fully ccw 11 0FF11 1 1 RF lOK11 11 LOCK11 11 001 000 011 11 GEN 11 Fully ccw Fully ccw If any of the following test procedures fails to produce the proper results refer to Correc tive Maintenance Flowchart in Section 1 for appropriate corrective action 1 Set Power Switch 17 in 11 LINE11 or 11 BATT11 position as appli cable Verify LOCK Lamp 22 illumination is steady and that FREQ ...

Page 52: ... kHz TONE Level Control 16 fully cw Verify MODU LATION Meter 1 indicates deviation greater than 20 kHz 15 Rotate 1 kHz TONE Level Control 16 fully ccw 16 Rotate Modulation Meter Range Switch 4 to 2 Verify MODULATION Meter 1 indicates deviation less than 100 Hz 17 Rotate Modulation Mode Selector Switch 9 to AM NORM 18 Rotate 1 kHz TONE Level Control 16 cw until MODULATION Meter 1 indicates 20 modul...

Page 53: ... 3 Receiver Performance Evaluation 3 23 3 3 4 Generate System Performance Evaluation 3 27 3 3 5 Frequency Error Meter Performance Evaluation RF and SSB 3 31 3 3 6 Frequency Error Meter Performance Evaluation Audio 3 33 3 3 7 Modulation and Power Meter Performance Evaluation 3 35 3 3 8 3 3 9 SINAD Meter Performance Evaluation Power Meter Performance Evaluation 3 17 3 18 Blank 3 39 3 41 ...

Page 54: ... I00ouoo I FREOUENCY COUNTER I I CJ DISTORTION ANALYlER orJ IDJ Dl ITAL LTIIETEI L C J i Figure 3 1 1 kHz Tone Generator Lab Test Set Up INITIAL FM AM S00A CONTROL SETTINGS Reference Figure 1 2 KEY CONTROL SETTING 14 VAR TONE Selector Switch OFF 15 1 kHz TONE Selector Switch INT MOD 16 1 kHz TONE Level Control Fully cw 17 Power Switch OFF STEP PROCEDURE t 2 If any of the foilowing test procedures ...

Page 55: ...p illumination 1s steady 3 Verify DMM indicates 2 50 VRMS or more 4 Rotate 1 kHz TONE Level Control 16 ccw until DMM indicates 2 50 VRMS 5 Using Distortion Analyzer verify distortion is less than 0 5 6 Disconnect coax cable from Distortion Analyzer and connect it to the Frequency Counter 7 Verify Frequency Counter indicates 1 kHz 0 l Hz 3 20 ...

Page 56: ...able BNC BNC 1 son Coax Cable BNC Alligator Clip TEST SET UP DIAGRAM I OOl GLJU I FREQUENCY COUNTER I I 1 Resistor DISTORTION ANALYZER 1son 5 1 8 W l L L J J Figure 3 2 Variable Tone Generator Lab Test Set Up INITIAL FM AM 500A CONTROL SETTINGS Reference Figure 1 2 KEY CONTROL 13 VAR TONE Level Control 14 VAR TONE Selector Switch 15 1 kHz TONE Selector Switch 17 Power Switch 18 VAR TONE FREQ Thumb...

Page 57: ...tortion is less than 0 5 6 Rotate VAR TONE FREQ Thumbwheels 18 to 0010 0 Verify distortion is less than 1 5 7 Rotate VAR TONE FREQ Thumbwheels 18 to 9999 911 Ver ify distortion is less than 1 5 8 Disconnect coax cable from Distortion Analyzer and connect it to the Frequency Counter Verify Frequency Counter displays 9999 9 Hz 1 Hz 9 Rotate VAR TONE FREQ Thumbwheels 18 in each of the settings below ...

Page 58: ...0 00 or with 10 MHz phase lock reference input or output available Distortion Analyzer Measures 1 ess distortion at 1 kHz Digital Multimeter DMM 100 Kn V 3 Digit True RMS son Coax Cables BNC BNC son Coax Cable BNC Alligator Clips T Coax Connector B_NC OOCOi 70 SIGNAL GENERATOR IO IO than 0 5 sensitivity IIFOUT i IN I J y I l DISTORTION ANALYlER Figure 3 3 Receiver Lab Test Set Up 3 23 D J JITI DIG...

Page 59: ...to produce the proper results refer to Correc tive Maintenance Flowchart in Section 1 for appropriate corrective action 1 Connect FM AM 500A to accessory test equipment as shown in Figure 3 3 2 Adjust Signal Generator to produce a 150 2 MHz CW signal at 110 dBm 3 Set Power Switch 17 in LINE position 4 Slowly increase output level of Signal Generator until FREQ ERROR Meter 21 indicates 0 Hz 100 Hz ...

Page 60: ...VOLUME Control 27 and SQUELCH Control 9 fully ccw 11 Rotate Modulation Mode Selector Switch 9 to AM NORM 12 Set Signal Generator to produce a 1 kHz 80 AM signal on a 500 0000 MHz carrier at 50 dBm Verify DMM indicates 400 mV 100 mV 13 Set Signal Generator to produce a 500 0000 MHz CW signal at 50 dBm 14 Place Modulation Mode Selector Switch 9 in SSB position 15 Set RF FREQUENCY Thumbwheels 25 to 5...

Page 61: ...ulation Mode Selector Switch RF LEVEL Attenuator Control RF LEVEL FINE Adjust Control VAR TONE Selector Switch 1 kHz TONE Selector Switch 1 kHz TONE Level Control Power Switch Frequency Error Meter Range GEN LOCK Control RF FREQUENCY Thumbwheels GEN REC Mode Switch VOlUME Control SQUELCH Control PROCEDURE SETTING 112011 11 FM MID11 11 20 dBm11 Fully ccw 11 0FF11 11 0FF11 Fully ccw II LINE11 11RF l...

Page 62: ...N LOCK Control 24 fully ccw into LOCK detent 6 Rotate RF FREQUENCY Thumbwheels 25 to each of the following positions and verify the corresponding frequencies are within the tolerances given SETTING TOLERANCE a 011 1111 1 1 Hz b 012 2222 1 2 Hz c 013 3333 1 3 Hz d 014 4444 1 4 Hz e 015 5555 1 6 Hz f 016 6666 1 7 Hz g 017 7777 1 8 Hz h 018 8888 1 9 Hz i 019 9999 2 0 Hz j 010 0000 1 0 Hz 7 Disconnect...

Page 63: ...Rotate 1 kHz TONE Level Control 16 cw to verify a deviation capability of 20 kHz or greater 17 Rotate Modulation Mode Selector Switch 9 to AM NORM 18 Rotate 1 kHz TONE Level Control 16 ccw or cw as required to verify a modulation capability at 100 or greater 19 Rotate 1 kHz TONE Level Control 16 as required to obtain 50 modulation 20 Rotate RF LEVEL FINE Adjust Control 12 fully cw then back fully ...

Page 64: ..._____J 10 MHz SsJ JACK II l USE EXTERNAL 10 MHz REFERENCE IF SIGNAL GENERATOR DOES NOT PRODUCE 10 MHz PHASE LOCKED REFERENCE Figure 3 4 Frequency Error Meter Lab Test Set Up RF and SSB INITIAL FM AM 500A CONTROL SETTINGS Reference Figure 1 2 KEY CONTROL 9 Modulation Mode Selector Switch 15 1 kHz TONE Selector Switch 16 1 kHz TONE Level Control 17 Power Switch 19 Frequency Error Meter Range 24 GEN ...

Page 65: ...F FREQUENCY Thumbwheels 25 to 500 003 0 Verify FREQ ERROR Meter 21 indicates 3 kHz 300 Hz 7 Rotate Frequency Error Meter Range Switch 19 to RF lK 8 Rotate RF FREQUENCY Thumbwheels 25 to 500 001 0 Verify FREQ ERROR Meter 21 indicates 1 kHz 90 Hz 9 Rotate RF FREQUENCY Thumbwheels 25 to 500 000 0 Verify FREQ ERROR Meter 21 indicates O Hz 30 Hz 10 Rotate RF FREQUENCY Thumbwheels 25 to 499 999 O Verify...

Page 66: ...MHz REFERENCE IF SIGNAL GENERATOR DOES NOT PROOUCE 10 MHz PHASE LOCKED REFERENCE Figure 3 5 Frequency Error Meter Lab Test Set Up Audio INITIAL FM AM SOOA CONTROL SETTINGS Reference Figure 1 2 KEY CONTROL 9 Modulation Mode Selector Switch 13 VAR TONE Level Control 14 VAR TONE Selector Switch 15 1 kHz TONE Selector Switch 17 Power Switch 18 VAR TONE FREQ Thumbwheels 24 GEN LOCK Control 25 RF FREQUE...

Page 67: ...nge Switch 19 to AUDIO 30 Verify FREQ ERROR Meter 21 indicates 30 Hz 1 8 Hz 7 Rotate VAR TONE FREQ Thumbwheels 18 to 11 1003 0 8 Rotate Frequency Error Meter Range Switch 19 to AUDIO 311 Verify FREQ ERROR Meter 21 indicates 3 Hz 0 18 Hz 9 Rotate VAR TONE FREQ Thumbwheels 18 to 11 1000 011 Verify FREQ ERROR Meter 21 indicates O Hz 0 18 Hz 10 Rotate VAR TONE FREQ Thumbwheels 18 to 11 0997 0 Verify F...

Page 68: ...Aa II l USE EXTERNAL 10 MHz REFERENCE IF SIGNAL GENERATOR DOES NOT PRODUCE 10 MHz PHASE LOCKED REFERENCE Figure 3 6 Modulation Meter Lab Test Set Up INITIAL FM AM 500A CONTROL SETTINGS Reference Figure 1 2 KEY 4 9 15 17 18 24 25 26 27 28 19 CONTROL Modulation Meter Range Switch Modulation Mode Selector Switch 1 kHz TONE Selector Switch Power Switch VAR TONE Selector Switch GEN LOCK Control RF FREQ...

Page 69: ...ulation Meter Range Switch 4 to 6 Verify MODULATION Meter 1 indicates 2 kHz 240 Hz deviation 7 Set deviation on Signal Generator to 5 kHz Verify MODULATION Meter 1 indicates 5 kHz 430 Hz 8 Rotate Modulation Mode Switch 9 to FM MID 9 Rotate Modulation Meter Range Switch 4 to 20 MODULATION Meter 1 indicates 5 kHz 850 Hz VeMfy 10 Set deviation on Signal Generator to 20 kHz Verify MODULA TION Meter 1 ...

Page 70: ...STEP PROCEDURE 16 Rotate Modulation Meter Range Switch 4 to 2 Verify MODULATION Meter 1 indicates 20 1 6 3 37 3 38 Blank ...

Page 71: ...II INT MODII INT MOD II LINEII 11 2400 011 If any of the following test procedures fails to produce the proper results refer to Correc tive Maintenance Flowchart in Section 1 for appropriate corrective action A USING DISTORTION ANALYZER 1 Connect coax 11 Tee11 to TONE OUT jack 10 2 Connect one coax between 11 Tee11 and Distortion Analyzer and second coax between 11 Tee11 and EXT MOD SINAD jack 7 3...

Page 72: ...illoscope and second coax between Tee and EXT MOD SINAD jack 7 3 Adjust 1 kHz TONE Level Control 16 for a 4 Vp p sinewave display on Oscilloscope 4 Adjust VAR TONE Level Control 13 for a 1 Vp p sinewave dis play on Oscilloscope 5 Verify Modulation Meter 1 reads 12 dB on the SINAD scale 6 Adjust VAR TONE Level Control 13 for a 0 4 Vp p sinewave display on Oscilloscope 7 Rotate Modulation Meter Rang...

Page 73: ...llowing test procedures fails to produce the proper results refer to Correc tive Maintenance Flowchart in Section 1 for appropriate corrective action 1 Connect 5 10 W Transmitter RF OUT Jack to Power Meter IN jack with coax 2 Connect Power Meter OUT jack to FM M 500A T R jack 5 with coait l lraftsnit a 150 170 MHz u1111111odulated C and werify Mlodulation Meter 1 WlJ TiS sea1e reading agrees wriit...

Page 74: ... Modulation Meter 1 WATTS scale reading agrees with Power Meter 10 Rotate Modulation Meter Range Switch 4 to 11 15 WATTS AVG 11 Connect AM Transmitter in place of 50 100 W Transmitter 12 Transmit an unmodulated CW and record the power applied on the Modulation Meter 1 13 Transmit a modulated signal Modulation Meter 1 should read approximately the same as in Step 12 14 Rotate Modulation Meter Range...

Page 75: ...formance specifications as provided in SECTION 3 PERFORMANCE EVALUATION 2 If a module is found to be defective and requires replacement 3 If he recommended annual calibration is due 4 1 1 SAFETY PRECAUTIONS As with any piece of electronic equipment extreme caution should be taken when troubleshooting live circuits When performing the cal ibration procedures in this section be sure to observe the f...

Page 76: ...dure 4 2 1 the exterior case must be removed from the FM AM 500A 4 1 3 RECOMMENDED CALIBRATION SEQUENCE Before making any calibration adjustments always observe the signal measurement If the measurement is within tolerances given do not proceed with that specific adjustment The only time an adjustment 1s required for an in tolerance measurement is when a subsequent inter active adjustment is not s...

Page 77: ...NG MODULE LISTED BELOW MODULES ARE IN PROPER CALIBRATION 10 MHz OSCILLATOR 1 POWER SUPPLY VARIABLE TONE GENERATOR 1 POWER SUPPLY FREQUENCY ERROR METER 1 MECHANICAL ZEROING OF FREQUENCY ERROR METER 2 POWER SUPPLY 3 10 MHz OSCILLATOR MODULATION METER 1 MECHANICAL ZEROING OF MODULATION METER 2 POWER SUPPLY 3 10 MHz OSCILLATOR SINAD METER 1 MECHANICAL ZEROING OF MODULATION METER 2 POWER SUPPLY 3 10 MH...

Page 78: ...GITAL MODULE RECEIVE AUDIO GENERATE AUDIO OUTPUT AMPLIFIER VARIABLE TONE GENERATOR VARIABLE FREQUENCY POWER 10 MHz TONE ERROR MODlLATION SUPPLY OSCILLATOR GENERATOR METER METER GENERATE SINAD POWER OUTPUT IF MODULE METER METER LEVEL SECTION 7 HIGH LOOP LOW LOOP RECEIVER MODULE MODULE GENERATOR SECTION 7 SECTION 7 MODULE SECTION 7 Table 4 2 Module Replacement and Alignment Requirements 4 5 ...

Page 79: ...it ia 1 J i J R3246 2 CAL R3224 NULL Jl R4052 HIGH LIMl T J _ 1 R4042 __ n 1 LO W LIMIT R4047 LOOP GAIN R4053 LA J 1 r _ _ _ _ _ _ _ _ _ j_ X3 CAL R4509 X10 CAL __ W _ 7 1 1 il R4510 ZERO CAL R4407 BATT VOLTAGE R5241 tt i 1 12 V ADJ R5216 LEVELER OFFSET R5114 OPTIONAL OVEN TUNE 4 6 01 1S 1210 MHz ADJ C2003 Figure 4 1 Calibration Points ...

Page 80: ...r TEST SET UP DIAGRAM None CALI BRATION POINTS See Figure 4 1 STEP PROCEDURE C J If any of the following calibration procedures fails to produce the proper results refer to Corrective Maintenance Flowchart in Section 1 for appropriate corrective action 1 Place Power Switch 17 in OFF position 2 Adjust the appropriate Meter Zero Adjust screw 2 20 until the Meter 1 21 indicates O 0 4 7 4 8 Blank ...

Page 81: ...A BATTERY CHARGER CIRCUIT 1 With Power Switch 17 in OFF positi 0n disconnect Battery and connect Battery Load Simulator to P5004 tci l DISCONNECT ALL EXTERNAL POWER CORDS BEFORE DIS CONNECTING BATTERY CONNECTOR P J5004 2 Rotate Battery Load Simulator s Load Control Pot to center of its mechanical travel approximately 500 load 3 Connect External AC power cord to power source and FM AM 500A 4 Connec...

Page 82: ...s 9 through 11 as necessary to obtain tolerances on pins 3 89 and 10 J5201 Pin 3 10 Voltage DC 12 0 V 43 0 V Norn 5 0 V Tolerance 0 2 V 5 0 V 0 2 V 5 Set Power Switch 17 in OFF position then disconnect AC power cord 6 Disconnect P5004 from Battery Load Simulator and reconnect to J5004 from Battery 7 Connect DVM to pin 1 of P5201 8 Rotate Modulation Meter Range Switch 4 to BATT TEST 9 Set Power Swi...

Page 83: ... 4 1 STEP PROCEDURE If any of the following calibration procedures fails to produce the proper results refer to Corrective Maintenance Flowchart in Section 1 for appropriate corrective action A COARSE CALIBRATION Coarse calibration should be performed only if the REF Frequency Adjustment 29 has insuffi cient range to accurately calibrate the 10 MHz frequency standard 1 Connect Frequency Counter to...

Page 84: ...B FINE CALIBRATION TO WWV 1 Connect antenna to ANTENNA Connector 23 2 Connect unshielded test lead to 10 MHz REF Connector 32 on Rear Panel 3 Set Front Panel controls as follows see Figure 1 2 KEY CONTROL 9 Modulation Mode Selector Switch 24 GEN LOCK Control 25 RF FREQUENCY Thumbwheels 26 GEN REC Mode Switch 27 VOLUME Control 28 SQUELCH Control SETTING 11 AM NORM or 11 LOCK11 11 010 000011 11 REC1...

Page 85: ...URE 2 Rotate REF Frequency Adjustment 29 on Front Panel as required to obtain 10 MHz within a 1 Hz with standard oscillator b 0 5 Hz with optional oscillator c 0 1 Hz with optional oven oscillator 4 13 4 14 Blank ...

Page 86: ...h 17 Power Switch 18 VAR TONE FREQ Thumbwheels CALIBRATION POINTS See Figure 4 1 STEP PROCEDURE SETTING Fully clockwise 11 INT M0D 11 IIQFFII 115000 011 Hz If any of the following calibration procedures fails to produce the proper results refer to Corrective Maintenance Flowchart in Section 1 for appropriate corrective action 1 Remove Variable Tone Generator PC Board and connect extender cable bet...

Page 87: ...l Frequency Counter indicates 2048 kHz 1 Hz t 49 I l If preferred Frequency Counter is not available and alternate equipment is used connect Fre quency Counter to TONE OUT Jack 10 and adjust C3110 until counter indicates 5000 0 Hz 4 16 ...

Page 88: ...trol 28 SQUELCH Control CALIBRATION POINTS See Figure 4 1 STEP PROCEDURE SETTING FM NAR OFF OFF OFF RF 10K LOCK 010 000 0 REC Fully counterclockwise Fully counterclockwise If any of the following calibration procedures fails to produce the proper results refer to Corrective Maintenance Flowchart in Section 1 for appropriate corrective action 1 Connect coax cable between ANTENNA Connector 23 on Fro...

Page 89: ... 9 009 999 9 10 009 999 9 11 009 999 7 12 009 999 0 13 009 997 0 14 009 990 0 Frequency Error Meter Range Switch RFlOK RFlOK RF3K RFlK RF300 RFlOO RF30 RF30 RF30 RFlOO RF300 RFlK RF3K RFlOK FREQ ERROR Meter Reading 0 1 0 3 1 0 3 1 0 Pegged 0 Pegged 1 0 3 1 0 3 1 0 Table 4 3 Frequency Error Meter Calibration 4 18 Adjustment Trimpot R4507 R4510 R4509 ...

Page 90: ... AM and 0 15 kHz Deviation FM 1 Signal Generator Capable of Producing 120 MHz at 0 dBm with 0 50 Modulation AM and 0 15 kHz Dev iation FM 3 son Coax Cables BNC BNC 1 Directional Coupler son 20 dBm or 1 30 dB pad IPPOOOd I SIGNAL GENERATOR IIIECTIIIAL caa u MODULATION METER USING SINGLE INPUT MODULATION METER IOooOoO I SIGIAL GENERATOR IODULATION IETER ffllPAI USING DUAL INPUT MODULATION METER Figu...

Page 91: ... calibration procedures fails to produce the proper results refer to Corrective Maintenance Flowchart in Section 1 for appropriate corrective action 1 Connect Test Equipment as follows see Figure 4 2 2 3 4 5 a For single input Modulation Meter connect both Modulation Meter and Signal Generator to Directional Coupler and con nect Directional Coupler to ANTENNA Jack 23 on Front Panel b For dual inpu...

Page 92: ...ter l indicates 5 kHz 0 43 kHz 13 Repeat Steps 4 through 12 until the correct level is attained in all three settings 14 Set Signal Generator to produce a 120 MHz CW carrier at O dBm 15 Rotate Modulation Meter Range Switch 4 to 2 16 Rotate Modulation Mode Selector 9 to AM NORM 17 Adjust R3371 as necessary until MODULATION Meter 1 indicates 0 0 1 18 Rotate Modulation Meter Range Switch 4 to 6 19 Se...

Page 93: ... 18 VAR TONE FREQ Thumbwheels CALIBRATION POINTS See Figure 4 1 SETTING Method A 11 SINAD11 IIQFFII 11 INT MOD 11 IILINE11 11 2400 011 STEP PROCEDURE N Ei Method B 11 SINAD 11 11 INT MOD 11 11 INT MOD 11 II LINEII 11 2400 011 If any of the following calibration procedures fails to produce the proper results refer to Corrective Maintenance Flowchart in Section 1 for appropriate corrective action A ...

Page 94: ...3 thru 10 changing the null trimpots slightly each time until approximately 10 distortion is achieved in Step 10 B USING OSCILLOSCOPE 1 Connect coax Tee to TONE OUT jack 10 2 Connect one coax between Tee and Oscilloscope and second coax between Tee and EXT MOD SINAD jack 7 3 Adjust VAR TONE Level Control 13 for a 1 Vp p sinewave on the Oscilloscope 4 Set VAR TONE Selector Switch 14 in OFF position...

Page 95: ... position and rotate Modulation Meter Selector Switch to DIST Modulation Meter 1 should indicate approximately 10 12 Repeat Steps 1 through 11 changing the null trimpots slightly each time until approximately 10 distortion is achieved in Step 11 4 25 4 26 Blank ...

Page 96: ... Figure 1 2 KEY CONTROL 4 Modulation Meter Range Switch 17 Power Switch 26 GEN REC Switch CALIBRATION POINTS See Figure 4 1 STEP PROCEDURE f SETTING 11 15 WATTS AVG11 11LINE11 11 REC11 If any of the following calibration procedures fails to produce the proper results refer to Corrective Maintenance Flowchart in Section 1 for appropriate corrective action 1 Adjust Power Zero trimpot R3354 to zero t...

Page 97: ...ct readings at both frequencies 7 Rotate Modulation Meter Range Switch 4 to 150 WATTS AVG 8 Connect 50 100 W Transmitter in place of the 5 10 W Trans mitter 9 Transmit a 150 170 MHz unmodulated CW preferrably at 50 W Note reading on Power Meter and adjust 150 W trimpot R3362 until Modulation Meter 1 WATTS Scale reading agrees with Power Meter u oN DO NOT EXCEED POWER LIMITATIONS OF 100 W 1 minutes...

Page 98: ...CY Thumbwheels 26 GEN REC Mode Switch 27 VOLUME Control 28 SQUELCH Control CALIBRATION POINTS See Figure 4 1 STEP PROCEDURE t 1 SETTING 11 FM NAR11 11 30 dBm 11 30 dBm 11 0FF11 11 0FF11 11 0FF11 11 LOCK11 11 120 000011 MHz 11 GEN11 Fully counterclockwise Fully counterclockwise If any of the following calibration procedures fails to produce the proper results refer to Corrective Maintenance Flowcha...

Page 99: ...NE Adjust Control 12 to 31 dBm 12 Adjust R3224 as necessary for Power Meter to indicate 31 dBm 13 Rotate RF LEVEL FINE Adjust Control 12 to 42 dBm ffi Do NOT alter setting of RF LEVEL Attenuator Con trol 11 14 Adjust R3246 as necessary for Power Meter to indicate 42 dBm 15 Rotate RF LEVEL FINE Adjust Control 12 to 37 dBm 16 Adjust R3227 as necessary for Power Meter to indicate 37 dBm 17 Repeat Ste...

Page 100: ... or PC board is identified then proceed with the recom mended repair replacement procedures 5 1 2 TROUBLESHOOTING HINTS Before proceeding with extensive troubleshooting it is advisable that the technician first make a few simple checks which may eliminate many of the possible causes of the malfunction These checks may save the technician many hours of labor which might needlessly be spent on exten...

Page 101: ...D COMPONENTS DURING TROUBLESHOOTING OR CALIBRATION REMOVE ALL JEWELRY OR OTHER COSMETIC APPAREL BEFORE PERFORMING ANY CALIBRATION PROCEDURES INVOLVING LIVE CIRCUITS WHEN WORKING WITH LIVE CIRCUITS OF HIGH POTENTIAL KEEP ONE HAND IN POCKET OR BEHIND BACK TO AVOID SERIOUS SHOCK HAZARD USE ONLY INSULATED TROUBLESHOOTING TOOLS WHEN WORKING WITH LIVE CIRCUITS FOR ADDED INSULATION PLACE RUBBER BENCH MAT...

Page 102: ...5 3 Flowchart Page Troubleshooting Power Supply 5 5 Incorrect Output Voltages 5 5 Incorrect Battery Charging Rate 5 9 Troubleshooting Receiver 5 11 Sensitivity Low at Certain Frequencies 5 11 Sensitivity Low at All Frequencies 5 13 Improper Demodulation 5 15 Troubleshooting Generator 5 19 Incorrect Carrier Amplitude 5 19 Incorrect Carrier Frequency 5 27 Inadequate Response to Variable Generator Co...

Page 103: ...J5201 pin 2 and p n 8 4 Measure voltage between J5201 pin 2 and pin 3 5 Measure voltage between J5201 pin 2 and pin 10 6 Power Supply outputs do not test faulty 7 Measure voltage across E5212 E5213 and across E5214 E5213 DECISION Is voltage 43 VDC 5 V Is voltage 12 VDC 0 2 V If voltage is not correct do not proceed with Steps 4 through 9 until the 12 V fault is corrected Is voltage 12 voe 0 2 V Is...

Page 104: ... Board Repair or replace as required Refer to Power Supply paragraph in Section 7 12 Measure voltage across E5210 E5211 13 Test 40 V rectifier cir cuit on Power Supply PC Board Repair or replace as required Refer to Power Supply paragraph in Section 7 14 Measure voltage across Transformer black and white leads and across the brown and yellow leads 15 Replace Transformer to Rear Panel Removal Disas...

Page 105: ...ION YES NO 16 Trace circuitry back to 17 power source to locate open Repair or replace as required Refer to Section 6 for appropriate removal and disassembly procedures 17 End of procedure Repeat as necessary 5 7 5 8 Blank ...

Page 106: ...oad Simulator Is voltage 14 4 voe set at 0 3 A load use 0 1 V Digital Voltmeter to mea sure voltage at E5202 E5203 4 Slowly increase simulated Is maximum current between battery load past the point 1 2 A and 1 4 A of maximum current i o Nl IN NO EVENT SHOULD THE CURRENT EXCEED 1 7 AMPS OR DAMAGE TO THE POWER SUPPLY PC BOARD MAY RESULT 5 Set Power Switch in 11 LINE11 Does current drop to position b...

Page 107: ... Repair or replace as required Refer to Power Supply paragraph in Section 7 8 Test the battery charger voltage regulator circuit on the Power Supply PC Board Repair or replace as required Refer to Power Supply paragraph in Section 7 9 End of procedure Repeat as necessary 5 10 DECISION YES NO 9 9 ...

Page 108: ...y with faulty sensitivity 2 Connect Spectrum Analyzer Is output level 8 dBm to J2103 and set center 4 dB frequency at 1300 MHz plus the RF FREQUENCY Thumb wheel setting to observe the 1st VCO output level 3 Test the IF Module Repair or replace as required Refer to IF Module para graph in Section 7 4 Troubleshoot the 1st VCO in the Dual VCO Module Refer to paragraph 5 5 2 5 End of procedure Repeat ...

Page 109: ...o P4302 and set center frequency at 10 7 MHz Connect Signal Generator Does Spectrum Analyzer to ANTENNA Jack and inject display a 10 7 MHz signal a 120 MHz signal at between 25 dBm and 30 dBm 35 dBm in amplitude Test the Receiver Generator Module Repair or replace as required Refer to Receiver Generator Module paragraph in Section 7 Connect Spectrum Analyzer Is 79 3 MHz signal level to J4202 7 dBm...

Page 110: ...o Dual VCO Module para graph in Section 7 10 Test output amplifier cir cuit of 2nd VCO in Dual VCO Module Repair or replace as required Refer to Dual VCO Module para graph in Section 7 11 Test output amplifier cir cuit of VCO in Low Loop Module Repair or replace as required Refer to Low Loop Synthesizer Module paragraph in Section 7 12 End of procedure Repeat as necessary DECISION YES NO 12 12 12 ...

Page 111: ...LUME Control SQUELCH Control OFFII 11 120 000 11 REC11 Fully ccw Ful l y ccw 0 Inject a 120 MHz signal at approximately 50 dBm Test the Receive Audio PC Board Repair or replace as required Refer to Receive Audio Module para graph in Section 7 Troubleshoot Receiver Sensitivity Refer to paragraph 5 3 1 and 5 3 2 Rotate Modulation Mode Selector Switch to FM NAR11 position DECISION Which of the follow...

Page 112: ...o Receiver Generator Module paragraph in Section 7 11 Rotate Modulation Mode Selector Switch to AM NORM 12 Inject a 120 MHz signal at approximately 50 dBm with AM modulation of 1 kHz at 30 13 With Oscilloscope Probe sample the AM audio signal at J4301 pin 19 DECISION Does Oscilloscope display a 1 kHz audio signal Is audio signal a Approximately 0 6 VAC p p with approximately YES NO 8 9 10 17 17 12...

Page 113: ... in Sectio_n 7 15 Test AGC circuit in 17 Receiver Generator Module Repair or replace as required Refer to Receiver Generator Module paragraph in Section 7 16 Test AM Detector circuit 17 on Receive Audio PC Board Repair or replace as required Refer to Receive Audio Module para graph in Section 7 17 End of procedure Repeat as necessary 5 17 5 18 Blank ...

Page 114: ...0 dBm RF LEVEL FINE Control Fully ccw VAR TONE Selector Switch OFF 1 kHz TONE Selector Switch OFF Power Switch LINE GEN LOCK Control LOCK RF FREQUENCY Thumbwheels 010 0000 GEN REC Switch GEN 2 Connect Spectrum Analyzer to T R Jack and observe output level 3 Remove Generate Audio PC Board and measure voltage at J3201 pin 32 on Motner Board Re install the PC Board DECISION Is signal level a 20 dBm 3...

Page 115: ...rate Audio Module paragraph in Section 7 7 Test for an open in the Mother Board and or wire harness for the circuit without power Repair or replace as required Refer to Section 6 for Mother Board removal procedures 8 Set GEN REC Switch in REC and the Modulation Mode Selector Switch in FM NAR 9 Connect Signal Generator to ANTENNA jack on FM AM 500A and test receiver sensitivity Return GEN REC Switc...

Page 116: ...lifier Module paragraph in Sec tion 7 16 Measure voltage at FL5104 17 Measure voltage at J4301 pin 1 18 Test Receiver Generator Repair or replace as required Refer to Receiver Generator para graph in Section 7 19 Test AM Modulator Leveler circuit on Generate Audio PC Board and RF LEVEL FINE Adjust Control on Front Panel Repair or replace as required Refer to Generate Audio Module para graph in Sec...

Page 117: ...t Amplifier Repair or replace as required Refer to Output Amplifier Module paragraph in Sec tion 7 Connect Spectrum Analyzer to J4302 Connect Spectrum Analyzer to J4202 Connect Spectrum Analyzer to J2003 Connect Spectrum Analyzer to J2002 DECISION YES NO Is 10 MHz signal level 21 24 approximately O dBm Is 10 MHz signal level 22 23 approximately O dBm 49 49 49 Is signal frequency 26 33 10 7 MHz Is ...

Page 118: ... voltage at FL5104 35 Test Level Detector Circuit of Output Amplifier Repair or replace as required Refer to Output Amplifier Module paragraph in Section 7 36 Measure vo1 tage at J3002 pin 33 37 Test AM Modulator Leveler circuit on Generate Audio PC Board and RF LEVEL FINE Adjust Control on Front Panel Repair or replace as required Refer to Generate Audio Module paragraph in Section 7 38 Measure v...

Page 119: ...serving output level on Spectrum Analyzer 43 This test indicates proper level of the carrier gen erator system 44 Calibrate the RF LEVEL FINE Adjust Control in accordance with Generate Output Level Calibration Procedure in Section 4 45 Test RF LEVEL FINE Adjust Control on Front Panel and AM Modulator Leveler Cir cuit on Generate Audio PC Board Repair or replace as required Refer to Generate Audio ...

Page 120: ...e Output Amplifier for RF leakage Repair or replace as required Refer to Output Amplifier Module in Section 7 48 eplace RF LEVEL Step Attenuator Refer to Sec tion 6 for removal and installation procedures 49 End of procedure Repeat as necessary DECISION YES NO At each detent is signal 47 48 level 20 dB 3 dB above the attenuator marking 49 49 5 25 5 26 Blank ...

Page 121: ... LEVEL FINE Control Controls as 11 20 dBm Fully ccw VAR TONE Selector Switch OFFII 1 kHz TONE Selector Switch Power Switch GEN LOCK Control RF FREQUENCY Thumowheels GEN REC Switch 11 0FF11 11LINEII 11LOCK11 11 010 000011 11GEN11 Connect Frequency Counter to EXT STD Jack on Rear Panel Calibrate FM AM 500A Fre quency standard to Fre quency Counter Refer to Section 4 Connect Frequency Counter to T R ...

Page 122: ...Hz and finally to 999 MHz Observe Frequency Counter at each increment 7 Carrier frequencies do not test faulty 8 Troubleshoot High Loop and Dual VCO Refer to para graph 5 5 2 9 Troubleshoot Low Loop Refer to paragraph 5 5 3 10 Connect Frequency Counter to J4302 11 Reconnect P J4302 and con nect Frequency Counter to T Jack 12 Measure voltage at J4301 pin 16 DECISION Are frequencies correct Are all ...

Page 123: ...e as required Refer to Receiver Generator Module paragraph in Section 7 17 Test GEN LOCK Control Cir cuit and Timebase Divider Circuit in Digital Module Repair or replace as required Refer to Dig ital Module paragraph in Section 7 18 Test FM Modulation Circuit on Generate Audio PC Board Repair or replace as required Refer to Gener ate Audio Module paragraph in Section 7 19 End of procedure Repeat ...

Page 124: ... Module Repair or replace as required Refer to Digital Module paragraph in Section 7 5 Measure voltage at J3002 pin 38 while rotating GEN LOCK Control from fully cw to fully ccw just short of detent 6 Measure voltage at J3002 pin 37 7 Test Mother Board and Wire Harness Repair or replace as required Refer to Sec tion 6 for Mother Board removal procedures Is voltage greater than 3 5 voe nominally 5 ...

Page 125: ...EP DIRECTIONS DECISION YES NO 8 Test GEN LOCK Control on 9 Front Panel Repair or replace as required Refer to Section 6 for Front Panel removal and disassem bly 9 End of procedure Repeat as necessary 5 32 ...

Page 126: ...ont Panel 2 Observe Phase Lock Indica tor lights on High Loop and Low Loop Modules 3 Measure voltages at J4102 pin 4 and J4201 pin 8 4 Test Phase Lock Indicator Circuit on Generate Audio PC Board Repair or replace as required Refer to Generate Audio Module paragraph in Section 7 5 Troubleshoot module s with low voltage Refer to paragraphs 5 5 2 and 5 5 3 Is illumination a Out 18 b Steady 11 c Flas...

Page 127: ...aragraph 5 5 3 10 Troubleshoot High Loop and Dual VCO Refer to paragraph 5 5 2 11 Rotate 100 MHz Thumbwheel quickly from 9 through 0 to 1 12 Rotate 100 MHz Thumbwheel to 2 then back to 1 13 Test 200 MHz limit circuit in High Loop Repair or replace as required Refer to High Loop Synthesizer Module paragraph in Sec tion 7 14 Test Phase Lock in High Loop Repair or replace as required Refer to High Lo...

Page 128: ...ndicator LED lead and green wire 19 Turn Power Switch to OFF and test continuity between junction of LED lead and J5201 pin 2 ground 20 Test Wire Harness and Mother Board Repair or replace as required Refer to Section 6 for Mother Board removal procedure 21 Replace LED Refer to Front Panel Disassembly paragraph in Section 6 for LED removal procedure 22 Install Generate Audio PC Board on extender a...

Page 129: ...pair or replace as required Refer to Section 6 for Mother Board removal procedure 24 Test Phase Lock Indicator 25 Circuit on Generate Audio PC Board Repair or replace as required Refer to Generate Audio Module paragraph in Section 7 25 End of procedure Repeat as required 5 36 ...

Page 130: ...1 4 Connect 0 40 VDC Power Supply to P4003 5 Smoothly vary voltage between O and 40 V and observe frequency response on Spectrum Analyzer 6 Reconnect P J4003 Con nect Spectrum Analyzer to P2205 and DVM to P2101 7 Again smoothly vary volt tage between O and 40 V Observe frequency response on Spectrum Analyzer and voltage response on DVM DECISION Is light illuminated on High Loop Module Is 500 kHz r...

Page 131: ...ages at J4101 pins 1 3 5 7 9 13 17 19 and 20 15 Rotate RF FREQUENCY Thumb wheels to 222 MHz and measure voltages at J4101 pins 11 and 15 16 Test Thumbwheel Switches Repair or replace as required Refer to High Loop Synthesizer Module paragraph in Section 7 DECISION Does voltage vary smoothly and correspond with vol tage from variable Power Supply YES NO 9 18 Does frequency begin at 11 14 1300 MHz a...

Page 132: ...dule paragraph in Section 7 20 Test Dual VCO Module Repair or replace as required Refer to Dual VCO Module paragraph in Section 7 21 Set 1 kHz TONE Selector Switch in SPEAKER posi tion and rotate Level Con trol cw until tone is audible 22 Test divider circuit of Frequency Standard Repair or replace as required Refer to Frequency Stan dard Module paragraph Section 7 23 Connect Frequency Counter to ...

Page 133: ...andard Module paragraph in Sec tion 7 25 Disconnect P J4001 Does light illuminate with 2 26 Observe light on High Loop P J4001 disconnected Module then reconnect P J4001 26 Test Phase Lock and Phase 27 Lock Indicator circuit on High Loop Repair or replace as required Refer to High Loop Synthesizer Module paragraph in Sec tion 7 27 End of procedure Repeat as required 5 40 ...

Page 134: ...er to J4201 pin 6 3 Connect Frequency Counter to J4202 and observe fre quency 4 Rotate RF FREQUENCY Thumb wheels through the follow ing positions and observe for corresponding fre quencies at J4202 THUMBWHEEL MHz 1 1111 2 2222 3 3333 4 4444 5 5555 6 6666 7 7777 8 8888 9 9999 FREQUENCY MHz 78 1889 79 0778 77 9667 78 8556 77 7445 78 6334 77 5223 78 4112 77 3331 DECISION YES NO Is light illuminated o...

Page 135: ...7 19 23 and 24 8 Test Thumbwheel Switches Repair or replace as required Refer to RF Frequency Thumbwheels BCD Logic Table in Section 6 9 Test frequency select net work of Low Loop Repair or replace as required Refer to Low Loop Synthe sizer Module paragraph in Section 7 10 Test Low Loop Module Repair or replace as required Refer to Low Loop Synthesizer Module paragraph in Section 7 11 Connect Freq...

Page 136: ...rcuit on Fre quency Standard PC Board and oven oscillator if installed Repair or replace as required Refer to Frequency Standard Module paragraph in Sec tion 7 16 Disconnect P J4503 Observe light on Low Loop Module then reconnect P J4503 17 Test Phase Lock and Phase Lock Indicator Circuits on Low Loop Repair or replace as required Refer to Low Loop Synthesizer Module paragraph in Sec tion 7 18 End...

Page 137: ...edures The only specific reassembly instruction is for the RF LEVEL attenuators To assist in locating routing and con necting coaxial cables refer to Coaxial Cable Interconnect drawing in Section 10 6 1 2 PRELIMINARY CONSIDERATIONS A Tools required for Disassembly Reassembly 1 1 2 Phillips Screwdrivers 2 3 16 Spade Slotted Screw driver 3 1 4 and 5 16 Open End Wrenches 4 1 4 5 16 3 8 Nut Drivers Au...

Page 138: ...2 16 6 3 6 3 1 Title Disassembly Case Battery Oven Oscillator Frequency Standard Power Supply 1100 MHz Low Pass Filter Speaker Mother Board Audio PC Boards Enclosed Modules Output Amplifier IF Module Dual VCO Rear Panel Front Panel Generate Amplifier Reassembly RF Level Attenuator 6 2 Page 6 3 6 3 6 5 6 5 6 5 6 5 6 6 6 6 6 6 6 7 6 9 6 11 6 13 6 15 6 16 6 19 6 25 6 26 6 26 ...

Page 139: ...VAL AND DISASSEMBLY 6 2 1 CASE A Removal Figure 6 1 1 Loosen two captive screws 1 on rear escutcheon 2 and remove escutcheon 2 Carefully slide chassis 4 out of case 3 N J During installation case must engage in groove in front and rear escutcheons ...

Page 140: ...2 RECEIVE AlDI VAAIH3LE TONE GENERATOR 36 35 38 3 7 48 49 50 51 5 53 54 55 56 46 4 7 _ __ t 1 4 4 45 2 I _ I __ 3 1 4 5 6 I 7 I 8 f b __ _ _ c 7 I f S A I 9 1 i l X ___5 s t 1 1o I JV Q t 11 I y 7 12 13 14 15 16 17 L L 18 T 19 I 20 le J 21 22 r 7 26 30 32 31 33 6 4 Figure 6 2 FM AM SOOA Composite Assembly ...

Page 141: ...m the compartment then remove four screws 59 and lock washers 60 3 On test sets which have the oscillator 62 mounted directly on the chassis 33 remove four screws 59 and lock washers 60 then remove the oscillator 6 2 4 FREQUENCY STANDARD PC BOARD 38 A Removal Figure 6 2 1 Remove two screws 32 and lock washers 31 attaching PC board assembly 38 to bottom of chassis 33 2 Remove screw 12 and lock wash...

Page 142: ... 3 Disconnect flexible coax cables from each end of Filter 22 and withdraw filter from chassis 33 6 2 7 SPEAKER 27 A Removal Figure 6 2 1 Remove nual VCO 14 paragraph 6 2 13 2 Remove 1120 MHz Low Pass Filter 22 paragraph 6 2 6 3 Tag and unsolder wires from two terminals on Speaker 27 4 Remove four nuts 29 three lock washers 28 one terminal lug 30 four compression washers 26 and four screws 25 atta...

Page 143: ...able connector from Variable Tone Generator PC Board 42 2 Lift PC Board Retainer 41 from over the PC boards 3 Pull straight up on PC board 42 to disengage connector from Mother Board 39 and lift from chassis 33 Sheet metal of chassis is formed into PC board guides 6 7 ...

Page 144: ...2 3 I 12__ _ j 11 i 10 HIGH LOOP SYNTHESIZER 7 8 r l 3 I LOW LOOP SYNTHESIZER 4 5 6 7 8 2 3 4 5 6 7 RECEIVER GENERATOR I 12 11 2 3 v I I I I 10 9 7 DIGITAL Figure 6 3 Enclosed Module Assemblies 6 8 4 6 7 8 ...

Page 145: ...isassembly Figure 6 3 1 Remove nut 3 securing each coax connector 5 to top panel 2 2 Remove all screws 1 securing top panel 2 to PC board assembly 6 Lift top panel from canister 7 and remove lock washers 4 from coax connectors 5 3 Remove two screws 8 securing PC board assembly 6 to bottom of canister 7 Lift PC board assembly from canister 4 To separate the paired PC boards of the High Loop Synthes...

Page 146: ...9 10 11 DETAIL A 0 0 0 0 jO 0 0 o 0 0 FM AM 500 Olt Y FM AM 500A ONLY DETAIL B Figure 6 4 Output Amplifier Assembly SN 1001 thru SN 3224 6 10 03 0 0 0 ...

Page 147: ... 49 apply a thin coat of Thermal Joint Compound Wakefield Engineering Inc Type 120 or equivalent to sur face of enclosure block which contacts Rear Pane1 B Disassembly Figure 6 4 1 Remove twelve screws 2 attaching cover 3 to enclo sure block 1 2 Remove ten screws 7 attaching cover 6 to en closure block 1 3 Unsolder leads from two coax connectors 8 and four feed thru filters 9 at PC board 4 Remove ...

Page 148: ...J5106 K5 1 Z J5101 L5110 L5109 L5108 DETAIL A J5103 9 Figure 6 4a Output Amplifier Assembly SN 3225 On 6 lla 03 8 6 ...

Page 149: ...t of Thermal Joint Compound Wakefield Engineering Inc Type 120 or equivalent to surface of enclosure block which contacts Rear Panel B Disassembly Figure 6 4a 1 Remove twenty screws 2 attaching cover 1 to enclosure block 13 2 Remove twenty one screws 7 attaching cover 6 to enclosure block 13 3 Unsolder leads from two coax connectors 5101 and 5103 and three feed thru filters L5110 L5109 and L5108 a...

Page 150: ...17 21 20 19 DETAIL A J2208 ef O O DETAIL B ff _ 5 0 1A r 6 r i 19 20 21 t LtJ W B 17 18 t 1 L 1 b Pr 8 i X IF A w i 9 15 14 10 13 12 Figure 6 5 IF Module Assembly 6 12 03 ...

Page 151: ... c Remove three screws 3 attaching PC board 4 to enclo sure block 5 3 Remove sixteen short screws 11 and one long screw 12 attaching large cover 10 to enclosure block 8 4 Remove IF Amplifier PC Board 15 a Unsolder and remove two feed thru filters Detail 1 1 8 11 Items 23 24 and two coax jacks 17 21 and lock washers 18 b Unsolder three leads 7 which feed through enclosure blocks 6 8 from PC Board 1...

Page 152: ...DETAIL A 11 Figure 6 6 Dual vco 6 14 01 Assembl Y ...

Page 153: ...xtensive trial and error adjustments 1 Remove seventeen screws 2 and lock washers 3 attaching cover plate assembly 4 to enclosure block 10 U l l N DO NOT ALTER POSITIONS OF COMPONENTS ON PC BOARDS OR OPERATING CHARACTERISTICS MAY BE SIGNIFICANTLY CHANGED 2 Unsolder feedthru filters 5 13 from PC boards 8 11 3 Unsolder lead from each PC board 8 11 to mixer bandpass filter assembly 14 4 Remove nut 12...

Page 154: ...ry 47 if so equipped Paragraph 6 2 2 2 Disconnect coax cable from External 10 MHz connector 55 3 Remove two screws 1 and lock washers 2 attaching Output Amplifier 49 to Rear Panel 48 4 Remove two screws 51 and 52 and lock washers 50 and 53 attaching Power Supply PC Board 5 to chassis 33 6 16 ...

Page 155: ...screw 7 and lock washer 6 attaching Powe Supply PC Board 32 to Rear Panel 8 b Tag and unsolder all wires from transformer 13 to Power Supply PC Board 32 c Tag and unsolder three wires from transformer 13 to volt age select switch 20 d Unsolder wire from External DC Power jack 1 to torroid coil 18 e Remove four screws 16 three lock washers 15 four flat washers 14 and grounding lug 17 mounting trans...

Page 156: ...coax connector 3 a Loosen set screw 2 b Unscrew coax connector 3 from Rear Panel 8 4 Remove external DC Power Supply Connector 1 a Tag and unsolder two wires from external DC Power Supply Connector 1 if not already disconnected in disassembly procedure b Remove nut 5 and lockwasher 4 and withdraw connector 1 frotn Rear Panel 8 6 18 ...

Page 157: ...nel 35 Remove escutcheon 3 Remove one screw 37 securing each side of chassis to Front Panel 35 4 Slide Front Panel 35 out of chassis 33 and disengage rib bon cable connectors from Mother Board 39 5 Disconnect semi rigid coaxes from T R connector Figure 6 8 Item 26 and step attenuator Figure 6 8 Item 7 6 Identify and unsolder two wires in wrapped two wire bundle running to chassis from Power Switch...

Page 158: ... 1 60 59 DETAIL A 40 A 42 DETAIL B 4 44 43 46 36 35 34 33 4 54 55 53 7 27 26 24 25 lJ j 2 3 58 56 y 4 5 7 8 2 9 22 21 3 19 18 20 10 5 11 12 Figure 6 8 Front Panel Assembly 6 20 ...

Page 159: ...nstalled then withdraw connector 26 28 from Front Panel 46 l TU Generate Amplifier power connector 26 does not have lock washer 24 3 Remove GEN REC Switch 13 and REF Adjust Potentiometer 12 a Tag and unsolder all leads b Remove nut 27 and flat washer 25 attaching GEN REC Switch 13 to Front Panel 46 withdraw switch 13 with nut 14 and flat washer 15 and remove REF Potentiometer 12 Assembly C 1 Durin...

Page 160: ...bracket 51 to meter 49 and remove bracket 6 Remove RF Level Attenuator 7 a Remove RF FREQUENCY Thumbwheel Switch Step B 4 of this paragraph b Loosen two set screws 39 and remove knob 38 c Remove two screws 40 and dial 37 d Remove two screws 36 and FINE Adjust cursor 35 e Remove two screws 34 and FINE Adjust knob 33 f Loosen two set screws 32 and remove hub 31 g Lift FINE Adjust drive gear 30 and n...

Page 161: ... such as Lock Tite Tack Pak or fingernail polish to retainer 61 and Front Panel 46 8 Remove all other controls and switches Typical for all remaining potentiometers and switches a Loosen two set screws 41 and remove knobs 42 as required b Tag and unsolder wires from controls and switches 48 being removed c Remove nut 43 and flat washer 44 and withdraw control or switch 48 and washer 47 from Front ...

Page 162: ...J Rotate GEN LOCK Control fully counterclockwise into detent then align knob with LOCK index mark Rotate VOLUME and SQUELCH Controls fully counterclockwise and position knob with index at 7 00 o clock 6 24 ...

Page 163: ...raight away from Front Panel B Disassembly Figure 6 9 1 Remove six screws 10 attaching cover 11 to enclosure block 9 2 Unsolder leads to BNC connectors 5 6 and 8 Unscrew and remove male connectors 5 and 6 3 Unsolder lead to connector 7 Loosen set screw 12 4 Remove four screws 3 attaching BNC connector 8 to enclosure block 9 5 Remove four screws 1 and lock washers 2 attaching PC board 4 to enclosur...

Page 164: ...ert set screw 10 through spring 9 and install in pivot block 8 to secure potentiometer 6 4 Place potentiometer drive gear 2 on potentiometer 6 shaft and tighten set screw 10 5 Place pivot block 8 assembly on stud of Front Panel 46 and install spacer 1 flat washer 3 lock washer 4 and nut 5 6 Hook spring 9 over stud on Front Panel 46 and seal with an adhesive such as Lock Tite Tack Pack Item No 1229...

Page 165: ...ts gear and install two flat head screws 34 Figure 6 10 Monitor ohmmeter to prevent accidental change in potentiometer setting Remove shimstock 21 Spacing with shimstock is essential to prevent excessive drag of knob 33 on hub 31 13 Rotate FINE Adjust knob 33 fully cw and back ccw Ohmmeter should return to its original reading of betwe n 10 and 250 ohms 14 Position cursor 35 on FINE Adjust knob 33...

Page 166: ...16 Install knob 38 on attenuator 7 shaft Recesses are drilled into knob to allow knob to fit over dial attaching screw heads and rest flush against dial 37 Secure knob with two set screws 39 6 28 ...

Page 167: ... repairing or replacing a module it is essential to conduct appropriate Calibration Procedures before returning the FM AM 500A to service 7 1 1 MODULES RECOMMENDED FOR FACTORY REPAIR The Dual VCO Module and the 88 90 MHz bandpass filter poles in the IF Module are not field repairable and should therefore be returned to the IFR Factory for repair 7 1 2 DISASSEMBLY REQUIREMENTS Removal of the exteri...

Page 168: ...NG TROUBLESHOOTING OR CALIBRA TION AS LONG AS THE BATTERY IS INSTALLED OR EXTERNAL AC OR DC POWER IS APPLIED A 12 voe POTENTIAL EXISTS AT VARIOUS POINTS ON REAR PANEL REGARD LESS OF THE FRONT PANEL POWER SWITCH POSITION AS LONG AS THE FM AM 500A IS OPERATING ON INTERNAL BATTERY OR EXTERNAL DC A 115 OR 230 VAC POTENTIAL EXISTS AT THE AC POWER CONNECTOR DO NOT OPERATE ON BATT INCLUDING EXTERNAL DC W...

Page 169: ... Power Supply IF Module Dual VCO High Loop Synthesizer Low Loop Synthesizer Receiver Generator Frequency Standard Digital Module Rece i ve A udi o Generator Audio Output Amplifier Variable Tone Generator Optional Generate Amplifier 7 3 7 4 Blank Page 7 5 7 11 7 17 7 23 7 33 7 37 7 43 7 47 7 57 7 67 7 75 7 79 7 85 ...

Page 170: ...h a 400 Hz squarewave and subsequently the two 24 V taps of the transformer s 30 VCT secondary winding Acting as an autotransformer this winding then furnishes the 15 VDC and the 15 VDC to the 12 VDC and 12 VDC regulators It also induces a current in the primary and other two secondary windings of the transformer A timer counts the pulses from the 400 Hz oscillator and after approximately 10 minut...

Page 171: ...ake up the regulator Capacitors C5203 C5205 and C5217 and toroid inductor L5201 filter the output Op Amp U5201B is connected to the output of the 12 VDC regulator which provides the 5 VDC regulator with a reference point Zener diode CR5205 limits the output to 6 2 VDC for overvoltage protection The 12 VDC uses bridge rectifier BR5201 from the 30 VCT winding of the transformer Op amp U5201A and tra...

Page 172: ...ese two transistors drive power transistors Q5207 and Q5208 respectively each of which feeds one leg of the 24 V tap of the 30 VCT secondary winding of the transformer The emitters of driver transistors Q5210 and Q5211 are returned to the 5 V supply to reduce heat dissipation in resistors R5224 and R5225 and to increase the efficiency of the power supply Transistor Q5206 supplies power to counter ...

Page 173: ...Switch 17 Power Switch 26 GEN REC Mode Switch II INT SETTING MOD INT MOD OFF 11 GEN11 7 2 3 TESTING Refer to Power Supply PC Board Drawing in Section 9 and Power Supply Circuit Schematic in Section 10 1 Connect AC power cord to FM AM SOOA and to power source u 1ciNl WHEN AC POWER IS APPLIED THE BATTERY CHARGER CIRCUIT IS ACTIVE USE CARE WHEN HANDLING THIS LIVE CIRCUIT 2 Adjust Battery Load Simulat...

Page 174: ... supply and External DC connector of FM AM 500A and apply 12 0 voe 9 Simultaneously start the stopwatch and place Power Switch fn BATT position 10 While stopwatch is running measure Power Supply output volt ages in accordance with Table 7 1 11 Verify FM AM 500A automatically shuts off after 10 minutes 54 seconds 1 minute 12 Set Power Switch in OFF position and back to BATT Verify FM AM 500A is onc...

Page 175: ...le A second bandpass filter allows only the dif ference second IF signal of 88 90 MHz to pass After further amplification the second IF is mixed with the signal which is between 79 3 and 77 3 MHz from the third VCO in the Low Loop Synthesizer Module This third or final IF when the RF thumbwheels are set to the actual RF frequency received is the 10 7 MHz IF frequency used by the Receiver Generator...

Page 176: ...MHz LOW PASS FILTER SECOND MIXER FIRST MIXER 1298 1300 MHz BANDPASS 89 MHz BANDPASS FILTER FILTER Figure 7 2 IF Module Block Diagram 10 7 MHz TO FROM REC GEN static leakage through the switch to ground When the relay is not energized the T R jack on the Front Panel 1s coupled through the Output Amplifier to the Monitor Generate M G jack of the IF Module to the lowpass filter 7 12 ...

Page 177: ...transistors Q2203 and Q2204 and associated circuitry then coupled to the 88 90 MHz bandpass filter consisting of filters FL2301 FL2302 FL2201 FL2202 FL2203 and capacitors C2301 through C2304 and C2202 through C2206 Transistors Q2201 and Q2202 and associated circuitry form a two stage 1210 MHz ampli fier which is enabled by the GEN command signal In the Gen erate mode a signal passing through this ...

Page 178: ...ed for test purposes only 4 Connect Tracking Generator output to J2205 and its input to J2206 7 3 3 TESTING Refer to IF Module Component Location Drawing in Section 9 and IF Module Circuit Schematic in Section 10 1 Apply power to Power Supply then set Tracking Generator controls as follows a Center frequency b Output level c Dispersion 1300 MHz 30 dBm 20 MHz span 2 MHz Div 2 Adjust FL2205 FL2206 a...

Page 179: ... FL2301 FL2302 FL2201 FL2202 and FL2203 for the following characteristics as seen on the Tracking Generator a Center frequency 89 MHz b Bandwidth 1 MHz at 1 dB c Rejection at 79 MHz is 80 dB or greater d Gain 0 dB 4 dB 12 Connect Power Supply to FL2204 Do not disconnect from FL2209 at this time 13 Connect Tracking Generator output to J2201 and verify level displayed is 30 dBm 4 dB 14 Disconnect Po...

Page 180: ...xer An 1120 MHz Lowpass Filter is not a physical part of the module but is required to allow only the difference frequency from the mixer to reach the High Loop The High Loop Synthesizer generates an error voltage which con trols the frequencies of the two VCOs To do this a sample of each VCO frequency is mixed then filtered by the 1120 MHz Low pass Filter to allow the High Loop Synthesizer to com...

Page 181: ...ER CIRCUITS The first VCO output is inductance coupled through inductor L2108 to two identical two stage buffers One buffer feeds the first IF mixer through J2103 and the other goes to the mixer furnishing VCO feedback to the High Loop Synthesizer Since both buffers are identical except for reference designators the buffer feeding the first IF mixer will be discussed in detail The first stage ampl...

Page 182: ...IELD REPAIRABLE DUE TO CRITICAL LENGTHS AND SENSITIVE ALIGNMENTS IF THE DUAL VCO IS FAULTY IT SHOULD BE RETURNED TO THE IFR INC FACTORY FOR REPAIR IF THE FOLLOWING TEST IS PERFORMED BE EXTREMELY CARE FUL NOT TO DISTURB ANY COMPONENT A REMOVAL AND DISASSEMBLY Remove and disassemble the Dual VCO Module for testing as described in Section 6 Do not remove the PC boards from the cover plate assembly B ...

Page 183: ...t the stop refer to Dual VCO Assembly Drawing in Section 9 0 N1 DO NOT FORCE ROTATION OF C2003 PAST THE STOP 5 Connect 10 KO potentiometer 1 0 µF capacitor and 22 µH inductor to J2101 as shown in Figure 7 4 6 Connect coax cable to Signal Generator 7 Connect alligator clips to 001 µF capacitor and to VCO PC Board ground as shown in Figure 7 4 8 Solder 001 µF capacitor to junction of R2106 and C2103...

Page 184: ... establish VCO at 1300 MHz Spectrum Analyzer should show signal strength of 8 dBm 4 dB 8 Using DVM measure voltage at J2101 Voltage should be l voe 0 5 VDC Record voltage B SECOND 1210 MHz VCO c 1 Using DVM measure voltage at emitter of Q2001 Voltage should be approximately 11 voe 2 Connect Frequency Counter to J2003 3 Adjust C2003 until Frequency Counter displays 1210 MHz 1 MHz 4 Connect Spectrum...

Page 185: ...ith first VCO signal producing 1120 to 129 MHz sig nal This unwanted signal must be 40 dB or more below mixer output signal especially at crossing point of 605 MHz 7 4 4 REASSEMBLY With all power OFF disconnect all test equipment from Dual VCO Module Reassemble and replace module in reverse order of removal and disassembly procedures described in Section 6 7 22 ...

Page 186: ...cy changes the VCO difference frequency to the High Loop Synthesizer changes accordingly which changes the output frequency of the divider network When the two frequencies divider output and reference frequency are approximately equal the output becomes quiet In the first phase sampler the leading edge of the divider output approximately 500 kHz squarewave triggers a switch which provides 11 VDC p...

Page 187: ...e frequency changes on the thumbwheels A quad bilateral switch controlled by the BCD signal from the 100 MHz RF FREQUENCY Thumbwheel adjusts the gain of the second VCO error signal from the phase detector The AC components of the error signal pass through the selected switch or switches and corresponding paralleled resistors to an amplifier A choke smooths the amplifier output which then goes to t...

Page 188: ...10 and allows the input to amplifier U4103 to increase This results in a stronger signal to op amp U4111 When the signal strength is greater than the non inverting input the output becomes more negative which would increase the signal flow at CR4110 However capacitor C4155 which is parallel with the op amp prevents abrupt changes in the feed back signal and allows the op amp to adjust the signal l...

Page 189: ...IGNAL AMPLIFIER On Analog PC Board The reference signal amplifier is very similar to the second feedback amplifier discussed above When the incoming signal is high transistor Q4002 conducts grounding the amplifier output When the signal is low Q4001 conducts which brings the output high G FIRST PHASE SAMPLER On Divider PC Board The first phase sampler receives a 500 kHz signal from the second feed...

Page 190: ...erence signal amplifier and the 500 kHz feedback signal from the second feedback ampli fier are fed through inverters U4113B and U4113A respectively to phase locked loop U4112 U4112 has two outputs one is to transistor Q4103 in the phase lock indicator circuit the other is a correction signal to the first 1300 2298 MHz VCO inte grator The level of this signal which is approximately 5 2 VDC when th...

Page 191: ...the amplifier hysteresis loop A changing input signal level affects the amplifier output but when the input level is steady its output returns slowly to its preset level The output of the amplifier changes quickly in response to small input level changes in order to cause a fast response in the second VCO frequency However when the input stops changing the VCO returns to its output frequency of 12...

Page 192: ...ircuit Schematics in Section 10 1 Perform the tests prescribed in paragraph 7 4 Dual VCO prior to testing the igh Loop 2 Uncouple connectors P J4002 P J4003 and P J4102 3 Connect the 10 K potentiometer as follows Terminal 1 Terminal 2 wiper Terminal 3 Chassis ground P4003 Center Conductor J5201 pin 9 Power Supply 4 Connect Frequency Counter to J2103 on Dual VCO 5 Connect Spectrum Analyzer to J2003...

Page 193: ... 000 0 1 0 0 0 0 1 1 1 0 444 000 0 0 1 1 0 0 0 0 0 0 555 000 0 0 1 1 0 0 1 0 1 0 666 000 0 1 1 1 0 0 0 1 0 0 777 000 0 1 1 1 0 0 1 1 1 0 888 000 0 0 0 0 1 1 0 0 0 1 999 000 0 0 0 0 1 1 1 0 1 1 BCD 0 5 2 1 2 Mn Table 7 2 RF FREQUENCY BCD Logic Values 19 0 0 1 1 0 0 1 1 0 0 3 Using DMM verify the logic states of the RF FREQUENCY switches according to Table 7 2 N EJ If the logic is not correct test t...

Page 194: ... recorded in Step Ba 12 Adjust the 10 K pot to obtain a frequency of 1500 MHz 13 Adjust High Limit trimpot R4042 to obtain a voltage equal to that recorded in Step Be 14 Rotate RF FREQUENCY Thumbwheels to 199 000 0 15 Adjust the 10 K pot to obtain a frequency of 1400 MHz 16 Adjust 200 MHz Limit trimpot R4024 to obtain a voltage equal to that recorded in Step Sb 17 Disconnect the DVM and 10 K pot a...

Page 195: ...0 777 000 0 666 000 0 555 000 0 444 000 0 333 000 0 222 000 0 111 000 0 000 000 0 1st VCO Output Frequency MHz 2298 2188 2076 1966 1854 1744 1632 1522 1410 1300 26 Rotate the RF FREQUENCY Thumbwheels to 900 000 0 and verify the Front Panel phase lock indicator quickly achieves steady 111umination 27 Rotate the RF FREQUENCY Thumbwheels back to 000 000 0 Again verify the Front Panel phase lock indic...

Page 196: ...ich is controlled by the RF FREQUENCY Thumbwheels This divider divides by a factor of between 793 000 and 773 001 The output of the divider network when phase locked is a 100 Hz pulse furnished to a phase comparator The comparator compares this signal with a 100 Hz reference signal from the Digital Counter Any difference between the signals causes corresponding changes in the detector s output vol...

Page 197: ...er network D PROGRAMMABLE DIVIDER NETWORK The divider network consists of a tlO tll prescaler and chained dividers U4201 U4203 U4204 U4205 U4207 and U4208 which are programmed by the X XXXX RF FREQUENCY thumbwheel switches The network divides the VCO output frequency by a number equal to 793000 minus the setting of the XXXX thumbwheels minus 10 000 when the X thumbwheel setting is an odd integer T...

Page 198: ... BOARD BNC SMB OSCILLOSCOPE SPECTRUM ANALYZER Figure 7 7 Low Loop Synthesizer Test Set up C PREPARATION Refer to Figure 7 7 and Low Loop PC Board Drawing in Section 9 1 Connect ribbon cable connector P4201 to J4201 2 Connect spectrum analyzer to J4202 3 Connect oscilloscope to Q4206 pin 3 4 Set RF FREQUENCY Thumbwheels to 001 999 9 7 6 3 TESTING Refer to Low Loop PC Board Drawing in Section 9 and ...

Page 199: ...plitude of 7 dBm 4 dB at 79 3 MHz 10 Verify harmonics above 1000 MHz are at a level of 70 dBm or less 11 Connect Frequency Counter to J4202 Verify frequency dis played is 79 300000 MHz 20 Hz 12 Rotate RF FREQUENCY Thumbwheels to 001 999 9 Verify Frequency Counter displays 77 30010 MHz 20 Hz C C o Limit RF FREQUENCY Thumbwheel 5 selections to between 000 000 0 and 001 999 9 for this test Output fre...

Page 200: ...into the receiver circuit to allow the Receive Audio Module to monitor and display the signal on the Modulation and Frequency Error Meters B RECEIVE MODE In the Receive mode the modulated 10 7 MHz signal from the IF Module passes through the receive enable circuit two AGC amplifiers and one of three bandpass filters These filters have a center frequency of 10 7 MHz with bandwidths of 200 kHz FM Wi...

Page 201: ...transistors Q4304 and Q4305 controls the gain through Q4301 Q4302 and Q4311 0 40V FROM DIGITAL FREQ COUNTER FM MOD _ AM MOD GEN COMMAND FROM GEN AUDIO 10 7 M Hz _TOI FROM IF MODULE f 10 7 MHz RECEIVER MODULE AM MOD 2 ULATOR 200KHz 15 KHz I c l 6 KHz AGC FROM RECEIVER AUDIO BD 7 21 4MHz vco t 2 AM DEMOD L FM DEMOD Figure 7 8 Receiver Generator Block Diagram D BANDPASS FILTERS DEMOD AUDIO TO REC AUD...

Page 202: ...R4378 and capacitors C4341 C4342 and C4380 form a tuned circuit for the detector One output of the detector is a hard limited 10 7 MHz signal fed to the Digital Module The other output is a varying DC which is the demodulated FM audio signal This is amplified by op amp U4303A and filtered by inductor L4311 and capacitor C4343 to remove any residual RF then is fed to the Receiver Audio Module G 21 ...

Page 203: ... 1 Spectrum Analyzer 1 Frequency Counter Capable of 10 7 MHz Capable of 25 MHz with 1 kHz resolution 1 Audio Distortion Meter Resolution of 0 1 1 kHz 1 Oscilloscope 1 MHz with X Y capabilities 1 Digital Voltmeter DVM 3 Digit 1 50 Ohm Coax Cable BNC SNB Connectors 1 26 Gauge Shorting Strap Alligator Clips both ends C PREPARATION Refer to Receiver Generator PC Board Drawing in Section 9 1 With Recei...

Page 204: ...l amplitude of Oscilloscope display is approximately 1 major graticule divi sion then repeat Step 3 Repeat this procedure until a minimum level of 2 VDC is obtained at an input of 1 0 µV If 2 VDC is not obtained adjust R4385 as required 5 Rotate Modulation Mode Selector Switch to FM Wide position 6 Modulate Signal Generator with 1 kHz audio Select FM modu lation with 50 kHz deviation 7 Connect Osc...

Page 205: ...k 16 Rotate GEN LOCK Control fully cw 17 Adjust L4312 to obtain at least 10 010000 MHz typically 10 020000 MHz as measured on Frequency Counter 18 Rotate GEN LOCK Control fully ccw just out of detent Fre quency Counter should display less than 9 990000 MHz typically 9 980000 MHz If necessary readjust L4312 slightly 19 Connect Oscilloscope to DEMOD jack and adjust R4351 to obtain maximum amplitude ...

Page 206: ...ignal gates allows a low level signal produced by the TCXO to reach the external jack This provides sufficient radiation capability for a beat signal which can be used during calibra tion but is insufficient to trigger the level detector The resistor prevents an external signal from bypassing the level detector and gates B TCXO POWER CIRCUIT The level detector in the reference signal selector circ...

Page 207: ...UNTER DETECTOR SOURCE SELECT 1 I MULTIPLEXER 500 KHz TO HIGH LOOP l SYNTHESIZER 10 2 10 MHz Figure 7 9 Frequency Standard Block Diagram 7 8 3 PREPARATION FOR TESTING A REMOVAL AND DISASSEMBLY For testing the Frequency Standard removal is not normally required However if repair is necessary remove the PC Board assembly as outlined in Section 6 No module disassembly is required B REQUIRED TEST EQUIP...

Page 208: ...t fine adjustment using the REF potentio meter 3 Rotate REF potentiometer to obtain an indication of 10 MHz 1 Hz on Frequency Counter 4 Connect Frequency Counter to P2502 Verify displayed fre quency is 1 MHz 1 Hz 5 Connect Frequency Counter to P2503 Verify displayed fre quency is 500 kHz 1 Hz 6 Connect Signal Generator to P2501 Adjust Signal Generator to 10 MHz at 25 dBm 5 dBm Verify Frequency Cou...

Page 209: ...a corresponding analog voltage The Digital Module is divided for discussion purposes into three major circuits the Frequency Divider Circuit the Timing Circuit and the Counter System B FREQUENCY DIVIDER CIRCUIT On Digital Reference PC Board The incoming 1 MHz reference signal is divided successively by BCD counters U4505 U4506 and U4507 to produce frequencies of 10 kHz 1 kHz 100 Hz and 10 Hz These...

Page 210: ...er U4401B The control signal for multiplexer U4401B is from the Q output of slaved flip flop U4412B When this signal is low U4401B feeds the unknown audio frequency multiplied by 100 to multi plexer U4401C When the Q output is high U4401B feeds the reference signal also multiplied by 100 to U4401C When the Frequency Error Range Switch on the Front Panel is in one of the RF positions multiplexer U4...

Page 211: ... KHz MP X I I I AUDIO REF w I I SQUELCH GATE i TIMING CIRCUIT MASTER TIMING FLIP FLOP Q CK I Q I 4 I Q CK SLAVE TIMING CLR Q __ _ FLIP FLOP t RF INHIBIT _ XIOO n__ XIOO FREQ ERROR RANGE SWITCH I PRESET LOGIC GATES f I Q Q _ CK CK er g r _J r I 12V I __ I I I I COUNTER CIRCUIT l I I COUNTER S I I f BUS I LATCH BUS t DIGITAL TO ANALOG CONVER TER l DIGITAL l l I I C O U N TERS I I I I r BUS OVER RANG...

Page 212: ... A logic network consisting of NOR gates U4414A U4414B U4414C and U4414D NANO gates U44168 U4416C and U4416D and inverters U44178 U4417D U4417E and U4417F is controlled by binary codes from the Frequency Error Range Switch This network establishes the starting count for chained counters U4402 through U4406 Outputs from counters U4402 and U4403 are coupled to latch U4408 When triggered by reset mul...

Page 213: ...MB PREPARATION 1 Make the following initial control settings Refer to Con trols Indicators and Connectors Drawing in Section 1 KEY CONTROL 4 Modulation Meter Range Switch 9 Modulation Mode Selector Switch 11 RF LEVEL Attenuator Control 13 VAR TONE Level Control 14 VAR TONE Select Switch 15 1 kHz TONE Select Switch 16 1 kHz TONE Level Control 17 Power Switch 18 VAR TONE FREQ Thumbwheels 19 Frequenc...

Page 214: ...4 5 0 0 3 7 11 5 0 7 14 12 0 0 3 16 12 0 0 3 18 5 0 0 3 3 Rotate the GEN LOCK Control to LOCK and verify the follow ing voltages are present on J4501 4 Pin No 3 4 Voltage 12 0 0 N J Tolerance 0 3 0 3 If all the voltages required in Steps 2 and 3 are not present troubleshoot the Power Supply and the Distribution Circuit Using DVM verify the voltage on each pin of J4501 0 3 V of that given below for...

Page 215: ...4401 b P4501 to J4501 C P4503 to J4503 h b t Lh_b hJ J p 7 J QD f qfD QD n f n Q J O U O u u Digital Module Input Signals in OFF position and make the following d Coax SMB T connector to J4502 e P4502 to coax SMB T connector f Frequency Counter to coax SMB T connector 8 Set Power Switch in LINE position and allow a five minute warm up period 9 Verify Frequency Counter displays 21 4 MHz 20 Hz 10 Ro...

Page 216: ...humbwheels to 010 002 0 19 Adjust trimpot R4509 to obtain an indication of 2 kHz on the FREQ ERROR Meter 20 Rotate RF FREQUENCY Thumbwheels to 010 010 0 21 Adjust trimpot R4510 to obtain an indication of 10 kHz on the FREQ ERROR Meter 22 Connect the output of the Signal Generator to the ANTENNA Connector ut DO NOT EXCEED 0 25 WATT INPUT TO THE ANTENNA CONNECTOR 9 tEl For best results connect a com...

Page 217: ...rect indication FREQUENCY ERROR SIGNAL GENERATOR FREQUENCY ERROR RANGE SWITCH OUTPUT FREQUENCY METER INDICATION POSITION MHz 40 dBm Hz RF 1 K 111 1000 0 50 111 1005 500 50 111 0995 500 50 RF 3 K 111 0995 500 100 111 0980 2 K 100 111 1020 2 K 100 RF 10 K 111 1020 2 K 500 111 1050 5 K 500 111 0950 5 K 500 Table 7 3 RF Frequency Error Testing FREQUENCY ERROR VAR TONE FREQ FREQUE NCY ERROR RANGE SWITC...

Page 218: ...7 9 4 REASSEMBLY With all power OFF disconnect test equipment If module was dis assembled for repair reassemble in reverse order of removal and dis assembly procedures outlined in Section 6 7 56 ...

Page 219: ...selected on the Modulation Meter Range Switch this multiplexer disables the received audio signal and couples a signal from the EXT MOD SINAD jack to the AGC circuit in the Receive Audio Module The signal selected by the Modulation Meter range control multi plexer is rectified then combined with a DC offset The DC offset level is controlled by the Modulation Meter Range Switch the Modulation Mode ...

Page 220: ... Multiplexer U3322A selects the 250 Hz filter when a frequency of less than 400 Hz is selected on the optional Variable Tone Generator for audio frequency counting If the Modulation Mode Selector Switch is in the FM WIDE position multiplexer U3322C directs the signal from the 80 kHz filter to the Speaker and Modulation Meter circuits When the control voltage to either or both of these multiplexers...

Page 221: ...UME r CONTROL GEN AUDIO II SPE AKER II FROM MOD J MODE SWITCH I TO DEMoD 80 KHz JACK LOW PASS FM WIDE FROM MOD MODE SWITCH DUAL AMP TO DIGITAL MODULE_ LCH FROM SQUELCH CONTROL AMP NOTCH MODULATION FILTER METER OFFSET SCALE GAIN CIRCUIT TO REC GEN FUNCTION SELECT _ DEMULTIPLEXER FROM BATTERY TO MODULATION METER FROM MOD METER RANGE SWITCH FROM OUTPUT AMP POWER MONITOR TO GEN AUDIO Figure 7 12 Recei...

Page 222: ...3309B diodes CR3307 and CR3308 and asso ciated resistors R3334 R3336 R3339 R3340 and R3341 then to an integrator consisting of op amp U3305B capacitor C3305 and diode CR3306 The integrator output then is fed to the LED in the photoresistor to achieve level control The second output is converted to a square wave by op amp U3308 and fed to the Digital Module for frequency counting The third output o...

Page 223: ... R3400 R3401 R3404 and on the FM AM 500A only R343 One tap goes to the DEMOD jack the other t ps go to multiplexe U3316 On the FM AM 500A only two taps first go through multiplexer U3324C to provide the X60 range on the Modulation Meter The output of U3316 is buffered by op amp U3314A then rectified by a precision full wave rectifier consisting of op amps U3315A and R3315B diodes CR3314 and CR33 5...

Page 224: ...cope 10 MHz Bandwidth 1 Digital Multimeter 100 KO V 1 Extender Cable 26 Pin M F Connectors 1 1211 20 GA Lead E Z Mini Hook C PREPARATION 1 Make the following initial control settings Refer to Con trols Indicator and Connector Drawing in Section 1 KEY CONTROL 4 Modulation Meter Range Switch 9 Modulation Mode Select Switch 11 RF LEVEL Attenuator Control 12 RF LEVEL FINE Adjust Control 13 VAR TONE Le...

Page 225: ...ure voltage at J3301 pin 22 Adjust trimpot R3354 to obtain a reading of O V 20 mV 4 Using DMM verify the following pins of the male connector of the Extender Cable have the correct voltages Pin No Voltage Tolerance 3 0 5 12 0 8 0 10 0 15 11 12 0 12 12 0 13 5 0 15 12 0 26 14 4 Record this voltage for later reference C 1 If any test in Steps 3 through 14 fails the cause of that failure is not in the...

Page 226: ...15 V 0 15 V 0 15 V 12 0 V Tolerance 0 3 V 0 3 V 0 3 V 0 3 V 0 3 V 10 Using Oscilloscope verify positive and negative peaks of noise on pin 6 of extender cable male connector do not exceed 15 V and O V respectively 11 Set Power Switch in 110FF11 position 12 Connect Receiver Audio Board to extender cable 13 Set Power Switch in 11 LINE11 position 14 Confirm the following voltages at P3301 Pin No 2 20...

Page 227: ...in 1 is less than 0 06 VRMS 26 Rotate VAR TONE FREQ Thumbwheels to 1300 0 and confirm the sinewave at P3301 pin 1 increases in amplitude to approxi mately 2 Vp p 27 Rotate VAR TONE FREQ Thumbwheels to 0300 0 28 Set 1 kHz TONE Selector Switch in OFF position 29 Set VAR TONE Selector Switch in INT MOD position and con firm a 300 Hz sinewave of approximately 1 8 Vp p is present at P3301 pins 1 and 18...

Page 228: ... within 5 of the reading recorded in Step 3 39 Set GEN REC Switch in REC position 40 Using DVM verify voltage at P3301 pin 7 exceeds 11 0 V 41 Rotate SQUELCH Control fully cw and verify voltage at P3301 pin 7 exceeds 10 V 7 10 4 REASSEMBLY With all power OFF disconnect test equipment Reinstall the Receive Audio PC Board in the reverse order of removal procedure outlined in Section 6 7 66 ...

Page 229: ...e or Receive of other modules is determined by an operating mode circuit in the Generate Audio Module In the Generate Mode a GEN command 12 VDC signal performs the following functions 1 it enables the generate amplifiers in the IF Module and Output Amplifier 2 in the Receiver Generator it enables the frequency divider and inhib its the receive enable multiplexer and 3 in the Receive Audio Module i...

Page 230: ... REC GEN FROM LPF IN REC AUDIO MODULE SOURCE SELECT i MODULATION MULTI MODE SELECT FROM EXT MOD SINAD JACK PLEXER FROM MIC KEY MICROPHONE AUOIO ENABLE MULTIPLEXER MIC AUOIO AM MODLATION q RF LEVEL TO REC GEN_ FINE I ADJUST FROM INT MOD DIGITAL ANT ENABLE COUNTER OFF AGC FROM 5f tAKER MODE OUTPUT AMP PWR REC ENABLE FROM PWR MONITOR CIRCUIT IN REC AUDIO MODULE GEN ENABLE FROM GEN REC SWITCH FROM HIG...

Page 231: ...put in the Receiver Generator The audio signal from the Low Pass filter circuit in the Receive Audio Module is routed through multiplexer U32O2C in the Gen erate Audio Module then back to the audio AGC circuit in the Receive Audio Module A signal received at the EXT MOD SINAD jack is routed through multiplexer U32O2A to U32O3B On the FM AM 5OOA if either SINAD or DIST is selected on the Mod lation...

Page 232: ...pplied to both inputs of NANO gate U3206A its output remains low If either the High Loop or Low Loop is not phase locked to the appropriate refer ence frequency one of the inputs goes low and the output of U3206A goes high While the output of U3206A is low and the GEN LOCK Control is in LOCK the input to NANO gate U3206B on pin 6 is a constant low and its output a constant high When pin 6 is a con...

Page 233: ...ol 14 VAR TONE Selector Switch 15 1 kHz TONE Selector Switch 16 1 kHz TONE Level Control 17 Power Switch 18 VAR TONE FREQ Thumbwheels 24 GEN LOCK Control 25 RF FREQUENCY Thumbwheels 26 GEN REC Switch 27 VOLUME Control 28 SQUELCH Control SETTING II sIG11 11 AM NORM 1 1 20 dBm Fully ccw Fully ccw 11 SPEAKER11 11 SPEAKER11 Fully ccw 110FFII 1 11000 011 Fully cw 11100 000 011 11 REC11 Fully ccw Fully ...

Page 234: ...scope to extender cable connector 5 Rotate 1 kHz TONE Level Control cw until Oscilloscope dis plays a 1 kHz sinewave at 1 Vp p 6 Connect Oscilloscope to extender cable connector pin 34 7 Rotate VAR TONE Level Control cw until Oscilloscope displays a 1 kHz sinewave at 1 Vp p 8 Set 1 kHz TONE and VAR TONE Selector Switches in INT MOD position 9 Using Oscilloscope verify 1 kHz sinewaves at 1 Vp p are...

Page 235: ... YES 11 5 0 0 GEN NO YES 0 11 5 11 5 GEN NO NO 11 5 0 0 Table 7 5 MIC ACC Jack Functions 19 Set 1 kHz TONE Selector Switch in OFF position 20 Using Oscilloscope verify a 1 8 Vp p 1 kHz sinewave is pre sent at J3201 pins 19 and 23 21 Using Oscilloscope verify a flat trace at O V 0 1 V on J3201 pin 19 appears when pins 1 and 2 of the MIC ACC jack are shorted 22 Connect Oscilloscope to J3201 pin 18 a...

Page 236: ...7 11 4 REASSEMBLY With all power OFF disconnect all test equipment Reinstall the Generate Audio PC Board in the reverse order of removal procedure outlined in Section 6 7 74 ...

Page 237: ...Panel then through a 50 ohm 20 dB pad in the Output Amplifier and to the T R jack When transmitting into the T R jack the 50 ohm 20 dB pad dissi pates up to 150 Watts of RF power A power detector senses the input power for automatic mode switching by the Generate Audio Module REC FROM GEN AUDIO GEN FROM GEN AUDIO MODULATED 10 7 MHz TO FROM IF MODUL E GENERATE Allf LIRER t STU ATTENUA tl RECEIVE EN...

Page 238: ...LEVEL Attenuator on the Front Panel then through RN5101 which is a 20 dB pad in the Output Amplifier before being connected to the T R jack A signal entering through the T R jack passes through the 20 dB pad then through the receive enable circuit to the IF Module A power detector circuit moni tors the incoming signal strength and provides feedback through the Receive Audio power level adjustment ...

Page 239: ... the generate amplifier and level detector circuits The relay couples the RF signal from the IF Module to the output amplifier circuit in the Generate mode Two amplifiers U5101 and U5102 amplify the signal and apply it to the base of RF transistor Q5101 which in turn controls the base of RF transistor Q5103 Q5102 is a bias transistor to adjust the base current of Q5103 to achieve a constant collec...

Page 240: ...y to obtain a level of O dB at Jl503 7 12 3 PREPARATION FOR TESTING A REMOVAL AND DISASSEMBLY If repair or replacement is required remove and disassemble the Output Amplifier as outlined in Section 6 B REQUIRED TEST EQUIPMENT 1 RF Power Source 5 W 175 MHz 1 Spectrum Analyzer with Tracking Generator 1 MHz 1 GHz 1 Power Supply 12 V and 12 1 Digital Multimeter 100 Kn V 1 son Coax Cable SMA SMA 2 50 1...

Page 241: ...racking Generator output to J5101 and the Spectrum Analyzer input to J5104 6 Adjust Test Equipment as follows and verify each display is flat within 6 dB at a level of 10 dBm 3 dB Tracking Generator Spectrum Analyzer Output Level Reference Level Sea1 e 2 0 dBm 0 dBm 2 dB DIV 7 Adjust Spectrum Analyzer Dispersion to 0 8 Connect DMM between FL5104 and Output Amplifier chassis and verify voltage is a...

Page 242: ...scillator output goes high The DAC converts the binary code to an analog voltage which as a result of the ROM programming forms a sinewave at the frequency established on the thumbwheels After amplification the output of the DAC passes through a 10 kHz lowpass filter When the frequency selected is below 1 kHz a 1 kHz lowpass filter is switched in series with the 10 kHz filter The signal is further...

Page 243: ...tworks RN3101 and RN3102 and resistors R3104 and R3105 to four inputs of each adder and to the VAR TONE FREQ Thumbwheels The thumbwheel switches ground the various code lines as required to establish the frequency coding With each pulse from the crystal oscillator latches U3104 U3106 and U3109 transfer the adder outputs back to their respective inputs to be added to the BCD frequency code Latch U3...

Page 244: ...ch function as a 1 kHz lowpass filter then to the output amplifier U3119B F FREQUENCY SELECTION DETECTORS The 4 input NOR gate U3101A is connected to the four BCD lines to the 1 9 kHz thumbwheel switch When all of these lines are low less than 1 kHz is selected a high output signal enables the lowpass multiplexer and is also fed to the Digital Module NOR gate U3101B is similarly connected to the 1...

Page 245: ... 9 5 Connect DVM to J3102 Pin 5 6 Rotate VAR TONE FREQ Thumbwheels to 9999 9 Hz 7 Set VAR TONE Selector Switch to SPKR 7 13 3 TESTING Refer to Variable Tone Generator PC Board Drawing in Section 9 and Circuit Schematic in Section 10 1 Adjust capacitor C3110 to obtain a reading of 256 0000 kHz on Frequency Counter 2 Verify DVM displays a voltage less than 0 5 voe 3 Verify Oscilloscope displays a cl...

Page 246: ...7 13 4 REASSEMBLY With all power OFF disconnect all test equipment Replace the Variabl Tone Generator in the reverse order of the removal procedure outlined in Section 6 7 83 7 84 Blank ...

Page 247: ...signal received on the accessory antenna is then routed to the Antenna jack An accessory coax cable is provided to couple this jack to the ANTENNA jack on the Front Panel of the FM AM 500A Au 10 NEVER TRANSMIT INTO THE UUT T R JACK OF THE GENERATE AMPLIFIER TO DO SO WILL DAMAGE EITHER THE GENERATE AMPLIFIER THE FM AM 500A OR BOTH B CIRCUIT DESCRIPTION Hybrid amps U9001 and U9002 form the first two...

Page 248: ...ule Drawing in Section 9 and Circuit Schematic in Section 10 7 14 4 1 Set Tracking Generator for 100 MHz Division with center fre quency of 500 MHz and output level of 25 dBm Verify loss is less than 4 dB 2 Connect Tracking Generator output to J9001 3 Connect Power Supply common terminal to Generate Amplifier chassis 4 Apply 12 voe from Power Supply to J9004 banana plug 5 Verify Tracking Generator...

Page 249: ...h dampened not wet with denatured alcohol 3 Remove dust and dirt from connectors with a soft bristled brush 4 Clean cables with a soft lint free cloth 5 Touch up painted metal surfaces as necessary to avoid rust or corrosion 8 1 2 INTERNAL CLEANING 1 Remove dust with hand controlled dry air jet of 15 psi 1 054 kg cm and wipe internal chassis parts and frame with soft lint free cloth moistened with...

Page 250: ... to any mounted components including crystals and IC s c Freedom from all foreign materials 6 Inspect resistors for a Cracked broken charred or blistered bodies b Loose or corroded soldered connections 7 Inspect semiconductors for a Cracked broken charred or discolored bodies b Loose or damaged seals around leads 8 Inspect switches for a Loose levers terminals and switch body contact to frame b Be...

Page 251: ...ard has components only on one side then only the component side is shown 9 2 ALPHABETICAL INDEX OF PC BOARD ASSEMBLY DRAWINGS Title Digital Counter PC Board 7010 5234 400 Rev D Digital Reference PC Board 7010 5234 500 Rev F5 Frequency Standard PC Board 7010 5232 500 Re v L Generate Amplifier PC Board 0ptional 7010 5239 000 Rev A4 Generate Audio PC Board 7010 5233 200 Rev G High Loop Analog PC Boa...

Page 252: ... AM 500A 7010 5233 301 Rev E6 Receiver Generator PC Board 7010 5234 301 Rev U4 RF Thumbwheel Switch PC Board 7010 5230 200 Rev Cl Variable Tone Generator PC Board 7010 5230 100 Rev F2 Variable Tone Thumbwheel Switch PC Board 7010 5230 300 Rev Cl 1210 MHz VCO PC Board 7010 5232 000 Rev Ll 1300 2300 MHz VCO PC Board 7010 5232 100 Rev AF 9 2 03 Figure 9 1 9 7 9 7 9 5 9 15 9 16 9 14 9 18 9 4 9 22 9 22...

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Page 272: ...e Digital Module 0000 5214 500 Rev D Dual VCO Module 0000 5212 100 Rev Ll 0000 5212 000 Rev Ll Frequency Standard Module 0000 5212 500 Rev D Front Panel FM AM 500 0000 5210 100 Rev D Front Panel FM AM 500A 0000 5210 101 Rev D Generate Amplifier Module Optional 0000 5219 000 Rev 62 Generate Audio Module 0000 5213 200 Rev E High Loop Module 0000 5214 100 Rev E 0000 5214 000 Rev Dl Eff S N T ru 3074 ...

Page 273: ...00 Rev Al SN 1001 thru 2215 Receive Audio Module FM AM 500A SN 2216 and On 0000 5213 301 Rev E3 Receiver Generator Module 0000 5214 300 Rev R5 RF Thumbwheel Switch 0000 5210 200 Rev Pl Variable Tone Generator Module 0000 5213 100 Rev B Variable Tone Thumbwheel Switch 0000 5210 300 Rev Pl 10 2 03 Figure Page 10 12 10 12 10 12A 10 12A 10 5 10 8 10 18 l0 22 10 19 10 24 10 17 10 20 10 10 10 11 10 21 1...

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Page 307: ...over from generate to monitor will occur at a nominal 100 mW level Internal Modulation See Audio Generator External Modulation Frequency Response FM 2 Hz to 30 kHz DC when in variable Modulation Sensitivity Distortion 1 kHz tone Input Impedance generate AM 10 Hz to 10 kHz 30 maximum modulation above 5 kHz FM 0 08 VRMS kHz AM 0 01 VRMS FM 1 to 20 kHz deviation AM 10 to 60 modulation Greater than 10...

Page 308: ...ier Installed 30 2 dB typical 100 kHz to 1000 MHz Variable to 10 dBm FM CW Variable to 4 dBm AM nominal A 4 RECEIVER MONITOR Ohm Frequency Range 100 kHz to 999 9999 MHz in 100 Hz increments Sensitivity Selectivity Adjacent Channel Rejection Demodulation Output 2 µv 1 Mode FM WIDE FM MID FM NAR SSB AM NAR AM NORM Output Impedance 600 Ohms MHz to 1000 MHz FM Narrow RCVR Audio Bandwidth Bandwidth 200...

Page 309: ...cale High Resolution Option 300 Hz 100 Hz 30 Hz full scale FM AM 500A 10 kHz 3 kHz 1 kHz 300 Hz 100 Hz 30 Hz full scale Audio Counter FM AM 500 with variable tone generator option only FM AM SODA Accuracy 0 01 of frequency 6 of full scale Ranges 300 Hz 30 Hz 3 Hz full scale A 7 MODULATION METER Monitor Mode Type FM Deviation Accuracy Ranges AM Modulation Accuracy Ranges Maximum of positive or nega...

Page 310: ...50 V Slow Blow 240 VAC Operation A 250 V Slow Blow Battery 3 Amp Slow Blow External DC in cord 3 Amp Slow Blow Microphone Jack Special IFR P N 5106 4900 125 Power Requirements Line 105 130 210 260 VAC 50 400 Hz at 30 Watts typical Ext DC 12 14 voe Nominal at 2 AMPS Operation on Internal Battery Optional Approximately 2 hours Operating Temperature Range 0 to 50 C Dimensions Weight Nominal Standard ...

Page 311: ...ator Frequency Counter MANUFACTURER MODEL Tektronix 2215 Tektronix 7613 Frame Tektronix 7Ll3 U Spectrum Analyzer Tektronix TM503 Frame Tektronix TR502 Tracking Generator Fluke Model 7220A Digital Multimeter Fluke Model 8010A Distortion Analyzer Sound Technology Model 17008 B 1 SPECIFICATIONS DC to 60 MHz 10 mV div vertical trace 5 nS div sweep rate Dual Trace Variable Persistance Storage Oscillosc...

Page 312: ...VSWR 25 512 MHz 1 10 max 512 1000 MHz 1 20 max Accuracy Incident Power 25 512 MHz 5 of full scale 512 1000 MHz 7 of full scale FM AM Modulation Meter Boonton Model 82AD Frequency Range 10 MHz to 1 2 GHz Accuracy FM 2 of reading from 30 Hz to 100 kHz Accuracy AM 2 of reading from 10 to 90 AM and 5 of read ing below 10 and above 90 from 30 Hz to 100 kHz Resolution 0 1 of full scale for FM and AM RF ...

Page 313: ...Accuracy 0 25 fs 0 15 dB 10 nW Boonton Power Sensor Frequency Range 200 kHz to 7 GHz Model 41 4A Power Range 1 nW to 10 mW Accuracy Q 3 dB 10 nW Triple Output Pow er Supply LAMBDA LPT 7202 FM Regulation 0 1 Ripple 5 mV Voltage Ranges o 7 voe 5 o A 0 20 voe 1 5 A 0 20 voe 1 5 A Power Supp1y B K 1601 Regulation 1 or 1 mV Ripple 5 mV Voltage Range o 50 voe 0 2 A B 3 B 4 Blank ...

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Page 316: ...NUATOR KNOB SPACER Material 005 Brass Shimstock 1 850 1 X 375 1 Fabrication Cut material to size and form into arc as shown in Figure C 2 I ___________ I r 1 a t 1 _____ _ Figure C 2 Attenuator Knob Spacer C 2 ...

Page 317: ...tomatic Leveling Control Amplitude Modulation Antenna Assembly Binary Coded Data Degrees Celsius Continuous Wave clockwise counter clockwise Digital to Analog Converter decibel decibel referred to one milliwatt Direct Current Digital Multimeter Digital Voltmeter External Volts per Division Degrees Fahrenheit Frequency Generator Gigahertz Hertz Integrated Circuit Intermediate Frequency Illustrated ...

Page 318: ...rnating Current Voltage Controlled Oscillator Voltage Direct Current Volts Root Mean Square Vertical Standing Wave Ratio Watt Transmitter D 3 ABBREVIATIONS FOR REFERENCE DESIGNATORS BR C CR E FL G J K L M MX or MXR p Q R SW T TU u VR X V YFL Bridge Rectifier Capacitor Diode Terminal Filter Ground Connector Fixed Relay Inductor Meter Mixer Connector Movable Transistor Resistor Switch Transformer Tu...

Page 319: ...R packing materials If original shipping containers and m terials are not available contact IFR Customer Service Dept for shippin instructions All freight costs on non warranty shipments are assumed by customer See Warranty Packet for freight charge policy on warranty claims E 2 REPACKING PROCEDURE Reference Figure E 1 1 Make sure bottom packing mold is seated on floor of shipping container 2 Care...

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