EFJohnson 764X, 761X service manual Table of Contents CONT’D

Page 4

TABLE OF CONTENTS (CONT’D)

4.5 UNIQUE PMR (EUROPEAN) SCREENS . . 4-15

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-15

Unique PMR Screens . . . . . . . . . . . . . . . . . . . . 4-15

4.6CLONING (PROGRAMMING ONE

TRANSCEIVER WITH ANOTHER) . . . . . 4-16

5A VHF (7610) CIRCUIT DESCRIPTION

5.1 VHF RECEIVER CIRCUIT . . . . . . . . . . . . . . . . 5-1

Antenna Switching Circuit . . . . . . . . . . . . . . . . . 5-1

RF Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

First Mixer And First IF Circuits . . . . . . . . . . . . 5-1

Second IF and Demodulator Circuits . . . . . . . . . 5-1

Audio Amplifier Circuit . . . . . . . . . . . . . . . . . . . 5-2

Receiver Mute Circuit . . . . . . . . . . . . . . . . . . . . 5-2

5.2 VHF TRANSMITTER CIRCUIT . . . . . . . . . . . . 5-3

Microphone Amplifier Circuit . . . . . . . . . . . . . . 5-3

Modulation Circuit . . . . . . . . . . . . . . . . . . . . . . . 5-3

Transmit Driver Circuit . . . . . . . . . . . . . . . . . . . 5-3

Power Amplifier Module . . . . . . . . . . . . . . . . . . 5-3

APC Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4

5.3 VHF PLL CIRCUIT . . . . . . . . . . . . . . . . . . . . . . 5-4

PLL Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4

VCO Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5

5.4 VHF IC PIN DESCRIPTIONS . . . . . . . . . . . . . 5-5

VHF Power Supply. . . . . . . . . . . . . . . . . . . . . . . 5-5

VHF CPU IC1 Port Allocation . . . . . . . . . . . . . . 5-5

VHF I/O Expander IC5 (Main Unit) . . . . . . . . . 5-6

VHF Port Expander IC11 (Main Unit) . . . . . . . . 5-6

5B UHF (7640) CIRCUIT DESCRIPTION

5.5 UHF RECEIVER CIRCUIT . . . . . . . . . . . . . . . . 5-7

Antenna Switching Circuit . . . . . . . . . . . . . . . . . 5-7

RF Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7

First Mixer And First IF Circuits . . . . . . . . . . . . 5-7

Second IF and Demodulator Circuits . . . . . . . . . 5-7

Audio Amplifier Circuit . . . . . . . . . . . . . . . . . . . 5-8

Receiver Mute Circuit . . . . . . . . . . . . . . . . . . . . 5-8

5.6 UHF TRANSMITTER CIRCUIT . . . . . . . . . . . . 5-9

Microphone Amplifier Circuit . . . . . . . . . . . . . . 5-9

Modulation Circuit . . . . . . . . . . . . . . . . . . . . . . . 5-9

Transmit Driver Circuit . . . . . . . . . . . . . . . . . . . 5-9

Power Amplifier Module . . . . . . . . . . . . . . . . . . 5-9

APC Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10

5.7 UHF PLL CIRCUIT . . . . . . . . . . . . . . . . . . . . . 5-10

PLL Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10

VCO Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11

UHF Power Supply. . . . . . . . . . . . . . . . . . . . . . 5-11

UHF CPU IC1 Port Allocation . . . . . . . . . . . . . 5-11

UHF I/O Expander IC12 (Main Unit) . . . . . . . 5-12

UHF Port Expander IC13 (Main Unit) . . . . . . . 5-12

6 ADJUSTMENT PROCEDURE

6.1 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-1 Suggested Test Equipment . . . . . . . . . . . . . . . . . 6-1 Test Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2 Test Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2Computer-Aided Tuning . . . . . . . . . . . . . . . . . . . 6-3 Reprogramming if EEPROM is Replaced or

Error Occurs . . . . . . . . . . . . . . . . . . . . . . . . . 6-46.2 PRELIMINARY SETUP. . . . . . . . . . . . . . . . . . .6-4 6.3 PLL ADJUSTMENT (VHF MODELS). . . . . . .6-4

6.4TRANSMITTER ADJUSTMENTS

(VHF MODELS). . . . . . . . . . . . . . . . . . . . . . . .6-4

Reference Frequency . . . . . . . . . . . . . . . . . . . . . 6-4

Output Power Adjust. . . . . . . . . . . . . . . . . . . . . . 6-5

FM Deviation Adjust . . . . . . . . . . . . . . . . . . . . . 6-5

DTCS Waveform Adjust. . . . . . . . . . . . . . . . . . . 6-6

6.5RECEIVER ADJUSTMENTS

(VHF MODELS) . . . . . . . . . . . . . . . . . . . . . . .6-6

Bandpass Filter Adjust . . . . . . . . . . . . . . . . . . . . 6-6

Squelch Adjust . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6

Beep Tone Level . . . . . . . . . . . . . . . . . . . . . . . . . 6-7

6.6 PLL ADJUSTMENT (UHF MODELS) . . . . . .6-8

6.7TRANSMITTER ADJUSTMENTS

(UHF MODELS). . . . . . . . . . . . . . . . . . . . . . . .6-8

Reference Frequency . . . . . . . . . . . . . . . . . . . . . 6-8

Output Power Adjust. . . . . . . . . . . . . . . . . . . . . . 6-8

FM Deviation Adjust . . . . . . . . . . . . . . . . . . . . . 6-8

DTCS Waveform Adjust. . . . . . . . . . . . . . . . . . . 6-9

6.8RECEIVER ADJUSTMENTS

(UHF MODELS). . . . . . . . . . . . . . . . . . . . . . .6-10

Bandpass Filter Adjust . . . . . . . . . . . . . . . . . . . 6-10

Squelch Adjust . . . . . . . . . . . . . . . . . . . . . . . . . 6-10

Beep Tone Level . . . . . . . . . . . . . . . . . . . . . . . . 6-10

7 PARTS LIST

VHF (761x) Models

Main Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-1

Front Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-18

Chassis Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-20

Exploded View . . . . . . . . . . . . . . . . . . . . . . . . . .7-21

UHF (764x) Models

Main Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-8

Front Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-18

Chassis Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-20

Exploded View . . . . . . . . . . . . . . . . . . . . . . . . . .7-22

 

November 1998

iii

Part No. 001-7600-001

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Contents 761x VHF 764x UHF Conventional Mobile Conventional FM TWO-WAY Radio Table of Contents Table of Contents CONT’D Schematic Diagrams and Component Layouts General Information 75xx Accessories AccessoryToll-Free 800 Factory ReturnsReplacement Parts Internet HomeThis page intentionally left blank VHF and 7640 UHF Mobile Specifications GeneralGeneral Information Installation and Disassembly Transceiver InstallationInstalling Mounting Bracket Installing Microphone HangerPower Cable Installation Cable InstallationPower Cable Fuses Changing 20-Ampere Power Cable FusesUsing AN External Speaker Accessory Cable InstallationRemoving PC Board Transceiver DisassemblyRemove shield E 2-TONE/5-TONE Module Installation Installation ProcedureSetting 5-Tone Deviation 2 2-TONE ProgrammingInstallation and Disassembly Features OperationTransceiver Back Panel Controls and DisplayBasic Operation Direct Selection The F1-F4 Receiving and Placing Calls TIME-OUT Timer Programmable FunctionsOption Key Programmable Functions Function Key Label Description Section NoMonitor Mode Select Output Power SelectCall Guard Tone Select Channel SelectChannel Scan Priority Channel Sampling Programming Setup Section ProgrammingProgramming Cables Programming SoftwareStarting the Program Special Keys and FunctionsMenu Flow File MenuScreen Menu Program MenuPrint Menu Model MenuMemory Channel Screen Description LMR Models Setup MenuParameter Description Bank Select Timer Ch AtrFrequency Rx/TxAuto Reset LockoutScan ToneKey and Display Assign Screen Description Key DescriptionKey Description Label RF Power Dtmf Autodial Screen DescriptionSelection Bank/FreeScan Function Screen Description Continuous Tone Screen DescriptionParameter Description Stop Timer 2-Tone Code Channel Screen DescriptionResume Auto CHEXO Timer Timer Auto TxAuto Tx StunCommon Screen Description Expert Screen Description Unique PMR European Screens Unique PMR ScreensCloning Programming ONE Transceiver with Another Memory Channel Screen PMR Models This page intentionally left blank VHF 7610 Circuit Description VHF Receiver CircuitAudio Amplifier Circuit Receiver Mute CircuitPower Amplifier Module VHF Transmitter CircuitMicrophone Amplifier Circuit Modulation CircuitVHF PLL Circuit APC CircuitPLL Circuit Line Description VHF IC PIN DescriptionsPin Port Description VHF I/O Expander IC5 Main Unit PinVHF Port Expander IC11 Main Unit Pin Port Description NameUHF 7640 Circuit Description UHF Receiver CircuitSecond if System IC1 UHF UHF Transmitter Circuit PLL Circuit UHF UHF PLL CircuitUHF Power Supply UHF CPU IC1 Port AllocationUHF I/O Expander IC12 Main Unit UHF Port Expander IC13 Main UnitAdjustment Procedure Test SetupSuggested Test Equipment Equipment Grade and RangeTest Channels Test CableVHF Test Frequencies COMPUTER-AIDED TuningUHF Test Frequencies VHF Adjustments VHF AdjustmentsPreliminary Setup PLL Adjustment VHF ModelsOutput Power Adjust VHF Adjustments CONT’DFM Deviation Adjust Dtcs Waveform Adjust Receiver Adjustments VHF ModelsBandpass Filter Adjust Squelch AdjustBeep Tone Level Adjustment Beep Tone LevelPLL Adjustment UHF Models UHF AdjustmentsTransmitter Adjustments UHF Models UHF Adjustments CONT’D UHF Adjustment PointsUHF Adjustments CONT’D Receiver Adjustments UHF Models Parts List Æçìíýõ9+ôý0$,1ý81,7Íäç HUDPLFý&ìçíåý-%ýì+ýìíë.ð7ð$ Íëëðêäíçðíçí Íäæ Ìää HUDPLFý&ìçíåý-%ýì&ýìíé.7ð1 Íëëðêäíçðçìé Ëíí Ëäí HUDPLFý&ìçíåý-%ýìýìíê.ð7ð$ Íëëðêäíçðíçê Ëäì RLOý0/ìçíå$ýì5í.ð7 Íëëðêäíçðçèç 03ì Ýìäëëý9&2ýFDVH 5íéé 5HVý5-ê*-ýìííý9ýõìíýRKPô Íëëðêäíçðìêå 5íéè 5ìèé 5HVý5-ê*-ýìíéý9ýõìííýNýRKPô Æçéíýõ8+ôý0$,1ý81,7 Íêì HUDPLFý&ìçíåý-%ýì+ýìíë.ð7ð$ Íëëðêäíçðíçí Íêë Íäé HUDPLFý+0çí6-ý&+ýíêíýèíí9ý Õéäíðèìëý0+ô Ìèì 5HIý1Rï Êëç Íëëðêäíçðäèë 4éì 7UDQVLVWRUý7&êçê.ý7ìéæ 5íæé 5ìçå 5HVý5-ê*-ýìíéý9ýõìííýNýRKPô 5217ý81,7 Õ9+ý$1ý8+ý02/6ô =HQHUý0$åíèìð0ýõ7ô Æçìíýõ9+ôý&+$66,6ý3$576 VHF 7610 Exploded View Front UnitUHF 7640 Exploded View Schematic Diagrams and Component Layouts VHF 7610 Block DiagramMain Unit Front UnitVHF 7610 Transistor Basing Diagrams Foldout → VHF 7610 Main Board TOP View VHF 7610 Main Board Schematic VHF Main UnitUHF 7640 Block Diagram UHF 7640 Main Board Bottom View UHF 7640 Main Board TOP View J4 T o O p tion al Un itUHF 7640 Main Board Schematic VHF/UHF Front Unit Board TOP View VHF/UHF Front Unit Board Bottom ViewVHF/UHF Front Unit Schematic UHF 7640 Transistor Basing Diagrams
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