EFJohnson 761X, 764X instruction

Service Manual

761x (VHF)

764x (UHF) Conventional Mobile

VHF 146-174 MHz

45 Watts

Part No. 242-7610-0xx

UHF 400-430, 450-470, 470-490,

490-512 MHz

35 Watts

Part No. 242-7640-0xx

First Printing November 1998

Image 1

EFJohnson 761X, 764X service manual 761x VHF 764x UHF Conventional Mobile

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 Accessory 75xx AccessoriesToll-Free 800 Factory Returns Internet Home Replacement Parts This page intentionally left blank General VHF and 7640 UHF Mobile Specifications General Information Transceiver Installation Installation and Disassembly Installing Microphone Hanger Installing Mounting BracketPower Cable Installation Cable Installation Changing 20-Ampere Power Cable Fuses Power Cable FusesUsing AN External Speaker Accessory Cable Installation Removing PC Board Transceiver DisassemblyRemove shield E Installation Procedure 2-TONE/5-TONE Module InstallationSetting 5-Tone Deviation 2 2-TONE Programming Installation and Disassembly Operation Features Transceiver Back Panel Controls and DisplayBasic Operation Direct Selection The F1-F4 Receiving and Placing Calls Programmable Functions TIME-OUT TimerOption Key Programmable Functions Function Key Label Description Section No Output Power Select Monitor Mode SelectCall Guard Tone Select Channel Select Channel Scan Priority Channel Sampling Section Programming Programming SetupProgramming Cables Programming Software Special Keys and Functions Starting the ProgramMenu Flow File Menu Program Menu Screen MenuPrint Menu Model Menu Memory Channel Screen Description LMR Models Setup MenuParameter Description Bank Select Ch Atr TimerFrequency Rx/Tx Lockout Auto ResetScan Tone Key Description Key and Display Assign Screen Description Key Description Label Dtmf Autodial Screen Description RF PowerSelection Bank/Free Scan Function Screen Description Continuous Tone Screen DescriptionParameter Description 2-Tone Code Channel Screen Description Stop TimerResume Auto CH Timer Auto Tx EXO TimerAuto Tx Stun Common Screen Description Expert Screen Description Unique PMR Screens Unique PMR European Screens Cloning Programming ONE Transceiver with Another Memory Channel Screen PMR Models This page intentionally left blank VHF Receiver Circuit VHF 7610 Circuit Description Receiver Mute Circuit Audio Amplifier Circuit VHF Transmitter Circuit Power Amplifier ModuleMicrophone Amplifier Circuit Modulation Circuit VHF PLL Circuit APC CircuitPLL Circuit Line Description VHF IC PIN DescriptionsPin Port Description Pin VHF I/O Expander IC5 Main UnitVHF Port Expander IC11 Main Unit Pin Port Description Name UHF Receiver Circuit UHF 7640 Circuit Description Second if System IC1 UHF UHF Transmitter Circuit UHF PLL Circuit PLL Circuit UHF UHF CPU IC1 Port Allocation UHF Power Supply UHF Port Expander IC13 Main Unit UHF I/O Expander IC12 Main Unit Test Setup Adjustment ProcedureSuggested Test Equipment Equipment Grade and Range Test Cable Test Channels VHF Test Frequencies COMPUTER-AIDED TuningUHF Test Frequencies VHF Adjustments VHF AdjustmentsPreliminary Setup PLL Adjustment VHF Models Output Power Adjust VHF Adjustments CONT’DFM Deviation Adjust Receiver Adjustments VHF Models Dtcs Waveform AdjustBandpass Filter Adjust Squelch Adjust Beep Tone Level Beep Tone Level Adjustment PLL Adjustment UHF Models UHF AdjustmentsTransmitter Adjustments UHF Models UHF Adjustment Points UHF Adjustments CONT’D UHF Adjustments CONT’D Receiver Adjustments UHF Models Æçìíýõ9+ôý0$,1ý81,7 Parts List Íäç HUDPLFý&ìçíåý-%ýì+ýìíë.ð7ð$ 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 Front Unit VHF 7610 Exploded View UHF 7640 Exploded View VHF 7610 Block Diagram Schematic Diagrams and Component LayoutsMain Unit Front Unit VHF 7610 Transistor Basing Diagrams Foldout → VHF 7610 Main Board TOP View VHF Main Unit VHF 7610 Main Board Schematic UHF 7640 Block Diagram UHF 7640 Main Board Bottom View J4 T o O p tion al Un it UHF 7640 Main Board TOP View UHF 7640 Main Board Schematic VHF/UHF Front Unit Board Bottom View VHF/UHF Front Unit Board TOP View VHF/UHF Front Unit Schematic UHF 7640 Transistor Basing Diagrams