EFJohnson 764X, 761X service manual DB-9 Pin Function, Changing 20-Ampere Power Cable Fuses

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INSTALLATION AND DISASSEMBLY

2.Route the red and black wires from the transceiver to the battery. Connect the red wire to the positive

(+) terminal and the black wire to the negative (–) terminal.

3.Plug the cable into the pigtail coming from the trans- ceiver and reconnect the negative battery cable.

4.Install the antenna according to the manufacturer’s instructions. The transceiver has a standard UHF connector. Check VSWR. Reflected power should be less than 4% of forward power (VSWR less than 1.5 to 1).

2.3.3 POWER CABLE FUSES

Each power cable wire is protected by a 20- ampere fuse. These fuses are inspected and changed as shown below. If a fuse blows, locate the cause if possi- ble and replace it with one of the same rating.

input that can be used to control the backlight (see Section 3.3.9). This cable is installed as shown in Figure 2-3.

This cable has a standard DB-9 female connector for interfacing to external equipment. The pin number- ing and functions are as follows:

DB-9 Female Connector

Outside View

DB-9 Pin

Function

 

 

1

LCD backlight control in

2

AF out

3

Detected AF out

4

Modulation in

5

PTT control in

6

Horn drive control out

7

AF ground

8

Detected AF ground

9

Modulation ground

 

 

Changing 20-Ampere Power Cable Fuses

2.4 USING AN EXTERNAL SPEAKER

An external speaker can be plugged into the external speaker jack on the back of the transceiver. This speaker should have an impedance of 4-8 ohms and a power handling capability of at least 3.5 watts. The internal speaker is automatically disabled when a speaker is plugged into this jack. The external speaker jack is a standard 1/8-inch, two-conductor phone jack.

2.5 ACCESSORY CABLE INSTALLATION

Optional Accessory Cable, Part No. 585-7600-

027, can be used for connecting accessories such aFigure 2-3 Accessory Cable Installation horn alert or modem to the transceiver. It also has an

 

November 1998

2-3

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 Toll-Free 800 75xx AccessoriesAccessory Factory ReturnsReplacement Parts Internet HomeThis page intentionally left blank VHF and 7640 UHF Mobile Specifications GeneralGeneral Information Installation and Disassembly Transceiver InstallationPower Cable Installation Installing Mounting BracketInstalling Microphone Hanger Cable InstallationUsing AN External Speaker Power Cable FusesChanging 20-Ampere Power Cable Fuses Accessory Cable InstallationRemove shield E Transceiver DisassemblyRemoving PC Board Setting 5-Tone Deviation 2-TONE/5-TONE Module InstallationInstallation Procedure 2 2-TONE ProgrammingInstallation and Disassembly Features OperationBasic Operation Controls and DisplayTransceiver Back Panel Direct Selection The F1-F4 Receiving and Placing Calls Option Key Programmable Functions TIME-OUT TimerProgrammable Functions Function Key Label Description Section NoCall Guard Tone Select Monitor Mode SelectOutput Power Select Channel SelectChannel Scan Priority Channel Sampling Programming Cables Programming SetupSection Programming Programming SoftwareMenu Flow Starting the ProgramSpecial Keys and Functions File MenuPrint Menu Screen MenuProgram Menu Model MenuParameter Description Bank Select Setup MenuMemory Channel Screen Description LMR Models Frequency TimerCh Atr Rx/TxScan Auto ResetLockout ToneKey and Display Assign Screen Description Key DescriptionKey Description Label Selection RF PowerDtmf Autodial Screen Description Bank/FreeParameter Description Continuous Tone Screen DescriptionScan Function Screen Description Resume Stop Timer2-Tone Code Channel Screen Description Auto CHAuto Tx EXO TimerTimer Auto 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 CircuitMicrophone Amplifier Circuit Power Amplifier ModuleVHF Transmitter Circuit Modulation CircuitPLL Circuit APC CircuitVHF PLL Circuit Pin Port Description VHF IC PIN DescriptionsLine Description VHF Port Expander IC11 Main Unit VHF I/O Expander IC5 Main UnitPin 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 UnitSuggested Test Equipment Adjustment ProcedureTest Setup Equipment Grade and RangeTest Channels Test CableUHF Test Frequencies COMPUTER-AIDED TuningVHF Test Frequencies Preliminary Setup VHF AdjustmentsVHF Adjustments PLL Adjustment VHF ModelsFM Deviation Adjust VHF Adjustments CONT’DOutput Power Adjust Bandpass Filter Adjust Dtcs Waveform AdjustReceiver Adjustments VHF Models Squelch AdjustBeep Tone Level Adjustment Beep Tone LevelTransmitter Adjustments UHF Models UHF AdjustmentsPLL Adjustment 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 Main Unit Schematic Diagrams and Component LayoutsVHF 7610 Block Diagram 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