Motorola IC-T81A, IC-T81E service manual Introduction, Ordering Parts, Repair Notes, Sample Order

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INTRODUCTION

This service manual describes the latest service information for the IC-T81A/E at the time of publication.

MODEL

VERSION

SYMBOL

 

U.S.A.

USA-1

IC-T81A

Australia

AUS

 

S.E.Asia

SEA

 

Europe

EUR

IC-T81E

U.K.

UK

 

Italy

ITA

To upgrade quality, all electrical or mechanical parts and internal circuits are subject to change without notice or obligation.

DANGER

NEVER connect the transceiver to an AC outlet or to a DC power supply that uses more than 16 V. Such a connection could cause a fire hazard and/or electric.

DO NOT expose the transceiver to rain, snow or any liquids.

DO NOT reverse the polarities of the power supply when connecting the transceiver.

DO NOT apply an RF signal of more than 20 dBm (100mW) to the antenna connector. This could damage the trans- ceiver's front end.

ORDERING PARTS

Be sure to include the following four points when ordering replacement parts:

1.10-digit order numbers

2.Component part number and name

3.Equipment model name and unit name

4.Quantity required

<SAMPLE ORDER>

1130009370 S.IC

TB31242FN

IC-T81A/E

RF UNIT

1 pieces

8810008990 Screw

PH BT M2x10 ZK

IC-T81A/E

Chassis

10 pieces

Addresses are provided on the inside back cover for your convenience.

REPAIR NOTES

1.Make sure a problem is internal before disassembling the transceiver.

2.DO NOT open the transceiver until the transceiver is disconnected from its power source.

3.DO NOT force any of the variable components. Turn them slowly and smoothly.

4.DO NOT short any circuits or electronic parts. An insulated turning tool MUST be used for all adjustments.

5.DO NOT keep power ON for a long time when the transceiver is defective.

6.DO NOT transmit power into a signal generator or a sweep generator.

7.ALWAYS connect a 40 dB to 50 dB attenuator between the transceiver and a deviation meter or spectrum analyzer when using such test equipment.

8.READ the instructions of test equipment thoroughly before connecting equipment to the transceiver.

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Contents Multiband FM Transceiver Repair Notes IntroductionOrdering Parts Sample OrderTable of Contents Transmitter SpecificationsGeneral Version 50 MHz 145 MHz 440 MHz 1200 MHz MHz RX onlyWFM ReceiverBand WFMRF Unit Inside ViewsLogic Unit CPURemoving the Logic Unit Removing the RF Unit Disassembly InstructionsRemoving the Chassis Panel Removing the Shield Plate Logic unitReceiver Circuits Antenna Switching Circuits RF UnitCircuit Description Duplexer Circuit RF Unit7 1ST Mixer Circuit RF Unit Transmitter Circuits MHz PA DRIVE/POWER Amplifier Circuits RF UnitAPC Circuits RF Unit APC Control CircuitLine Description Power Supply Circuits Voltage LinePLL Circuits VCC2 I/O Expander IC RF Unit IC3 Port Allocations1 I/O Expander IC RF Unit IC2 Pin Port Description Number NameCPU Logic Unit IC1 ‘ Required Test Equipment Adjustment ProceduresPreparation ConnectionPLL Adjustment VLV RF Unit Bottom ViewULV RF Unit TOP View 6MLVSensitivity Receiver AdjustmentDial VHFLogic Unit TOP View Top Push and hold MHz band MeterSSG 101 dBm445.000 MHz USA-1 Displayed frequencyPush and hold SQL keyTransmitter Adjustment Dtmf DeviationHPF OFF LPF AUS, SEAParts List =Surface mountTrimmer Ceramic ECUE1H121JCQ Transistor UN911D TX Coil Eljnd R10J 0.1U Themistor Ceramic ECUE1H060CCQ Ceramic ECUE1H390JCQ VCO Board Ceramic ECUE1H120JCQ Chassis Parts Mechanical Parts and DisassemblyAccessories VCO UnitMP29 C Diodes SEMI-CONDUCTOR InformationTransistor and FET’S TOP View Board LayoutsLogic Unit IC3 Bottom ViewIC1 GND Pset IfinL912 RF UnitIC6 J4 to Logic unit J1IC2 MP1IC3 OUT 12VCOOUT VCO BoardJ302 to RF unit VLVCO3 VHF GND VHVCO3 UVCO3 Uhfout GND 12VCO3 GNDQ354 Block Diagram TX/RX Buff Mode Xtal BPF PDA2, CK AMPTX/RX Frequency ANT LPF HPF AMPMOD TX/RX Frequency ResetMode Xtal Initial BPF ANT Buff HPF LPF YGRSection Voltage Diagram Logic UnitDEC Ifout Filout Quad 2NDLOOscin Mixin Oscout GND Mixout REC VCC DET Ifin Rssi WFM NTCCF20124AH 473KCT TXCClonein VCC VIN Cpuhv 12VCO COM2 ResetCOM3 COM2 Reset Power COM4 COM3 COM2 COM1400M RF UnitVHF 1200M1200MHz 50M00M 400MHzENB VCC2 GND1PLST1 IN1 LOK GND2Icom America Inc 5566I-S Icom Inc