Motorola IC-T81E, IC-T81A service manual Logic Unit TOP View

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• LOGIC UNIT TOP VIEW

SD

50 MHz, WFM BAND, AIR BAND and 145 MHz Sensitivity check point

5 - 5

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Contents Multiband FM Transceiver Sample Order IntroductionOrdering Parts Repair NotesTable of Contents Version 50 MHz 145 MHz 440 MHz 1200 MHz MHz RX only SpecificationsGeneral TransmitterWFM ReceiverBand WFMCPU Inside ViewsLogic Unit RF UnitLogic unit Disassembly InstructionsRemoving the Chassis Panel Removing the Shield Plate Removing the Logic Unit Removing the RF UnitDuplexer Circuit RF Unit Antenna Switching Circuits RF UnitCircuit Description Receiver Circuits7 1ST Mixer Circuit RF Unit Transmitter Circuits APC Control Circuit DRIVE/POWER Amplifier Circuits RF UnitAPC Circuits RF Unit MHz PAVCC Power Supply Circuits Voltage LinePLL Circuits Line DescriptionPin Port Description Number Name Port Allocations1 I/O Expander IC RF Unit IC2 2 I/O Expander IC RF Unit IC3CPU Logic Unit IC1 Connection Adjustment ProceduresPreparation ‘ Required Test EquipmentPLL Adjustment RF Unit TOP View 6MLV RF Unit Bottom ViewULV VLVVHF Receiver AdjustmentDial SensitivityLogic Unit TOP View 101 dBm MeterSSG Top Push and hold MHz bandSQL key Displayed frequencyPush and hold 445.000 MHz USA-1Transmitter Adjustment AUS, SEA DeviationHPF OFF LPF Dtmf=Surface mount Parts ListTrimmer Ceramic ECUE1H121JCQ Transistor UN911D TX Coil Eljnd R10J 0.1U Themistor Ceramic ECUE1H060CCQ Ceramic ECUE1H390JCQ VCO Board Ceramic ECUE1H120JCQ VCO Unit Mechanical Parts and DisassemblyAccessories Chassis PartsMP29 C Transistor and FET’S SEMI-CONDUCTOR InformationDiodes Logic Unit Board LayoutsTOP View GND Pset Ifin Bottom ViewIC1 IC3J4 to Logic unit J1 RF UnitIC6 L912IC3 MP1IC2 VLVCO3 VHF GND VHVCO3 UVCO3 Uhfout GND 12VCO3 GND VCO BoardJ302 to RF unit OUT 12VCOOUTQ354 Block Diagram ANT LPF HPF AMP Mode Xtal BPF PDA2, CK AMPTX/RX Frequency TX/RX BuffANT Buff HPF LPF YGR ResetMode Xtal Initial BPF MOD TX/RX FrequencyLogic Unit Section Voltage DiagramWFM NTCCF20124AH 473KCT TXC 2NDLOOscin Mixin Oscout GND Mixout REC VCC DET Ifin Rssi DEC Ifout Filout QuadCOM4 COM3 COM2 COM1 12VCO COM2 ResetCOM3 COM2 Reset Power Clonein VCC VIN Cpuhv1200M RF UnitVHF 400M400MHz 50M00M 1200MHzLOK GND2 GND1PLST1 IN1 ENB VCC2Icom America Inc Icom Inc 5566I-S