Motorola IC-T81A, IC-T81E service manual Receiver Adjustment, Dial, Sensitivity, Vhf, ΜV* -107 dBm

Page 18

5-3 RECEIVER ADJUSTMENT

The following adjustment must be performed at “ADJUSTMENT MODE”.

 

 

 

 

 

MEASUREMENT

 

 

ADJUSTMENT

ADJUSTMENT

ADJUSTMENT CONDITION

 

VALUE

POINT

 

 

 

 

 

 

 

 

 

UNIT

 

LOCATION

 

UNIT

ADJUST

 

 

 

 

 

 

 

 

 

50 MHz

1

• Displayed frequency :

LOGIC

Connect a multime-

Maximum voltage

Top

[DIAL]

SENSITIVITY

 

50.000 MHz

 

ter

to check

point

 

panel

 

 

 

 

• Connect an SSG to the antenna

 

SD.

 

 

 

 

 

 

 

 

connector and a SINAD meter

 

 

 

 

 

 

 

 

 

 

with an 8 Ω load to the [SP] jack.

 

 

 

 

 

 

 

 

 

 

• Set an SSG as :

 

 

 

 

 

 

 

 

 

 

Level

: 1 µV* (–107 dBm)

 

 

 

 

 

 

 

 

 

 

Deviation

: ± 3.5 kHz

 

 

 

 

 

 

 

 

 

 

Modulation

: 1 kHz

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

• Displayed frequency :

 

 

 

 

 

 

 

 

 

 

54.000 MHz

 

 

 

 

 

 

 

 

 

 

[EUR], [UK], [ITA]

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

WFM

1

• Displayed frequency :

LOGIC

Connect a multime-

Maximum voltage

Top

[DIAL]

SENSITIVITY

 

76.000 MHz [SEA], [USA-1]

 

ter

to check

point

 

panel

 

 

 

 

88.000 MHz

 

SD.

 

 

 

 

 

 

 

 

[EUR], [UK], [ITA], [AUS]

 

 

 

 

 

 

 

 

 

 

• Set an SSG as :

 

 

 

 

 

 

 

 

 

 

Level

: 3.2 µV*

 

 

 

 

 

 

 

 

 

 

 

(–97 dBm)

 

 

 

 

 

 

 

 

 

 

Deviation

: ± 52.5 kHz

 

 

 

 

 

 

 

 

 

 

Modulation

: 1 kHz

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

• Displayed frequency :

 

 

 

 

 

 

 

 

 

 

107.000 MHz

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AM

1

• Displayed frequency :

LOGIC

Connect a multime-

Maximum voltage

Top

[DIAL]

SENSITIVITY

 

108.000 MHz

 

ter

to check

point

 

panel

 

 

 

 

• Set an SSG as :

 

SD.

 

 

 

 

 

 

 

 

Frequency

: 108.000 MHz

 

 

 

 

 

 

 

 

 

 

Level

: 1.0 µV* (AM)

 

 

 

 

 

 

 

 

 

 

 

(–107 dBm)

 

 

 

 

 

 

 

 

 

 

Modulation

: 1 kHz

 

 

 

 

 

 

 

 

 

 

Mod. depth

: 30 %

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

• Displayed frequency :

 

 

 

 

 

 

 

 

 

 

135.980 MHz

 

 

 

 

 

 

 

 

 

 

• Set an SSG as :

 

 

 

 

 

 

 

 

 

 

Frequency

: 135.980 MHz

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VHF

1

• Displayed frequency :

LOGIC

Connect a multime-

Maximum voltage

Top

[DIAL]

SENSITIVITY

 

136.000 MHz

 

ter

to check

point

 

panel

 

 

 

 

• Set an SSG as :

 

SD.

 

 

 

 

 

 

 

 

Level

: 3.2 µV*

 

 

 

 

 

 

 

 

 

 

 

(–97 dBm)

 

 

 

 

 

 

 

 

 

 

Deviation

: ± 3.5 kHz

 

 

 

 

 

 

 

 

 

 

Modulation

: 1 kHz

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

• Displayed frequency :

 

 

 

 

 

 

 

 

 

 

160.000 MHz

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

*This output level of the standard signal generator (SSG) is indicated as SSG’s open circuit.

5 - 4

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Page 17 Page 19
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 SEMI-CONDUCTOR Information Transistor and FET’SDiodes Board Layouts Logic UnitTOP View IC3 Bottom ViewIC1 GND Pset IfinL912 RF UnitIC6 J4 to Logic unit J1MP1 IC3IC2 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
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