Icom IC-2GAT Service Manual

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ICOM
SERVICE
MANUAL
VHF FM TRANSCEIVER
Icom Inc.

Icom IC-2GAT Specifications

General

Frequency Range	144-146 MHz
Modulation	FM
Power Output	5 W
RF Power Output	5 W
Channels	10
Voltage	13.8 V
Receiver Sensitivity	0.25 µV (12 dB SINAD)

Summary

Introduction and Service Notes

Repair Notes

Important precautions and guidelines to follow during repair and maintenance procedures.

Specifications Overview

Transmitter Specifications

Details on output power, modulation system, frequency deviation, and impedance for the transmitter.

Receiver Specifications

Details on receiver system, intermediate frequencies, sensitivity, spurious rejection, and audio output.

Block Diagram

Circuit Descriptions

Receiver Circuitry

Detailed explanation of the receiver signal path, including antenna switching, RF amplification, and IF stages.

Transmitter Circuitry

Detailed explanation of the transmitter signal path, including microphone amplification, drive, and power amplifier stages.

PLL Circuitry

Explanation of the Phase-Locked Loop circuit, including reference oscillator and frequency control.

Power Supply Circuits

Description of the voltage lines and regulator circuits powering the transceiver.

Other Circuits

CPU Port Allocation

Adjustment Procedures

PLL Adjustment

Step-by-step guide for adjusting the PLL circuit, including required instruments and connection points.

Receiver Adjustment

Procedures for setting receiver sensitivity and S/RF level indicator using test equipment.

Transmitter Adjustment

Procedures for adjusting transmitter output power and FM deviation for various versions.

Schematic and Voltage Diagrams

Logic Unit Schematic

Detailed schematic diagram for the Logic Unit, including voltage references.

Main Unit Schematic

Detailed schematic diagram for the Main Unit, showing component interconnections and voltages.

VCO Unit Schematic

Schematic diagram for the VCO Unit, illustrating its circuit and voltage levels.

Tone Encoder Unit Schematic

Schematic diagram for the Tone Encoder Unit (IC-2GAT).