Icom IC-77 Service Manual

Essential safety warnings for operating the transceiver to prevent damage or injury.

Guidelines for specifying and ordering replacement components for the unit.

Key considerations and precautions to follow during service and repair procedures.

Details on frequency coverage, modes, channels, impedance, and operating environment.

Key performance parameters for the transmitter section, including output power and modulation.

Performance metrics for the receiver, such as sensitivity, selectivity, and audio output.

Identification of components on the PLL, PA, and Filter circuit boards.

Component identification for the primary Main circuit board.

Detailed explanation of the receiver's signal path and functional blocks.

Explanation of the transmitter's signal generation and amplification stages.

Description of the Phase-Locked Loop circuits for frequency synthesis.

Description of the CPU and logic control circuits.

Explanation of the power supply voltage regulation circuits.

Required test equipment and setup procedures before performing adjustments.

Step-by-step instructions for adjusting the PLL circuit parameters.

Procedures for calibrating receiver performance parameters.

Procedures for calibrating transmitter output and modulation.

List of mechanical and structural components for the chassis.

List of electronic components and parts for the front unit.

List of electronic components and parts for the PLL unit.

List of electronic components and parts for the PA unit.

List of electronic components and parts for the filter unit.

Identification and listing of external front panel and cabinet components.

Diagram and list of chassis-mounted mechanical parts.

Component placement diagram for the Main circuit board.

Component placement diagrams for Front, VR, and Jack units.

Component placement diagram for the PLL circuit board.

Component placement diagram for the PA circuit board.

Component placement diagram for the Filter circuit board.

Schematic showing voltage distribution across Main, PA, and Filter units.

Schematic showing voltage distribution across PLL and Front units.