Icom IC-25E - User Manual

Technical specifications for the radio's general features.

Technical specifications for the transmitter section.

Technical specifications for the receiver section.

Overview of microcomputer control, scanning, and VFO capabilities.

Details on the continuous tuning system and outstanding performance aspects.

Instructions for unpacking, checking accessories, and selecting a mounting location.

Information on the necessary DC power supply and voltage/current needs.

Guidelines for connecting and using antenna, microphone, and external speaker.

Identification and description of front panel controls.

Descriptions of additional front panel buttons, switches, and indicators.

Identification and description of rear panel connectors.

Description of internal controls accessible under the top cover for scanning.

Steps for tuning frequencies and operating VFO/memory channels.

Guide to setting up duplex mode and resetting the offset frequency.

How to program and read frequencies from memory channels.

Explanation of various scanning modes: Memory, Programmed, and Full Range.

Detailed steps for programmed and full range scanning operations.

How the scan function restarts after being stopped by auto-stop or manual stop.

How to monitor a favorite channel while using a VFO.

Step-by-step guide for setting up and operating the receiver.

Step-by-step guide for setting up and operating the transmitter.

Diagrams identifying components on the main and PLL units.

General circuit outline and detailed description of receiver stages.

Detailed description of RF, IF, audio amplifier, and squelch circuits.

Description of transmitter circuitry and audio signal path for modulation.

Description of mixer, driver, power amplifier, ALC, and metering circuits.

Description of power supply, PLL unit, and local oscillator circuits.

Explanation of the programmable divider's role in the PLL circuit.

Description of driver unit, clock generation, and scan/mic control circuits.

Explanation of the CPU's control logic and input/output signal flow.

Diagrams illustrating CPU control logic flows for various functions.

Troubleshooting steps for power-on and no sound problems.

Troubleshooting steps for low sensitivity and RF output problems.

Troubleshooting steps for modulation failures and contact problems.

Troubleshooting steps for memory, programmed scan, and scan stop issues.

A comprehensive block diagram showing all major units and their interconnections.