The Icom IC-25A/E maintenance manual provides detailed instructions on the setup, operation, and troubleshooting of the 144MHz FM transceiver, including descriptions of front and rear panel controls, block diagrams, and adjustment procedures for components like the PLL and transmitter. It also includes a troubleshooting guide, parts list, and specifications for ensuring optimal performance and resolving common issues.
Manual Overview
The Icom IC-25A/E maintenance manual provides detailed instructions for servicing the 144MHz FM transceiver. It includes a comprehensive troubleshooting guide that outlines a systematic approach to diagnosing issues, with specific focus on error codes and diagnostics to facilitate efficient problem resolution. The manual emphasizes the importance of calibration and adjustments, detailing procedures for PLL, receiver, transmitter, and modulation adjustments to ensure optimal performance. Technicians are guided through board-level repairs with insights into circuit functions and voltage charts, aiding in pinpointing faults at the component level. The manual also includes a block diagram for a visual representation of the transceiver’s internal structure, assisting in understanding the signal flow and component interconnections. Additionally, the order of disassembly is clearly outlined, ensuring safe and effective access to internal components for maintenance and repair tasks. This structured approach is designed to support technicians in maintaining the transceiver’s functionality and reliability.
Quick Issues Covered
- Diagnose power-up failures with voltage charts and circuit tracing.
- Adjust PLL and modulation settings for optimal performance.
- Troubleshoot receiver and transmitter issues using error codes.
Overview
The IC-25A/E is a 144MHz FM transceiver. The maintenance manual covers various aspects of the device, including controls and their functions, inside views, block diagram, operation, order of disassembly, adjustments, circuits and voltage charts, troubleshooting guide, and parts list. It provides detailed specifications for both the transmitter and receiver components, as well as instructions for adjustments and operation.
Specifications
- GENERAL
- Numbers of semiconductors
- Transistors 48
- FETs 5
- ICs 21 (IC-25A: 20)
- Diodes 89 {IC-25A: 91)
- Frequency coverage 144.000 ~ 145.995 MHz (IC-25A: 143.800 ~ 148.195 MHz)
- Frequency resolution 5 kHz/25 kHz steps (1C-25A: 5 kHz/15 kHz steps)
- Frequency control Microcomputer based 5 kHz step Digital PLL synthesizer
- Independent Dual VFO Capability.
- Frequency stability Within + 1.5 kHz
- Frequency channels 5 channels with any inband frequency programmable
- Usable conditions Temperature: ~10°C ~ 60°C (14°F ~ 140°F)
- Operational time: continuous
- Antenna impedance 50 ohms unbalanced
- Power supply requirement 13.8V DC + 15% (negative ground) 6A Max.
- Current drain (at 13.8V DC) Transmitting
- HIGH (25W) Approx. 4.8A
- LOW {1W) Approx. 1.3A
- Receiving
- At max audio output Approx. 0.6A
- Squelched Approx. 0.4A
- Dimensions 50 mm (H) x 140 mm (W) x 177 mm (D)
- Weight Approx, 1.5 kg
- TRANSMITTER
- Output power 25W (HIGH), 1W (LOW)
- Emission mode 16F3
- Modulation system Variable reactance frequency modulation
- Max. frequency deivation 5 kHz
- Spurious emission More than 60 dB below carrier
- Microphone 1.3 K ohm dynamic microphone with built-in preamplifier and push-to-talk switch
- Operating made Simplex, Duplex (Any inband frequency separation programmable}
- Tone burst 1750 Hz + 0.1 Hz (1C-25A: Not installed)
- RECEIVER
- Receiving system Double-conversion superheterodyne
- Modulation acceptance 16F3
- Intermediate frequency 1st: 16.9 MHz
- 2nd: 455 kHz
- Sensitivity More than 30 dB S+N+D/N+4D at IpV
- Less than 0.6 for 20 dB Noise quieting
- Squelch sensitivity Less than 0.4uV
- Spurious response rejection ratio More than 60 dB
- Selectivity More than +7.5 kHz at —6 dB point
- Less than +15 kHz at —60 dB point
- Audio output power More than 2.0W
- Audio output impedance 4~8 ohms
Controls & Indicators
VFO SWITCH: Selects VFO “A” or “B” for tuning. VFO INDICATOR: Illuminates when VFO “A” is selected. PRIORITY INDICATOR: Illuminates when priority function is ON. PRIORITY BUTTON: Switches priority function ON/OFF. FREQUENCY DISPLAY: Shows carrier frequency. RECEIVE INDICATOR: Illuminates when squelch is open in RECEIVE mode. TRANSMIT INDICATOR: Illuminates in TRANSMIT mode. VFO SCAN-FUNCTION SWITCH: Selects full or program scan. S/RF INDICATOR: Shows S-unit and RF output level. SIMPLEX/DUPLEX SWITCH: Selects SIMPLEX or DUPLEX operation. DUPLEX-MODE SWITCH: Selects relationship of reception and transmission frequency in duplex mode. TONE CALL SWITCH (IC-25E only): Activates tone-burst generator for repeater access. OFFSET SWITCH (IC-25A only): Adjusts transmission frequency offset. VFO/MEMORY CHANNEL SWITCH: Selects VFO or memory channel operation. TUNING CONTROL KNOB: Adjusts frequency. SCAN START/STOP BUTTON: Starts/stops scan functions. MEMORY/VFO WRITE BUTTON: Writes VFO frequency to memory or transfers frequency between VFOs. VOLUME CONTROL/POWER SWITCH: Adjusts audio level and power. SQUELCH CONTROL/RF POWER SWITCH: Adjusts squelch threshold and RF power. MIC CONNECTOR: Connects microphone.
Installation / Setup
Refer to the PDF for details.
Operation
The manual provides detailed information on the operation of the 144MHz FM Transceiver IC-25A/E, including sections on the receiver, transmitter, PLL unit, and driver (logic) unit. However, specific basic usage steps or modes of operation are not explicitly outlined in the provided source text.
Troubleshooting & Error Codes
Refer to the PDF for details.
Safety & Warnings
Refer to the PDF for details.
Download MANUAL Service manual (PDF – 14.2 MB)
Icom IC-25A/IC-25E service manual PDF for troubleshooting and calibrating transceiver systems. File size: 14.2 MB.
- Brand: Icom-ic-25a-ic-25e-service
- Model: MANUAL
- Type: Service manual
- File size: 14.2 MB
Overview
Brief overview of the product.
Specifications
- Key spec 1
- Key spec 2
Controls & Indicators
Control panel/button layout.
Installation / Setup
- Step 1…
- Step 2…
Operation
Basic usage, modes, cycles.
Troubleshooting & Error Codes
| Issue / Code | Fix |
|---|---|
| Example | How to fix… |
Safety & Warnings
- Important warning…
Downloads
Download MANUAL service manual (PDF)
Icom IC-25A / IC-25E Service Manual Overview
The Icom IC-25A and IC-25E are compact, reliable handheld transceivers designed for professional and amateur radio communication. These devices operate on VHF frequencies, providing clear, secure voice communication over short to medium distances. Ideal for outdoor activities, emergency services, and event coordination, the IC-25A and IC-25E deliver robust performance with user-friendly controls and durable construction.
Main Features and Specifications
- Frequency Range: VHF 136-174 MHz
- Power Output: Up to 5 Watts
- Channel Capacity: 16 programmable channels
- Battery Type: Rechargeable NiMH battery pack
- Display: LCD with channel and status indicators
- CTCSS and DCS tone signaling for selective calling
- Emergency alert function
- Compact and lightweight design for portability
Basic Usage and Operation Tips
To operate the IC-25A/IC-25E, power on the device and select the desired channel using the channel selector knob. Press and hold the Push-To-Talk (PTT) button to transmit your voice; release it to listen. Utilize the CTCSS/DCS tones to communicate selectively within your group without interference from other users. Regularly charge the battery pack to ensure optimal performance, and familiarize yourself with the emergency alert feature for quick assistance in critical situations.
Troubleshooting and Maintenance
If you experience weak transmission or reception, verify that the antenna is securely attached and that the battery is fully charged. Noise or static may indicate interference or a need to adjust the squelch level. Clean the device exterior and connectors periodically with a soft, dry cloth to prevent dust buildup. For persistent issues, consult the service manual for detailed diagnostics and repair procedures.
Safety Reminder
Always operate the Icom IC-25A/IC-25E in accordance with local regulations and licensing requirements. Avoid using the transceiver near explosive materials or in environments with flammable gases. Keep the device dry and avoid exposing it to extreme temperatures to prevent damage. When charging the battery, use only the recommended charger to ensure safety and prolong battery life.