The Icom IC-H28 VHF Transceiver service manual provides detailed instructions for setup, operation, and troubleshooting, including guidelines for safe servicing, power supply connections, and adjustments of receiver and transmitter circuits. It also includes specifications, parts lists, and diagrams for understanding the internal components and ensuring proper maintenance and repair.
Manual Overview
The Icom IC-H28 VHF Transceiver service manual provides detailed guidance for technicians on troubleshooting, diagnostics, and adjustments. It emphasizes the importance of ensuring a problem is internal before disassembly and advises against opening the transceiver while connected to a power source. The manual outlines the necessity of using an insulated tuning tool for adjustments and warns against shorting circuits or keeping power on for extended periods when the transceiver is defective. Calibration procedures include PLL, receiver, and transmitter adjustments, with specific instructions for each. The manual also covers board-level guidance, detailing the layout and function of various units such as the logic, RF, and IF boards. Error codes and diagnostics are not explicitly detailed, but the manual stresses the importance of using a 40-50 dB attenuator when connecting test equipment to avoid damage. Intrinsically safe servicing conditions are specified, including the use of approved batteries and safety-critical components. The manual provides part ordering instructions, requiring specific details like order numbers and component names.
Quick Issues Covered
- Diagnose power-up failures due to incorrect voltage supply.
- Adjust PLL circuits for frequency stability and performance.
- Trace circuits using detailed schematics for troubleshooting.
Overview
The IC-H28 is a VHF transceiver, and the service manual provides detailed information about its specifications, circuit descriptions, mechanical parts, and adjustment procedures. It includes safety instructions, especially regarding its intrinsically safe qualification, and guidelines for ordering replacement parts. The manual covers various sections such as specifications, inside views, circuit descriptions, mechanical parts and disassembly, parts list, adjustment procedures, board layouts, optional units, block diagrams, and voltage diagrams.
Specifications
- Frequency range: See VERSIONS
- Type of emission: 16KOF3E (#01, #02, #11, #12), BKSOFSE (#03, #04)
- Number of channels: Up to 16 channels
- Frequency stability: ±0.0005 %
- Antenna impedance: 50 Ω (nominal)
- Usable battery pack: CM-80, CM-92, CM-97
- Usable temperature range: —30°C~+60°C (#01, #02, #11, #12), —25°C~+55°C (#03, #04)
- Dimensions (with CM-80): 58 (W)x 149 (H)x 29 (D) mm
- Weight (with CM-80): 440 g
- RF output power (at 7.2 V DC): High: 5 W, Low 1: 2 W, Low 2: 1 W
- Modulation system: Variable reactance frequency modulation
- Current drain (at 7.2 V DC): High: 3.5 A, Low 2: 1.8 A
- Microphone impedance: 1.2 kΩ
- Maximum deviation: ±5 kHz (#01, #02, #11, #12), ±2.5 kHz (#03, #04)
- Spurious emissions: —65 dB (High), —60 dB (Low 1, Low 2)
- FM noise and hum: —45 dB (#01, #02, #11, #12), —35 dB (#03, #04)
- Audio response: +1 dB~—3 dB of +6 dB/octave with 300 Hz to 3000 Hz input (#01, #02, #11, #12), +1 dB~—3 dB of +6 dB/octave with 300 Hz to 2550 Hz input (#03, #04)
- Sensitivity: 0.25 µV for 12 dB SINAD
- Intermediate frequency: 1st 30.875 MHz, 2nd 455 kHz
- Squelch threshold sensitivity: 0.25 µV
- Modulation acceptance: ±7 kHz
- Current drain (at 7.2 V DC): Audio Max. 450 mA, Standby 70 mA
- Audio output power: 500 mW
- Adjacent channel selectivity: —70 dB (#01, #02, #11, #12), —60 dB (#03, #04)
- Spurious response: —70 dB
- Image rejection: —70 dB
- Intermodulation rejection: —65 dB (#01, #02, #11, #12), —60 dB (#03, #04)
- FM noise and hum: —40 dB (#01, #02, #11, #12), —35 dB (#03, #04)
- Audio response: +1 dB~—3 dB of —6 dB/octave with 300 Hz to 3000 Hz modulation (#01, #02, #11, #12), +1 dB~—3 dB of —6 dB/octave with 300 Hz to 2550 Hz modulation (#03, #04)
Controls & Indicators
Refer to the PDF for details.
Installation / Setup
Refer to the PDF for details.
Operation
Refer to the PDF for details.
Troubleshooting & Error Codes
Refer to the PDF for details.
Safety & Warnings
NEVER connect the transceiver to an AC outlet or to a DC power supply that uses more than 9 V. This will ruin the transceiver. DO NOT expose the transceiver to rain, snow, or any liquids. DO NOT reverse the polarities of the power supply when connecting the transceiver. DO NOT apply an RF signal of more than 20 dBm (100 mW) to the antenna connector, as this could damage the transceiver’s front end.
When servicing the IC-H28, the following conditions must be met to maintain the INTRINSICALLY SAFE certification: Servicing should only be done by suitably qualified personnel in a non-hazardous area, and the case should never be removed in a hazardous area. Only the approved battery, ICOM’s CM-92 or CM-97, may be removed or charged in a safe area. Use only safety-critical components as specified in the parts list if replacement is necessary.
Make sure a problem is internal before disassembling the transceiver. DO NOT open the transceiver until it is disconnected from its power source. DO NOT force any of the variable components; turn them slowly and smoothly. DO NOT short any circuits or electronic parts. An insulated tuning tool must be used for all adjustments. DO NOT keep power on for a long time when the transceiver is defective. DO NOT transmit power into a signal generator or a sweep generator. Always connect a 40 dB~50 dB attenuator between the transceiver and a deviation meter or spectrum analyzer when using such test equipment. Read the instructions of test equipment thoroughly before connecting equipment to the transceiver.
Download MANUAL Service manual (PDF – 15.7 MB)
Icom IC-H28 Service Manual PDF: A 15.7 MB guide for technicians to troubleshoot and calibrate the Icom IC-H28 model.
- Brand: Icom-ic-h28-service
- Model: MANUAL
- Type: Service manual
- File size: 15.7 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-H28 Service Manual Overview
The Icom IC-H28 is a compact and durable handheld VHF marine transceiver designed for reliable communication on the water. This device provides clear voice transmission and reception, ensuring safety and coordination during marine activities. The service manual offers detailed guidance on maintenance, repair, and troubleshooting to keep your IC-H28 operating at peak performance.
Main Features and Specifications
- Frequency Range: 156.000 MHz to 163.275 MHz (marine VHF band)
- Output Power: 5 Watts (high), 1 Watt (low)
- Waterproof Construction: IPX7 rating, submersible up to 1 meter for 30 minutes
- 16 Marine Channels with priority channel monitoring
- Battery Life: Up to 12 hours of continuous operation (NiMH battery pack)
- Large LCD display with backlight for easy reading in low light
- Compact and ergonomic design for comfortable handheld use
Basic Usage and Operation Tips
To operate the IC-H28, first ensure the battery is fully charged. Turn on the transceiver by rotating the volume knob. Select the desired channel using the channel selector knob. Press the Push-To-Talk (PTT) button to transmit your message, and release it to listen. Utilize the scan feature to monitor multiple channels. Always keep the antenna fully extended for optimal signal quality. When not in use, power off the device to conserve battery life.
Troubleshooting and Maintenance Notes
If you experience weak transmission or reception, check the battery charge and antenna connection. Clean the microphone and speaker grills regularly to prevent dust buildup. For persistent issues, refer to the troubleshooting section in the service manual for detailed diagnostics. Avoid exposing the unit to extreme temperatures or prolonged moisture beyond its waterproof rating. Replace worn or damaged parts only with genuine Icom components to maintain performance and safety.
Safety Reminder
Always use the Icom IC-H28 in accordance with marine communication regulations and guidelines. Avoid operating the transceiver while navigating or performing tasks that require full attention. Keep the device away from flammable materials and do not attempt unauthorized repairs. Proper handling and maintenance ensure safe and reliable operation on the water.