The Icom IC-T90A service manual provides detailed instructions for setting up, operating, and troubleshooting the multiband FM transceiver, including specifications, disassembly procedures, circuit descriptions, and adjustment procedures. It also includes safety warnings, such as avoiding connections to AC outlets or DC power supplies over 12 V, and emphasizes the importance of using insulated tools for adjustments to prevent damage.
Manual Overview
The Icom IC-T90A Multiband FM Transceiver service manual provides detailed guidance for technicians on troubleshooting, diagnostics, calibration, and board-level repairs. Troubleshooting follows a systematic approach, emphasizing the importance of verifying internal issues before disassembly and ensuring the transceiver is disconnected from power sources to prevent damage. Error codes and diagnostics are not explicitly detailed, but the manual stresses using insulated tools for adjustments and avoiding prolonged power application when defects are present. Calibration and adjustments require careful handling of variable components, with specific instructions to use attenuators when connecting to test equipment like deviation meters or spectrum analyzers. The manual includes board-level guidance, highlighting components such as the logic unit, AF unit, and RF unit, with detailed descriptions of key parts like the CPU, EEPROM, and various regulators and amplifiers. Technicians are advised to follow precise procedures for part replacement, ensuring correct order numbers and component specifications.
Quick Issues Covered
- Diagnose power-up failures with voltage diagram insights.
- Identify error codes related to RF signal overload.
- Calibrate frequency stability using adjustment procedures.
Overview
This service manual provides detailed service information for the IC-T90A Multiband FM Transceiver. It includes specifications, disassembly instructions, circuit descriptions, adjustment procedures, parts lists, mechanical parts, semiconductor information, board layouts, block diagrams, and voltage diagrams. The manual is intended to assist with servicing the transceiver and includes warnings about safe operation and handling.
Specifications
- Frequency range: USA 144 — 148 MHz, 430 — 450 MHz; CAN 50 — 53.995 MHz, 0.495-999.990 MHz; GEN 136 -— 174 MHz, 400 — 470 MHz; SEA 140 — 150 MHz, 430 — 440 MHz
- Mode: FM, AM (RX only), WFM (Rx only)
- Number of memory channels: 555 (incl. 50 scan edges and 5 call channels)
- Frequency stability: +6 ppm max. (-10°C to +60°C; 14°F to 140°F)
- Tuning steps: 5, 6.25, 8.33, 9, 10, 12.5, 15, 20, 25, 30, 50, 100, and 200 kHz
- Usable temperature range: -10°C to +60°C; 14°F to 140°F
- Power supply requirement: 5.5-—11 V DC or specified battery pack
- Usable battery pack/case: BP-217 (7.4 V) and BP-216 (3.2 V)
- Polarity: Negative ground
- Current drain (at 8.0 V DC): 50/145 MHz High power 2.0A, Low power 0.8A; 440 MHz High power 2.0A, Low power 1.2A; Rated output 220 mA; RX Standby 100 mA; Power saved 65 mA
- Antenna connector: SMA (50 Ω)
- Dimensions (projections not included): 58(W) x 87(H) x 29(D) mm; 21742(W) x 37A6(H) x 1542(D) in
- Weight (with BP-217/Ant.): 280 g; 974 oz
- Output power (at 8.0 V DC): High 5.0 W typical, Low 0.5 W typical
- Modulation system: Variable reactance modulation
- Max. freq. deviation: +5 kHz
- Spurious Emissions: Less than —60 dB
- External MIC connector: 3-conductor 2.5(d) mm (14”); 2 kΩ
- AF output impedance: 78Ω
- Receiver system: Double-conversion superheterodyne
- Intermediate frequency: 1st 13.350 MHz (FM/AM), 2nd 450 kHz
- Sensitivity: Various values depending on frequency range
- Selectivity: AM and FM Less than 15 kHz/-9 dB, More than 30 kHz/—60 dB; WFM Less than 350 kHz/—3 dB, More than 700 kHz/—20 dB
- Spurious and image rejection ratio: 50 MHz More than 60 dB, IF/2 More than 50 dB, IF More than 40 dB; 145 MHz More than 60 dB, IF/2 More than 50 dB; 440 MHz More than 50 dB, IF More than 60 dB
- Audio output power: 200 mW typical at 10 % distortion with an 8 Ω load
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 12 V. Such a connection could cause a fire hazard and/or electric shock. 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. 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 or 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 – 2.0 MB)
Icom IC-T90A Service Manual PDF (2.0 MB): Guide for troubleshooting, repair, and calibration of the IC-T90A radio model.
- Brand: Icom-ic-t90a-service
- Model: MANUAL
- Type: Service manual
- File size: 2.0 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-t90a-service MANUAL – Service Manual Overview
The Icom IC-T90A is a versatile handheld transceiver designed for reliable two-way communication in various professional and recreational settings. This service manual provides detailed instructions for maintenance, repair, and troubleshooting to ensure optimal performance of the device. Ideal for technicians and users who want to extend the lifespan of their Icom IC-T90A, the manual covers all essential aspects of the radio’s operation and servicing.
Main Features and Specifications
- Frequency Range: VHF 136–174 MHz
- Power Output: Up to 5 Watts
- Channel Capacity: 128 channels with memory
- Battery Type: Rechargeable NiMH battery pack
- Display: LCD with backlight for easy readability
- Operating Temperature: -20°C to +60°C
- Durability: Water-resistant and rugged design
- Additional Functions: CTCSS/DCS tone signaling, VOX, and wide/narrow bandwidth options
Basic Usage and Operation Tips
To operate the IC-T90A, ensure the battery is fully charged before use. Turn on the device by rotating the volume knob, then select the desired channel using the channel selector. Use the push-to-talk (PTT) button to transmit and release it to listen. Adjust squelch settings to minimize background noise. For extended communication, utilize the VOX function to enable hands-free operation. Always keep the antenna securely attached for optimal signal reception.
Troubleshooting and Maintenance Notes
If the transceiver fails to power on, check the battery charge and connections. Intermittent audio or weak transmission may indicate antenna damage or loose internal components, which can be inspected using the service manual’s detailed diagrams. Regularly clean the exterior and connectors with a soft, dry cloth. Avoid exposure to moisture and extreme temperatures to prevent internal damage. Refer to the manual’s troubleshooting section for error codes and repair procedures.
Safety Reminder
Always follow safety guidelines when servicing the IC-T90A. Disconnect the battery before opening the device to avoid electrical shock. Use only approved replacement parts and tools specified in the manual. Avoid operating the radio near explosive gases or in environments with high electromagnetic interference. Proper maintenance and cautious handling will ensure safe and reliable operation.