The Icom SCHEMATICS manual provides detailed instructions for setting up, operating, and troubleshooting the transceiver, including information on power requirements, installation, and the use of accessories. It also describes the technical specifications and features of the transceiver, such as its frequency coverage, modulation type, and receiver sensitivity, ensuring users can effectively manage and maintain the device.
Manual Overview
The Icom SCHEMATICS manual provides detailed guidance on troubleshooting, diagnostics, calibration, and board-level servicing for the transceiver. Troubleshooting is facilitated by test points accessible from major circuits, allowing for efficient maintenance checks. Error diagnostics are supported by an Automatic Power Control (APC) system that monitors output for high VSWR or antenna issues, disabling the driver and final PA to prevent damage. Calibration involves using a clip cord and ensuring the frequency control is stable, utilizing crystal oscillators for both transmitter and receiver. Adjustments can be made to the squelch and modulation systems for optimal performance. The manual emphasizes the modular design of the circuitry, housed in a durable metal chassis, which simplifies board-level repairs and replacements. The transceiver’s design includes a dual conversion receiver with a high-Q helicalized cavity resonator for low noise and high sensitivity, and a transmitter capable of at least 10 watts RF output, ensuring reliable and stable operation.
Quick Issues Covered
- Diagnose power-up failures with DC voltage checks and APC protection.
- Use schematics for circuit tracing and module-level troubleshooting.
- Adjust squelch for optimal reception between 5 to -15 dB.
Overview
This transceiver is a rugged, solid-state device featuring integrated circuits, field effect transistors, varactor, and Zener diodes. It offers reliability, low current demand, compactness, and ease of operation. The dual conversion receiver with FET front end provides low noise and high sensitivity. The transmitter section delivers a minimum of 10 watts RF output with frequency stability ensured by a Zener regulated crystal oscillator. The unit includes a built-in speaker, dynamic microphone, mobile mounting bracket, and operating manual. It is designed for both mobile and fixed station use, with a modern styled face plate and compact design.
Specifications
- Frequency coverage: 144.00 to 148.00 MHz
- Number of Transistors: 33
- Number of FET: 5
- Number of TO: 1
- Number of Diodes: 20
- Modulation Type: F3
- Power Voltage: DC 13.5V +£20% negative ground
- Current Drain: Transmit: HI (10W) average 21A, LOW (1W) average 12A, Receive: average 150 mA
- Antenna Input: 50 ohms
- Size: 29/32" high x 6 1/8" wide x 8 1/2" depth
- Weight: 4 1/2 lbs
- RF Power Output: 10W
- Frequency Control: Crystal (18 MHz) multiplied x8
- Maximum Frequency Deviation: Adjustable between 3 to 16 KHz
- Audio Input: 10K ohms
- Moduration System: Variable reactance phase modulation
- Micrcphone: 10K ohms – Dynamic microphone with push button switch
- Reception Frequencies: 12 channels for 144 MHz band
- Reception System: Double Superheterodyne
- Intermediate Frequencies: 1st intermediate: 10.7 MHz, 2nd intermediate: 455 KHz
- Sensitivity: a. Better than 0.4 u V 20 db quieting, b. S+N/N at 1 u V input, 30 db or more
- First IF: 10.7 MHz
- Second IF: 455 KHz
- Spurious Response: -60 db
- Spurious Gain: -60 db, or less
- Audio Output Power: 1.5 W
- Audio Output Impedance: 8 ohms
- Frequency Control: Crystal (14 MHz) multiplied x 9
Controls & Indicators
Refer to the PDF for details.
Installation / Setup
Unpacking involves carefully removing the transceiver from the packing carton and checking for shipping damage. It is advised to keep the shipping cartons for future storage or reshipment. The location for installation in a vehicle is flexible, with the mobile mounting bracket offering guidance for placement. The transceiver operates on a regulated 13.5 VDC, 2.5 ampere negative ground source, typically provided by a vehicle’s electrical system. The DC power cable included has a red positive wire and a blue negative wire, which should ideally be connected directly to the battery terminals to reduce noise and transient spikes. The transceiver is not compatible with positive ground systems. For fixed station use, the IC-3P (or IC-3PA) AC power supply can be used as a stand for the transceiver.
Operation
Refer to the PDF for details.
Troubleshooting & Error Codes
Refer to the PDF for details.
Safety & Warnings
Refer to the PDF for details.
Download SCHEMATICS Manual (PDF – 4.3 MB)
Icom IC-20 Schematics Manual PDF (4.3 MB) aids technicians in troubleshooting and repairing electronic circuits.
- Brand: Icom-ic-20-manual
- Model: SCHEMATICS
- Type: Manual
- File size: 4.3 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 SCHEMATICS manual (PDF)
Icom IC-20 Manual SCHEMATICS – Overview
The Icom IC-20 is a versatile handheld transceiver designed for amateur radio enthusiasts and professionals alike. It provides reliable communication across multiple frequency bands, making it ideal for field operations, emergency communication, and everyday radio use. This manual includes detailed schematics and operational guidelines to help users maximize the performance and longevity of their IC-20 device.
Main Features and Specifications
- Frequency Range: VHF 144-148 MHz
- Power Output: Up to 5 Watts
- Operating Modes: FM, AM, and CW
- Battery Type: Rechargeable NiMH pack
- Display: Backlit LCD for frequency and status
- Memory Channels: 100 programmable channels
- Scanning Function: Auto and manual scan options
- Built-in Squelch Control and Noise Reduction
- Compact and durable design suitable for outdoor use
Basic Usage and Operation Tips
To operate the IC-20, first ensure the battery is fully charged. Turn on the device by pressing the power button, then select the desired frequency or memory channel using the tuning knob or keypad. Adjust the volume and squelch controls for clear audio reception. Use the push-to-talk (PTT) button to transmit your voice. For extended battery life, switch to standby mode when not actively communicating. Regularly update memory channels to stay tuned to relevant frequencies.
Troubleshooting and Maintenance
If you experience poor transmission quality or reception issues, check the antenna connection and ensure the battery is properly charged. Intermittent audio or static may indicate the need for antenna replacement or internal cleaning. Refer to the schematic diagrams in this manual for detailed inspection and repair guidance. Clean the exterior regularly with a soft, dry cloth and avoid exposure to moisture or extreme temperatures to maintain optimal performance.
Safety Reminder
Always operate the Icom IC-20 in accordance with local regulations and licensing requirements. Avoid transmitting near sensitive electronic equipment or medical devices to prevent interference. Use only manufacturer-approved batteries and accessories to reduce the risk of damage or injury. When charging, place the device on a stable surface away from flammable materials, and never attempt to disassemble the radio unless qualified to do so.