Transmitting into a high SWR (Short Wave Ratio) antenna, an accidental short on the BNC jack, or static shock.
Leveling the power across all bands (HF, 50MHz, 144MHz, and 430MHz) to guarantee clean 5W or 10W limits without overdriving.
: Complex maps of the electrical paths on the circuit boards. icom ic705 service manual
If you blow a final transistor or a protection diode, you cannot simply buy a generic replacement at a local store. The IC-705 uses specialized SMD (Surface Mount Device) components. The parts list gives you the exact Icom part numbers to order from authorized distributors.
Calibrating the receiver signal strength meter. Safety and Precautions Transmitting into a high SWR (Short Wave Ratio)
Unlike the IC-7300, the IC-705’s final amplifier is on the main board. It sits on a separate small PCB (PA-UNIT) attached to the chassis heatsink. The manual lists the RD15HVF1 MOSFET as the final device—good for 5W CW/SSB, 2.5W AM carrier. Common failure : Drain-source shorts due to high SWR (no internal ATU).
"Reassembly," Elias read from the manual. "Reverse order of steps 3.2 through 3. If you blow a final transistor or a
The Icom IC-705 service manual is available from various sources:
The first fifty pages were the usual safety warnings and disassembly guides—"Remove screw A, detach connector B." Elias clicked through, his mouse clicking rhythmically. He knew how to take it apart. He needed the deep cuts.
| Block | Function | Key ICs | |-------|----------|---------| | | Preselection, attenuation, T/R switching | 3SK299 MOSFET (LNA), PIN diodes | | Direct Sampling RX | ADC conversion (12-bit @ 122.88 MHz) | Analog Devices AD9866 | | FPGA/Baseband | Digital down-conversion, filtering, demodulation | Altera Cyclone IV EP4CE22 | | TX Chain | Reconstruct DAC, upconversion, PA | Renesas RF transceiver IC, RD15HVF1 (PA) | | Clock/PLL | Master oscillator (32 MHz TCXO) + synthesizers | Si4133 (UHF/VCO) |