IC-705 Teardown

| octubre 1, 2020

Icom IC-705 Teardown

IC-705 Teardown look inside the new transceiver and find out what ICOM has hidden in the depths of this wonderful black box

How to Open ICOM IC-705

Opening the transceiver is very simple. To do this, you will need some good Phillips screwdrivers of different sizes, PH type. It is desirable to have a set.

Disconnect the battery and unscrew 4 screws at the corners of the transceiver case, as well as two screws at the top and bottom. This is where we need a good screwdriver of the correct size, since the top and bottom screws sit on the blue thread lock. You will have to make some effort to unscrew them. When all screws are removed, the front panel can be easily separated from the transceiver body.

Carefully disconnect the two cables and move the front panel to the side.

IC-705 Teardown

Note that all wide signal loops are shielded, which is a plus.

We turn off the screen and along with it the receiver board.


Installation, traditionally for ICOM, is very neat. Unwashed flux is absent. Wherever necessary, the manufacturer has used screens. Let’s go through the components.

The processor that controls all the peripherals in ICOM IC-705 is RENESAS R7S721000VCFP. It is a powerful ARM processor with a Cortex-A9 core. 400MHz frequency. Built-in memory 10MB.

As an FPGA (FPGA), which processes radio signals digitized using an ADC, a rather powerful FPGA from Intel / Altera is also used – Cyclone 10 – 10CL025ZU256I8G. For comparison, the ICOM IC-7300 also uses an Intel / Altera EP4CE55F23I7N FPGA. The ADC used to digitize the incoming radio signals is from Analog Devices AD9266. 16-bit ADC, in reality, there is most likely 14-bit as in ICOM IC-7300.

ic-705 Cyclone 10 - 10CL025ZU256I8G

The DSP is ADSP-21478 from Analog Devices.

Another DSP. TMS320C55 from Texas Instruments. A block with diodes is located next to it (circled in red). The photo shows the Japanese version. Using these diodes, you can somehow open the transceiver to transmit.

ICOM IC-705 Wi-Fi transceiver module

There’s even a jack for an external antenna.

ICOM IC-705 Wi-Fi transceiver module

ICOM IC-705 transceiver Bluetooth module

Under the board, we have a metal shield screwed to the chassis with many screws. We turn off and observe the low-pass filter board.

We remove the filter boards and get to the heart of the transmitter.

The IC-705 transmitter is based on an AFT5M31N transistor. Such a transistor can easily deliver 30 watts, but it is strangled to 10 watts, which is generally correct.

How we open the ICOM IC-705 transceiver for transmission

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