Changing a TM-V708A to a TM-D700A

Alexandre Souza

Yes, it is possible. It is not cost-efficient, it is not reasonable, but it is possible indeed.

I will write a complete and detailed article about that in my blog. But basically, all TM-*70* radios are the same. Including the front panel. The changes are the serial port, the gps port and the internal TNC. If you populate the board with all the missing parts, it works like a TM-D700, the firmware is the same! If you populate just the serial connection/circuit, it will identify as a TM-D700!

Of course, it is not reasonable to do so. Although the only "mostly impossible" part to find is the internal TNC, the smd components are VERY SMALL and the footprints on board are not manual-assembly-friendly. I can consider myself a seasoned builder/repairer and I suffered to install all missing parts. It was a day's worth of work and the result isn't so pretty.

But at least one part is very useful: If you install the serial circuit, you can control and program the radio using a RS232/USB connection. If you don't want to populate the board, you can take the connections from the processor directly to an USB to TTL board.

I don't think anyone would want to do that but me. Anyways, it is done, documented and I'll do a write-up about it. Maybe someday it will be useful to someone

73 de PU2SEX Alexandre
(and I still need the front panel processor...)

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