I’ve been eyeing the Yaesu FTM-400D for quite some time. A friend of mine had one installed in his car, and I was impressed by its true dual-band functionality, the sleek display, and its 9k6 data connection.
Since these models are no longer available for sale, I managed to find a used, defective unit on eBay. The fault description seemed straightforward, and I was about 90% certain that the issue lay with the final stage transistors shorting the radio. I purchased it at a reasonable price, and it arrived today.
Initially, the radio wouldn’t power on. However, after removing the finals dual-MOSFET (an RD70HUF2), the unit powered up and operated flawlessly.
While I wait for the replacement finals chip to arrive, I thought I’d share some photos of the ongoing repair process. A big thanks to the team at Funk24 for stocking the part and ensuring fast shipping!
Special shoutout to Heinz HB9EKH for his incredible report detailing how to repair an FTM-400D. It was immensely helpful:
https://hb9be.ch/images/berichte2023/yaesu-ft-m-400-d.pdf
Here are my own first pictures:
Update: the new RD70HUF2 arrived and I finished the radio repair:
