Adam, I had the same problem with my OT2m and TM-V71a.
I verified it to be the homebrew data cable from the tracker to the radio's data port. The cable I made cause the radio to TX if I used a KPC-3 or a OT2m. It also had the same results on my Yaesu FT8500. I decided to just unsolder one connector at a time on the homebrew to find out where I went wrong. Hopefully you can learn from my mistake. 73 Phil / w2lie
