I know absolutely nothing about building boards or anything of that nature.

I have found that when I do SYSEX backups via the TM-1/C6 I have to use a particular MIDI cable for the IN, and a particular cable for the OUT (creating the complete MIDI handshake with the MD and TM-1). If I have the MIDI cables reversed, the TM-1 does not transfer any data.

It is really weird, and I have no idea why it’s this way, but perhaps you have a similar issue?