I spent a frustrating day trying to get the Tx to work. I was seeing nothing whatever going onto the bus. I got my cheapy, clone Logic 8 logic analyser out and spent another couple of hours trying to get that to resurrect with no joy.
Voltage checks showed that STA/SEN pin 9 of the TH3122 was not toggling and was stuck high, even disconnected. Next step for later today is to remove the rat's nest which is getting out of hand, tidy it up and then swap over the IC. That's not something I will enjoy as it was difficult enough to get this one onto its adapter. I ended up having to wire link a track I damaged! Careful inspection with magnifying glass and DMM show no O/C or short, so maybe I killed it somehow.
