Update --if anybody cares. I didn't get any responses and calling Bachmann just pointed me to resetting the decoder (setting CV8 =
, which I did; no joy. I had an old Digitrax DZ 126 laying around from an earlier to-sound conversion, so I removed the Bachmann factory DCC board and soldered in the DZ 126 --works fine; no vibration/hum, no sounding like a bad toy!!
![Cool 8)](https://www.bachmanntrains.com/home-usa/board/Smileys/default/cool.gif)