Wayne I opened my locomotive that I was talked about in the first post I put here I just removed all the boards and cleaned them and the motherboard and reseated them. That took care of all my sound issues that I was having. I also had the same problems with another SD40-T2 6-28225 SP #8521 so I did the same thing with it and that took care of all the sound problems with that locomotive also. I hope this helps you also with your issues.
Gary