Just finished upgrading a pair of Atlas GP-35 High Noses TMCC/RS engines to PS-2 and smoke. These engines are extremely nice and despite the compact design the smoke unit and PS-2 fit in nicely.
But one of the engines did not have TMCC sound working before the conversion. So I swapped out the boards and found out the RS board with chips was the bad board.
After a close inspection I found the audio amp had a blister. So I picked off the number, ordered one and installed it. Fixed the board and now it works fine.
So if anyone has bad Railsounds boards it may be repairable with a new audio amp. G