Although the sound board may check good, it sounds like the board is not getting the proper command signals.

Try running the loco in Conventional mode and hook up the Sound Activation buttons to check if the basic bell and whistle sounds can be operated this way. If not, there is a bad board, even though the sounds can be triggered in the test jig.

If the sounds operate with the buttons but not in Command mode, the board is again bad, as it is not receiving the proper trigger signal.

Either way, there is a bad board.

Larry