Sound shut off

Check your speaker wiring, is the coil wire too close to the metal frame, or your solder job have stray wire strands.  If the speaker leads are shorting to frame this can happen.  The Whistle is a heavy load and vibrates speaker.

Or, the speaker is faulty and saturates.  I have seen this multiple times despite the speaker ohming out ok.  It is internal issue.   G

Thank you, George.  I'll follow your advice and post results.

Good lead, George.  I found that one of the internal speaker wires, the bare wire that runs from the terminal to the hidden coil, was brushing the speaker frame.  Bending it slightly cleared the problem.  Thanks again.

Lucky find. Otherwise you may have eventually blown the audio amp on the board.

You are correct, Joe, and it is a brand new board.  Until George's reply, it didn't occurred to be to look inside the speaker.

The exchange of problem-solving ideas on the forum is a tremendous benefit.

Glad it worked.  I always check those wires before installing speaker and even insulate with liquid rubber if necessary.  G

Good work G