I can tell you how to replace it with a genuine Radio Shack part if you wish

That would be awesome, if for nothing else a backup if this thing
starts to mis-behave again. Since fiddling with the relay at the
restaurant it hasn't yet failed, but that was only 25 minutes of
flying, post fiddle...

Give me the manufacturer and part
number again and I'll go back into the dusty part of the library and see if
I can find an old data sheet. I can then tell you how to cobble a
replacement part in.

I'm going up tomorrow and will post everything I can find... AMF
Potter Brumfield R40-E1-X4 was the only thing I can recall seeing, but
I'll take a look again. Definitely no manufacturer name on the audio
panel itself???

Thanks!
Todd