[rfeenstra]

I can relate!  Been working on a Bogen C100 used in a Maas-Rowe carillon.  Has given me fits over the years.  Sat for about 3 and I decided to give it one more try.  After blowing several sets of output transistors  I think I finally have it solved.  Maas Rowe puts a delay in these amps that lifts the ground to the output terminal for about 5 seconds.  I discovered that the amp went into oscillation all the way to clipping during that period.  Never saw it on the scope cuz the ground was lifted.  No power delivered to speakers but I guess the outputs didn't like it for very long. Still can't figure out why it does it but by bypassing the relay, all is well.  Not scratching my brain any more on this thing!

let it sit for another year, Ron.  Then give it one more try.