What happens if in process of owner stowing away or pulling out the cables ,
foot switch etc from that convenient stowage box next the speaker, he
unknowingly pulls out the internal speaker plug.
Turns the amp on and tries turning up the wick to get some output.
With no speaker plug inserted the 8 ohm line from the o/p transformer, it is
grounded via the built in switch contact in the socket like an input
socket..

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/