BTW:

The reason for the dual channel failure is almost certainly that the owner
plugged both outputs into the same speaker cab.


... Phil




I'm not sure how this is easily achievable, even by the most Numpty of all
Numptys.


More likely IMHO that said Numpty connected the amp to a speaker where
either the speaker cable or the speaker itself was shorted.
He then did it again with the other side.

Or possibly he was otherwise exceeding the specs of amp and speakers, and
that one side blew ages ago, and he only brought the amp to you when the
other side also gave up the ghost.

Or it could have been not due to Numptyism at all, e.g. the manufacturers
had put some sort of substandard silicon pad between Power device and
Heatsink that did not perform as it should.
Again, one side blew ages ago, he only brought it to you when the other side
blew, rendering the amp useless.



Gareth.