"Gareth Magennis"

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


I'm not sure how this is easily achievable,

** It is very easily achieved.

Lotsa speaker cabs have twin, parallel wired sockets.

Imbecile.


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.

** So you have no clue that TDA7293s fail short ?

Guess what instantly follows ?


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.

** So you have no clue how TDA7293s fail short ?

Guess what instantly follows ?

The AC fuse blows of course.

So if you find *both* ICs on a common DC supply have failed short, they
must have done so simultaneously.

BTW:

TDA7293 have over temp protection, which generally saves them from an
inadequate heatsink but not from, sudden massive over dissipation.

Do you know anything about amplifiers at all ?


..... Phil