Ummm....question? (Smoke-pouring-from-tube-amp related)

[karmma1]

Ok, there i was minding my own business, playing through my Rivera...when suddenly i noticed an aroma which was not altogether pleasant...and one which history has taught me generally doesn't ever mean anything good.

Glancing about the room, i noticed tendrils of smoke wisping upwards from the right side of the head...which led me to brilliantly deduce that something was very wrong. I immediately powered down, and d/cd the power cord. The smoke by this point was pretty thick. The smoke was definitely coming from the area of the OT.

I'm guessing that the output transformer has elected to commit suicide, but...never having had one go bad before, just wanted to ask if this is typically the way they go...smoking and hot?

Not sure as to any possible causation...impedences were correctly set as always, and a top-notch speaker cord connected from head to cab....i suppose they just sometimes fail after so many miles?

Any shared experiences would be appreciated...

Edit...it may not be the OT...there are 2 similarly enormous transformers...maybe it is an input-power transformer (it is very close to the power cord socket)... ?

[Thundernotes]

Sometimes they smoke by themselves, but usually that's a shorted output tube or a bias failure that will burn up an output transformer.

[karmma1]

Popped the chassis out, nothing cooked inside.

Pic of the amp, transformer on left is the one that went (smoke re-enacted):

View from the inside, the transformer is wired through the large hole in the chassis:

[Thundersteel]

You let out the magic blue smoke!

I had a VCR do that once--took it apart, didn't see anything burnt, put it back together, still worked!

[Armitage]

It's funny... you just can't get that magic smoke back in once it gets out.

A bad output tube, wrong impedance or bad cable are the usual culprits.

CHECK that cable with an ohm meter before you plug it back in to anything... no matter what.