In my infinite wisdom, I left my amp (a Peavey Delta Blues) in the lounge of a dorm at my college. While it was there, someone decided to play a musical saw with a piezo pickup through it, and in his words, "shorted-circuited it". I've since brought it back to my room and had a look at it. One of the preamp tubes is lighting, but the rest aren't. No sound at all comes out. The last time I turned it on, I saw a blue flash from the output transformer side of the amp (and promptly flipped a shit and unplugged it). The amp also has a funny smell. I'm a bit worried about that -- toxic? Hopefully not.

So I think it's the OT. I want to be completely sure, though -- the guy has offered to pay for repairs , and I don't want to make him pay for anything unnecessary (I don't have any tools here, so it'll be labor as well as parts). So, do the good people of UG think I'm right? Is there anything else I should check before heading to the shop?

EDIT: I also looked at each tube -- they all look fine, with no obvious damage.
Last edited by cokeisbetter at Sep 23, 2011,
I think you should just head to the shop. There's not a lot of diagnosis we can do here with third-person accounts and speculation. We can almost certainly rule out the power transformer and the mains fuse, but there's no way to say conclusively that it's the OT. It sounds like it could be power tube arcing, which might or might not take the OT out with it.

What I can say is that it sounds major. Sparks and smoke generally mean something has gone very, very wrong.
I have to quote an old co-worker of mine. "Electronics run on smoke. 'Cause when the smoke comes out, they don't work anymore."
Seriously, though take it to a shop. It is probably an output transformer at least but the damage may not be limited there.
yeah what Roc said

blue flashing lights from the transformer and funny smells is never good. unplug and take it in asap. Worst case give it to one of your EE buddies and even then they need to be real careful. In the end you will need an amp tech of some kind.

good luck