I noticed this question had 2 off-topic close votes.
In my mind this is a fairly significant part of an audio engineer's duties. If you look at other communities like the rec.audio.pro group there are lots of these questions.
So, let's have some discussion.
I think question is legitimate, and I think Ian C's answer is exactly the right kind of answer for such a question: it doesn't try to be a tutorial on wiring and electrical engineering (which, in sufficient depth, is beyond the scope of this site) but it does offer enough information to be helpful and suggests a course of action. My vote would be to keep it, and I can't see any reason NOT to have such questions in the future. I'm no EE but I'm interested in reading them.
I agree that a sound engineer has a lot of use of the knowings of the solderings and transistors. But I do think it's wildly off topic. A sound engineer should rather have accounts on electronics.SE as well.
Replacing parts and cleaning could very well be on topic here, but finding the error in broken electronics is in my opinion clearly off topic. There is nothing audio recording-specific in how to repair a tube amp compared to how to repair a tube radio. :)
I'm an EE and I voted to close it. He's asking about troubleshooting electronics, nothing audio-specific about it save it happens to be electronics for a speaker. As it's stated the question is far too vague to offer any useful advice. A schematic at least with arrows pointing to the transistors in question would help. Without knowing the amp topology in use you're really going to hard pressed to tell him where to look.
The time it'd take to ask the clarifying questions and understand his general level of knowledge so that you could guide a troubleshooting expedition seem too high.
Plus, this is not an overdrive pedal powered by a 9V battery we're dealing with here. This is plugged-in-to-the-mains bit of tech and if you screw up the debug the end result could be death.
Maybe I'm over cautious in this ultra-litigious society, but I don't want that liability hanging over my head, do you?
Edit: I suggested he doesn't try to fix this himself.
Can I back out of my vote to close? If so, I will.
Edit: Nope, can't back out my vote to close...oh well...
I earn my wages as a sound engineer. Granted, not the studio recordist one but maintaining studios and lecturing is a big part of my job. I also do record and mix post and am a freelance engineer.
Being able to understand wiring, components and some unit's signal flow allowed me to save many gigs in both live and studio - identifying dodgy channel strips to soldering a cable straight to a point in the unit we needed, down to improvising resistor serie networks to provide power to pedals.
Also, am building my own distortion pedal in my spare time.
Now, I do have these units in the bench. Maybe it is crossing the line into electronics but I honestly thing nothing bad can come from knowing a piece of gear inside out - I don't, but I'd sure love to know more and more about this stuff. Being able to mod pieces of gear or bring stuff back to life is a sweet skill to have.
I don't mind if this topic is closed due to be really outside audio bearings, and I do understand. It's maybe more towards recording "engineering" than recording arts and production.
