When I remember to, I put links to where I got some of the ideas. What's here are some bits of information that may be useful to someone. This is more like my notes rather than advice, and the stuff here could be wrong, so critically weigh anything that you find with my first sentence in mind.
Standard precautions apply.
Amplifiers work with potentially lethal voltages that remain even when the power is off and the thing unplugged. Discharge the filter caps and follow basic safety precautions. If you don't know the basics, it's not a good idea to play around inside an amp. Click on one of the blue buttons above to get started.