I bought an old amplifier at a garage sale and found these two YouTube clips on repairing and servicing it. The guy makes great clips, just thought that I would post them. Naturally an old audio amplifier could come in handy for bench work, or it can be used for the amp for a great computer sound system.
https://www.youtube.com/watch?v=GPrIdu1SYpA
https://www.youtube.com/watch?v=qCVrsUTuo4U