I was asked to look at this amp for a friend. I work quite a bit with small circuitry but amplifiers are outside of my normal field. The circuits on this amp look pretty basic so I was hoping to visually inspect and see a bad cap/resistor. However that is not the case.
This amp just turns on and buzzes/hums. the buzz doesn't change no matter what knobs are turned. What should I replace first? Someone has been in the amp before. The reverb unit was disconnected and the black cover has been peeled mostly off of it. Also mud dobbers had a nest in it that I cleaned out well before testing.