My son inherited an old Crate brand instrument amp from his uncle last summer. It worked well for about 3 months, and now is a white noise generator and only the smallest amount of audio from any of the 3 inputs leaks thru.
I have schematics, but the PC board is not marked at all, and I’ve spent several hours trying to determine the cause. I have access to a fluke scope-meter,
The noise is constant and does not vary with any knob adjustment.
Would anyone here mind a look at the drawings and venture a guess as to what component(s) might be guilty?
Private message me if you’re interested.