Peavey Musician 400 Repair Questions

[Enzo]

Fair enough, the distortion circuit is a sort of feedback around the first stage.  It would appear that if we turn the FUZZ and DISTORTION controls to zero, it would ground the paths for each, and leave mostly just the first stage.  But no reason not to check them.  In any case it would seem narrowed down to this area.

If we can verify the hum is 60Hz rather than 120Hz, it would also help.  120Hz is power supply ripple, and I tend to doubt that given that the other channel and effects channel post gain seem unaffected.  I think this board is well enough designed that power supply return ripple currents are not shared by this stage's ground.

[LateDev]

I agree and did not see the fuzz control grounding out, so just turning that full anti cw, should be able to rule out if it is the effects side.

Fuzz control "0" gain up = hum then it is from the 3 transistors or jacks.
Fuzz control fully CW and hum its the fx circuit.

[jako_rang]

switched out the caps and everything appears fine. The amp made it through one practice. Thanks for all your help!