chasing an amp fault in this solid state Marshall

[Brian Roth]

Yes c10. Typo.


Further testing measuring pin5 of ic 4 and get clean and boost channels without switching. So I can adjust level changes by adjusting gain on clean and boost.

?????? That is totally wrong. Switching should allow only ONE pathway through ONE set of volume controls and tone stacks at any given time. Switch to clean, boost controls have no effect and vice versa.

Pin7 of ic 4 yields -35(od1) and -18o(od2) Dani respectively,

This is consistent with previous measurements and the level drop at R22.

 

[Brian Roth]

What DC voltages do you see (referenced to ground/0V) on pin 1 of each 5201 as you switch between clean and boost?

Bri (glad I have a stash of straws to grasp at)