Hi All, I am helping a friend fix his Fender Princeton Chorus PR82. This is the one with two 10 inch speakers. The overdrive does not work. everything else does. The schematics that I find online do not match up to what I see in the circuit board. The switch works the op-amp(u11) changes states, after that I am at a loss, because I do not have the right schematic. I think it goes to U12, where it changes states, but cannot verify the output. I am guessing ayt this point. Does anyone have the scmatic or snip of the circuit?

 

There are at least two different versions of the Fender Chorus amplifiers, the older ones were better but very different from the newer models of the same name. Are you sure that the pedal circuit is working? That is the first place I would check. Then, all of the voltages in the overdrive circuit must be correct or it does not overdrive.