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?