Boss TW-1 T Wah turned to Fuzz

[AM]

Hello,
I got an old Boss TW-1 auto wah from a friend. It was broken, giving only a high pitched squeal instead of a wah/filter sound.
I changed the caps in case there was something wrong with them. Now I get a fuzzy sound (even with the pedal on bypass mode.
Any ideas how I can possibly fix it? Schematic attached.
Thanks in advance

[nickbungus]

Any chance you could post the voltages of ICs and transistors etc?

Also, have you tried following the signal with an audio probe? Perhaps find when the fuzz is introduced?

[AM]

I will try to follow the signal and see if that gives me any clue. Thank you!