Trying to repair Fender fuzz wah

[9 volts]

Hi there, I'm trying to repair my fender fuzz wah. Its' the model that uses a 2n3392 and a 4 legged tin can with 4eh32 pressed into it. Basically it works except there is noise every time the wah foot pedal is even slightly moved and the effect seems to fade out when the wah pedal is in the centre or moving.
( eg  there is a strong sound on the treble and bass end but not in the centre).
I've pulled apart and cleaned all the pots (3 individual ones and the dual wah pot) and this hasn't seemed make any difference.
Any advice appreciated or if there is a schematic floating around I'd much appreciate it.

PS - I'm not sure if this is related but I remember reading in an R G Keen article about the dallas rangemaster that positive powered affects can be noisy when the pots are adjusted......could this be related?
Thanks

[R.G.]

I think it's likely that the pots are not just dirty, but worn out in spots. It's possible that just replacing the pots with exact replacements would restore it to full operation.

That's a problem, of course. Getting exact replacement pots may be very difficult. What makes this problem difficult is that (a) exact replacements may or may not exist commercially and (b) if they don't, you're left with modifying pots somehow to achieve a fix.

B is possible, if difficult. It is possible to disassemble the cases of many pots and replace the internal wafer that does the actual work. You need to find a donor pot with similar wafer size if not external size and bushings, then disassemble both, transfer the innards of the donor, then test.

A second possibility for b. is to  get a few new pots that ARE commecially available in the same values, and rework the mountings so that those new pots work mechanically. That may be easier, depending on what you can get.