Strange Wah Problem

[Tightpants]

Got real puzzler here - I built an Axis wah on vero from the plans on the Tagboard Effects site (you know the controversial one that is really a BBE Ben wah). I am really pleased with the wah but here is the rub: sometimes there is a lot of noise while sweeping the wah. It sounds like a scratchy or dirty pot and is quite intrusive. The odd thing is that it will go away for a few days (totally noise free) and then come back as bad as ever so it can't be a dirty pot. I tried all the obvious things like looking for dry joints and loose wires (even re-soldered the whole board) and nothing has fixed it. Has anybody come across anything similar or have any suggestions on how to fix it?
Thanks in advance,
Pat

[jimilee]

Audio probe when it happens. Also, flaky transistors?

[Quackzed]

i seem to remember a thread about the big caps putting dc across the pot and causing scratiness... something about scratchy wah pots being more an issue of dc on the pot rather than worn out / dirty pots... i'lll see if i can find it... but you might double check the caps or any drain resistors around them, near the pot...
heres a similar issue and some ideas... 
http://www.diystompboxes.com/smfforum/index.php?topic=55018.0

[Tightpants]

Thanks for the help folks. After reading the thread above I think it may have been a problem with one or both the electrolytic caps (intermittent leaky cap, is that likely?). Anyway I swapped them both for new ones and the problem seems to have gone! Thanks again,
Pat

[joegagan]

more likely a broken lead or solder joint at pad that was intermittently making connection on and off - esp w movement.