Wah cutting out in toe down position

I've got a Crybaby 535Q (with the band adjuster knobbie) and in the past few weeks or so, I've been having some problems with it. I'll be wah-ing away, not a care in the world, and, all of a sudden, every time that I hit the toe down (full treble) position, it cuts out. If I adjust the travel of the wah to avoid the upper section, it works fine, but as soon as I hit full-on treble, there is no sound (or perhaps almost no sound; it's only happened when jamming, so it's hard to hear).

I think it could be either:
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The switch, since it may be that it's a little loose and sensitive to slight taps, or

The pot, but I don't see how the top 10% or so of the pot's rotation can die.[/list=1]

I thought I'd ask in the forum since maybe this is a common problem and there's a quick fix out there (like swapping out the pot or the switch).

Thanks for your help, guys!

I think your diagnosis is probably correct. I suggest starting with the switch. There's a good chance you're tapping it just enough to make it cut out.

If you have an Ohm meter, you can check the pot by measuring from one of the end terminals to the centre terminal while slowly turning the shaft. If the reading suddenly jumps around a lot, there's some damage to the track.

A shot of contact cleaner may solve that (if dirt on the track is the only problem), but it's usually a more reliable repair if you replace the pot.