Strat vol and tone bypassed?

[subendo]

Hi. I have a 1994 Am Std Strat. Got a prewired blender pot set up from Acme about 6 months ago. During a recent gig, I noticed that my tone was very bright, even though I had the tone knob rolled down. Turns out the tone AND volume controls were not doing their jobs. I tapped on the pickguard and the sound changed back to how the knobs were set, but a minute later it was back to sounding like the knobs were bypassed. I opened it up and tugged on the connections - everything seems soldered ok. All wires look like they are hooked up correctly according to blender pot diagrams i found online.

Can any of you shed some light on what could be causing this? There is no problem with signal output, but the knobs are being bypassed somehow. I want my controls back!!!! Thanks.

Dave

[Jim Collins]

If the control cavity is shielded, either with some type of foil or shielding paint, and something is touching that shielding, there could be a short, since the shielding is grounded.

[guitargod0dmw]

If the control cavity is shielded, either with some type of foil or shielding paint, and something is touching that shielding, there could be a short, since the shielding is grounded.

My first thought as well...

[subendo]

I'll need to check it out when I get home, but I don't believe the cavity is shielded. Was that standard practice on Am Standard strats in the 90's? This one's a '94.
The vol/tone controls pop in and out of the signal unpredictably. My workaround is to just keep all the knobs at 10 so the sound doesn't change when this happens. I hear a "pop" thru the amp when I tap on the pickguard near the tone knob. Any more ideas? Thanks.

[fumbler]

Is the cavity covered in (a) the same finish as the rest of the guitar (b) a different color paint (c) metal foil? If it's (b) or (c) then it's shielded and I agree with the other posters.

If not then:

Guess 1. Maybe the pot has worked loose and the nut needs to be tightened? If the whole pot is rotating then it could be making the intermittent short.

Guess 2. Cold solder joint or some other bad wiring. Test connectivity with a multimeter, not by "tugging".

But Acme does good work - was it just the pot you bought or was it the whole pre-wired pickguard assembly?