2016 S2 Tone knob not working

[Zorbanator]

I have S2 Custom 24 that I bought used last year. Couple days ago I noticed that the tone knob was wiggly and loose. So I opened up the back and tightened the nuts. However, right after that I noticed that the tone knob stopped working - as in changing the tone does not make any effect on the sound anymore. I don't know if my opening the guitar and messing around with it caused this or it happened independently. I checked all the wiring and it seems to be generally ok, but it does look like the previous owner may have done some questionable quality work - one of the bare wires is frayed, and close to snapping, but should be fine electrically. Everything else is working - the volume pot works, the 3 way switch works, the pull-push works.

Any idea how I can figure out why the tone control is not working and how I can go about fixing it? I have done some basic soldering on strats, but those seem to be way simpler than the PRS wiring.

Thanks!

 

[Herr Squid]

A couple of things I can think of: maybe that loose pot has rotated after being tightened up and something is shorting together that wasn't before. I once had a non-working tone control on a Paul's Guitar, can't remember whether the original tone control capacitor was bad or poorly soldered in, but replacing it fixed it right up.

Also just this week on my SC594, I was investigating a problem where the neck pickup didn't make any sound in humbucking mode, but worked fine in single-coil mode. Turns out the shield on the wire from the neck pickup wasn't making contact with the ground. I'd been screwing with the pickups months ago, I guess I never nailed that wire back to ground the way I should have and it finally just stopped making contact.

 

[Zorbanator]

Checked all the contacts and they seem to be solid. Cannot find any shorts or loose connections.