[codefox1]

I agree. Sometimes wirewounds are used instead of carbon pots because they can dissipate more power. I don't have the schematic in front of me, but typical carbon pots can dissipate a half watt, and most wirewounds can dissipate 4 watts or more. The wirewounds last longer, but as has been pointed out can really screw things up at higher frequencies.

Knowing nothing further, and assuming that this was a substitute part, I would just check for anything in the vicinity that may have caused the original control to fail, (other than plain old age.)

I've blown up parts on perfectly good test equipment when connecting it wrongly to a set I was working on a couple of times. So that may have been what happened originally.

As for the trimmer caps, yeah, you gotta take them apart, clean out the crud with deoxit or whatever your favorite solvent is, let everything dry out, and reassemble. The mica chips are really fragile, so take your time. If you ruin one, think unobtanium or scrounge-ola! Good luck.