The Polaris had two types of slide pots… The earlier ones werereally fragile. They have the white bodies. They were replaced with muchstronger ones, but there is a different footprint. All then later panel boardswere drilled for both types. The earlier ones (at least most of them) have theholes for both, but don’t have the same mounting holes. When MusicTek boughtthe Chroma and Polaris stock from Fender, we got about 1700 of the new pots. Toinstall them on the early boards, you had to cut some of the legs from eachpot. These later ones are really solid. The early ones would get bad if theygot pushed in from the top, or bumped from the side. I replaced LOTS of them.

I’d be really suspicious of the pots, if they’re the early ones,before worrying about the MUX or other electronic stuff. Just see if the wipervoltage is correct on the bad ones.