Princeton Reverb Reissue Tremolo issue

[Enzo]

Do you still have the bad pot? If so, do us a favor, measure resistance from any of the legs to the metal frame of the pot.

[LarBal]

From legs to frame :
in full ccw position, in leg 65k, middle 325k, out 325k
in full cw position, in leg 65k, mid leg 65k, out leg 325k

[Leo_Gnardo]

From legs to frame :
in full ccw position, in leg 65k, middle 325k, out 325k
in full cw position, in leg 65k, mid leg 65k, out leg 325k

That looks like a pot that's just crying to be replaced. On rare occasion I've run across a pot with a direct short to the frame. On dissection there's a snippet of wire cutoff that found its way inside on the assembly line. What could cause a 65K "partial short" is beyond me, but you could take the bad pot apart and have a look inside, see what surprises may be found there.

[Enzo]

There was your problem, the pot had a internal path to ground and so made a voltage divider of itself. Good call on replacing it. Probably some bit of foreign material inside it.