ok, this is probably a stupid problem to have, but here we go anyway
So for the tone control you can see in the picture above (with and without plastic knobs), the bottom part of the knob normally rotates independantly from the top part, controlling different things. However this one seems to have gotten stuck - you turn the bottom, the top comes with it, etc. The nut below isnt turning or anything, so its not a problem with it not being properly attached to the base, seems just that the two parts of the control are refusing to turn independantly.
First plan of action = WD40 to see if it just needs lubricating?
So for the tone control you can see in the picture above (with and without plastic knobs), the bottom part of the knob normally rotates independantly from the top part, controlling different things. However this one seems to have gotten stuck - you turn the bottom, the top comes with it, etc. The nut below isnt turning or anything, so its not a problem with it not being properly attached to the base, seems just that the two parts of the control are refusing to turn independantly.
First plan of action = WD40 to see if it just needs lubricating?