screech in speaker when turning off set

[zeno]

Shafts can be swapped on the same brand of pots, its easy.
Mounting style does matter. Twist tab, nut, plastic etc.
Almost any VC from a flat chassis or hybrid should be the same
ohms. The uprights may be also. Remotes may use a different value.
Finding an NOS OEM pot is probably impossible. They were almost
never changed, cleaning worked for years. Only exception is if
it has an on/off switch. They were usually changed with OEM part
due to switch failure.
Last thing is be sure all the ground straps are well tightened.
They should run from main chassis to CRT, convergence, tuners,
secondary & primary controls etc. They are the heavy flat straps
covered in yellow plastic.

73 Zeno
LFOD !