Here's another problem that keeps reoccurring regularly over the years... broken pots on the K7000 neck board. These discontinued pots had a reverse footprint to common pots still on the market today, so even when you find a vertical mount one with a seemingly matching footprint & go to install it you get the bad news.... the knob is facing inward toward the CRT neck!
How do you save the neck board? Well... here is my way: Remove the cardboard shield & replace the pot/s that you need with horizontal mount "E" type pots right on the solder side. Then you can drill holes in the shield corresponding to the pot/s allowing them to poke out the back. If you're replacing all then you can adjust everything carefully until you are satisfied & then put the shield back on with a couple cable ties without making any holes. It's not very often that one of these needs to be readjusted after the initial setup, but should the need arise it is simply a matter of clipping one of the cable ties to expose the pots.
This one used the following pots from the Pot Page :
3 x P1090 - 200 Ohms