[jerryhawthorne]

Mike, with one leg of that 12K resistor lifted from the pot that controls the RF screen voltage you should be able to measure end to end on both pots to assure proper value for max. Then sweep the center tap to one end for measuring each pot and hopefully both move smoothly from zero (roughly) to max value of the pot. Easiest to do this on an analog meter to watch the needle move smoothly. Digital is OK but drives my mind crazy. I wouldn't "open" them up at this point, let's see if they respond to resistance as they should.
Best, Jerry