Take a good look at R13, this is the larger adjustable power resistor. These are often bad. I would replace it in any case. It serves two functions, it forms a voltage divider for the clamper circuit and it is also the HIGH VOLTAGE BLEED RESISTOR. (Yes I am yelling, bleeding off your high voltage is a good thing)
Mine ohm'd out ok but failed when powered so I had high voltage long after the unit was turned off.
After replacement follow the directions in the manual to adjust you clamper circuit.
(that is where you get to reach a long screwdriver into the rig with the HV on!
Weeee!
73
rich
W7SOE
PS Newark has those resistors.