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The caps C90, C92, and C93 were replaced with those modern yellow plastic 630V caps that we all buy and install in our restorations, but despite that I removed C92 and C93 and tested them on my eye tube type cap checker and they both tested good both for value, and leakage (my tester can only do leakage testing up to 450V). Aside from those three caps all parts shown in that piece of the horizontal schematic are original.
The grid goes to (if I remember right) +9VDC with the HOT out of the set.
I have another working set with a virtually identical circuit (the horizontal/HV section IS identical), and I subbed the HOT and osc. tubes from the bad chassis into the good one and got healthy operation in the good chassis so I have little (if any) suspicion left of those tubes.
CTC17, I'll see if I can scratch up a 4K ohm resistor to try your suggestion.
Would it be a stupid idea to put a battery or an adjustable DC bias supply of some sort on the grid of the HOT to see if adjusting the bias helps things?
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