Tubejunke , Im not bored with this thead yet , im actually having fun

have you checked the filter \ choke , it's on the start of the B+ line just after the 5AU4 .
while you got the chassis out check the B+ voltage and see how much it is putting out according to my schematic it should be producing +265 volts .
I was looking at the schematic that I have and it looks like it would be allright to pull the horizontal output tube to stopp the high voltage supply .
That way we can eliminate the B+ as a source of the problem .
It might be hard to measure this because of all the remote circuits , but it might be worth it to do .
Let me know how thing go with it .