Hi,
I am entering your discussion late.
ACCORDING TO YOUR VIDEO YOU HAVE TO CHECK RESISTORS!
The fault in question could be a problem with caps, tubes and resistors!
Just when you pull the old caps, it is a chance to test resistors, with one end
in the air!
There are not so many in the vertical section.
From my experience I like to say, your issue is a combination of caps and resistor(s)!
They are aging fine...
Regards,
TV-collector
