Okay, "picture" it this way
The picture is expanding and defocusing as the brightness control is turned up. After the set has been playing for say 15 minutes or so, if I crank the brightness all the way up, the picture gets very dim, and just goes dark. I can get the picture to come back to a dim light by turning the brightness down, and I can get it back to its previous level by turning the brightness ALL the way down, then bringing it back up.
From my reading, this seems to be caused by insufficient high voltage, that the pulse from the horizontal output tube is too low, or the HV rectifier is weak or dead (which isn't the case).
I do know that this issue is worsening progressively as I replace capacitors and tubes, leading me to believe that it's the whole "weakest link" thing, and that it's all coming down to replacement of one stupid component. Once I nail that one component, I think everything will work perfectly.
If that's the way synchro lock works, well then, dammit, mine is perfect
