1966 GE PortaColor Restoration

[Dubis7]

Originally Posted by old_tv_nut

The problem is most likely in the antenna leads, but I suppose the signal from your source could be weak - do you have another good TV to try it on as a quick sanity check?

Yeah, right next to the workbench actually. I'll do that the next time I'm down there.

Originally Posted by old_tv_nut

The "big noise" is normal switching transient when you change channels. Even though the sync separator circuit may see it as a momentary erratic sync signal, it should not cause the vertical to collapse. This would lead me to check components between the sync separator and vertical sweep section, as well as components in the vertical section itself.

That's the 8BU11 again. That's been giving me some strange behavior. I've got a spare coming, I wonder if the tube itself is acting up. I say that because the vertical collapse is a new issue, and that tube only recently started giving me trouble.