Revisiting an old topic - Adding DC Restoration to a 1950s TV

[old_tv_nut]

Note: I have built DC restorers that work with a diode at the base of a transistor amplifier. They work just fine, even though there is base current that must be supplied. Current flows into the input coupling cap during sync and out of it into the transistor during active video.

[Penthode]

I understand it could work. But how do you set up the quiescent point? If there is no video, how do you control brightness? The capacitor and diode block the beam current so with no video the screen is black.

That is why, perhaps facetiously, I suggested perhaps the coupling capacitor has not yet been changed, was leaky, conveniently providing the quiescent current.