Quote:
Originally Posted by jr_tech
The line between pin 10 (grid2/anode1) of the crt and the red wire of the vertical output transformer merely supplies boosted B+ from the damper to both points. As far as I can tell, the tv does not have a retrace blanking circuit.
jr
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Yeah, that's starting to make sense.
I really couldn't find a whole lot about DC restoration... other than unhelpful theoreticals, and
this.
I have attached the video output portion of the schematic. Can someone tell me if this is grid or cathode driven video?
I *think* it's cathode drive. But it seems I don't know nearly enough about the actual theory of operation to know what I'm doing. I tried putting a silicon diode and 200k resistor in series with the cathode wire, basically, and it made no difference. The resistor alone just made the image very soft and blurry. If it was cathode drive, wouldn't it dim the image?? I suppose maybe the diode I have leaks too much reverse current at that voltage? Then I tried putting the diode across R35, and it arced rather loudly (oops), tried it the other way around and it made no difference at all. I did also try adding a ~4uf capacitor to ground, also no difference.
I'd really appreciate a suggestion.