Quote:
Originally Posted by oldtvman
Just remember I saw lots of guys try to make improvements in things and sometimes end up screwing them up. My suggestion would be to see if you can find any service bulletins addressing the issue. I fould service bulletins to be very helpful. And sometimes they kept techs from chasing around on very weird problems
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Well, it's not a 'problem' per se. Like I said, I'm looking to improve the picture quality of this already well running set. If I have to experiment on the Porta Color before moving on to the CTC-9, then that's what I'll do- for the experience I guess.
I just looked at the schematic for the -9, and it looks like it has video directly coupled from the video output tube to the picture tube cathodes, with chroma capacitively coupled on the grids from the R/G/B-Y amps. So does that that mean I don't need DC resto, or can I still do something? My understanding is that the signal on the cap coupled grids causes DC 'sag', which messes with the black level. Perhaps I could just use voltage regulator IC's to 'prop up' and stabilize the DC on the grids or something. Just throwing out ideas at this point.