Quote:
Originally Posted by old_tv_nut
Those differences in color difference signal levels with a rainbow generator are because the R-Y and B-Y signals in a normal video signal are scaled down before modulation on the color subcarrier to prevent overmodulation on particular colors. With a color signal of real color bars or program video, those differences in gain restore the final R, G, and B signals to the right level once the luminance signal is added. For example, full amplitude saturated green bar has luminance of 59% of white, so the G-Y only has to make up 41% to turn green on completely. (The final values of R, G, and B for white may not be equal due to differences in R, G, and B phosphor efficiency, plus NTSC sets typically had increased R-Y gain to make up for the yellowish modern green phosphor.) Since the rainbow pattern consists of constant amplitude subcarrier, it does not have prescaling depending on hue, and therefore the gain differences in the color difference demodulators show up.
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Ok thanks. So those voltages are assuming an NTSC test pattern. I'm sure it says that in the Sam's and I forgot. There's a lot to remember
Quote:
Originally Posted by ARC Tech-109
It's the copyguard causing the issues, they insert a 180 phase inversion in so many horizontal lines to thwart the chroma AFC in the color under VCRs. Look at the signal on a pulse cross monitor and turn the color up. Your Sony is slow to respond to the phase inversion
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I see. That's really interesting. It's good to know what was causing that. Interesting also that it only shows up one DVD out of all that I've tried. It's not nearly the newest DVD I have either.
But actually, that was a separate issue. old_tv_nut was trying to help me figure out why the Blue vertical lines seem to be so much stronger than the Blue horizontal lines when displaying a crosshatch pattern from a B&K pattern generator. The Red and Green seem to come up in equal intensity.
He was suggesting that the capacitor in the Blue area seems to be a different value for some reason and that might be why.
I'm also still trying to figure out what I should order if I wanted to bodge a focus pot into the set. The optimal focus seems to fall somewhere in between the 200V setting and the 500V setting, so I wanted to get a pot and see how good I can get it. It was recommended I get a 1 watt pot, but 500V 1 watt pots are *huge*. The best I can find is like this
https://www.mouser.com/ProductDetail...hfGtyjeA%3D%3D
I found a bunch of smaller 1 watt trimmers, but they are rated for like 400V.