#16
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Looks like a power chassis, but I know squat about these forgotten stepchildren of early color.
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Evolution... |
#17
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One thing about the CT-100, I really like how they look. This set kind of emphasizes how small the picture is compared to the cabinet, in contrast with the RCA. Regardless, I would love to have it anyway. Just no money in my budget even if it wasn't across the whole country, and it isn't going to sell for just $2200 in any case. I will be happy with my CT-100, and when funds are available they will go toward completing it and getting its restoration going.
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Chris Quote from another forum: "(Antique TV collecting) always seemed to me to be a fringe hobby that only weirdos did." |
#18
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...
Last edited by andy; 11-18-2021 at 05:35 PM. |
#19
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Quote:
Then came the boom of auto correction circuit. ACC was the first in the CTC-4 i think?Then came auto flesh circuits they pulled the phase of the chroma demodulator for a color close to flesh even closer. The auto flesh circuits that operated on color difference signals were less obnoxious than those that pulled the color sub-carrier. Does anyone know if the Westinghouse have an ACC circuit?? Does it use a standard demodulator circuit? |
#20
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rcafan, the 15" Westinghouse color set has a separate power supply chassis for B+ and filaments down below. How can you sen not have one? How about a photo of your chassis? I am very curious.
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John Folsom |
Audiokarma |
#21
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There was no ACC signal being broadcast in 1954-56. None of the early color sets had and automatic color correcting. They all used a color oscillator phase locked to the burst. Some designs had a crystal in the loop, others (like Westinghouse and Sparton) did not. The Westy used R-Y/B-Y demodulation as opposed to I/Q demodulation.
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John Folsom |
#22
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The ACC circuit in the 4 was used to control the gain of the bandpass amp, and depended on the strength of the burst signal. I've wondered if RCA issued a mod to bypass the ACC, allowing for manual-only control of the gain. There isn't any such mod in the lit I have on the 4, and my chassis has all the other mods.
Kevin
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stromberg6 |
#23
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Gotta luv sitting in on this deep engineering arcana that the average tube jockey was never privy to 'back in the day'.
oc |
#24
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I'm happy just to have a few hours a week to devote to vintage video and radio. If I ever retire, ha-ha, I have a bleep-load of projects just waiting to be attempted. Kevin
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stromberg6 |
#25
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Yeah, at the risk of sounding sacreligious, its kinda like lookin' over the Good Lord's shoulder & reading His "Crib Notes" when He made the World...
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Benevolent Despot |
Audiokarma |
#26
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I and Q demodulation will give you the same color rendition as an R-Y /B-Y system if the gains and phases are set properly. You can't get the wide I channel but that is really hard to see. |
#27
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It was senior moment John! It's there.
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#28
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Ah, good! :-)
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John Folsom |
#29
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The irony, now that analog TV is on its way out, is that RY demod was used because it's easier and cheaper in the analog domain, and one could "play around" with the angles to "improve" flesh tones to compensate for picture tube colorimetry; you can't "play around" with IQ demod. But now digital methods make IQ demod easy, and a digital matrix can make any required adjustmant to vectors. Part of the fascination of early colour sets is that the design did everything the hard way. Last edited by MelodyMaster; 06-25-2011 at 12:19 PM. |
#30
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Block diagram of H-840CK15
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Audiokarma |
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