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Old Today, 01:01 AM
jhiesey jhiesey is offline
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Join Date: Oct 2017
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RCA CTC-10 color (and other) issues

Hi everyone, a while ago I picked up a nice CTC-10 (with remote!) and I've been gradually working on fixing it up. This is my first TV restoration, so I might have missed obvious things, but I have been working with solid-state electronics most of my life.

I've gotten most things, including the remote, working well! The biggest issue at this point is that some colors, especially red, seem too far to the right on the screen.


Everything looks fine if I turn the color control down for a black and white image.

My initial thought was that there is something wrong between the color demodulators and the resistor matrix that drives the CRT grids. I did discover a bunch of the Sprague "orange drop" caps had increased in value quite a bit (many 30% to 100% high), so I went and replaced all of those. All of the other resistors and caps in that part of the circuit seem fine as far as I can tell, and I replaced the 12az7 color demodulators and 6cg7 color amplifier tubes as well. None of those have solved the issue. I would think that problems earlier in the color circuit would just cause tint problems instead of making the color shift to the right, but maybe that's not true?



I realize the convergence isn't amazing, but it's not THAT far off. One more oddity: the horizontal hold seems to have significant effect on the tint. Is that normal?

I have the official RCA service manual and also a spare CRT that I got with the set.

There are also a few more issues with the set:
2. There is MAJOR sync buzz in the audio. It is worse when there is lots of color or detail in the picture, so I assume it's the high frequencies in the picture signal getting through the audio IF filter. I followed the instructions in the RCA service manual to align the audio section, but that didn't fix the buzz.

3. Black levels seem inconsistent as the picture changes, and sometimes one or more colors of retrace lines are visible. What should I try before replacing the CRT? As I said, I do have a spare!
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