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#46
05-15-2009, 10:04 AM
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Interesting... I had that similar problem with the blue G1 wire into the crt socket, but after I just shoved it in more, it didn't give me any more trouble, so I never took the socket apart. But later next week I'll try that first, then look more into the focus circuit if the problem isn't in the socket.
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#47
05-22-2009, 08:44 AM
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The corroded focus lead in the socket was exactly the problem. It was so corroded there was very little left of the sleeve the pin on the crt goes into. Also all the connections on the left side of the socket (all the blue and green and the focus) were broken right in between where the wire crimps on and the sleeve starts. I tried to solder everything back together, but it didn't hold very well. I eventually cut up a color crt extension cord I had and replaced the socket and wires going to it entirely, this worked.
The intermittent focus and white horiz lines flashing across the screen went away. The intermittent jittery vertical did not. It's very slight (only really noticeable on a still picture) and mostly goes away after the set warms up for a few minutes, so I'm going to leave it for now. I tried cleaning the vert hold/size/lin controls and that didn't fix it. I tried swapping the 6HE5 vert tube, and that didn't either (but the only spare I had tested pretty weak), so I'm going to order another one and try that next. Despite all the little problems I keep having with this set, it still produces the best picture I've seen on a color roundie, and is easily in the running for best color picture on any set I've had. Last edited by Adam; 05-22-2009 at 12:44 PM.
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#48
05-22-2009, 04:35 PM
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I'm glad checking out the crt socket tip helped you. Its funny how i see this alot on Zeniths but not as much on other color roundies. Sounds like your heading down the home stretch now and glad its working pretty good for you now.
-Tony
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#49
10-06-2009, 07:07 PM
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I thought I had convergence trouble on this set, but it must be something else. I connected up the color bar generator, set it on the cross-hatch pattern, and the convergence is right on. Yet in certain images it looks like the convergence is off, see the left and right edges of the bumper sticker in the picture below. Any thoughts on where the trouble is?
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#50
10-06-2009, 09:20 PM
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nice zenith.that is not convergence causing your issue.it is in the demod coils.you may have to adjust them to get a good color saturation.i have a zenith with the same chassis.it had a similiar problem.the alignment of the color.just a slight turn of the coil and it is fixed.dont force it and never use a metal tool!!i know some of these guys will scream because of not using a signal generator but a slight turn should get it right.try to get something red on the screen such as a banner or shirt,etc.turn the coil until the red is fully saturating the image.a dvd or a fixed image so you can work.the coils are right beside your demod tubes.there is also a coil near the transformer that will need to be adjusted.good luck on this.
Last edited by sampson159; 10-06-2009 at 09:24 PM.
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#51
10-06-2009, 10:32 PM
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Adjusting those coils could make the same problem worse, but I couldn't get it to improve it much. I can go through the alignment procedure in the sams, it requires a color bar generator and a scope. Is there another procedure with a signal generator? If there's a way to do it with a vtvm instead of a scope that would be better, so I don't have to haul my tek545 down the stairs.
Last edited by Adam; 10-06-2009 at 10:49 PM.
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#52
10-09-2009, 08:03 PM
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Quote:
__________________
Just look at those channels whiz on by. - Fred Sanford
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#53
10-09-2009, 09:14 PM
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Two of my Zenith's 23XC36 and 23XC38 sets had that quirk.. Mine turned to be a vertical height and vert lin pot. Squirt them with deoxit..
__________________
Honey, turn on the tv.. I'm cold!
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#54
10-09-2009, 10:10 PM
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Quote:
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#55
10-09-2009, 11:18 PM
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I adjusted those demod coils a little either way with the color bar generator connected, and it didn't help. So I dragged the scope downstairs and followed what it said in the sams, I still didn't improve the problem. But I noticed the adjustment A23 (coil connected to the cathode of the 2nd chroma bandpass amp), did nothing. So I checked to see if the coil was open, it wasn't. I checked the 6KT8, it was good, tried swapping it anyway, no difference. So I started checking the voltages at that tube, plate voltage is fine, but pin 8 is about 100v low, pin 7 is only a few -volts (supposed to be -30). I check the resistor between pin 8 and the 240v B+, and it's ok. While at the 1st chroma bandpass amp, the plate and pin 8 read about 100v too high. But if I pull out the control which engages the color killer (or turn to a channel that's all snow so the color killer kicks in), all the voltages return to what they're supposed to be.
... I just noticed it says voltages are taken with "no signal applied" at the bottom of the schematic, which could mean that those voltage measurements are only what they're supposed to be with the color killer working, as it would with "no signal applied", then the set may be working as it is supposed to, and A23 really just doesn't do much? Last edited by Adam; 10-09-2009 at 11:51 PM.
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#57
10-10-2009, 12:45 AM
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I tried turning the sound trap a little one way, then a little the other, didn't seem to make much difference. Then I tried connecting a dvd player to my ch 5 modulator instead of ch3. Then, if I had the set not on ch 5 but on ch 4, the reception isn't great, but this problem goes away. Fine tuning control doesn't seem to do anything at all, I'll have to take the tuner out and look at that later.
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#58
10-11-2009, 01:59 PM
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I don't know if adjusting the fine tuning can fix this problem, but I was correct about it not working. The rubber belt that's on there fits too loosely, and the shaft that it eventually turns is all gummed up and won't move. I'll have to take it apart further to see what's going on. But does anyone have a replacement for that belt, or know where I can get one?
It is true that this problem goes away on a b/w picture. If it comes down to IF alignment, I'm just going to put the set back together, and wait until later. I just acquired a complete set of the old RCA sweep/marker generators last month. But first I have get them in working order, and I'd want to try doing a few b/w sets before I messed with color. Last edited by Adam; 10-11-2009 at 02:04 PM.
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#59
10-11-2009, 04:21 PM
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A primary rule of good living: fix the obvious things first.
I would not fiddle with anything internal before trying the fine tuning.
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#60
10-13-2009, 08:21 AM
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Interesting focus problem, I have 2 RCA CTC10 having some focus problem only on the bright parts and sharp white details on the picture. The dark parts of the picture having low contrast are fine. Are they known to have focus or socket problems as well. I would not like to open the socket for no reason. Both sets behave the same way and I thought I had bad CRT's. They check good and one of them is a newly installed rebuilt tube.
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