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Old 07-10-2011, 10:43 PM
DaveWM DaveWM is offline
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another convergence question

ok so lets say your are done and have an ok convergence, if you were to remove the convergence coils from the neck (leaving the board plugged in) would it make since that the static convergence be ok or completely out of whack (as it was on mine). As i refine my technique I rely less on the 'this pot or coil does this approach" and rather focus on just trying to get the cross hatch as straight as possible. When done that way it seems to drop into convergence better than endless twiddling while focusing on just the area assigned to that control. I know that is not how its shown to be done, but I know that I ofter have less that perfect convergence that defies any amount of adj, like the entire line is tilted.

I often wonder if you should start by centering all the pots and center the slugs (1/2 in the coil) before touching the static, then start the process.

example if you have one pot cranked over and since it effects the static, then adj the static will only result in less than optimum adj range (if possilble at) for convergence of dynamic.
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Old 07-11-2011, 12:06 AM
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miniman82 miniman82 is offline
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Trust me when I tell you: just follow the damn instructions! I twiddled with convergence a million times on the CTC-4, trying this way and that attempting to get it right. It's just not gonna happen. The instructions were written for a reason, I'm humbled to say that I am not smarter than the RCA techs who designed my sets.
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Old 07-11-2011, 07:48 AM
old_coot88 old_coot88 is offline
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Quote:
Originally Posted by DaveWM View Post
...I often wonder if you should start by centering all the pots and center the slugs (1/2 in the coil) before touching the static, then start the process.
Nay, nein, nix. Leave 'em where they were as the starting point.
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Old 07-11-2011, 08:55 AM
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Convergence adjustment is an iterative process. ALL the adjustments interact to some degree. Do static, then dynamic, then retouch static, and retouch dynamic. You will converge on the final solution (no pun intended).
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Old 07-11-2011, 09:10 AM
DaveWM DaveWM is offline
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I guess what I am getting at is did the factory start out with everything centered up (I would assume so), or how about the sets that jr, got his hands on and set evethhing at max CW.
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Old 07-11-2011, 09:22 AM
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It should not matter the starting conditions. If the procedure does not call out a starting position for the dynamic adjustments, It may require more than 2 iterations to end up at the final solution.
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Old 07-11-2011, 10:02 AM
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Wherever the controls were set from the last time at least gives you some sort of baseline. If everything was "ideal" at the factory and everything aligned the same then I'm sure that there would have been some preset conditions. And this is only good if everything is working right.
Change out the CRT and everything starts over again! Lots of varibles!!
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Old 07-11-2011, 01:04 PM
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Kevin Kuehn Kevin Kuehn is offline
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I found out by complete accident that my CTC-11 is very watchable without the dynamic convergence board plugged in. Looks just as good as the Sylvania test jig CRT. I did however still have the dummy load plugged into the CTC-11 convergence board socket
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Old 07-11-2011, 03:03 PM
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Unhappy

My 4 is a PIA to converge. I wound up rotating the convergence yoke slightly to achieve reasonable results, but it sure ain't perfect, nor will it be.
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Old 07-11-2011, 03:47 PM
kvflyer kvflyer is offline
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Gee, I just replaced the CRT in my CTC-9A. Look what I have to look forward to
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Old 07-11-2011, 05:25 PM
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Quote:
Originally Posted by stromberg6 View Post
My 4 is a PIA to converge. I wound up rotating the convergence yoke slightly to achieve reasonable results, but it sure ain't perfect, nor will it be.
Same exact thing here! Is it rotated slightly anti-clockwise as viewed when looking at it through the top from the front of the set?
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Old 07-11-2011, 07:23 PM
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[QUOTE=kvflyer;3008771]Gee, I just replaced the CRT in my CTC-9A. Look what I have to look forward to [/QUOTE

Might not be too bad, as by the time the 7's were released they had the convergence problem under control, sort of. I was able to achieve perfect convergence in one of my 7s, but spent about 6 hours on the task. The settings held for a very long time, and the pic was great with a RE21FBP22 Sylvania tube, all new, not re-built. It was a Sanford in mahogany. Before that, RCA used carbon pots in the convergence circuits. In the 7, and subsequent chassis, they used wire wound pots, and improved circuits. It worked, for the most part, at least...
Aren't these damn TVs fun to play with and restore!?
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Old 07-11-2011, 07:32 PM
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Quote:
Originally Posted by miniman82 View Post
Same exact thing here! Is it rotated slightly anti-clockwise as viewed when looking at it through the top from the front of the set?
Yes, exactly. My tube is what I believe to be an early tube with a "greenish" screen, not "silvery-grayish" as has been discussed before. Maybe the gun assemblies in some tubes are "off" a bit. Not really a problem here, as the amazing color reproduction makes up for minor convergence trouble.
I'm going to again go through the entire set soon, and will post any strange or appropriate findings.
Kevin
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Old 07-12-2011, 12:56 PM
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I have found very few sets that have perfect convergence, I agree with John Folsom that there is always some type of interaction between adjustments, always remember to let the set warm up for a while before adjusting the convergence. I agree that if you follow the recommended proceedure you will end up with a reasonable result.
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Old 07-12-2011, 02:15 PM
kvflyer kvflyer is offline
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Last time I did a convergence was in about 1979. It was on a Heathkit color TV. So, I am sure that when I get the CTC-9A going, it will be just like starting from scratch. Thanks for the helpful hints in this thread.
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