another convergence question

[DaveWM]

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.

[miniman82]

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.

[old_coot88]

Originally Posted by DaveWM

...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.

[John Folsom]

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).

[DaveWM]

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.

[old_tv_nut]

Originally Posted by DaveWM

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.

Don't know what they did on particular sets. I do know that much later factory procedures would often involve first setting control slugs to a nominal mechanical position. So I would assume that any set you got is close to correct unless someone just went in and "tightened" all those "screws."

If you look back at my experience with replacing a broken blue H dynamic slug, you will see that I really had to try the full range (which I was afraid to do at first). But if you receive it unbroken, I'd assume it's close to start.

Edit: the nominal factory mechanical starting position might very well NOT be centered - so if the service literature doesn't tell you, don't assume.
2nd Edit - on the CTC-5, the pots are tapped at 25% rotation, and that (or very close) turned out to be the correct setting for the 21FBP22 substitute tube. It could depend on how close the guns are aimed for center convergence without any DC.

[old_tv_nut]

Originally Posted by John Folsom

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).

On later sets (post CTC-5) the circuits were designed so that the dynamic would not upset the static too much. However, on the CTC-5 and earlier, if you read the instructions, they say do the dynamic first for parallel lines, then do the static, then iterate.

I also noted on mine that a little fine rotation of the convergence yoke plus sliding back and forward to find the position of maximum effect was helpful.

[John Folsom]

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.

[marty59]

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!!

[Kevin Kuehn]

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

[stromberg6]

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.

[miniman82]

Originally Posted by stromberg6

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?

[kvflyer]

Gee, I just replaced the CRT in my CTC-9A. Look what I have to look forward to

[stromberg6]

[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!?

[oldtvman]

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.