Okay, hopefully last issue (convergence) - Videokarma.org TV - Video

TinCanAlley · #1 07-18-2013, 01:49 PM

I spend quite a bit of time on the convergence yesterday and was able to get a decent convergence on most of the screen. I know perfect convergence isn't possible, but the areas I couldn't get converged are more off than I like. More off than any properly set up set I've seen. If you look at the attached image, the right side of the screen I can pretty much get the red and green aligned, but the blue has a mind of it's own. It doesn't even follow the same bend the other guns do. Also, the very top of the grid is quite distorted for some reason, but I was able to get pretty close. On the left side, the blue is doing the same as the right, but not as bad.

The sides being off is quite noticeable in most viewing material and is distracting. I'm used to seeing a little red or blue poking out here and there, but these are magenta, yellow and blue over a good portion of the sides.

Thanks.

Username1 · #2 07-20-2013, 09:51 AM

That is actually pretty bad if you don't mind me saying. (for that far side, overall very good.) You have to be sure the controls that are for that side are not near their extremes. If they are, you need to set them mid point in the range, and start over. You should begin with all the other controls mid point as well....

As you do this alignment, it should be easy to have to make only minor adjustments to bring the picture back to perfect. I learned this later on in life. If you move around the yoke to get purity right, then move around the convergence assembly you should be able to get it almost prefect before having to adjust all the stuff on the convergence board.

I experimented with this approach after working on a set for 4 hours and ending up with what you have. The coarse adjustments can be off from bumping the set over the years, and make it look really bad. But doing a very good job on the coarse adjustments should only require the smallest of adjustments on the convergence board.

Set all the resistors back to where the dust marks are, do what you can with the coils, then do all the coarse adjustments, yoke, conv. assembly, purity, then move the fine adjustments only a little...

Your first step is degaussing the tube, then don't change its orientation till yer done.

PS - You should also be sure each of the fine adjustments is responding as they should be.

TinCanAlley · #3 07-20-2013, 11:30 AM

Quote:

Originally Posted by Username1

That is actually pretty bad if you don't mind me saying. (for that far side, overall very good.) You have to be sure the controls that are for that side are not near their extremes. If they are, you need to set them mid point in the range, and start over. You should begin with all the other controls mid point as well....

As you do this alignment, it should be easy to have to make only minor adjustments to bring the picture back to perfect. I learned this later on in life. If you move around the yoke to get purity right, then move around the convergence assembly you should be able to get it almost prefect before having to adjust all the stuff on the convergence board.

I experimented with this approach after working on a set for 4 hours and ending up with what you have. The coarse adjustments can be off from bumping the set over the years, and make it look really bad. But doing a very good job on the coarse adjustments should only require the smallest of adjustments on the convergence board.

Set all the resistors back to where the dust marks are, do what you can with the coils, then do all the coarse adjustments, yoke, conv. assembly, purity, then move the fine adjustments only a little...

Your first step is degaussing the tube, then don't change its orientation till yer done.

PS - You should also be sure each of the fine adjustments is responding as they should be.

I had already degaussed the screen with an external coil, set purity, set static convergence and set grayscale. The convergence was the last step, but isn't cooperating. There are no dust marks as the boards were cleaned and all the pots (not coils, though) were cleaned with deoxit and then fader lube. So there's not point to go back to. When I got the set someone had already messed with every single control and they sure didn't have a clue.

I'm assuming the center point is not as simple as turning the pot to its center position, is it? Yeah, didn't think so. Hmmmm.....

I will attempt this convergence next weekend as I've just ordered some replacement electrolytic caps. Seems in really dark scenes I'm getting the "jail bar" effect and on my last set it was a 10uf 300V cap. Figured I'd replace all of them under the chassis while I'm there. Once those are done, I'll start the adjustment process over again.

Thanks for the input. I'll keep you updated of my progress and with your help I might just get there.

sampson159 · #4 07-20-2013, 02:30 PM

dont beat yourself up over this.this is perfectly acceptable.you will never,ever chieve perfect convergence.not in a million years.a little tweak here and there is all that is needed.the blue lateral needs to be balanced out slightly and the blue horizontal needs a slight adjustment.thats it.turn the color on and enjoy!set looks fine as it is

Username1 · #5 07-20-2013, 04:14 PM

Thats right, you can watch it as is, you don't need to get it perfect.

Centering the adjustments just pick a center, middle of the range, thats it.

But I have been there, adjust all day and you end up with that one side that is so far off and the controls are at their max and you still have not got it. Its basically because the coarse adjustments were not close enough before you started turning stuff on the board.

You just have to set them so you have a range to play with and begin again. Its good practice, its not like you gotta get it done to get paid or anything, take yer time and enjoy it. I love doing convergence now.... Wait till you do it on a inline tube with only the ring magnets around the neck of the tube.... Much different animal there....

**....Sorry, I did not notice that you had made all these other threads for each step you have taken with this set.....**

sampson159 · #6 07-20-2013, 08:02 PM

my job in the shop was convergence.the other techs hated it.i was the youngest and got stuck with it.done way too many sets.this zenith looks good as it is.didnt see anything that was way off at all.typical blue droop on on one side.common problem.doesnt detract from the picture from 5-6 feet away.i have done many inline crts too.we always try for perfection,rarely achieve it.we still keep trying though,dont we!

walterbeers · #7 07-20-2013, 08:56 PM

On most of the older tube sets, I very rarely got perfect convergence. I was told back in the 70s, that if you got 85% perfect convergence just consider it good. Convergence got a lot better when they came out with the inline guns like the trinitron.

TinCanAlley · #8 07-20-2013, 09:19 PM

I'm used to the slight red or blue near the edges, but this is more than that. it's green, magenta, red, blue.... Over two inches of the right side is way off and very noticeable. Some of the lines on the left are up to 1/4" or more apart. The left isn't as bad, but is over an inch. The top isn't too bad, but I know it could be better.

I do understand that older sets do not have the convergence of newer sets. This one is has 12 controls for convergence and my other CC2 has none. The set with no controls has a much better convergence. If the controls can't get even close to the one with no controls, then why provide them? Also, if this was as good as it could get, no one would have purchase these sets.

I'm not giving up, though. I will get this thing in tip top shape w/a picture that will be as good as when new.

andy · #9 07-20-2013, 09:56 PM

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TinCanAlley · #10 07-20-2013, 11:31 PM

Quote:

Originally Posted by andy

One tip I have is that you have to be willing to compromise a little. Quite often by trying to get one spot perfect, you end up throwing another area off by a lot. You might be able to get the edges a lot closer if you allow other areas to be not quite perfect.

Also, don't take the labeling of the controls too literally. For example, the "left" controls have almost as much effect on the right as they do on the left. You have to alternate between them until the best balance is achieved.

You might have better luck if you start by trying to get the blue horizontal lines as straight as possible, and then trying to line the blue up with the red and green.

It's odd that the blue ends seem to bend down slightly and the red and green up slightly. It makes it quite difficult to align them.

I'm not giving up. I will use each control, note what it's major change is and then it's minor change on other areas of the screen. Once I have both those down for a each control, I might have better luck.

sampson159 · #11 07-21-2013, 08:34 AM

the other cc2 is probably an inline gun crt.no convergence adjustments just the cdenter magnets.sylvanias 19 inch inline sets had center magnets and a few controls for the sides.these sets could actually achieve perfect convergence.you can experiment with moving the panel slightly,the purity rings,yoke,etc ever so slight to try and correct the problem.your picture doesnt really indicate anything being way off at all.if you post pic of the issue we can help you with it