Question that applies to most TV's

What do the plastic rings on the TV's CRT neck yoke do? Usually there is more than a few and they are adjustable with tabs, I moved them around; but they didn't change anything on the screen.

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Well! Werent you lucky or what. There are purity rings and convergence rings. Are you sure there is no fringeing on the outer parts of the screen since you "adjusted" them? Or maybe uneven colour across the screen!

Are you trying to fix it till it breaks?

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Why on earth adjust something you do not undertstand? Those 'plastic rings' are there to adjust the convergence (the as near perfect as possible overlap of the red, green and blue images) when the CRT is manufactured. Each ring affects a different beam or part of the raster, and each ring can be dependent on the others, making setup very tricky. They generally do not require adjustment as part of a service, and they certainly must never be touched by unskilled hands. Unless you have set them back exactly where you found them you will certainly have messed up the convergence, and even an untrained eye should be able to spot convergence errors on a CRT. Look for coloured fringes around edges, teletext can be useful for this if you have it You may notice letters that should be crisp and white now have two or three seperate coloured letters not quite overlapping properly.


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Dave D


If he's really, really lucky they may have had dabs of paint (nail polish?) marking the original locations that he can use to return them to their original positions :)

Course now we have computers and dvd burners, we can make our own dvd's with dots and cross hatch patterns. Lots easier than in the real old days carrying a huge, heavy B&K generator :)

Take care.


Reply to
Ken Weitzel

I think it would be more fun to explain to him how to set the rings.

Set like shaped tabs all together, At zero correction (make sure the display doesn't change) move them in pairs away from each other so you can get to them with those sausage fingers. (I swear the people in those factories must have fingers the diameter of pencils)

On sets with four sets of rings set them like 90 degrees apart, three sets, 120 degrees.

Determine which are the purity and set that first. If you have not moved the yoke you can basically set those for the brightest picture, but that is not perfect, slide the yoke back and adjust the rings for equal purity error on each side of the raster. Alternately bring the yoke into position and adjust the rings until the purity is perfect.

Hopefully everything else was in zero correction like I said, if not you might have to repeat the whole procedure.

Now comes the good part, on a set with three sets of rings, the 4 and 6 pole ringsets will converge the red and blue to the green. One set of rings should move the red and blue pretty much equally, the other set will move them equally but in opposite directions.

Once you get the center set, then adjust edge convergence with the wedges between the bell of the CRT and yoke. Move up and down for "Xing" and laterally for vertical lines at the sides.

For a pro, once you get done with minimal frustration because you know what your doing, glue the whole friggin mess together so nobody can screw it up again, but wait, you must check purity on each axis relative to the Earth's magnetic field, degaussing each time. DO NOT use the glue until you have optimized the purity.

If you are not a pro who knows what he is doing, get frustrated, get a sixpack of beer because now it has been pointed out to you and the color fringes now DRIVE YOU CRAZY. Start cleaning your gun, but check to see if it is loaded by pointing it at the TV and pulling the trigger. (put the back back on it first)

Clean the gun and check the action. If it was not chambered before cleaning those nasty color fringes will persist. Of course you check the action by loading and chambering the weapon, how else can you be sure ? You may remove the clip if you wish, and then, especially if you have kids (do this while they are away) make sure the weapon is clear by again pointing it at the TV and pulling the trigger.

If everything has gone right the TV will never again exhibit these anomalies, such as color fringing or impure color. If the cops come, don't answer the door. You need to go buy a TV before everyone else gets home. Don't bother taking it to a pro who knows what he's doing, these F______s are keeping the money in this country, we can't have that. Don't you know there are poor slave laborers in China who need to feed their families on $12 a month ? Besides, a TV shop will just check it in and it could be a day or more before they get to it. This is not immediate gratification, and not the American way.

When you get your new TV, do not take the back off. Remember what happened last time.


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Ezzaactly what I thought.... a great reply.

Best Regards,
Daniel Sofie
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sofie ha escrito:

I hope you were trying this experiment on some crappy old supermarket tv and not something actually worth repairing! ;-) Ben.

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Actually those are timing rings . They set up the sound so it matches the peoples mouth .One set is adjusted so the tv lasts longer . Dont move them to mutch .

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Ken G.

Joe Leikhim K4SAT
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Us Americans, with our fat fingers and large round eyes, can't do anything right with t.v.s, ya'll.

(Joke, ha-ha.)

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