4600 color misalignment in one corner

delroy666

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After recapping, resoldering some connections and adjusting pots, the 19k4600 I've been working on is looking pretty good. I have one problem remaining though - the colors near the bottom left corner of the screen are not aligned. It's almost like the convergence is off, but only in this one area. The rest of the image looks good. (see attached pics) Is this a degaussing problem?
 

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No, it is a convergance problem. Looks like you may have bumped the yoke. Loosen the yoke screw and see if you can get rid of it by moving the yoke closer to the tube. DO NOT over tighten the yoke screw when you have it aligned.
 
No, it is a convergance problem. Looks like you may have bumped the yoke. Loosen the yoke screw and see if you can get rid of it by moving the yoke closer to the tube. DO NOT over tighten the yoke screw when you have it aligned.

Actually, don't! It's a convergence issue for sure, but it's really localized.

Level42 has a video on how to fix this, let me see if I can dig it up.
 
No, it is a convergance problem. Looks like you may have bumped the yoke. Loosen the yoke screw and see if you can get rid of it by moving the yoke closer to the tube. DO NOT over tighten the yoke screw when you have it aligned.

I figured its worth a try, so I undid the yoke screw and tried to move the yoke but it won't budge. It's really stuck on there - I can't rotate it or even move it back toward the neckboard. Is there a trick to it? Or should I leave it alone now that I'm pretty sure it wouldn't have moved just from bumping it?


That does look like the problem I'm having. I'm curious how those strips work. They guy in the video says they're not magnetic, so are they just shielding part of the tube from the yoke coils causing reduced deflection in that area? Where can I get those strips? Can I improvise with something else, like foil EMI shielding tape?

Thanks for the responses!
 
How cool. I think I left a few of those in the driveway a couple of days ago. Need to go retrieve them pronto!
 
Yeah they are magnets. You can use refrigerator magnets as well, just cut small squares, and glue them to something that will slide under the yoke.

I've seen monitors that have had about 8 of those magnets stuck all over to get corners in..
 
Ha, so I got a fridge magnet and started sliding it under the yoke, but it kept hitting something. I got a light and looked in there, and saw the end of a piece of tape or something in the way, so I pulled it out. It was actually a crusty old piece of masking tape wrapped around a metal washer and stuck against the tube under the yoke. :001_ssuprised: It wasn't stuck on very well.. it came off so easily, I'm surprised it didn't just fall out when I moved the monitor from the cabinet to the bench. Guess someone had some edge convergence problems with this monitor before. Anyways, I powered up the monitor and the picture looks perfect now. Thanks guys!
 
It was actually a crusty old piece of masking tape wrapped around a metal washer and stuck against the tube under the yoke. It wasn't stuck on very well.. it came off so easily, I'm surprised it didn't just fall out when I moved the monitor from the cabinet to the bench. Guess someone had some edge convergence problems with this monitor before. Anyways, I powered up the monitor and the picture looks perfect now.

Interestingly, I tonight I was working on a K4900 with top left corner convergence problems. Searching KLOV lead me this this thread, and having no strips handy, I decided to pull the yoke back and try to re-square it with the tube. Guess what fell out? Yep! A small washer affixed with crusty dried up masking tape. After that, the picture wasn't perfect, but the corner issue went from a '9' to a '1'

Either you and I have the same tech, or this was a factory kludge that is showing up as corner convergence issues when the tape fails and the washer shifts.
 
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