Tube swap convergence: when do you decide the tube quality isn't good enough?

TheShanMan

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Tube swap convergence: when do you decide the tube quality isn't good enough?

I don't know how to decide if the trouble I'm having is due to my lack of skill or because the tube (or the tube in combination with the yoke from my chassis) isn't high enough quality to give me the convergence on the edges that I'm expecting. Bear in mind I keep the rings with the tube and the yoke with the chassis.

Static convergence is easy. Corners are easy with the addition of a magnet strip. But I'm having trouble getting the centers of the edges to look good. Frankly I'm not sure if I should be able to correct this with the rings (since it seems there are multiple ring positions that work for the center) and I just haven't stumbled onto the right combination yet, or if I should give up and try another tube. I have also tried adjusting the dynamic convergence (yoke) and shifting both the rings and the yoke forward and back but haven't been able to get it much better.

If you were in my shoes, what would you do? Keep playing with the rings (I've probably spent 2 or more hours playing with them)? Solve it with a dozen magnet strips (lol)? Try another tube?

When starting a tube swap I really need to start by looking at a TV image to see how good the convergence is before I even start so I get a sense for how good it should be when I'm done.

If anyone has a set of steps you go through with your tube swaps that ensure a high rate of success, please share in detail! Our community really needs to work on a good tube swap/convergence howto! Everything I have found in my searching has turned up basic information that does nothing to help in tough situations like this out. Just not good enough!

2010-10-24ConvergenceProblem001.jpg


Center of left edge:

2010-10-24ConvergenceProblem002.jpg


Center of right edge:

2010-10-24ConvergenceProblem003.jpg


Center of top edge:

2010-10-24ConvergenceProblem004.jpg


Center of bottom edge:

2010-10-24ConvergenceProblem005.jpg
 
thats cyberballs screen test....

you should be able to get it closer with moving the rings. I am sure someone will tell you a good way. I hate messing with them. So I won't even try. But I do mark the starting point and work from there. Figure out what each one is doing and try to find the best spot. I don't think you can get perfect, but you should be able to get closer than that..
 
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Sometimes you need to actually rock the yoke side to side to get the edges converged. You can also use more of those little adjustment strips to affect it as well. It's hard to get the edges converged - it really is. And occasionally you'll wind up with a tube/yoke combo that just won't work, since the tube wasn't meant to work with that yoke (usually only happens if you try to stuff a 20" tube on a yoke meant for a 19" tube).

Another trick is to slide the whole stack of rings forward and backward on the neck - their position over the guns affects a lot of things too.

-Ian
 
Yep. Cyberball. Great for testing monitors as far as the actual monitor test screens and the fact that it has 2 monitors so you always know what you should see on the screen.

Retro, as stated I've already tried the things you mentioned.

Bill, thanks for encouraging me to spend more time and pull more hair out. ;) Seriously though, I won't give up yet based on what you said.

If anyone has specifics on how they dial in the edges when the center is already dialed in, I'm all ears. :)
 
Wel, I have to ask these questions, as I can't really tell from your post:

1) Did you swap the original arcade yoke with the chassis, or did you reuse the TV chassis yoke?

2) If you swapped the yoke, did you measure the distance from the tube of the old tube, and place it the same distance on the new tube?

3) What chassis is it?

4) Have you tried putting the old rings on the new tube, just to see if they are a slightly different power - and work better with that chassis?
 
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1. I didn't realize I could use a TV chassis (assuming it would need modification - interesting idea that maybe would be worth considering). Like I said though, I kept the yoke with the chassis (meaning the arcade chassis).

2. I didn't measure the distance at all, but it basically ended up in the only spot in which I could get perfect color purity with the purity rings. Move it toward the tube and the purity is lost in the corners, move it back and it's lost on the left and right sides. I've found through a few tube swaps that there is very little margin for error with purity.

3. K7000 (I have not been able to determine the exact model even after posting about it here.

4. I have not tried that, but at this point I'd be willing to try anything. :D
 
I was just messing with one for about half an hour yesterday trying to converge it. When the lines were off in just areas of the tube, like yours is, it seems the first two rings were what manipulated that (the purity rings). Also if you read the instructions, it'll tell you what the maximum angle is, so you'll know you don't have to fool around outside of that. For instance, on my 4900, the maximum width of the purity rings was 30degrees... so the rings had to be within 30 degrees of each other, one way or the other, or turned around 180 degrees. I hope that makes sense. Line up the two top rings right on top of each other, then just turn them slightly and see what that does (it'll probably move the whole image around the screen)... you can seperate them no more than 30degrees from each other and see what that does too, then turn them both around at that angle and see what you get.

It just takes forever, it's a pain in the ass.
 
The only other option I can think of would be to use the magnetic chevrons on that side with the convergance off.
 
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did you ever fix this problem? I am having the same problem and i cant seem to adjust out the top and bottom edges. The green line seems out of place.
 
Yep, the tube is not a good match. All tubes aren't created equal. They have different gun configurations, and that affects convergence. In other words, not only does the yoke need a proper chassis mate, but it also needs a proper tube mate. You will probably never "fix" the problem so your choice is to either get a tube that's a better match, or live with the results you got.

This was confirmed by Scotty at Hawk Eye btw.
 
thanks man. I had a suspicion that was the case. Did you swap yours out and get a good picture?
 
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