K7000 convergence fine tuning - yoke or rings?

jimbodeanny

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Right now I've got my K7000 close to the way I want it - I've even added and adjusted some convergence strips for the corners. But the last little issue I want to correct is the horizontal red (and maybe just a LITTLE blue). It looks good over most of the monitor but towards the bottom of the crosshatch/grid pattern it's just a little bit off (red horizontal lines are a little lower than the other colors.) There's also something similar at the very top of the grid -- the top one or two horizontal lines (may not be red).

So would I be right in using the sets of rings (2 sets closest to neckboard) to correct this or should I be trying to tilt the yoke?



EDIT: Upon looking at the K7000 manual (http://www.wellsgardner.com/pdf/Service/K7000.pdf --page 6/7) I'm guessing that fixing my problem relates more to tilting the yoke (like it mentions on page 7 at the bottom in figure 9).

Is this correct?

Thanks
 
I'm thinking it's a yoke adjustment since the rings are pretty glued down. Unless someone chimes in, I think I'll try that first.
 
From what you describe I am guessing you are displaying a cross hatch pattern? If it were me I would try to correct it with the rings. I know the manual says something to the effect this ring set moves this color, move them together for vertical, split them for horizontal. Keep in mind I am just guessing at the wording, I don't have one in front of me. Anyway, the ring movement, in either fashion, will not necessarily move the color in lock step vertical or horizontal. If you have a little color wagging out of line toward a side it's possible to dial in back in with the rings. I have done it several times. Just did it a couple of weeks ago on a 25" K7000.

I would take a Sharpie and mark a line across the rings then put a corresponding dot on the tube. Now you know where they were to start so you can experiment and always get back to where you began. Sometimes I will make a huge movement with a set of rings to see how that set is going to act on that specific monitor. Then I return everything to home and start again. Small moments can make a big difference. Adjust from behind using a mirror in front but make sure you get up and look directly at the tube from time to time as the reflection can "dampen" what you see. When you get it dialed in hot glue the rings in place.
 
Yes, I'm using a crosshatch pattern.

I ended using another tube (same model #) and moved the chassis to that one. The convergence was a little off, but I was able to get it pretty close to perfect -- better than the one I was working on previously. Getting the static convergence (cross hatch lining up in the center) was fairly simple using moddset's tutorial, but the tricky part is getting the edges to line up (dymnamic convergence I think.) I was able to get the corners converged using some homemade convergence strips, but the outer edges (vertical and horizontal) were still off. I ended up loosening the yoke, removing the wedges and playing with how it was tilted. In the end I found that tilting it up was the sweet spot. I re-inserted the wedges into their new places (along with the help on another from the other tube) and the crosshatch looked nearly perfect.

I wasn't so lucky with the other (original) tube. Tilting and playing with the yoke really didn't help much with the outer convergence, even after fixing the corners with the strips. Since the purity tests all seemed to looked good (colors were on), I didn't mess with the purity rings at all -- with either of the tubes.

I'm happy that I was able to get one of the tubes properly converged, but it's still frustrating that I wasn't able to get the other one converged better. Perhaps sometime I'll try to tackle it again.




EDIT: I'm beginning to wonder if perhaps there's a more systematic process for properly converging a monitor. Moddset's tutorial covers the rings, but since the yoke and convergence strips also affect the overall convergence, I'm wondering if one of these areas is best tackled first? For example, perhaps it's better to use the rings to purposely push the crosshatch out of alignment and then use that to adjust the yoke so that the entire image is shifted the same distance? Then perhaps once the yoke is tilted/set properly, you'd move on to the rings to get the static convergence aligned followed by fixing the corners with the strips? Just something I'm thinking about...
 
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one thing I have noticed with some 25" that I am working on now is that right from the start the convergence is not that good for dynamic edges even though I did not have to remove the yoke from the donor tube. I wonder if the change of frequency (even though small) could cause this.

Also, some tubes I have seen use extra magnets in a v shape to aid in dynamic convergence. I wonder if that would help?
 
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