"parallelogram" correction... is it possible?

RobMcRaf

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"parallelogram" correction... is it possible?

This is a color vector put together with a re-wound yoke <--- important.

I have great convergence on most of the monitor, but... It looks like a parallelogram. Severe slanting to the top-left and bottom-right. I was able to reign in the top-left corner with a convergence strip so it isn't as pronounced as in the picture, and the colors overlap better.

I haven't seen this type of geometry issue with a monitor before. Is it possible/probable that I'll have to just rewind the yoke again and try to do it "better" (i.e. more uniform and symmetric)?


Just for info, its running on a standard 19" tv with a rewound vertical yoke mated with the XY color vector kit and DVG-Lite for the test pattern (both from Fred Konopaska)
 

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Jeez, hope I don't have these problems when I attempt the same thing. Will be watching with great interest.
 
That's pincushioning. Some game boards have the ability to correct for it, while in other monitors the compensation is built into the yoke.

What game board are you using there? (EDIT: I see you said DVG lite, but I don't know if that has it or not. Ask Fred.)
 
That's pincushioning. Some game boards have the ability to correct for it, while in other monitors the compensation is built into the yoke.

What game board are you using there? (EDIT: I see you said DVG lite, but I don't know if that has it or not. Ask Fred.)

You really think that is pincushioning? I've seen that before and usually the sides are bowed in along with possibly the top and bottom, but the corners are kinda symmetric. This looks more skewed than bowed.

I can hook it up to Major Havoc pcb and test again, and I believe it has pincushion correction, but I think it was doing that same thing with that pcb.
 
You really think that is pincushioning? I've seen that before and usually the sides are bowed in along with possibly the top and bottom, but the corners are kinda symmetric. This looks more skewed than bowed.

I can hook it up to Major Havoc pcb and test again, and I believe it has pincushion correction, but I think it was doing that same thing with that pcb.


MH doesn't have pincushion correction (unless you have an adapter board, which will give it to you in one axis).

Tempest has it in both directions. It isn't adjustable though. (However it's possible to make it adjustable, with a mod. But that's another story).

I can't tell from your pic exactly what you're referring to though. All I see is the bowing in on both sides. If it is lopsided, yeah, that's more likely your yoke being imbalanced.
 
MH doesn't have pincushion correction (unless you have an adapter board, which will give it to you in one axis).

Tempest has it in both directions. It isn't adjustable though. (However it's possible to make it adjustable, with a mod. But that's another story).

I can't tell from your pic exactly what you're referring to though. All I see is the bowing in on both sides. If it is lopsided, yeah, that's more likely your yoke being imbalanced.

We had good success on getting things straight on the first kit we finished (using same electronics to test), I probably just didn't get the windings on this one straight or something. It's a bit of a technique thing, but pretty easy to try again. Magnet wire is cheap. Take an hour -max- to redo it.

Just want to get this one put to bed so I can put faster crystals on my MH and bring it up to original speed!
 
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Hi Rob
If you haven't glued yet, the vertical windings need to be rotated so it's even

As viewed from the screen, you need to rotate the new windings ferrites clockwise
This may "fix" the problem, or get it close enough etc
 
Last edited:
Hi Rob
If you haven't glued yet, the vertical windings need to be rotated so it's even

As viewed from the screen, you need to rotate the new windings ferrites clockwise
This may "fix" the problem, or get it close enough etc
Ok, cool. It's glued, but that can be re done. Thanks!
 
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