Can this be fixed?

[8way]

I was planning on using this monitor for a vertical setup in my cab. As you can see its not happy setting on its side. My question is can this be fixed by adjusting the yoke or is it the purity rings I have to mess with? The monitor in question is an NEC CM-2791. And yes the monitor works perfectly when sitting right side up.

[SirPeale]

It's a gaussing issue.  Degauss the monitor.

[8way]

I tried to degauss it, does not help. When you first turn it on, it takes about minute for the distortion to appear. And its weird that the distortion in the corner is always in that corner. What I mean is say I have it on its right side and the distortion is on the bottom corner, then I turn it off and rotate it to its left side and wait about 10-15 minutes turn it back on and the distortion will be on the top corner. I also tested this in different parts of the house, with no difference for the better or worse. Should I just try adjusting the yoke and rings and see what happens? I have done a tube swap before, so I do have experience. The reason I ask is because it took  me forever to get it adjusted right.

[grantspain]

is there a speaker near that area,its even possible a fixing bolt is magnetic-when you say you degaussed,is that with a manual wand?

[8way]

Yes it does have speakers on each side. But when it’s sitting right side up the speakers don’t affect it, would the affects from the speaker change when it’s on its side? I don’t have a manual wand, so it’s just the degauss when you first turn it on.

UPDATE

I messed around with the rings some which had no effect at first so I just put them back to their original position. Then I realized the distortion was magically almost gone. Theirs only slight distortion on the top corner. Also this thing is a freaking nightmare to try to work on. I can only get a back service panel off, the rest of the case looks like a mystery. The best I can tell is you have to get to some screws inside the case to get it off. The problem with that is can’t discharge it with the case on. Also this thing has 3 separate boards and crap load of wires . Anyways unless some easy solution comes up, looks like I wont be using this monitor.

[grantspain]

you're brave mucking around with the purity rings like that,its quite difficult to get them right unless you use a test grid and have alot of patience.
i would remove the whole tube to set the purity rings just in case something in your cab has a magnetic field

[8way]

The monitor is sitting on a table in the middle of the room. Nothing metallic or magnetic around it. And yes I was using Nokia Monitor Test program when messing with the rings. The first time I did a tub swap I didn’t have a test grid just had the game image . It took me like seven hours to adjust it right, what a nightmare that was. Well I guess my next step will be to completely decase the monitor. In the progress im hopping I can get it to run without some of the boards. Im hopping each board controls a separate function. Ill report back with any progress. Thanks for the suggestions.

[8way]

Well I ended up readjusting the yoke and rings, and the results are pretty good. Actually they are better then before, looks like the last person to service it did a pretty crappy job. The weird thing is during the process of adjusting it, I noticed sometimes I would get the distortion and sometimes I would not. This was happening without moving the monitor’s position or its surroundings. After investigating the situation I noticed I only get the distorting if im displaying an interlaced resolution. Is this a normal side affect? Anyway im pretty happy with it overall. I really can’t complain, i mean a free working 27” CGA\EGA monitor with zero burn in. This things going to look crazy for my vertical cab setup. The cab ill be using is a Nintendo Playchoice 10. The 27” monitor replaces the two 19” monitors nicely. I should have some pics up soon. Im still in the process of measuring and figuring out how im going two mount the monitor and replace the two pieces of glass with one piece. Wish me luck and here are some pics of the monitor in action. I still need to fine tune it.