Something is buzzing on the neckboard of my Mitsubishi XC3717

[Jack Burton]

Update:  Last night I was using my monitor, when it started clicking really loud and I looked into the back and could see little sparks every once and a while.  This was accompanied by a very bright and blurry image on screen.  Sometimes the monitor seemed to turn itself off and reset. 

Today I took the back cover off again and could see that the neckboard was making the buzzing sound.  It sounds like electricity arcing somewhere on the board. 

What should I do, look for shorts?  Replace a capacitor?  Is this fixable?

I think I'm getting close to finding a solution for this problem.

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I just got this monitor and it has an intermittent problem in which the screen glows and becomes blurry every once and a while.  Somes time it will quickly pulse and become blurry.  Additionally, turning the contrast up on this monitor causes white text to become very blurry. 

Does anyone know if this monitor has an internal focus control or how to access a debug menu?  What kind of component could be malfunctioning to cause this behavior?

Also, numerous sites list this monitor as having a maximum resolution of 1280x1024, but I am only able to achieve this resolution at 30hz.  I am however, able to display 1400x900.  Does anyone know anything about what the highest res this monitor can display is?

This is an awesome monitor for playing games in their native resolutions and this intermittent nagging problem is really frustrating me.

[qrz]

could be a weak crt and/or a problem in the crt socket.  such as corrosion on the focus spark gap
 ( inside the socket )

the focus pot is usually the top ctl on the flyback . and may be labled "F"
bottom one is the screen ( G2)

qrz

[Jack Burton]

Ok, I took the back off last night.  There were three controls to adjust.

One was focus I think.  I turned it completely clockwise and text became much clearer.  Turning it counter clockwise resulted in a much blurrier picture.

Another control was labeled "Screen".  I think this is equivalent to gamma.  Turning it up brighted my screen considerably and also helped make the text look better when I combined it with turning down the contrast and turning up this control.

The final control I am not certain what it did.  White and blue text seemed to have a glow coming off the bottom of it.  Whenever I turned this control the glow reduced itself until it reversed direction and began glowing from the top of the text.  I tried to center the glow as best as I could but I could not get it perfect.  I think this is a convergence control but I am not certain.

I fired up 1944 in advancemame and took a look at the color bars in the service menu.  It looks like the blue color is slightly too high on the right side of the monitor.  It is not nearly as sharp as the other two.  I turned the convergence control as best as I could to minimize the color bleed.  I also turned down the contrast, gamma,  and brightness to compensate.  I got it looking pretty nice, but the screen was kind of dark. So I turned the gamma back up and decided to live with it.

My monitor also has controls onscreen for R:,G:, and B: Drives.  I turned the B: drive down by about 8 points and that also seemed help.  So now my monitor settings are

Contrast 20
Brightness 0
Red 15
Green 15
Blue 7
Purity S15
Moire minimum

I think the core problem here is a convergence issue with the blue electron gun.  What can I do to correct this? 

Also, on the back of the monitor I found a small white pot that can be turned to the left and right on one of the motherboards.  I turned it all the way to both sides but saw no visible change in picture quality.  Any ideas as to what it does?

[Ummon]

I'd like to see some pictures of the image displayed. You know, there's a diagnostic program that shows convergence, etc. I can't find it on this computer, and forget what it's called - something like NEST - but it's probly in the wiki.

[Jack Burton]

Well, after my tuning I've got the picture pretty clear except for the aforementioned color bleed from the blue gun.  But one other thing is bothering me.  Ever few seconds or so the screen will quickly turn a little bit blurrier and the image will darken.  From far away during gameplay this is barely noticable, but in windows it makes the text noticably blurrier.  Any idea what is going on.

I will try to record a video of this phenomenon.

[Jack Burton]

Ok, new issue. 

When I turn the monitor on the flickering and darkening of the screen is much  much worse.  Today I turned the monitor on after having turned it off last night and it wouldn't stop flickering and buzzing, sometimes I could hear loud clicks like electricity sparking, it sounded like it was coming from the glowing orange part on the neck.  Lines rolled down the screen very rapidly when this was happening.

Any ideas?

[Ummon]

My idea is you got a lemon. These monitors are a large mess of components and wiring, some of it very tightly connected such that it seems they soldered some thing just before screwing the sections together, meaning you have to desolder to open it up decently. I don't know. You might consider another monitor. Or if whever you got it from has a warranty period?

[Jack Burton]

I don't have a warranty.  I bought it off local the local Craigslist.  I can probably adjust the purity rings to resolve my convergence problem, though it's not a big deal and I could probably just live with it if I could just get the screen to stop flickering and getting blurry.

[grantspain]

sounds like a dual focus flyback,which in turn is shorting internally

[Jack Burton]

Updated first post.

[Ummon]

A little messy here. You should've changed only the title in the first post and then added a new post at the end. Or just made a totally new thread.