Neo Geo - Picture Gets Jumpy When Screen Goes White

jalpert

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Neo Geo - Picture Gets Jumpy When Screen Goes White

I'm not sure on what type of monitor this is, but it's a Neo Geo dedicated 2 slot. Anyway, when the screen shows all white, or strobes, the picture gets jumpy.

I did a search, but couldn't find the answer. Could this be a cap issue? Hopefully an easy fix. Thanks
 
with out some pics of the chassis or any clue to what type it is it could be a board problem rather than a monitor problem.

so pics or a vid would help to figure out your problem.

Peace
Buffett
 
Crack open the cabinet and take some pictures of the boards attached to the tube. We can tell the chassis model by the layout of the boards, but unless we know what chassis we're dealing with, we can't help you.
 
I'm not sure on what type of monitor this is, but it's a Neo Geo dedicated 2 slot. Anyway, when the screen shows all white, or strobes, the picture gets jumpy.

This is a common problem on monitors and television sets. When the picture goes all white, the beam current increases and it puts more load on the B+ supply, which sags. When that sags, it throws off the other stuff in the set and if anything is marginal in the sync, the picture will jump or roll. Sometimes simply readjusting the vertical hold control is enough to fix it - find the two extremes where it just barely holds the picture, and try to center it right in the middle.

The underlying cause can be caps in some instances, but in some cheap monitors/televisions, it's just the way it is - a poor design. Other symptoms of poor regulation is when the picture changes size with the content of the screen.

-Ian
 
Thanks. I'll try and take some pictures, but I was hoping for some general knowledge and a starting point.

I did mess with the sync, I'll do it a little more carefully. On games like Pulstar it's pretty bad, lots of strobing.

I figured I could always try a cap kit, I just wanted to make sure I wasn't completely wasting my time before I ordered one.

This is a common problem on monitors and television sets. When the picture goes all white, the beam current increases and it puts more load on the B+ supply, which sags. When that sags, it throws off the other stuff in the set and if anything is marginal in the sync, the picture will jump or roll. Sometimes simply readjusting the vertical hold control is enough to fix it - find the two extremes where it just barely holds the picture, and try to center it right in the middle.

The underlying cause can be caps in some instances, but in some cheap monitors/televisions, it's just the way it is - a poor design. Other symptoms of poor regulation is when the picture changes size with the content of the screen.

-Ian
 
The sticker on the tray the chassis is on says "25k7197" A Wells Gardner.

Thanks for the help
 
This is a common problem on monitors and television sets. When the picture goes all white, the beam current increases and it puts more load on the B+ supply, which sags. When that sags, it throws off the other stuff in the set and if anything is marginal in the sync, the picture will jump or roll. Sometimes simply readjusting the vertical hold control is enough to fix it - find the two extremes where it just barely holds the picture, and try to center it right in the middle.

The underlying cause can be caps in some instances, but in some cheap monitors/televisions, it's just the way it is - a poor design. Other symptoms of poor regulation is when the picture changes size with the content of the screen.

-Ian

Rep added for a great and correct answer :)

You can try a cap kit, but it doesn't always help a whole lot if the monitor is of a crappy design.
 
I'll try a cap kit because it's cheap and easy. The problem is, lots of Neo Geo games strobe. Metal slug especially, while explosions are going off and the screen is strobing it starts jumping and it looks horrible.

Might the B+ need to be adjusted? Besides caps, is there anything I can do?

Also, as a side note, how the hell do you get to the chassis? It looks like you have to take the entire monitor out. There is a panel with screws above and below the monitor, but it looks solid behind where I would need access to to get to the chassis.
 
I'll try a cap kit because it's cheap and easy. The problem is, lots of Neo Geo games strobe. Metal slug especially, while explosions are going off and the screen is strobing it starts jumping and it looks horrible.

Might the B+ need to be adjusted? Besides caps, is there anything I can do?

Also, as a side note, how the hell do you get to the chassis? It looks like you have to take the entire monitor out. There is a panel with screws above and below the monitor, but it looks solid behind where I would need access to to get to the chassis.

B+ should always be checked, but not always easy to... You'll want some plastic monitor adjustment tools and some electrical tape to join a couple together so you can make adjustments to hard to reach pots without having to stick your hand way inside the monitor. ;)

When recapping the monitor you should always check for and resolder any cracked solder joints. Common places for those are any high wattage resistor, yoke connector, flyback transformer, and plug-in connectors.

As for the access to the monitor - it depends on the cab. Post pics of the cab so we can see what you have or check the manuals out on http://www.hardmvs.com

RJ
 
Another question. When you turn up the brightness or contrast, and the colors look like they spread or bleed off to the side, could a cap kit fix that or is that a tube issue? I would like the monitor brighter, but can't because of this color bleeding. I can take a picture if this doesn't make any sense. Thanks.
 
yes it will do the cap kit and it should solve all your bleed problems. and should reduce the flash issue as well.

also change the filter cap and the 3 bipolar's as well. you will be amazed on how good it looks after word.

Peace
Buffett
 
I sent an e-mail to Bob asking him if those caps are included, thanks.

Anyone have any idea on how to get the chassis out without taking the entire monitor out? There is a panel with 4 screws below the monitor you can remove, and then another above. The wood area on the back 6" either way behind the chassis is solid.

It's an MVS-2-25 dedicated unit.
 
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