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View Full Version : Monitor Stops Displaying Neo Geo - Wells Gardner 2500



TheSegaDude
11-18-2015, 06:21 AM
Hey guys,

What do you think is causing this?
When I boot up my Neo Geo everything is working well. The game play and the image quality is very good.

After playing for about 45-60 minutes the monitor will stop displaying the game. The monitor wont turn off but it's clearing not showing the game anymore. And I can still hear the sounds and music.

After powering down and turning it back on everything looks good again.

The vertical hold; or whatever it is when you adjust the picture left and right is set all the way to the left. It's still not perfectly center (close) but the dial cannot adjust it further left.

The monitor is a Wells Gardner 2500.

RetroTechRewind
11-18-2015, 08:55 AM
When the picture dies, does it slowly fade out? Or does it just disappear instantly?

Could be a few different things depending on the chassis that's being used on the tube.

Do you have any experience with electronics? Would you be comfortable with removing the chassis and discharging your tube?

TheSegaDude
11-18-2015, 09:31 AM
When the picture dies, does it slowly fade out? Or does it just disappear instantly?

Could be a few different things depending on the chassis that's being used on the tube.

Do you have any experience with electronics? Would you be comfortable with removing the chassis and discharging your tube?

When it switches to what you see in the image it happens very quickly (instantly). And it's static. In real life it looks just like the image. It's not rolling or moving.

My original chassis needed the capacitors replaced. So I bought a used chassis (the one in the Neo now) and it worked well for a good while (the seller said it had a new cap kit and was re-flowed).
Yes, I am comfortable removing the chassis. I've done it once before.

I actually have a cap kit for my original chassis and I was about to start doing that. But I would still like to fix this chassis too (if it is the problem).

Thanks for the reply RetroTechRewind!

RetroTechRewind
11-18-2015, 09:45 AM
When it switches to what you see in the image it happens very quickly (instantly). And it's static. In real life it looks just like the image. It's not rolling or moving.

My original chassis needed the capacitors replaced. So I bought a used chassis (the one in the Neo now) and it worked well for a good while (the seller said it had a new cap kit and was re-flowed).
Yes, I am comfortable removing the chassis. I've done it once before.

I actually have a cap kit for my original chassis and I was about to start doing that. But I would still like to fix this chassis too (if it is the problem).

Thanks for the reply RetroTechRewind!


No problem!

It might be capacitors. The critical safety Polypropylene caps could be overheating, and failing. That would explain why it works, then cuts out immediately. Or, could even be the large power resistor located near the big AC filter cap. Those can overheat and fail as well. If the guy did a cap kit, I'd assume he only replaced the electrolytic, and not any of the PP caps. If you can get the chassis out and post a pic of it, or even just the model of the chassis itself, I could point you in the right direction. I'm guessing it's probably a k7000 series chassis.

When the screen dies, does the image look wavy at all? like its rippling like the surface of water etc? I know you said it wasn't moving, but figured i'd ask to make sure.

Lastly, when you turn it on, and it dies, does the neck of the yoke have any glow in it?

TheSegaDude
11-19-2015, 07:01 AM
Yes, you're right. It's a K7000 Monitor Chassis. The guy who did the caps also labeled the neck -> P448 Neck.
I turned on the Neo and let it run. This time the problem did not happen. It just stayed on without issue.
I didn't have time to take out the Chassis but I took a few pics that maybe will help out.

Also, I don't see what looks like rippling or anything that looks wavy. While I played it for a bit I did notice that when a game transitions to a new image the black screen that will briefly appears looks exactly like my first image above. Showing those horizontal line that are at a slight angle with no rolling, waving or rippling. It's not a pure black... likely I have the brightness and or contrast too high.
The light in the neck was always on. I didn't get a chance to see if it went out because the issue did not happen this time. I will try again.

And again, thanks for the help!

Westcb
11-19-2015, 08:35 AM
Yes, you're right. It's a K700 Monitor Chassis. The guy who did the caps also labeled the neck -> P448 Neck.

I turned on the Neo and let it run. This time the problem did not happen. It just stayed on without issue.

I didn't have time to take out the Chassis but I took a few pics that maybe will help out.



Also, I don't see what looks like rippling or anything that looks wavy. While I played it for a bit I did notice that when a game transitions to a new image the black screen that will briefly appears looks exactly like my first image above. Showing those horizontal line that are at a slight angle with no rolling, waving or rippling. It's not a pure black... likely I have the brightness and or contrast too high.

The light in the neck was always on. I didn't get a chance to see if it went out because the issue did not happen this time. I will try again.



And again, thanks for the help!


If your fly back is borked you can get symptoms like that. It's only about 30 bucks for a new one and simple to put in yourself even with a crap RadioShack desolder iron for 15 bucks. When they are weak after a period of time everything can drift with heat, I see you still have raster lines though so can't say for certain. A lot of times the focus will drift or the brightness will go way up or away completely if that's the culprit. They are famous for failing after a cap kit though and if that's not a new one then it's a good place to start.

Edit: I finally got your pic to come up, the wg7000 flys with white knobs are famous for taking a shit, it's not an exact science but is established bro science for sure in the k7000 threads to change those out, when they go out they tend to take other parts with it. So do that regardless :-)

daskrabs
11-19-2015, 11:56 AM
Another easy thing to check is the pots on the remote board, specifically the brightness and contrast ones. The stock pots crack easily and may need replacement. It might help to reflow those joints. If you wiggle the remote board and it cuts out, that's the issue.

GTRetro87
11-19-2015, 02:27 PM
Yea first thing I would say is change the flyback to one with *black* knobs; specific thing on K7000's like yours. BUT, while changing the flyback, check **every single little point/pin and trace**. Make sure that each solder joint is reflowed with new solder and then test each trace with a multimeter to make sure none of the (obviously not tiny) traces are not damaged or lifted - do this for most components like caps and the HOT, (horizontal output transistor attached to the big metal bracket by the flyback), etc... Don't worry about the IC's in the middle of the chassis, those are fairly last resort.

Then, if all checks out pretty well, test and see if the flyback and reflowed points helped. If not, THEN change the capacitors (or change the caps during the check/reflow period).

As long as the monitor is turning on, perfect. The problem should be easily fixed from there.. if it was not turning on, blowing fuses, or giving neck-glow but the monitor not actually giving an image (hehe My current issue).. then you'll be scratching your head for the problem. These chassis are easy to fix, but it takes testing to do so


If you have any issues, you should look for "The Arcade Buffet" and he'll help you out cause he repairs chassis left and right AND does it well! He has parts as well (flybacks, caps, everything to fix our chassis').

TheSegaDude
11-24-2015, 03:56 PM
Hey guys,

Thanks very much for the advice. I think I'll try all of your recommendations.

1) Replace critical safety polypropylene capacitor *still have to identify what this is.

2) Replace the large power resistor located near the big AC filter cap *still have to identify what this is.

3) Replace fly back (watched a youtube video and I'm sure I can do this)

4) Reflow solder joints on the pots (pots are the small white plastic dials, right?)

5) Reflow all solder joints

6) Test each trace with a multimeter. I recently bought a multimeter so it's about time I try it out.