Brightness/Whitewashing Issue. Happens when machine is warmed up.

aaronmjr

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Brightness/Whitewashing Issue. Happens when machine is warmed up.

I'm new, and have read the FAQ's so please be gentle. I'm having an issue with the monitor on my Marvel vs. Capcom machine. I found a tag on the monitor or a bracket connected to it that says "WG 1527111". Is that a Wells Gardner monitor model? I can look closer tonight and try to find another identifying mark. Anyways, once the machine is warmed up, the picture alternates from being really bright, like too bright/white'ish and a little blurry, to a little dark but in focus. I'm also noticing a bit of a burning dust smell when this occurs. May be a coincidence. It's not burning PCB components I don't think, I know that smell well. Also, if I tap on the CP, or the cab near the monitor the screen will flicker between the aforementioned light and dark. Strikes me as a connection issue maybe?

The guy who sold me the cab got in touch with a repairman he knows and he told me that after being moved it may just need to be adjusted with a knob on the back of the monitor. The tapping affecting the screen makes me think more may be at play here. Supposedly the monitor is newer. Anyone heard of a similar issue? I can get any information, and take any pictures you guys might like tonight and post them tomorrow. Thanks in advance.


Pictures of the cab are in my welcome thread, here: http://forums.arcade-museum.com/showthread.php?t=227484
 
sounds like cold solder joints to me.

you need pics of the monitor chassis to see what it really is. sometimes chassis and frames get swapped and are a mismatch to what they really are.

also update your general location in your CP so a local member may be able to assist you.

Peace
Buffett
 
Good news. I had the machine on for a few hours tonight and couldn't duplicate the issue. I hard booted a few times in the middle, banged on the cab a bit and everything seems good. I found the adjustment control panel and got everything lined up and tweaked to my liking. I took some pictures of the monitor setup and will post them tomorrow so at least for the future I might know what I have and how ghetto it might be rigged up!
 
Here are the pictures I took. Sorry for the quality.


Adjustments for the monitor. I'm assuming this should have been mounted somewhere, but it's nice that it's not because the ribbon is long enough to come around to the front so I could watch the screen while I fine tuned.

6834534542_1fe6c0cec0_z.jpg



Looking in from the back panel. Anyone know what that wound copper thing mounted on the left is? It's not plugged into anything:

6834534672_a3fe405732_z.jpg

6980662499_e3ca857430_z.jpg



Back of the monitor:

6834535260_17256dd507_b.jpg
 
That's a Wells Gardner K7400 25" monitor. That's Buffett's FAVORITE monitor to work on. :D

Your light screen could be due to a few things:


  1. Cracked solder joints (will come and go with heat and cold)
  2. Old, worn out tube. MIGHT be fixable with a rejuvenator.
  3. Bad caps (less likely)
  4. Bad Flyback (even less likely)


FYI, if you need a replacement tube for this monitor, I have one. My K7400 chassis seems to be haunted and unfixable, so I may just let the tube go.



Also, that little copper thing you see mounted to the side of the cabinet is an isolation transformer. The iso's are used to protect the voltage going to the monitor's chassis. Since your K7400 monitor already has an iso transformer built into the chassis, it's not needed in your cab. But I could use it - I've been looking for one to use in a test bench build.


I know you're not far away from me, so if you need help rejuvenating the monitor, LMK. I could run up there and shoot the tube for ya.
 
Brad,

If you can use the isolation transformer, it's all yours. Shoot me a pm. I appreciate the offer on the rejuve, is that just good practice to do anyways? I ran the game for at least 3 hours yesterday and couldn't get the monitor to do anything wrong. I adjusted everything so the picture is as complete and clear as I could get it and it's been flawless. And the burning dust smell was from the marquee light. I'm going to keep an eye on it but I think were in the clear. I wouldn't be completely upset if we ended up having to replace it though. The front of this tube is pretty scratched up, slightly distracting during gameplay. Just makes it look a little dirty.
 
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Not necessary to shoot the tube - only if you're disappointed with the picture quality and you can't get it looking right after a cap kit AND adjustment.
 
I think it looks good. The brightness knob is pegged, I'd like it a bit brighter but meh. It'll do:

 
Hi all,

Wanted to take advantage of this topic!

I have Cosmic Avenger with original monitor, and I have the "whitening" issue too, like the contrast is turned up too high. When I adjust the contrast/picture all the way up, and then down, the picture holds the correct contrast/brightness (space field on the screen is approriately dark) for about 1.5 seconds, and then the screen lightens up quickly to its current "overbright" default. The game is playable but clearly not ideal.

I surmised it might be related to the pot/solder since the monitor does initially respect the correct contrast when first adjusted. Curious what greater and more experienced minds might surmise from this situation.

Thanks!
 
Hi all,

Wanted to take advantage of this topic!

I have Cosmic Avenger with original monitor, and I have the "whitening" issue too, like the contrast is turned up too high. When I adjust the contrast/picture all the way up, and then down, the picture holds the correct contrast/brightness (space field on the screen is approriately dark) for about 1.5 seconds, and then the screen lightens up quickly to its current "overbright" default. The game is playable but clearly not ideal.

I surmised it might be related to the pot/solder since the monitor does initially respect the correct contrast when first adjusted. Curious what greater and more experienced minds might surmise from this situation.

Thanks!

Too difficult to diagnose your issue by the description alone, and you can't really piggyback on this thread for it. We don't even know if you have the same monitor as the OP. The game does not tell us what monitor you have, as monitors were commonly swapped around between game cabinets all the time.

You should really start your own thread in the monitor repair section, with clear pictures of your chassis, model numbers if you know them, and other details such as the game you're running, if the chassis has been capped, etc etc etc
 
Poop. Issue re-appeared tonight while playing with my niece. It gets more obvious after like 15 seconds. Talking to the seller about possibly returning it. Thoughts now that you guys can see the issue?

 
Yeah, I'm afraid that looks like a flyback issue.

One way to test - disconnect the video feed, but leave the monitor on. Turn up the brightness a bit until you can see a white screen of raster. Back it off a bit so you can still see raster, but not scanlines (diagonal lines). Watch for the brightness problems to appear. If they do, then you issue is most likely with the flyback.

Good news: you can still get the flyback for that chassis.

Bad news: it might not solve your issue, and you have to find someone to replace the flyback for you.

Good news: I would be willing to replace the flyback for you at no charge. Two stipulations:


  1. You must bring the monitor's chassis to me to do the work.
  2. I would like to test your new flyback in my (sick) 7400 chassis before we put it in yours. I have had just about everything replaced on mine EXCEPT the fly, and I've been looking for a reason to buy a flyback. This is as good as any other reason.
I wouldn't try and work a return with the seller. These games are almost always sold 'as is, where is.'


But don't fret, we can help you get running properly.
 
Thanks for the offer Brad, I might take you up on that. My only hesitation is that I don't want to just throw parts at this thing without having some solid indication that a part is dying, but I really do like it and want to keep it. He has already offered me a full refund just in case. Can you tell me from my photos, or maybe someone else's which cable or connector is the actual video feed so I can try your test? And also remember my brightness pot is already pegged. I looked on that Bob Roberts site and see a flyback is about $27. In order to remove the chassis and bring it to you, I would need to discharge the monitor right? I remember reading that there is a tool for that so I don't zap myself into the next dimension. Is this "the" one to buy? http://www.therealbobroberts.net/safeback1.html


Aaaaaand here we go. :D
 
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If your brightness knob on the remote board is pegged, try this:

locate the two knobs on the back of your flyback. The top one is focus, the bottom is called 'screen.'

The 'screen' adjustment is your coarse brightness adjustment. Your remote board pot is the fine adjustment. Back off the pot on your remote board to 50%, and turn up the screen knob a tad on your flyback. Let us know what happens.
 
I can do that. In my crystal clear photo here can you tell me where I should be looking for these knobs? I took a quick peek around the board area when I took these pics and found 2 teeny tiny little adjustment knobs. I think they were just to the left of the right hand frame rail that the remote board ribbon is draped over in this photo. Does that sound right? In reading all of the FAQ's I'm looking for some oozing black box with knobs on it for the flyback but maybe this monitor's guts are different.

6980662499_e3ca857430_z.jpg
 
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