25K7193 Brightness/Backlight Problem?

Crowbar

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Hey, everyone. I apologize for the beginner type question on here, but I just recently bought my first arcade units (A Mortal Kombat II machine and a Neo Geo sans pcb board) and I'm still trying to figure out all the kinks. Please bear with me on this.

I've recently added a new board to the Neo Geo machine and it looks like everything is working fine with the board itself. However, I noticed the brightness on the monitor (A Wells Gardner 25K7193) is slightly dim when it first starts up, with a slight reddish tint on most things, making things look off. Adjusting the brightness and contrast only succeed to make the image look "washed out". I expect some amount of this to be normal, but after about 15-25 minutes, the problem will stop persisting and the image will look like how it should, similar to that of a backlight suddenly turning on. The image will sometimes flicker between the two when it "fixes itself" like this, but it's generally okay from then until the unit is shut off again. Is there something simple that could be causing this? Is it old age (It says it was manufactured in January of 1992)? Or is there something far more sinister at work?

I apologize for not having any pictures of the unit and the problem, but I will get them once I get home from work if needed.
 
What you are describing sounds very much like a monitor suffering from "old age". Fortunately, there is a Fountain of Youth for monitors.

What you need to do is have the monitor rebuilt - all new electrolytic caps, maybe a new HOT, VR, and possibly even a new flyback. While it is being rebuilt, it should be inspected for cold solder joints as well.

That will brighten up your picture and improve stability.

As for it taking a while to "warm up", that may go away with the rebuild, or your tube may need to be rejuvenated....

EDIT - Oh yeah, and welcome to the forums!
 
Yeah, what he said heh...

welcome to the forums crowbar!!!

Theres a wealth of info here and some really really great guys. You came to the right place!! Welcome!
 
Thanks for the warm welcome. :D

I looked at the monitor again once I got back and I believe I may have found the source of the problem. A touchy flyback, when pushed gently on the screen knob brightened up the screen to how it should be. Not sure *why* this fixed it and I'm pretty sure it can't be a permanent or good thing. I'll see about replacing it soon.

Thanks for the help!
 
replace it NOw!! (or dont use the game)

if the fly goes, itll take out alot more components and will cost ya alot more to repair vs juat replacing it now....
 
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