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Contrast/color issues on universal replacement chassis
snappleman:
Out of curiosity I got one of those Chinese universal arcade monitor chassis and installed it onto one of my 19" CRTs. The installation process was easy and the picture looks great except it has this strange behavior where it changes tint depending on what's on the screen. For example if there is a lot of blue and green on the screen, the red will get get much more visible making the blue slightly purple etc, this happens with all three colors. I connected an MVS to it and I'll get the screen looking perfect in the service menu, but as soon as the game starts the colors/brightness/contrast all go off. The Neo Geo boot screen will flash white for a split second but then quickly go gray soon as the black Neo Geo logo comes in. This behavior is the same with consoles hooked up via SCART. I know that pure RGB that comes out of a JAMMA connector and the RGB out from SCART are different, and arcade monitors don't always look right with SCART, but as far as I know the MVS output should be correct.
I've tried setting the drive/cutoff/screen/brightness as I've been doing for years to calibrate monitors, but every control is in Chinese and there is no contrast control. At this point I'm wondering since this is a very (very...) cheaply put together part that if it isn't some bad components on the board? The RGBS connector was wired backwards which was just annoying at first (only because I got excited that they had actually used properly colored wire, just in the wrong order...) but I noticed the colors/sync go nutty a bit when I was just moving the cabling out of the way, so just touching it makes it go stupid. I could take it apart and do a recap but would a crappy/faulty flyback be causing this also?
Another thing I should mention is that the yoke on the TV measures about 13ohms on the vertical where as the chassis is rated for 6-12ohms, though I wouldn't think that would be the issue.
snappleman:
Update: I went to discharge the monitor to check the board for faulty components, but the spark I got when discharging was pretty monstrous and gave me a solid scare (and blew back the suction cup even). I realized that I was having the flyback up way too high to get a raster with the game on, so I figured it's an RGB input voltage issue. Then I remembered the MVS I was using was the 2slot that I modified to work as a console back in 2001, and even though I connected the RGB via JAMMA I used the little 2A 5V power supply that I modified it to work with, so the video signal was just not capable of driving the monitor. I hooked up an unmodified MVS board to it and the video is fine.
Osirus23:
--- Quote from: snappleman on October 24, 2020, 05:09:07 pm ---Update: I went to discharge the monitor to check the board for faulty components, but the spark I got when discharging was pretty monstrous and gave me a solid scare (and blew back the suction cup even).
--- End quote ---
Damn. I usually just get a little click.
grantspain:
shame you don't have a hv probe to see what level the eht is
snappleman:
The flyback on this thing is suspect regardless. Whenever there's a white flash on the screen (or a solid white screen) it makes that little sizzly dying flyback pop that really makes me nervous, and the screen shifts brightness just a little bit before it recovers to white. I'm going to check the sticker on it to see if I can find a replacement somewhere just to have on hand.