K7000 color issue

SuperGunGuru

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Hi all,

I have a K7000 19" in my Double Dragon cabinet that seems to have a small discoloration issue. I snapped a pic of the screen and hopefully you can see what I'm talking about. Notice how the bad guys pants are supposed to be white, but they have a redish discoloration in them. Notice also the credit display at the bottom isn't a clear white. Same thing with the timer near the top. FWIW, the monitor has been capped and I also tested and rejuvenated the tube today. Thanks for any advice. This problem is minor, but I would like to take care of it.

DSCN0592.jpg
 
Have you tried balancing your colors? The red may just be turned up too high and this leads to it washing out the blue and green. The adjustments for the colors are on the neckboard.
 
I have been messing with the colors in the past and today but have never been able to get it right. The good news is the rejuv I did today went fine and the guns all have good emission now so because of that I wouldn't *think* it's a tube problem. I also did a rejuv on a spare exact same model tube which I may try swapping since it is pretty much burn free and this thing has Xenophobe burn of all things.
 
TURN down the red gain and cutoff... or mess with a combination of boit till its right...

looks like it could also use a tad less blue and a little more green

usually what i do is look at the black or white parts of the screen, crank up a pot untill the color bleeds through then back it down a tad till its cleaner.. do that for all of the colors all gains and cutoffs then see what ya get.. if you did it right you should have pure blacks and whites when your done... and you can fine tune form there if need be.

before doing this make sure your contrast is set in the center that way you still have some fine coltrol there too and have your black level and bnrightness anout 3/4 up... same reason
 
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Could be a board issue.

We have a winner! Ok so I did some more adjusting this morning and still couldn't get the change I was looking for. The black level at this point was up too high and I just decided to stop where I was and try some other boards in there, figuring I'd have to tweak more but maybe another board would cooperate. When I tested 3 other boards, all of them looked good on the last adjustments I tried with Double Dragon. The problem with the Double Dragon board is it's a bootleg, which I have known from the beginning. It looks very similar to the authentic Taito boards, but there is no key in the jamma card among other things. Since the op was willing to just throw in a crt from a Xenophobe, I guess there's no reason they wouldn't just replace the original board with a bootleg also. I'm just going to buy an original Double Dragon board and then I should be good to go. I guess it just goes to show you need to be 100% certain where the problem is before you mess with a good part. On the plus side, the picture looks pretty good with the other boards so rejuvenation was successful.
 
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We have a winner! Ok so I did some more adjusting this morning and still couldn't get the change I was looking for. The black level at this point was up too high and I just decided to stop where I was and try some other boards in there, figuring I'd have to tweak more but maybe another board would cooperate. When I tested 3 other boards, all of them looked good on the last adjustments I tried with Double Dragon. The problem with the Double Dragon board is it's a bootleg, which I have known from the beginning. It looks very similar to the authentic Taito boards, but there is no key in the jamma card among other things. Since the op was willing to just throw in a crt from a Xenophobe, I guess there's no reason they wouldn't just replace the original board with a bootleg also. I'm just going to buy an original Double Dragon board and then I should be good to go. I guess it just goes to show you need to be 100% certain where the problem is before you mess with a good part. On the plus side, the picture looks pretty good with the other boards so rejuvenation was successful.

What did I win? :D
 
yes, looks like a palette swapping issue of sorts. I've never dabbled with RAMs before, but aren't those usually the cause for bizarre graphic artifacts or other misc. garbage on-screen issues?

I've hail mary-ed some stuff back to proper operation by just digging in with rubbing alcohol and a toothbrush... perhaps all your ROMs might need to be re-seated or cleaned.
 
yes, looks like a palette swapping issue of sorts. I've never dabbled with RAMs before, but aren't those usually the cause for bizarre graphic artifacts or other misc. garbage on-screen issues?

I've hail mary-ed some stuff back to proper operation by just digging in with rubbing alcohol and a toothbrush... perhaps all your ROMs might need to be re-seated or cleaned.
I did try to re-seat them, but no change. The board is actually pretty dirty in spots so maybe I'll try giving them a cleaning.
 
yeah, probably RAMs. I think actually if it was ROM related, that the graphics would be scrambled or missing, etc. and it wouldn't be a palette issue.

hope you can find the cure soon. good luck.
 
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