Bootleg DK Jr. Video Issues

highscoreheroes

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I've been puttzing around with a bootleg 2-board DK Junior I got a few months back. The PCB is pretty much an exact hardware duplicate of the real Nintendo board, just minus the Nintendo logo. The sound and video are handled a bit differently, no need to invert the video or amp the sound, etc.

After wiring up a Jamma adapter for it and finally getting to boot it up, I'm getting some strange video problems.
20170225_090828.jpg

The screen isn't filling up properly and there's vertical lines here and there of solid black. Some of the sprites look a bit squat and crushed, too. The screen also shakes.

I'm fiddled with the adapter more and nothing has changed, but tinkering with the VR1 and VR2 pots on the bottom of the second board screw with the video as expected. I'm just kind of stuck at a standstill from this point tho- I don't know how to correct the video, fill up the screen, and get everything aligned properly.

I'm using a Chinese RGB-to-NTSC adapter that's worked fine for me on other boards and still works fine using my Pac boards so I know it's not the adapter right now either. I'm not totally sure where to begin.
 
That's a board fault not an issue with the monitor or the adapter. You need to start reading into board repair, look for previous repair logs of similar boards that may have had a similar fault and go from there :)
 
video ram on bottom pcb uses -5 cant remember off hand number of it so check those are working correctly i had a same type of issue when -5 was low would cause that

finished fixing the same board set earlier this week
 
After months of not touching this board I was fiddling with it the other day and getting a different problem altogether-
yfeANOf.png


And I dunno how to even describe this one. The screen is solid black other than a very thin white outline of where certain things should be, like the score text, the logo, some sprites, etc.

I was actually getting a different picture initially, one with visible sprites but no colors other than blue. I let the cab run for a few minutes and came back to the problem above, and now I can't get "Donkey Kong Bluenior" back.
 
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