Are you certain the monitor works properly, particularly in low res mode? If you haven't tried it before it's possible the electronics require servicing. (if you have other boards you use without issue this probably isn't the problem) If you haven't already tried a different game board, and you have another available to try, it maybe worth trying another low res board (or if you have the original NBA Showtime board trying it in low res mode - the gameboard should have a dip switch on board to swap between medium and low res).
In your photos of the adjustment pots I cannot make out the labels on the chassis neck board however the adjustment daughter board V-hold adjustment should fix the picture rolling. Does the main board of the monitor chassis have any adjustment pots on it? (maybe not with a adjustment daughter board too I'm not sure why they'd split the controls...)
Struggling to think of what to suggest. I don't own a dual res monitor, there maybe some little detail I'm not aware of. Wish I was more help here... if I think of anything else I'll update.
Thinking about getting a RaspberryJAMMA, or have just purchased one and have a newbie question? Walls here are padded, come on in and bounce your question off of them!