Nice cab! I always start troubleshooting pac boards like this one by removing the daughter card (in this case the black epoxy one) that fits into the z80 socket, since this is a Pac plus you will need a spare z80 processor.
test that first then go from there, if it plays standard pacman but with a green maze it is the ribbon on the epoxy daughter card, try that and reseat the vram addresser and sync bus controller cards and post your results.
look at these resources as well they may help you:
http://www.arcadegameover.com/pactrouble.htmlhttp://lawnmowerman.rotheblog.com/imma go over and check everything again this morning.
The game sometimed worked , I move something in the back and it toggles between what I have in the vid and normal
