I fixed a CC board this weekend that was pretty jacked up. Most time was spent fixing the missing pads and ripped up traces under the EPROM sockets that someone apparently pried off with a sharpened wood chisel or something. Maybe they just skipped the whole desoldering step?? Dunno. Please take brzezicki's advice and be careful with removing chips on that board. Those pads and traces are easy to lift / break. I would suggest clipping the legs off the chip and desolder one pin at a time.
Anyway, once I got the board to boot up, I had nearly the identical graphics issue where some motion objects were being drawn together, scrambled, or missing. I swapped out the LS374 @ 7A and it rectified that issue.
Good luck to you, and thank you for the tip Hudson.