I lost a piece of video; not sure what happened. The 7474 D flip-flop IC at location C3 was replaced, and that fixed all of the video problems. I still had a problem of no audio, but cleaning the volume potentiometer fixed that. The game seems to be working 100%. Still need to test the steering and gear selection for both PCBs; trying to come up with a good way to test them. Other than that, these are done and I'm moving on to the next project.