Archived from groups: rec.games.video.arcade.collecting (More info?
According to the schematics, the *CSYNC (negative-going composite sync)
signal is generated by a 7408 chip at location 6H, pin 6.
Coincidentally, just last week I worked on a Pac board with a similar
problem. It too had a bad 7408 chip. The output was reading a very leaky
100 or so ohms to ground. Replacing the chip cured the problem.
Matt J. McCullar