Are your lamps getting power? Stick one lead of your DMM to one of the bulb socket mounts, and the other lead to a known good ground. You should get 6 volts. If not, it's a power issue, and you should probably check for broken wires (assuming other lamps are getting power and working). From memory, System 1 games don't have a matrix like other games from the same era have. Check your grounds. I believe that lamps are clustered into separate grounding connectors as well. Without a manual/schematics, it's difficult to tell exactly where your problem lies.