"game not recognizable by main board"
pretty much means one of the following:
a) the cartridge just needs to be reseated
or
b) their power supply's +5 walked too high and burned out the buffer chips on the cartridge. Capcom I/O feeds the main board exactly 5.00, and the highest you can go with it is 5.10.
Sega's wiring scheme is a little different. you can probe direct into the back connectors, but note that the yellow is the +5, red is the +12, brown is the +3.3 and white is the ground.
I stole this off another site just now if you want the pinout.
of course even if you do happen to correct the power supply, should it be adjusted wrong, the cartridge may potentially need to be repaired.
hopefully it just needs to be reseated.