Can you hear any sounds etc? Have you ruled out the monitor?
First thing would be to check you are getting 5 volts to game pcb.
Super monaco GP, uses the sega x board hardware, shared with After Burner/ Thunder Blade etc.
The X board uses a battery powered processor, which after a number of years, can go dead, and the game board will not boot.
You can fit a normal 6800P12 processor, and you will need to then install a set of unencrypted roms. Before It gets to involved, I would check the game board, is getting 5 volts first.