What is this connector
That's an AMP Universal Power connector. Sega used them on the Naomi cabinets.

The two pin housing to plug into that board is part #176271, and the pins are #175151 (or 175152 for larger wire). These are female pins for the male plug. Digikey should have them.

See https://wiki.arcadeotaku.com/w/AMP_Universal_Power for more info.