Does the board look like this? I have this board marked as a gremlin dual but have no idea what it is or the pin out. Looks like one ROM is marked Carnival.
That's probably because it's Carnival. Occam's razor works!
There was at least 20 games on that hardware, most of which aren't that common. The Dual games are all pretty hard to find, but Invinco/Head on 2 seems to me the most common. That's the only Dual I have, and I don't recall ever seeing any others except for one Deep Scan/HO2.
So Carnival (smart guy) but still don't know what would the other be? Anybody know a pinout to test these? What signal changes the state from one game to the other (OP figurered that one out—very nice job).