My guess is that the ROMS are probably corrupt. The good news is that the board appears to be working since there is something being displayed. Normally these machines have removable EPROM chips. This is one of the games you can find ROMS online for. With an EPROM programmer you could probably fix it up. (EDIT: As long as you can find a direct dump online)
I've never seen one of these though - so my assumptions could be wrong. I don't have as much experience on pre-1980 units.
Also these units are pretty rare so just finding a board in the wild will probably be impossible. To be honest I never even knew there was a Cosmic Monsters II. I had only ever heard of the first one.
