I don't think I've ran any 2x6 System in a Blast but I would still use the io to ensure you're getting power to the system.
The ribbon cable I think is power to the cd rom drive or data. And the other is probably power. I can't recall but they're needed.
I think you did well if it's working. I believe that's a System 246. Be careful not to get games that only work on 256, some won't work even on 246+ mode.
I been after a 246 as my 256 plays 246 games in a audio high pitched "chip munk" style. Not all games but Capcom Fight Jam is one.
Purchased some color-matched Sega white paint for a project I was going to do. 1 quart worth of paint should be more than enough for 1 cab, maybe 2 if only doing the outside. It's single stage paint. Price is for paint and primer
Located in Northern California 95307.
I can't return the paint so...