You found a potential cause... awesome. I looked that game up on KLOV, looks damn fun. Now ifyou only looked like the kid from ET, you'd be all set (I did as a kid). Cool looking cab, too, though doesn't look like you have it.
Keep us updated, I'd love to see this sucker living again. Since you've made your own adapter anyway, I'd bring the 12v down to 10.3 on that line. May as well, it's not like you're using that harness for anything else.