So, I have an IGame from AC Coin and slot. Second one from them in my collection. Can't get rid of the Door Open M. As you know, not much you can do with that message being there. No optics in these games. The board is spotless. Doesn't look like it ever even had a varta, but just to check, I took another 3902 with a different game, and put that in. Same thing. The game (lobster Larry) loaded perfect, but same error. Door Open M.
I put lobster Larry back in its original cabinet and no issues.
So, I'm ruling out an MPU issue, and I changed both Door switches with known good ones. Not sure what direction to go in from here. Any help appreciated
***topic solved. Bad belly door switch was causing the problem. ****