Ok, ive sorted the button conflicts now, thanks. I have gotten the player start buttons to light (permently) for the amount of players a game uses, ie Alien VS predator lights player start buttons 1 to 3, but not 4. But i cant seem to get the player start buttons to flash when a credit has been inserted. Now i know that the UK arcade version of TMNT use to have the player start buttons flash when u inserted a credit, but i cant seem to get this to work on mame. That said the UK version used to have just one coin shutte, and was able to select which turtle you wanted via the start button you pressed, on mame you cant do this!!?, you cant select just 1 coin shutte in the mame menu (although alot of the options are listed as unknown??) and adding a credit (button 5) always only allows you to select leonardo, so i dont think this is anything to go on. I'll try Dig dug later