My local arcade has a problem with their X-Men arcade cabinet where whenever a "credit" is inserted the game restarts and runs its self-test. I put credit in quotations because the machine is set to Free Play. I don't know much else about this machine other than I'm willing to fix it for the arcade if I'm able. If you need any more info, I'll try to figure it out for ya.
Thanks in advance,
~gszx1337