Quoted from Jakers:
Yup, I’m thinking I’ll go with the rottendog MPU replacement, then eventually get this original board repaired so I have an extra for testing purposes down the road. Who’s the go to for MPU repair?
I did try unplugging J5 from the opto board like dumbass mentioned. When I power the game up the dmd says “check fuses f115 and f116, j112 and opto 12v supply”. It’s been sitting in attract mode like that for 20 minutes now and I haven’t gotten that phantom beep yet. However, I cannot start a game and only the escape button inside the coin door works.
I’ve also checked the coin door interface board for cold solders and it doesn’t have any.
Have you checked all the wiring on the coin door and components? I had a similar issue when two wires came off of their lugs on the switches for the coin slots and would cause some funky stuff to happen with the game and service buttons.