Quoted from fotoboy:the machine will only let me add 2 players instead of 4... Wondering where to start. Any help would be greatly appreciated.
Most likely the Coin Unit Last Position switch is opening too soon.
For a switch to work 3 things are necessary:
1) When open, there should be a small space between the contact points (duh)
2) When closing, the long blade's contact point should push the short blade's contact point enough to move the short blade
3) The contact points should be clean, which they usually will be if #2 is happening