My friend picked up a Williams Big Guns machine that we have been working trough various problems with.
I am looking for some ideas about this issue though. It is failing the boot up test with switch 5 which according to the manual is center coin slot. The problem is the machine does not have a center coin slot so why is it looking for that switch? Is it a bug in the ROM?
I understand the concept of the test:
"If a switch is not activated in 30 games, or is permanently closed, the switch is assumed to be bad. This will create a test report, which is shown when the game is turned on. If a particular feature of a game is difficult to score, it's associated switch may be (falsely) assumed bad (if not activated in 30 games). To correct the test report, remove the playfield glass, and activate the switch by hand within a game, or within the diagnostics switch edge test. "
But there is no switch to activate. I have actually looked at schematics and found the pin on the board that coincides with switch 5 and jumped it with a test lead and it cleared the error but sure enough after 30 games it's back. Is there a way to stop it form looking for that switch?
Thanks!

Yes sorry, coin. Auto-correct screwing with me. They appear to be factory roms but we don't know the history of this machine at all. Some repairs that were done previously to it are not pretty I'll just say.

No we havn't tried that, will give it a try. So on free play by right it should not check any coin slot switches?
Thanks

There is no center coin slot in the door. Only left and right. The left and right switches work fine and they pass the boot test fine.

I just found a pictures of Big Guns with a center coin slot and some without so this must have been an option on some machines. This machine looks like it's been through a lot so who knows if this is the original setup or original CPU board. I would guess there is a mismatch somewhere or the wrong rom from a machine that had a center coin slot.