To Retropin:
yes, credits add ok, but start button does nothing at all. Once machine is powered on, the LOCK relay is definitely latched. I've turned the machine on and off a few times and definitely latches and the switch makes a connection where it is supposed to.
When I press START, nothing happens as I said. I then go round the back of the machine and look at the Williams coin unit (referred to in my previous posts as the stepper). This clicks into action if I press a coin door switch and the reel goes from nothing to 1, 2, 3 etc. etc. indicating that there are credits for a game to start. Unfortunately, the start button won't start a game. The coin unit also clicks into action if I press the top most switch together. With the machine turned on, I was doing this with a piece of cardboard....didn't want to get zapped a second time in one day.
Retropin, could you please explain the Ball Count ZERO position and 2nd COIN relay a bit more in relation to the diagram I just posted?
I might have to call it a night tonight. Thanks all.
Cheers!
Adam.