Tonight I needed to find a screwdriver. Couldn't find it in the toolbox. Then I remembered when I used it last - on Sunday to make some adjustments on the ball counter unit. Yep, opened up the backbox, and there it was.
[The adjustment I was doing was on a Gottlieb Volley. On the re-set, it would not show "Ball 1". The ball would load, I would shoot it up but nothing working. It would drain, then the ball counter would advance to ball 1 and everything would be OK from there.
I opened up the backbox, and adjusted the springs on the stepper thinking that tighter springs would pull the pins to make contact in the right spot.
Didn't fix it. What solved the problem was slightly moving the solenoid that steps up the counter. This allowed the plunger to travel the required distance to engage the cog and move it to the correct spot.]