Oakland, NE
Quoted from D-Gottlieb:If the ball count stays at 1 and won't advance, I would check that unit for free movement and operation. They do get mighty sticky over the years with the old grease that was used.
Schematic or not, I think this ^^^^^^^ is the logical first place to check. My first thought when reading the OP post was that the game just needs to be played. Steppers are probably getting sluggish from age and infrequent use. I bet a good inspection of the ball count stepper action will reveal the problem.
