While troubleshooting a Williams baseball game (without the schematics on hand) but luckily traced where the problem was occurring, I noticed on the Stepper Unit disks there were no wires connecting the snowshoes directly. I added some solder sucker braid as part of the troubleshooting process. But it's something I haven't seen before. I understand the the rivet holding the contactor is connected to the adjoining rivet but seems prudent to make a back up connection. I also noticed these spring loaded contacts were severely warn due to quite a bit of arcing when it advanced to that position. PBR website is down, but has anyone bought these separately?
My problem turned out to be a dirty contact on the pitch relay stack.

Baseball Stepper Unit (resized).png