I just bought this game as a project. I've got it mostly working now, thanks to Clay's guide and Pinside.

My last problem is that the game won't decrease the ball count...usually.

The ball count stepper unit works fine, was cleaned and lubed with a little Teflon. When the game has not been started yet I can hit the trough switch and the ball count will decrease just fine. Once the game is started though, it will *sometimes* advance, but usually get stuck on one of the balls, or never decrease. It sometimes also decreases as soon as the first ball kicks out. I noticed that when the relay "V" in the backbox is engaged, the trough switch doesn't work. If I engage the 10,100,1000 point relays that is what makes relay "V" engage and stay engaged. If I had a schematic, I would have likely solved it by now
I do not have a schematic, so if anyone has a copy out there please let me know, or if you have any ideas. I've looked at all of the relays and all appear fine, but obviously I've missed something. Thanks in advance.

Yup, I don't even know what the V relay is, but I do know that there is a switch on that relay that breaks the connection from the trough switch to the decreasing coil of the ball count unit. Every time any digit reaches 9, that V relay denergizes and the trough switch will work.

Ok thanks Wolf.

Someone graciously sent me a scan.

Problem solved. ALL of the zero switches on the reels remained closed when they moved into the next position (1-8) therefore never communicating to the relay that the game had begun scoring. Not having much knowledge in EMs, I only checked the score reels' relatively of the switches from reel to reel. Prying open a zero switch and watching the trough switch relay de-energize was very relieving.