Hello all. I am currently working on a Williams Pat Hand ('75 EM) and had an intermittent issue where the score would start racking up the 1000's. If the ball drained, it would still continue over to the next player and keep running on the 1000's. It wouldn't happen very often. I cleaned up some contacts on the motor drums (pretty much anywhere it said "pulses 1000 point relay") as that was where I initially thought the issue was. I did manage to find a stuck closed switch in the area where I thought there might be the issue, but it didn't seem to help.
After spending some time on it today, I finally managed to get this to be a constant issue instead of a intermittent one and narrowed it down to this one thing... It seems that the 3000 point relay is sticking ON. I can start the game, play every switch fine, and then hit the one that is currently lit that awards 3000 points. When I do that the 3000 point relay pulls in and won't turn off. The points just keep going up and up... I can manually disengage the relay and of course it stops, but the real question for me is, "Where do I look next to get the relay to shut off?"
I can read schematics and understand the symbols and such, but sometimes I have difficulty wrapping my brain around the way the current is flowing around between the two sides. Any help would be greatly appreciated!
I also read the primer by SteveFury and was very impressed. It took some time, but it helped a great deal. Still not enough to solve this issue for me though. I'm pretty sure you guys can nail this issue in about 2 minutes, but I'm relatively new to doing EM work so, like I said, any help would be amazing. Thanks!