I found this article that explains how early Bally score displayes work:

http://stevekulpa.net/pinball/bally_disp6.htm

I was curious if there were any articles that describe how Williams displays work in a similar way. It looks like there's a lot of overlap, but Williams and Bally did some things slightly different and it'd be nice to know what those differences are.

I've read both of those, but they don't really tell me how they work. They tell me what tests to do based on symptoms. It's like me asking how a dishwasher works, and you giving me the troubleshooting section of the manual.

I'm looking for something like the linked article. "The CPU sends this signal to this decoder which does this thing to these chips that ends up driving these segments." That kind of thing.

I appreciate the help, but sometimes I wonder why I bother listing out the steps I've already done if people are just going to gloss over them.