Hello everyone! This is my first post on the forum but I have been lurking for about a year. I will give the request and then some details to the issue I am having.

Request - I would love to get some reference photos of the Williams Ball Count Unit, Player Unit and Coin Unit. I inherited a few machines from my father in law and they are pretty roached out with some creative wiring inside. I want to verify that all of the correct wires are hooked up in the correct places and am having a hard time following the schematics for the mechanical side of the unit. I found wires that were loose or incorrectly placed based on the pictures I saw but wanted to take it to this group for a better photo and some advise on how to proceed.

Actual Issue - The game starts up fine with the left flipper then hitting the credit button puts a ball in the shooter lane with player 1 and ball one lights active as well as the light above the first player score reel. Once the ball is drained, the player two light above the score reel is active and it looks like it is firing the player S.U. to make that happen. This happens every time, not matter how many times the credit button is pushed. It never moves past player two or resets back to player 1. If the 2-3-4 "can play" lights are lit, the same thing still happens. The ball in play also never moves and always stays on 1. Another issue is the knocker never fires but I figure that is another issue all together.

As for wiring, since this thing was kept in questionable areas with moisture and large temp swings, the wiring is discolored and it is very hard to tell what is what...White appears yellow and blue appear black, so lots of fun there. I did clean all of the contacts in the relay contacts and pretty much all over to see if that was it but now I am pretty stuck. I am electrically knowledgeable (cars and digital stuff) but these EM machines are a completely different beast and the learning curve is steep for me. I feel like there are compounding issues and normally I can isolate and diagnose but this is proving to be difficult on these machines.

My first thought was to get some reference photos to see if it is wired correctly but that has proven difficult with Dr. Google. I have the original schematics and instructions but trying to find these contacts for the relays has proven a healthy challenge. I did bench test the solenoids and they do function on all the stepper units. Thanks in advance and y'all have a great community here!

I found the issue. What I (wrongly) assumed was a red - yellow wire was a red white. The issue ended up being one of the fingers that was on the player unit that was lifted off the contact. Thanks for the assistance and the links. Now I have to track down why the machine plays fine in 1 - 2 player but will not move past that.