My Williams Shangri-La pinball machine is mostly playing normally right now with the exception of all players fail much of the time to add thousands. Sometimes yes, many times no. I am not sure just which switches/relays I should look at for this? Any help much appreciated. Thank you.

Tried checking using your highlighted schematic points, I am limited with my understanding of a schematic but I did check specifically using the first player and my 100 point relay switches all touch each other just fine, and the ninth position on my 100 points drum unit was properly closed, so now I’m stuck with maybe it’s the player up unit? I’m not sure how to figure this one out - here is a picture of a player up unit.

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OK just for an update, I cleaned the contact wiper blades and even had to take a needle nose plier to pinch the one at the 5 o’clock position tighter in to make sure it made contact. It seems that that did help the thousands to turn over more regularly but they still are missing at times. I did find that the bottom wire connected to the 100s drum was a little loose so I soldered that tight again too. It mostly gives the turnover to the thousands now but frustratingly occasionally I note that it does not. Better than it was.

Okay Frenchmarky, you were right, I finally found time to mess with the 100 relay switches, and one just wasn’t pushing through hard enough. The thousands now work! Thank you.