The Z1 and Z2 relays are controlled by the disk and wiper at positions 20 and 21 on the Player unit. Does this help?

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What part of the following is not working correctly?

1. When the Player unit gets to position 20, that should energize Z1.

2. The Player unit should not move to position 21 until every 1st and 2nd player score reel is on 0.
3. Similarly, when the Player unit gets to position that should energize Z2.
4. The Player unit should not move to position 22 until every 3rd and 4th player score reel is on 0.

If Z1 and Z2 intermittently don't activate when they should, another place to check is the make/break switch on AX that I didn't highlight on the right side of the schematic fragment in this post
https://pinside.com/pinball/forum/topic/score-reels-reset#post-6457688

For a switch to work 3 things are necessary:
1) When open, there should be a small space between the contact points (duh)
2) When closing, the long blade's contact point should push the short blade's contact point enough to move the short blade
3) The contact points should be clean, which they usually will be if #2 is happening