Geday Mark & welcome to the Expressway club !
Have you checked the 2 post down switches for gap/operation.(i'd guess one's touching)
Cheers

Schematics !!? (That's cheating! I got my dead n hacked Exp going with a mix of tinkering, determination, frustration & other Bally schems of that era. A copy of the schems would help my Exp get to 100% (hint hint).
I think that the post down switches are normally open (I'll check tomorrow, is cold & dark outside now).
Lucky you with ur wife. My mrs once looked sideways at my pins.
Make room (they multiply!)
Cheers

Post down switches are normally open, they close onto br/y (brown with yellow stripe) wire. The br/y runs to the post relay.
On start game, post re pulls in, triggering post up mushroom releases post re (somehow thru a grayish looking wire). Triggering post down button, activates post re, etc...
Hope this helps.
Cheers