Hi gilles
do You have the schematics ? See the JPG - from Gottlieb North Star (same time, switch marked red) --- look up in Your schematics - also such an "Zero Position Replay Switch" mounted in the wiring ? We can cheat and make this switch to be always closed: Using a Jumper-Wire or solder-on a wire onto both solderlugs of the switch --- (I don't like it) some people bend the stationary blade of the switch - bend heavily so the switch never can open.
See here http://www.pinrepair.com/em/index3.htm#free . I believe pinrepair does not show the way to do setting to free play on such old pins like North Star (and World Fair) ? Greetings Rolf

0North-Star-Work-01 (resized).jpg