Aaah yes WMS games.
Im willing to go out on a limb here and tell you where to look to fix this as most likely its the only place you haven't looked.
My old Travel Time used to do the same thing.. continually reset when all conditions were correct.
You have a short, you know that but it isn't on the switches.. so where is it?

The loom on a WMS is normally attached to the back of the machine and its a flaw in the design as each time you lift the PF, the loom rubs against the edges of the cabinetry. I eventually found my fault at the point on the loom that rubs against the timber.. you end up with very small breaks in the insulation and because all machines are kept HI waiting for LO... it grounds itself.

Worth a look mate as ive fixed 2 WMS machines with head scratching issues because of this. The Travel Time was easy as I could see a tiny spark on start up when looking through the coin door. Since then, ive always regarded this as WMS' Achilles heel