Xenon owners please confirm switch 28 is open or closed, with balls out. In switch test. I think the gap or switch is stuck on .
Wait for a response from a xenon owner.

 Then Do the switch test again and test with and with out balls. And double check with other owners .
Also adam ,how many balls in xenon 2?

I hope i am not leading you astray.

I think, this is the extent of my trouble shooting skills. Got me stumped. Next i would swap board to see if its board related.? Not sure??
 I will leave the rest of the comments to the more experienced.

$500 offer is now looking better. Or some under water pinball could be fun.

Yes two ball in Xenon. Thanks for the all the advice Dan, at least I've been able to count a few things out.