Good thinking on not just going in and replacing switches. Especially since being part of your switch matrix, you could have a broken wire elsewhere killing a switch. Or a lot of work to find out one just needed adjusting. Or something on top of coin chutes is hitting switch wiring.

I would remove the apron and ball trough cover, go into switch test, and roll a ball along the switches and see if they all work.

Then roll all the balls in and see if they stay closed.

That should help you on what needs attention.

Also be sure you have the right number of balls in the game.

LTG

Sounds good. At least keep eliminating things.

And coil wires are daisy chained together from coil to coil back to board, be sure you don't have a crappy solder joint elsewhere.

The VUK - be sure it's switch is working, and again no poor connections for those color of wires at other switches around the game. Especially the tongue/trigger switch that shoots the ball into play.

LTG