My White Water has been running great for years. The other day, it started to get phantom switch issues. This wasn't a situation where I was fiddling with the machine and the problem arose. This just started happening out of the blue during play.
Specifically, the opto associated with the Lost Mine kick-out (a/k/a the "Whirlpool Popper") will register when the Insanity Falls (a/k/a the "Rapids Main Ramp") switch was activated. The Insanity Falls switch is a normal micro-switch. So, pressing the micro-switch triggers the opto to be "interrupted".
I checked all of the other switches and I'm not seeing any other problems or phantom closures. I unplugged the power to the opto board and the phantom switch no longer registers when I press the Insanity Falls switch. I'm not sure how much that helps though because all those optos normally register as "closed" in their resting state and when you unplug the power the all the optos from that board register as "open". Since "opening/interrupting" that opto usually registers the hit, it may be that I get no phantom switch because that opto is already registering as "open".
In any event, here's the switch matrix to show what's going on. My theory at this point is that I have a bad 7-opto board rather than a playfield switch issue, although I'd like to see if there are additional ways to diagnose the problem before sending out the boards for repair. I'd rather not spend the time and money to send the boards off and then find out it's a playfield issue. Unfortunately, I don't have any boards to swap so that's not a good option.