I have a perplexing problem with my Indy 500. The rear-most stand-up/light-up target often fired when I engage the right flipper button. It also sometimes fires at random when the machine is at rest. It otherwise nfires appropriately when hit. It does NOT fire if I give the machine a good nudge. It is most bizarre to me that the flipper seems to trigger it. Any tips? I am hoping to avoid having to replace the opto...

It lights up, makes a sound, and awards points all as though it were hit. The switch others functions normally when triggered by hand with the glass off
I'll dig into it again soon and see what I can figure out. I may have to call in a friend with more experience, since I'm pretty naive on this stuff, especially electrical issues. Thanks to all for the thoughtful and helpful insights!