Could be either, but I have always found it to be the opto in this case. I have replaced two on two different machines for the same issue. Make sure you have the machine hooked up to a surge protector. Seems to help prolong the time between issues.

This really sounds like an issue with the opto switch. Were you doing anything with the game before it happened?

Rob

I think you need to reflow solder on the opto. The bell opto on my game started registering phantom hits a few weeks ago... Got worse and worse... Reflow fixed it

Thx. I'm working on this for Phil. When I run test it triggers perfectly each time. I'll reflow but it seemed to work perfect in test mode

Ok. Replaced Opto board and both Optos. Problem remains. I'm stumped. Did a Little research The Opto works fine and launches ball fine the entire time lower pf is active. Unti for starts using his flippers. Then the lower ball launch kicker starts firing randomly.

I noticed when this problem occurs the led light on Opto board that show the switch firing faintly lights. It's acting like somehow other coils are grounding out Opto circuit. Any ideas??

I'll call stem on Monday