Good Morning Everyone (or similar greeting based on your time zone),

When both slings are pressed on my Monster Bash (original WMS) the game slam tilts. In switch test pressing both slings activates: up frank, down frank, left sling, right sling, left flipper opto (phantom flip) and of course slam tilt.

I've investigated the following: everything else on the green/black switch line, including disconnecting further down stream past the slings, still get a slam tilt, so I really don't think it has anything to do with the green/black wire. Checked the Frank switches, no clearance issues, diodes check out. Both Eddy sensors appear to function as they should (LED is only lit with a ball over it). I've disconnected the slam tilt swtich as well just for the sake of ruling things out, still get the phantom switch closing.

The one strange thing is that when the right sling switch is pressed, the left opto 'Phantom Flip' is also activated. These trace back to the opto switch board underneath the playfield on the white/red wire.

Is there testing I can do on the opto board? Bad LM339? Bad Diode?

Thanks,

Joe

Thanks for responding - this one has me stumped. What's most puzzling is the game has been playing for a few months without issue (was in storage for a few years before that). That being said, unplugged the opto board, couldn't get it to trip. On a hunch, I swapped the 2803 as it's socketed - no change. At this point I'm just checking everything and hoping something stands out.

Thanks,

Joe