Quoted from Coyote:I would seriously re-focus on that switch.
There should be *TWO* switches. One for lower flipper. One for upper.
Fliptronics flipper button boards have two optos - one for lower which activates first, then one for upper. If both buttons are wired through the same switch, there's no telling how the fliptronics board would interpret that.
I agree. Get the game back to its native state and see if it works. If not, then start diagnosing.