My Zaccaria has that same ball count unit. Had some weird things happening too (not incrementing ball count, no game over happening). The switches on it need to be carefully adjusted, in accordance to the "rest" position of the gear. Yours, sounds like the coils to increment it are possibly failed or not getting the power/signal to activate them.

My game over issue resolved itself after my brother played it and was bumping during game play, which seemed to knock connectivity in a switch somewhere correctly.

Tim