Every so often during play the game registers a drain, the flippers go dead and bonus counts, even though the ball is still on the playfield.

Ball ends mid-play for no reason: trough opto connector pulled half out

Cause: One of the trough opto connectors was under too much tension from its wiring and was not fully seated.

Checks

• Run the trough test in diagnostics.
• Check that the balls are not magnetised (this game has a strong magnet).
• Power off and reseat all trough and node board connectors, looking for any wire pulling a plug sideways.

Fix

• Give the opto wiring more slack and seat the connector fully.

Systems

• Spike 2

Games

• Godzilla (Pro)

Related tips

• Modern Stern trough kicks out two balls at once: check the trough opto boards
• Trough error and two balls served at once: faulty trough opto board

Source: Pinball Repair help group!! (Facebook group)