My Stern Star Trek Pro is ending the ball mid play. This is an intermittent problem and doesn't happen on every ball. The problem is sometimes the flippers will go dead and your ball will end on the dmd, but the ball is still in play on the playfield. I am suspecting it is a trough switch, but they all test correctly during the switch test. Is there anything else that can cause this that I am overlooking. I hate tracking down intermittent problems