I was playing my newly aquired stargate and when I reached a score that gave me a free game the knocker fired and both flippers froze and I thought mess the knocker blew my flippers.  Then all was okay but I lost two of the 3 balls in play.  Wonder what that was?  I had been way over that score already and won many games already but must not been hitting the flippers at that time to notice that or it just did not happen.  Anyone have that experience before and willing to shed some light.