Quoted from jag8511:And now after playing it some this afternoon it keeps shooting out two balls and won't stop trying to shoot out balls when starting a game...
Try this thread:
https://pinside.com/pinball/forum/topic/data-east-checkpoint-problem-double-balls
Turned out to be a broken solder join on a diode for one of the ball trough switches. Post #4 in that thread.