I've fixed Many trough issues over the years. This one im a little unsure of. Replaced 2 of the 6 rollover switches in the ball trough. Game starts and plays. I get no pinball missing error. Randomly on the 2nd or 3rd ball I hear the coil firing trying to kick ball up into shooter lane but the coil to release ball from trough is not firing so no ball is fed. So eventually it goes to ball search. I'm thinking one of the middle switches must be flaky ? Anything else besides ball trough switches or is the problem in the trough ? The switch just below Shooter lane works correct once a ball is there. All coils work fine.