This trough issue is driving me crazy! Every once in 30 or so balls, the trough lock mechanism gets hung up on a ball. The trough lock mechanism moves and operates very smoothly. There are not divots in the trough that I can feel or see. The balls were very mildly magnetized, but with replacements it still happened. The replacements also became mildly magnetized. I am awaiting magnet friendly balls, but even still I wouldn't expect them to be come significantly magnetized within a few games. Are the magnets in this game really that strong that they can magnetize balls after a few games?
So far I have:
Replaced all trough switches
Rebuilt and reflowed opto boards
Replaced connectors on the wire harness to optos
Cleaned and replaced sleeve on Trough lock mechanism
Tried several different strength springs on the trough lock mechanism
See attached photo where the lock mechanism has become hung up, and does not return to home position completely. In this state the game sees no balls (unless one is locked elsewhere). The balls are all sitting just in front of where they would normally, so the switch rollers are up. No balls are in the trough up kicker. The coil looks a little toasty but seems to operate just fine.