just for the records-might help someone at some point:
my TZ was driving me crazy with following sympthoms:
- ending the game altough ball was still in play
- firing a coil (ball feeder?) during game in play
- sometimes feeding 2 balls into shooter lane
after some investigations and struggles I cleaned the ballthrough, readjusted the switches but finally it seems the balls were manetized which caused the balls to get "stuck" in the through and not moving to the far right end...all the issues were gone after exchanging the balls with some new low magnetic ones...