If your Ticket Mine Puck is moving up and down during game play and the game is not displaying the location on the displays on the left of the tube the issue is most likely a loose connection going to the Sensor at the top of the tube. Please check the connection point between the main cabinet and the header and reseat connections. 

     If that does not work make sure the sensor is not touching the side of the sensor hole and picking up the side of the tube instead of the drill bit inside the tube.

   If both above are not the issue please see attached PDF and test the sensor and if defective replace.