I'm working on a Williams Doozie. Everything is now working EXCEPT the trough switch will not cause an advance in ball number or send the ball to the shooter lane. If I manually close the trough switch and close the trough relay then everything functions as it should. When the ball drains and closes the trough switch again nothing happens. I've been through it and stared at the schematics for too long. Please someone give me some help as where to look next.