Could be a lot of things at this stage:
What is it actually doing? Rotating around, making the "elephant" sound and then no ball coming out? not rotating at all? ignoring the idol and serving the ball from the plunger instead?
1 - does the door slide down easily by hand and not bind?
2 - does the door activate properly in the solenoid test?
3 - is the idol tightened onto the shaft properly, with the set screw lined up on the flat of the shaft (you will need a long allen key to reach that bugger, and via the drop down door!)
4 - does the test menu "idol test" work OK (the machine needs to know where the idol is to open the door at the right time)
Cheers
Jacob
