You can test the switch with a multimeter if you have one?
Try Greg at RTBB for a replacement switch if required. http://aussiepinball.com/index.php?topic=6209.0
+ 1 Greg will most likely have the part.
I have the manual in front of me and the part number is 5647-09957-00
Problem is that Greg does not have it one his site - but shoot him an email and he might have it antway.
I'd check that the switch is working first (with a multimeter).
