If the coil plunger sticks out it will break the opto beam. I had this happen in mine and pretty sure at power on it causes it to move back and forth a couple times and then stop somewhere that is not the home position. If it seems to only mess up with the plunger stuck out, it is probably that.
There is a test for the cannons specifically you can mess with. Some of the switches do not show up in normal switch test from memory because they are extras added in with the aux driver board in the top right corner of the head.
West Chester, PA
