Quoted from schudel5:

There is a switch inside the head that rides along the top metal piece that spins. There is an indent in that metal piece that will change the state of the switch when it's in the indent.
First, make sure the switch works. Remove the helmet and the two screws to remove whatever face is up when the game stops rotating. Go into switch edge test and work the switch by hand. You may need to go into head test and run the test manually to get it so the switch is in the indent area first, then go to switch edge test and test the switch. If the switch changes state in the switch edge test, make sure when you are in the head test that it shows that switch opens/closes when it rotates. You may need to bend the actuator arm so that it changes state when it goes in and comes out of the indent.
There's not much to the face position other than that one switch. If that switch doesn't work or it doesn't change state when it goes in the indent it will never know the position.