Thanks mech. This doesn't seem to be the case however. While turning the key I can see the shaft rotating but after appox. 5° of movement the entire shaft slips back to the starting position.
It's broke. If you dissect it I'd be interested in the failure mode. The aluminum disc covering the gear can be pried off but can't be reused. Drill a small hole and pry it out with a small screwdriver. The nub on the post that goes in the gear probably broke off.
mech