I found an allen wrench. I was able to turn the motor from the bottom, but it still buzzes. I can take the allen wrench and push the motor up a little but it falls right back down. Could that be an indication that the bearing is shot? If so can that be replaced, assuming that that is the problem?
Take an allen wrench to the bottom of the unit and see if you can spin it.
It doesn't take much to jam them. The blades will spin freely regardless.
Average use on these is eight years. But if you can get the inner part to rotate again, you may be fine.