Try placing the allen wrench into the socket on the underside of the disposer and working it back and forth, then trying it electrically. The blades can appear to be free, even with a jam. The moving of the inner workings with the allen wrench should free it all up. Flush the disposer with a potful of ice and water when it turns freely.
Best regards, --W/D--

Pull out spoon... with the thing off of course.
Otherwise with it running. stick a wooden spoon down from the top and try and turn it..
It may just be tired and need replacing..
Marc