Why has Electric Rake stopped working?

My electric lawn rake has stopped turning. Power is still getting through as it makes a noise, and the bit that spins round with the metal prongs sticking out of it moves a tiny bit when you pull the "on" lever, but then nothing else happens. I am thinking it could be physically jammed somehow but I have cleared out all the dried grass etc from the edges and it still won't work. It is a very old Black & Decker.