It sounds like either the main motor or the motor brushes. The brushes. If you take off the top of the machine, you will find a wiring diagram. It tells you what the resistance should be between various terminals on the motor. There are a lot of wires coming off the connector(s) but if you pay attention, you should be able to figure things out with an ohm meter.
Prices tend to be all over the place for those motors. The last one I bought was at appliancepartpros. But you should compare. Other places that have them are repairclinic.
Hagrinas, April 2006