I would first suspect the motor brushes, in these are ok then I would suspect the speed control module ( pcb normaly fitted on one side at the bottom)
I would unplug from the mains, remove back panel, remove drive belt, locate the speeed control module and find the two wires marked F and N, then link these two together with a piece of wire. set the machine to spin and then pug in and switch on (keep clear!) if the motor runs flat out, you know the motor is ok and the module is probably faulty, if no motor action, then it could be brushes or broken wire at motor plug
Frank, July 2006