It might not be the bearings, we've had these machines makeing an odd noise and the drum only twitches and locks up whilst makeing a loud vibrating hum. It turned out to be a small resistor on the small circuit board at the edge of the motor ring. I can't remeber the value, but there is a pair of them, they supply the feedback from the hall effect transistors that measure speed. Check them both, one will probably be open circuit and can be replaced with a resistor the same value as the working one. It doesn't matter which type of resistor you replace it with although metal oxide is probably best.
Karl, September 2008
