Carbon brushes check for wear they are on the motor 2 screws on each.the carbon shaft should be 1" to 2" long if its less then 1cm they need replacing.. but could still be the windings on your motor which would require a new motor.But you may find a shorting wire ect would suggest you take the back off and have a good look around inside with a good torch..make sure you un-plug not just turn off!
jez1973
December 2010
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