Hi Darren, mains filter would not stop it spinning, i would check the brushes are fitted correctly, if fitted by a proper w/m engineer then should not be a problem, if you fitted them check that the litttle brass catch on the brush holder has been bent out to allow brush to slide the holder on to the motor armature,as when these aer brought from a shop the brushes are held captive as so not to damage them
bunnykinjoe, February 2010