Titan laser sliding compound mitre saw SF210JSL
There's a secondary noise when running the machine, and sparks from inside the motor housing. The carbon brushes seem ok, but maybe need replacement anyway? or could it be dampness? (it's stored in a cold shed, when in use it's under carport)

Claire, November 2010

Dampness is a very unlikely cause as this will dissipate rapidly in use. The most likely cause is the brushes and the spring pressure on them against the commutator. As the brushes wear the connection between them and the commutator decreases and in operation will produce a gap and that gap produces the spark.

Brian Hall, November 2010