Recently our oldish KM600 Kenwood mixer started playing up. Strange
noises and even stranger burning smell. Upon investigation discovered a
lot of "carbon" dust distributed around the motor. Motor was sparking a
lot around the area of the carbon brushes. When removing them there were
white scorch marks on the leading edge of the carbon brushes. However,
the brushes otherwise seem to be in good condition and are about 15mm in
length.

One thought is that the carbon brushes are mounted on another material
and it is this material that is now deteriorating. Without seeing brand
new brushes I can't be sure.

It might, of course, be something entirely different causing the
problem. Any ideas anyone?