All the following with unit UNPLUGGED.
As long as nothing is jammed in the blades etc, Could be the motor brushes have worn out, so metal spring is on motor contacts, If that is the problem, would depend on extent of damage, But having said that, quite often cheaper in the long run to replace the motor rather than parts of the motor. Check the air path, to make sure no object jammed in the unit, take off what you can, make sure it is all clean. As long as no bits jamming motor impellers, If you can check if motor spins free, If it spins with out force, and makes the noise, definately motor. replace motor, Not difficult, fiddly.
SD, August 2011
