Hammer if there is smell is what reason
Then use the cleaning agent inside the machine rotor (rotating shaft alignment and brush friction) injection hole, rotary brush two edges will see the rotor slot, two sides to spray cleaner is insulated, but is a flammable liquid, need to wait ten minutes, when the cleanser evaporate after loaded on carbon brush, repaired.
The contact between rotor and carbon brush is not good. Go to the electronics store and buy a bottle of detergent (say, clean the switch, button, contact point). Come back and take out the carbon brush on the two sides
