This doesn't make that harsh grating sound associated with brushes, but there is a low frequency hum from the machine and it feels as if the drum is 'trembling' like a DC motor trying to run on AC. The self test aborts after the all LEDs flashing step and then the display is blank. It shows POO or P00 before the test starts but after entering self-test mode. I suspect either the main controller or the motor drive circuitry but that's only a guess. Thanks