That does not sound like a ground glass issue. It sounds like a motor issue. I would contact Letus Direct and get it fixed thru them. I am wary about opening high end pieces of equipment and performing surgery myself.
I agree with filthrich. It sounds like a motor issue. If the motor stops and starts without you pressing the power button then you may have weak wires that connect to the motor. Contact Letus Direct and have them do the repairs.