As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHEN OPENING AND CLOSING THE MAIN CABIN DOOR, THE IS A LOUD BINDING/GRINDING NOISE FROM THE DOOR CABLES. ITS LOUD ENOUGH TO HEAR OVER AN APU RUNNING NEXT TO US. FOUND MCD HINGE WAS THE SOURCE OF THE NOISE. CLEANED AND LUBRICATED HINGE. OPS CHECK OF MCD IAW CL-650 MM 52-11-00.