As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MOTORS HAVE HIGH RESISTANCE BETWEEN THE BRUSHES AND ARMATURE OF THE MOTOR. THIS CAUSES THE MOTOR TO STICK INTERMITTENTLY, CAUSING A FALSE ATTITUDE DISPLAY IN THE COCKPIT. THIS PROBLEM BEGAN WITH MOTORS DATE CODED 04/04. THIS MOTOR WAS VERY NOISY IN OPERATION ALSO. BEARINGS SOUND ROUGH WHILE MOTOR IS OPERATING.