As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON BRUSH INSPECTION IT WAS FOUND THAT ONE OF THE BRUSHES HAD A BROKEN RIVET. THE RIVET HOLDS THE WIRE BRAIDING TO THE BRUSH. WHEN THE BRUSH WAS PULLED OUT, THE RIVET FELL OUT ALONG WITH THE METAL TANG. UP TO THIS POINT THE STARTER GENERATOR HAD BEEN WORKING NORMALLY.