As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED THAT THE LOW VOLTAGE LIGHT ILLUMINATED ON TAXI. MECHANIC FOUND THAT THE ALTERNATOR HAD SEIZED AND THE BELT HAD BROKEN. WHEN THE ALTERNATOR WAS REMOVED, THE MECHANIC NOTED THAT THERE WAS A NOTICEABLE CATCH WHILE ROTATION THE PULLEY. ADDITIONALLY ONE OF THE CASE HALF THROUGH BOLTS HAD BACKED OUT SLIGHTLY AND WAS LOOSE.