As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) REBUILT ELECTROSYSTEMS ALTERNATOR INSTALLED DUE TO A PREVIOUS ALTERNATOR PROBLEM. APPROXIMATELY 11 FLIGHT HOURS AFTER INSTALLATION THE PULLEY WORKED OFF THE ALTERNATOR SHAFT BREAKING THE BELT. THE PULLEY WAS ASSEMBLED ON THE ALTERNATOR AS AN OVERHAULED UNIT. THE PULLEY RETAINING NUT WAS LIKELY NOT TORQUED PROPERLY AT THE FACTORY.