As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING SCHEDULED MAINTENANCE OXYGEN BOTTLE FAILED THE 600 HOUR SYSTEM FUNCTIONAL TEST. OXYGEN BOTTLE WAS REMOVED AND SENT OUT FOR SERVICE. OVERHAUL FACILITY INSPECTED THE BOTTLE AND IDENTIFIED THE REGULATOR ASSEMBLY TO BE ASSEMBLED INCORRECTLY. THE OXYGEN BOTTLE AND REGULATOR ASSEMBLY WAS OVERHAULED AND REINSTALLED ON THE AIRCRAFT. A SUCCESSFUL SYSTEM TEST AND LEAK CHECKED WAS PERFORMED. AIRCRAFT WAS RETURNED TO SERVICE.