As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TRANSIT CHECK, THE CREW OXYGEN FIRST OFFICER TEST WAS NOT SATISFACTORY WITH YELLOW LIGHT TURNED OFF. MAINTENANCE PERSONNEL PERFORMED REVISION DETECTING THE FIRST OFFICER OXYGEN MASK DAMAGED. THE OXYGEN MASK WAS REPLACED IAW AMM 35-12-85, TESTED CORRECT.