As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THREE OXYGEN MASKS WERE FOUND TO HAVE THE SAME FAULT. WHEN THE EMERGENCY/PRESS TO TEST CONTROL WAS TURNED TO EMERGENCY THERE WAS NOT A POSITIVE INCREASE IN PRESSURE. REF MFG MM 35-20-52, PAGE 502 TEST (13). PROBABLE CAUSE: UNKNOWN, RECOMMENDATION: INCREASE HOW OFTEN CREW OXYGEN MASKS ARE TESTED AND INSURE THAT THEY ARE BEING TESTED PROPERLY. (K)