As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FIRST OFFICER`S OXYGEN MASK FAILED TO TEST OVER THE SPEAKER. REPLACED THE OXYGEN BOX IAW AMM 35-11-15. DURING OPERATIONAL CHECKS, FOUND THE AECU LOOSE IN THE RACK. SECURED AECU 23-51-00. REPERFORMED OPERATIONAL CHECKS OF THE FO OXYGEN BOX, ALL CHECKS (AUDIO AND LEAK) GOOD.