As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ETOPS SIGNIFICANT SYS - WHILE TESTING OXY MODULES OF L AND R CTR LAV (DUE TO THE REMOVAL OF THEM FOR ACCESS) THE PASS OXY MANUAL DEPLOY SWITCH S2 ON P5 MODULE M43 FAILED TO DEPLOY ANY OF THE PASSENGERS OXY MASKS. FAULT FINDING CONFIRMED THE "OXY CONT MANUAL DEPLOY TIME DELAY RELAY K466 IN P19 (FWD LIGHTING DISTRIBUTION PANEL) IS FAULTY, IAW WDM 35-21-11, PAGE 1. REPLACED TIME RELAY K466. OPS CHECK GOOD.