As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT HAD AN UNCONTROLLED LOSS OF PRESSURE IN AUTO. THE OXYGEN MASKS WERE NOT DEPLOYED. *S/D* AFTER EXTENSIVE TROUBLESHOOTING, FOUND DELTA P MODULE LOOSE AT MOUNTING BRACKET, RIGHT HAND PACK VALVE BIASED TO THE CLOSED POSITION, AND LOW RESISTANCE TO THE AFT OUTFLOW VALVE. REPLACED AND SECURED THE DELTA P MODULE, RIGHT PACK VALVE, AND THE AFT OUTFLOW VALVE. OPS CHECK OK.