As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT 350FL THE CABIN PRESS AND CABIN ALT WAS CLBING AT 2K FT/MIN. BOTH PACKS WERE IN AUTO AND WERE NOT RESPONDING. DESCENDING TO 280FL STILL NG. WENT TO MANUAL NO HELP. BOTH PACK PRESS READ ZERO. DESCENDED TO 100FL AND THE CABIN WAS 180FL AND THE O2 MASK DEPLOYED. REPLACED FLOW CONTROL VALVES