As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING DESCENT PASSING FL 280 THE CABIN ALT WARNING HORN WENT OFF. THE CABIN ALT WAS 14;000. WE INITIATED A RAPID DESCENT. EMER. DECLARED & LANDING WAS UNEVENTFUL INTO OAK. / [01] PERFORMED EXCESSIVE CABIN PRESSURE LEAKAGE INSPECTION REF AMM 05-51-91. REF L/P 2335179 FOR REPLACEMENT OF VACUUM WASTE BLOWER FLEXIBLE LINE AND R/H PACK WATER SEPARATOR BAND CLAMP. C/W MT 721-00-01. OK FOR SERVICE.