As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INCREASE IN CABIN ALTITUDE AT FL335 - THE CABIN ALTITUDE WAS AMBER AND ABOUT 8400, STOPPED CLIMB AND DESCENDED TO FL330, ALTITUDE CONTINUED TO CLIMB. DECLARED AN EMERGENCY AND STARTED A DESCENT. THE DESCENT WAS UNEVENTFUL. MAINTENANCE FOUND RAM AIR AND PACK DUCTING DAMAGED ALONG WITH NR 2 CONDITION AIR CHECK VALVE BROKEN. MAINTENANCE UPGRADED CACVS, REPLACED PACK OUTLET DUCTS AND BOOTS AND RECONNECTED. OP'S CHECK GOOD.