As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CABIN PRESSURE CLIMBED THROUGH 10,000 FEET AT FL330. DECLARED AN EMERGENCY AND DESCENDED TO 10,000 FEET. CABIN PRESSURE WAS NOT REGAINED AND FLIGHT CONTINUED AT LOWER ALTITUDE TO AN UNEVENTFUL LANDING AT MSP. MASKS DID NOT DEPLOY. MAINTENANCE FOUND THE OUTPUT COUPLING ON THE LEFT PACK BLOWN OPEN. REPLACED THE OUTPUT COUPLING. AIRCRAFT RETURNED TO SERVICE.