As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT CREW HEARD A POP THAT SOUNDED LIKE THE PRESSURIZATION WAS FAILING. CREW DECLARED AN EMERGENCY AND STARTED AN EMERGENCY DESCENT TO 11000 FEET. MAINTENANCE FOUND LINES TO SECONDARY OUTFLOW VALVE TO BE LOOSE. LINES COULD NOT BE TIGHTENED. INSTALLED 2 EACH NEW CONNECTORS.