As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON DEPARTURE, CABIN FAULT LIGHT CAME ON AT 8,000 FEET CABIN ALTITUDE. FORWARD OUTFLOW VALVE STUCK AND HORN AT FULL OPEN, AFT WENT TO FULL CLOSED. AIRCRAFT RETURNED TO AIRPORT. MAINTENANCE REMOVED AND REPLACED THE PRESSURIZATION CONTROL PANEL PER MM 21-31-01. PERFORMED ADJUSTMENT AND TEST PER 21-31-00. OP CHECK NORMAL. (M)