As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CABIN DEPRESSURIZED WHILE CLIMBING OUT OF 13,000 FT AND WAS UNABLE TO CONTROL IT MANUALLY. RETURNED TO FIELD. SECURED OUTFLOW VALVES IN OPEN POSITION IAW MEL 21-30-01. REMOVED AND REPLACED ELECTRO-PNEUMATIC OUTFLOW VALVE. OPS CHECKS GOOD IAW 21-33-00.