What was found
CABIN PRESSURE WARNING CLIMBING THROUGH 12,000 FEET, BLEEDS ON, OUTFLOW VALVES CLOSED, AUTO MODE, CABIN PRESSURE AROUND 10,000, DONNED MASK AND FOLLOWED CABIN PRESSURE CHECKLIST. REMOVED FROM SERVICE. REPAIRED THE CARGO DOOR SEAL RETAINER AND REINSTALLED THE DOOR SEAL. OPS CHECKED GOOD. AIRCRAFT PRESSURIZED TO 5 PSI WITH NO DEFECTS. AIRCRAFT RETURNED TO SERVICE.