What was found
RETURN LANDING. WILL NOT PRESSURIZE CORRECTLY. 15,000 THRU 20,000 FT CAB ALT 6700 FT WITH RATE 1,000 - 3,000 ^P 4.8 AT IDLE LOSE PRESSURIZATION. REMOVED AND REPLACED NR 1 CABIN PRESSURE CONTROLLER IAW AMM 21-31-16. OP/C F/C GOOD. REMOVED SECONDARY OUTFLOW VALVE & INSPECTED ALL LINES TO OUTFLOW VALVE & PORTS INTO THE SECONDARY OUTFLOR VALVE. NO DEFECTS NOTED. RE-INSTALLED SECONDARY OUTFLOW VALVE IAW AMM 21-32-01. REMOVED AND REPLACED LT AND RT PRSOV FILTERS IAW AMM 21-51-43. FOUND BACKWARD INSTALLED DOOR SEAL ON CARGO DOOR. REMOVED AND REPLACED CARGO DOOR SEAL IAW AMM 52-31-07 GROUND TEST SATISFACTORY.