What was found
PDIS 667 21-30 9291 03DEC17 MEM OPEN U LOGPAGES:2686339 DURING CLIMBOUT AIRCRAFT FAILED TO PRESSURIZE W/ EITHER AUTO PRESSURE CONTROLLER. LEVELED OFF AT 10,000, CONSULTED QRH, CHECK APU BLEED SWITCH, DOOR PAGE, AND PRESSURE OF PACKS, ALL OKAY. SELECTED MANUAL PRESS AND RAN CABIN DOWN BUT OUTFLOW VALVES SHOWED CLOSED AND THE VENT OVERBOARD WAS CLOSED. STILL NO PRESSURE. ATB TO MEM. REMOVED AND REPLACED OVERBOARD EXTRACT VALVE (75HR) PER AMM A300-600 21-23-13-04. OPS CHECK GOOD . PRESSURIZED AIRCRAFT PER A300 AMM 21-31-00-05-0 (2) FUNCTIONAL TEST GOOD NO LEAKS NOTED.