What was found
UNABLE TO CONTROL CABIN PRESSURE WITH ANY MODE OF CONTROLLER. REMOVED AND REPLACED OUT FLOW VALVE IAW MM 21-31-11, PERFORMED ADJ TEST IAW MM 21-31-00, OPS CHECK NORMAL. IN ALL MODES OF PRESSURIZATION, CABIN PRESSURE/ALTITUDE CLIMBS WHEN DIFF PRESS HITS 7.7 PSI. FOUND LT PRESS RELIEF VALVE NOT SEATED. REMOVED AND REPLACED SAME PER M/M 21-32-11. FOUND RT SAFTEY VALVE OPENING EARLY. REMOVED AND REPLACED RT CABIN PRESS RELIEF VALVE PER MM 21-32-11. PRESSURIZED A/C ABOVE 8.2, A/C HELD PRESSURE OK FOR SERVICE.