What was found
CABIN ALT LIGHT AND EICAS MESSAGE APPEARED. CABIN ALT CONFIRMED AT 10000' CABIN RATE WAS CLIMBING. OUTFLOW VALVE WAS CLOSED. SWITCHED TO AUTO 2-NO EFFECT. MANUAL INITIALLY DID NOT CLOSE OUTFLOW VALVE. T/S BOTH NR 1 AND NR 2 CABIN PRESSURE CONTROLLERS PER FIM 21-30-00. NO FAULTS NOTED. PRESSURIZED A/C WITH RT PACK ONLY PER MM 05-51-24-2. COULD ONLY GET 1.5 PSID. PRESSURIZED WITH LT PACK OK. DEFERRED RT PACK PER MEL 21-51-1. NO DMP. INSTALLED PLACARD. ASSIGNED DEFERRAL M-342219.