What was found
PDIS 930 21-30 7416 10MAY19 MEM OPEN U LOGPAGES:3112369 DURING CLIMB RECEIVED CABIN ALTITUDE EICAS MESSAGE. DONNED OXYGEN MASKS AND DESCENDED BELOW 10,000 FT. NOTICED OUTFLOW VALVE IN FULL CLOSED POSITION WITH RIGHT PACK OPERATIVE WHICH SHOULD HAVE PRESSURIZED THE AIRCRAFT WITH NO PROBLEM. /DM PART 10MAY19 16:08 MEM U IDENTIFIED PARTS (W/KIT)EQUIP COOLING OVBD MPN: 60B40041-3 CPN: 2112858 QTY: 1 PART 10MAY19 16:08 MEM U ORDER PART MPN: 60B40041-3 CPN: 2112858 QTY: 1 ICT: 915963 REMOVED AND REPLACED RT PACK FLOW CONTROL SHUTOFF VALVE. REF MM 21-51-01-2. OPS CHECK AND TESTED GOOD. RAN PACKS WITH HUFFER AT 48PSI , BOTH PACKS OPERATED NORMAL. OUT FLOW VALVE OPERATED NORMAL. AIRCRAFT GOOD FOR SERVICE. PART OFF MANUFACTURER: PART # OFF: 396480-1, FLOW CONTROL VALVE, SERNO OFF 313 REF WRI 77-15/7417 R&R'D N3 TACH TRANSMITTER. THE SPEED SENSOR CAUSED NUMEROUS ADDITIONAL WRITE-UPS.