What was found
(CAN) FLIGHT HAD DEPARTED WITH NR 1 PRESSURIZATION ON MEL, AT FL340 THE CREW LOST SYS NR 2 PRESSURIZATION. CREW DECLARED A MAYDAY WITH ATC AND DESCENDED TO 10,000 FT , ALL CABIN OXYGEN MASKS DEPLOYED. FLIGHT LANDED APPROXIMATELY 4000 KGS OVER MAX LANDING WEIGHT, ACFT TAXIED TO GATE UNDER OWN POWER CREW ADVISES THAT THERE WERE SOME VERY SHAKEN PASSENGERS. RESOLUTION TSM 21-31-00-810-803 C/O. REPLACED OUT FLOW VALVE IAW AMM 21-31-51-00-001. NEW CPC NR 1 AND NR 2 INSTALLED IAW AMM 21-31-34, PB401. CPC 1 AND 2 BITE TEST OK.