What was found
AIRCRAFT WILL NOT PRESSURIZE, CABIN ALTITUDE WARNING WENT OFF PASSING THROUGH 10000 AFL WITH AIRCRAFT AT 10000 CABIN ALTITUDE DESCENDED TO 9500. DUCT PRESSURE 38 PSI – R 32 PSI – L, MANUAL PNEUMATIC CONTROLLER APPEARED TO OPERATE NORMAL. R & R NR 3 ENGINE SHUTOFF VALVE, IAW B727 AMM 36-10-10. OPS CHECK GOOD. R & R RT FLOW CONTROL VALVE. OPS AND LEAK CHECK GOOD, IAW B727 AMM 36-12-61. REPAIRED WIRES TO RT PACK, IAW SWPM 20-20-10 & 20-60-07.