What was found
ON CLIMBOUT BETWEEN 5K- 9K FEET WE HEARD SVRL THUMPS WITH HIGH CABIN RATE OF CLIMB. DIFF TO ZERO. PERFORMED CABIN PRESSURE CONTROLLER BITE PROCEDURE OF BOTH CONTROLLERS IAW FIM 21-31, FAULT TREE 803. NO FAULTS FOUND FOR THE CURRENT AND PREVIOUS FLIGHTS. FURTHER TROUBLESHOOTING REQUIRED. FOUND FWD EQUIPMENT COOLING OVERBOARD EXHAUSTER VALVE DUCT COLLAPSED. THE BELLY EQUIPMENT COOLING EXHAUST VALVE IS SUPPOSED TO BE CLOSED IN FLT, THESE DUCT FAILURES SUGGEST THAT THIS VALVE HAD FAILED OPEN. THIS VALVE FAILURE MAY ALSO BE THE ROOT CAUSE OF THE DEFECT DEFERRED IN ELB. OVERBOARD EXHAUST VALVE, INBD SUPPLY VALVE, & NUMEROUS EQUIPMENT COOLING DUCTS REPLACED AND REPAIRED.