What was found
AT APPROX 4000' WE HEARD AN ABNORMAL NOISE FOLLOWED BY A RUMBLE OF AIRFLOW FROM LOWER EQUIP COMPARTMENT. RECEIVED A FWD EQUIPMENT VALVE, EICAS. RAN ALL QRH PROLS. AND RECEIVED A, CABIN PRESSURE, EICAS & FOLLOWED QRH PROLS. DIVERTED. FOUND FWD EQUIP COOLING VALVE DEACTIVATED IN THE OPEN POSITION & EQUIPMENT COOLING EXHAUST DUCT FWD OF VALVE COLLAPSED. REINSTALLED ELEC CONNECTOR, REMOVED DAMAGED DUCT. R & R DUCT IAW MM 21-58-05-4 & OPS CHECKED OVERBOARD EXHAUST VALVE IAW MM. OPS CHECKED GOOD. A/C OK FOR SERVICE.