What was found
LOSS OF PRESSURIZATION AT ALTITUDE APPROX FL340, UNABLE TO PRESSURIZE IN AUTO OR MANUAL. AIA ABNORMAL AND EMERGENCY PROCEDURES ACCOMPLISHED. OPERATION OF NR 4 T/C CAUSED CABIN TO DEPRESSURIZE WHEN RAN, TRANSFERRED TO DMI NR 600 IN ACCORDANCE AIA MEL 21-1. PRESSURIZED AIRCRAFT FOR APPROX 5 MIN, FOUND NO LEAKS AND OPS CHECK GOOD ON GROUND IAW DC-8 MM CHAPTER 21 TO 30 PLACARDS REMOVED.