What was found
AIRCRAFT WAS GROUNDED: UPON PUTTING APU BLEED ON, ALL FLIGHT ATTENDANTS COMPLAINED OF DIRTY SOCK SMELL. MAINTENANCE PERFORMED JOB CARD 05-96-70 AND FOUND APU TO BE SOURCE OF ODOR. MAINTENANCE ACCOMPLISHED MCM CARD 05-96-86, DECONTAMINATION OF THE ENVIRONMENTAL CONTROL SYSTEM, AND PERFORMED SATISFACTORY OPERATIONAL CHECK, NO ODOR NOTED.