As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
F/A'S REPORTED STINKY SOCK SMELL FROM AIR CONDITIONING AFTER T/O. A/C WAS HARD TO COOL ON THE GROUND WITH APU OFF AND JUST RUNNING ENGINES W/ ON AND PACKS AUTO. GROUNDED - YES. REMOVED SECONDARY HEAT EXCHANGER LT PACK SYSTEM AND SECONDARY PLENUM AND ACM REF AMM 21-51-03-00-805-002. PULL 4 CBS AND SAFETY COLLARED. REINSTALLED LT PACK SECONDARY PLENUM/DIFFUSER ASSEMBLY AND AIR CYCLE MACHINE. INSTALLED NEW LT PACK SECONDARY HEAT EXCHANGER REF AMM 21-51-03, 21-51-04.