As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT ATTENDANTS REPORT ODOR OF BURNT RUBBER IN CABIN AFTER T/O WHEN PACKS TURNED ON. ALSO, NOSE GEAR RUMBLING AFTER RETRACTIONS. *S/D* REPLACED DAMAGED SEAL ON NR 3 PACK HEAT EXCHANGER, IN AIR CONDITIONING COMPARTMENT. THERE HAS BEEN NO REOCCURANCE SINCE REPAIR.