As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RECEIVED LAV SMOKE DET CAUTION AT 600 FT, CW QRH NO SMOKE OR HAZE EVIDENT. HOWEVER, THERE WAS AN ODER OF "ROTTEN EGGS" RETURN TO LNK LANDING WEIGHT 42870, NORMAL LANDING. NO INDICATIONS OF FAILURE IN PACKS. AIRCRAFT REMOVED FROM SERVICE. FOUND LT CONDITIONING PACK STUCK IN FULL HOT POSITION, UNCONTROLLABLE IN MANUAL OR AUTO MODE. REPLACED LT DUAL BYPASS VALVE, PER AMM 21-61-31. BOTH LT AND RT CONDITIONING PACKS OPERATE NORMALLY, NO FURTHER SMELL IN CABIN. C/W SUP 09-037C.