As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER APPROX 2 HOURS AT FLIGHT COULD SMELL FUMES COMING FROM CABIN. SHOW NO SMOKE. CLOSED ONE PACK A TIME AND APPEARS THAT WHEN NR 3 PACK OFF SMELL DID GO AWAY SOME. UPON LANDING WIGH NR 3 PACK OFF SMELL RETURNED. REMOVED AND REPLACED (A) ZONE COLUMN TIMER DECODER IAW 23-33-14, OPS CHECKS NORMAL. (K)