What was found
LIGHT/BRIEF ODOR OF SMOKE NOTICED AROUND SEATS 23A/B. THIS OCCURED AT 3.5 AND 7 HRS INTO FLIGHT AT CRUISE. NO VISIBLE SMOKE SEEN OR DETECTED. F/A'S REPORT SLIGHT ODOR OF BURNING MATCH, CAR BACKFIRE, RUBBER. FOUND SEAT 21A READING LIGHT BURNED OUT. REPLACED BULB. INSPECTED AVU, EMPOWER, SEU FROM SEATS 21-25. NO COMPONENT OVERHEAT/MALF. NO BURNING/ARCHING OF WIRES OR CONNECTIONS. PACK AND GASPERS HAVE NO ODOR.