As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT ATTENDANT REPORTING BURNING RUBBER TYPE & LOUD BUZZING NOISE MID CABIN. TURNED OFF IFE & NOISE DISSIPATED. TROUBLESHOT, FOUND LT RECIRCULATION FAN TO BE NOISY & MAKING HIGH PITCH NOISES. R & R LT RECIRCULATING FAN IAW B 737-7-8-9 AMM 21-25-02. OPERATIONS & LEAK CHECK GOOD. R & R AIR FILTER ASSEMBLY ROTABLE PARTS CHANGE WAS INDICATED TT 1602043 SN OFF 07864 FAN, AIR, DISTR OFF 29-2125-9-0001 7864 ON 29-2125-9-0001 3964