What was found
FLT 312, OAK-IAD, APPROX 1200Z, BURNING ELECTRICAL ODOR FROM OVERHEAD EYEBALL VENT AISLE 25, SECURED CABIN FAN AND PLACED PACKS TO HIGH, ODOR DISSIPATED. ODOR CAME BACK ON DESCENT. COMPLIED WITH TSM 23-39-00-810-801. COULD NOT DUPLICATE WRITE UP. COMPLIED WITH TSM 24-00-00-810-823. COULD NOT ISOLATE THE ELECTRICAL ODOR. OPERATED SYSTEM FOR TWO HOURS WITH NO INDICATIONS OF ANY ODOR. REMOVED AND REPLACED ALL VDU'S & SEB'S PRECAUTIONARY IN ROW 25ABCDEF.