What was found
DURING CRUISE, EXPERIENCED VERY LOUD ELECTRICAL ARCING SOUND IN OVERHEAD PANEL FOLLOWED BY THICK SMOKE FROM SAME AREA. DECLARED EMERGENCY AND DIVERTED. COMPLIED WITH QRH REMOVED SEVERAL OVERHEAD PANEL`S IN FLIGHT DECK TO LOOK FOR SOURCE OF SMOKE. INSPECTED ELECTRICAL AND ELECTRONIC`S IN OVERHEAD INST PANEL`S AREA, FOUND OVERHEAD INST LIGHTING DIMMER SMELLING SMOKED, R & R OVERHEAD INST LIGHT DIMMER IAW MM 33-11-03-2-0. OPS TESTED GOOD IAW SAME MM REINSTALLED REMOVED OVERHEAD CONTROL PANEL`S IAW MM`S 24-08-02-4-0, 29-08-02-2-0, 21-08-02-4-0 OK FOR SERVICE. REMOVED SEVERAL OVERHEAD PANEL`S IN FLIGHT DECK TO LOOK FOR SOURCE OF SMOKE. INSPECTED ELECTRICAL AND ELECTRONIC`S IN OVERHEAD INST PANEL`S AREA, FOUND OVERHEAD INST LIGHTING DIMMER SMELLING SMOKED, R & R OVERHEAD INST LIGHT DIMMER IAW MM 33-11-03-2-0. OPS TESTED GOOD IAW SAME MM. REINSTALLED, REMOVED OVERHEAD CONTROL PANEL`S IAW MM`S 24-08-02-4-0, 29-08-02-2-0, 21-08-02-4-0. OK FOR SERVICE.