AN MD SUPER 80 IN A CLB AT FL310 DECLARED AN EMER AND DIVERTED DUE TO A COCKPIT OVERHEAD PANEL MALFUNCTION CAUSING ELECTRICAL FLASHING AND POPPING ACCOMPANIED WITH ELECTRICAL BURNING ODOR.

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DURING CLB; CREW HEARD A LOUD POP AND SAW A FLASH OF LIGHT FROM NEAR THE EPC CIRCUIT BREAKER PANEL. NO BREAKERS WERE POPPED. APPROX 5-7 MINS LATER A SECOND POP AND FLASH OCCURRED. CREW ELECTED TO DIVERT TO STL. AN EMER WAS DECLARED AND CLRNC TO STL WAS RECEIVED. AT APPROX 3000 FT AGL A SMELL OF BURNING INSULATION WAS DETECTED. OXYGEN MASKS WERE DONNED FOR THE REMAINDER OF THE FLT. EMER FIRE/ELECTRICAL/SMOKE UNKNOWN SOURCE WAS COMPLETED AFTER LNDG. AFTER DECLARING EMER; FLT ATTENDANTS WERE ADVISED OF THE 'TEST' ITEMS AND WERE INSTRUCTED TO BEGIN THEIR CHKLIST FOR A POSSIBLE EVAC. WHEN FLT ATTENDANTS WERE DONE WITH THE LIST; THE #1 FLT ATTENDANT ADVISED THEY WERE COMPLETE. AT THAT TIME SHE ALSO SAID SHE COULD SMELL THE SMOKE. AFTER LNDG; WE BROUGHT THE ACFT TO A STOP ON THE TXWY AND COMPLETED THE CHKLISTS. AS THE SMELL WAS ABOUT THE SAME OR LESS; WE DID NOT EVAC THE ACFT. STL CFR ENTERED THE ACFT FROM THE REAR STAIRS. THEY RPTED TO THE CREW THAT THE REAR OF THE ACFT APPEARED TO BE OK. WE KEPT THE ACFT SHUT DOWN AND ELECTRICALLY DEAD ON THE TXWY AND WE WERE THEN TOWED TO THE GATE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE FIRST FLASH AND POPPING NOISE WAS LOCATED BEHIND THE EMER OVERHEAD CIRCUIT BREAKER PANEL. THE SECOND FLASH OCCURRED A FEW MINS LATER WHEN THE COCKPIT DOOR WAS CLOSED. THE RPTR SAID A FLT ATTENDANT ENTERED THE COCKPIT TO RPT SOME GALLEY LIGHTING THAT COULD NOT BE SWITCHED OFF AND ON LEAVING CLOSED THE COCKPIT DOOR WHEN THE SECOND FLASH OCCURRED. THE MAINT TECHNICIANS IN STL FOUND THE COCKPIT DOOR SWITCH SOLENOID LOCATED ON THE FORWARD OVERHEAD PANEL WAS SHORTING TO A PANEL FRAME AND BURNING ADJACENT WIRING IN A WIRE BUNDLE. THE RPTR STATED THIS WAS ALSO THE CAUSE OF THE GALLEY LIGHTING PROBS. THE RPTR SAID SOME OF THE WIRE DAMAGE OCCURRED TO 3 PHASE 115 VOLT INPUT WIRING TO TRANSFORMER/RECTIFIERS SUPPLYING 12 VOLTS DC TO LAPTOP COMPUTER OUTLETS THROUGHOUT THE PAX CABIN. THE RPTR SAID THE CIRCUIT BREAKER FOR THE COCKPIT DOOR LOCK WAS OPENED BY THE CREW A SHORT TIME AFTER THE SECOND FLASH WAS OBSERVED AND LOUD POP WAS HEARD. THE RPTR STATED AT NO TIME DID ANY CIRCUIT BREAKER TRIP.