B777 HAD CABIN CTL PANEL SCREEN EMITTING SMOKE.

Narrative

WE WERE IN A BLOCK OF AIRSPACE 370-390 AT FL380 APPROX 6 HRS 20 MINS INTO A PLANNED 8 HR 27 MIN FLT NE OF SEPT ILES (YZV). A FLT ATTENDANT ENTERED THE COCKPIT AND ANNOUNCED THAT FO #2; WHO WAS IN THE CABIN ON BREAK; HAD RESPONDED TO A REQUEST FOR HELP FROM A FLT ATTENDANT WITH CTL PANEL SCREEN AT DOOR 2L. FLT ATTENDANT #1 HAD NOTIFIED THE FO BECAUSE THERE HAD BEEN SMOKE COMING FROM THE SCREEN. THE FIRST EXTINGUISHER WAS USED WHEN SMOKE WAS COMING OUT OF THE TOP OF THE SCREEN AND THE SECOND WHEN SMOKE STARTED AGAIN FROM THE BOTTOM OF THE SCREEN. AT THIS POINT I WAS NOTIFIED OF THE PROB. THE SMOKING HAD CEASED; BUT THE SCREEN WAS STILL HOT. WE CALLED COMRDO AND WERE CONNECTED TO MAINT. FO #1 WAS FLYING AND I WAS COORDINATING. ADVISED US TO ENTER THE ELECTRONICS BAY AT DOOR 1L AND PULL A CIRCUIT BREAKER AT P110-A16. I ASKED FO #2 TO DO THIS. WHILE HE WAS IN THE ELECTRONICS BAY MAINT ADVISED US TO PULL CIRCUIT BREAKER P210-D9 INSTEAD OF P110-A16 WHICH WAS ACCOMPLISHED. THE SCREEN BEGAN TO COOL AND THERE WAS NO MORE SMOKE; PULLING THE CIRCUIT BREAKER APPEARED TO SOLVE THE PROB. FO #2 INSPECTED THE AREA CAREFULLY AND FOUND NO OTHER PROBS. WE ADVISED DISPATCH BY ACARS; REQUESTED POSSIBLE ALTERNATES IF THE PROB RECURRED. I ADVISED THE CHIEF PURSER TO DESIGNATE 1 FLT ATTENDANT TO CONTINUOUSLY MONITOR THE SCREEN FOR ANY RECURRING PROB. MAINT ADVISED US OF THE NONOPERATING AND NONCTLABLE EQUIP RESULTING FROM DEACTIVATING THIS CIRCUIT BREAKER. THE ITEMS AFFECTED WERE SOME LIGHTING; TEMP CTLS AND SOME MUSIC WHICH WOULD NOT BE ABLE TO BE ADJUSTED; BUT WOULD OPERATE IN THEIR PRESENT CONFIGN. FLT ATTENDANT #1 FOUND THE PROB AND HELPED PROFESSIONALLY THROUGHOUT. FO #2 DID THE WORK AND KEPT US ADVISED ON THE CONDITION OF THE SYS. FO #1 AIDED IN FLYING AND COMS. POSSIBLE CONTRIBUTING FACTORS: 1) DURING OUR LAYOVER IN AMSTERDAM THE GPU RAN OUT OF FUEL CAUSING A LOSS OF PWR UNTIL THE APU WAS STARTED AND ON-LINE. THIS CAUSED A NUMBER OF ELECTRICAL ANOMALIES. A NUMBER OF SYS WERE DEPWRED AND REPWRED TO GET PROPER INDICATIONS. 2) SCREEN AT 2L HAD BEEN DEFERRED INOP -- BUT NOT DEPWRED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR'S CONCERN IS CTRED AROUND THE FACT THAT THERE IS NO WAY FOR THE FLC TO ISOLATE AN ELECTRICAL SYS ON THE B777 WITHOUT GETTING THE INFO BY RADIO FROM THEIR MAINT BASE. HE STATED THAT; IF PUSH CAME TO SHOVE; HE COULD ATTEMPT TO ISOLATE THE PROB BY TURNING OFF ONE OR THE OTHER GENERATOR. BUT; HE WORRIED THAT SUCH ACTION MIGHT CAUSE MANY MORE PROBS THAN HE COULD SOLVE. HE ADDED THAT HE THOUGHT THE SMOKING EQUIP HAD TO BE COOLED AND THE HALON EXTINGUISHERS AVAILABLE TO THE CREW DO NOT COOL THE OVERHEATING EQUIP.