Narrative:

On oct/xx/96 I was told to meet aircraft (en route from YYY to lga) when it arrived because there was an MEL placed on the #1 generator in a non company maintenance station. I was asked to place the proper placards on the logbook. When I met the crew, the captain informed me that while flying into YYY, the #1 generator was lost, and several breakers popped. I recall him saying the #1 thrust reverser, hydraulic pump circuit breakers, and fuel pump circuit breakers. He also informed me that the non company personnel placed the generator system on MEL as per the maintenance controller, but didn't reset the circuit breaker for the #1 thrust reverser. He informed me that the normal equipment cooling fan was not working as well. I investigated and found the circuit breaker popped. I then checked all the circuit breakers to make sure no others were tripped and found the #1 normal hydraulic pump circuit breaker popped. It seems these circuit breakers were never reset from the other station. I reset them and those system operated normal. There was a concern. I informed my lead that there seems to be a larger problem because several circuit breakers popped and the #1 thrust reverser was never reset. There is no relief under an MEL for a thrust reverser being inoperative. The lead in turn set up a delay. I did some research to see if there was any history on the problem and on maintenance manual troubleshooting procedures, but because of it being during the operating day, the time is limited, and under suggestion of the maintenance controller, we tried replacing the #1 generator control unit. With all circuit breakers reset we ran the #1 engine and tested the generator and control circuits to verify the problem, but could not verify any fault -- system was operating normal. On the premise that it was an intermittent fault (because no history and unable to duplicate) we replaced the #1 generator control unit. We ran the #1 engine again, placed a heavy load on the system and performed the procedures as per maintenance manual. There were no defects noted. I completed the paperwork and released the aircraft for service. On the outbound leg, ZZZ-WWW, the aircraft diverted to VVV due to an automatic cabin pressure fault and smoke in the cabin, accompanied by a tripped #1 generator.

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Original NASA ASRS Text

Title: A B737-200 DIVERTED DUE TO #1 GENERATOR FAILURE, SMOKE IN CABIN AND CABIN PRESSURIZATION IN AUTO.

Narrative: ON OCT/XX/96 I WAS TOLD TO MEET ACFT (ENRTE FROM YYY TO LGA) WHEN IT ARRIVED BECAUSE THERE WAS AN MEL PLACED ON THE #1 GENERATOR IN A NON COMPANY MAINT STATION. I WAS ASKED TO PLACE THE PROPER PLACARDS ON THE LOGBOOK. WHEN I MET THE CREW, THE CAPT INFORMED ME THAT WHILE FLYING INTO YYY, THE #1 GENERATOR WAS LOST, AND SEVERAL BREAKERS POPPED. I RECALL HIM SAYING THE #1 THRUST REVERSER, HYD PUMP CIRCUIT BREAKERS, AND FUEL PUMP CIRCUIT BREAKERS. HE ALSO INFORMED ME THAT THE NON COMPANY PERSONNEL PLACED THE GENERATOR SYS ON MEL AS PER THE MAINT CTLR, BUT DIDN'T RESET THE CIRCUIT BREAKER FOR THE #1 THRUST REVERSER. HE INFORMED ME THAT THE NORMAL EQUIP COOLING FAN WAS NOT WORKING AS WELL. I INVESTIGATED AND FOUND THE CIRCUIT BREAKER POPPED. I THEN CHKED ALL THE CIRCUIT BREAKERS TO MAKE SURE NO OTHERS WERE TRIPPED AND FOUND THE #1 NORMAL HYD PUMP CIRCUIT BREAKER POPPED. IT SEEMS THESE CIRCUIT BREAKERS WERE NEVER RESET FROM THE OTHER STATION. I RESET THEM AND THOSE SYS OPERATED NORMAL. THERE WAS A CONCERN. I INFORMED MY LEAD THAT THERE SEEMS TO BE A LARGER PROB BECAUSE SEVERAL CIRCUIT BREAKERS POPPED AND THE #1 THRUST REVERSER WAS NEVER RESET. THERE IS NO RELIEF UNDER AN MEL FOR A THRUST REVERSER BEING INOP. THE LEAD IN TURN SET UP A DELAY. I DID SOME RESEARCH TO SEE IF THERE WAS ANY HISTORY ON THE PROB AND ON MAINT MANUAL TROUBLESHOOTING PROCS, BUT BECAUSE OF IT BEING DURING THE OPERATING DAY, THE TIME IS LIMITED, AND UNDER SUGGESTION OF THE MAINT CTLR, WE TRIED REPLACING THE #1 GENERATOR CTL UNIT. WITH ALL CIRCUIT BREAKERS RESET WE RAN THE #1 ENG AND TESTED THE GENERATOR AND CTL CIRCUITS TO VERIFY THE PROB, BUT COULD NOT VERIFY ANY FAULT -- SYS WAS OPERATING NORMAL. ON THE PREMISE THAT IT WAS AN INTERMITTENT FAULT (BECAUSE NO HISTORY AND UNABLE TO DUPLICATE) WE REPLACED THE #1 GENERATOR CTL UNIT. WE RAN THE #1 ENG AGAIN, PLACED A HVY LOAD ON THE SYS AND PERFORMED THE PROCS AS PER MAINT MANUAL. THERE WERE NO DEFECTS NOTED. I COMPLETED THE PAPERWORK AND RELEASED THE ACFT FOR SVC. ON THE OUTBOUND LEG, ZZZ-WWW, THE ACFT DIVERTED TO VVV DUE TO AN AUTO CABIN PRESSURE FAULT AND SMOKE IN THE CABIN, ACCOMPANIED BY A TRIPPED #1 GENERATOR.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.