A LEAD AND TWO MECHANICS REPORT ON LOCKING OUT THE LEFT ENGINE THRUST REVERSER ON A B757-200 ACFT; BUT PULLED AND COLLARED THE WRONG CIRCUIT BREAKER; RESULTING IN A 'LEFT OIL SCVG' MESSAGE AFTER TKOF.

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WHILE WORKING WITH ANOTHER MECH ON MEL PROC LOCKING OUT L THRUST REVERSER THE WRONG CIRCUIT BREAKER WAS COLLARED RESULTING IN A STATUS MESSAGE AFTER TKOF. THE FLT CONTINUED ON WITHOUT FURTHER INCIDENT. THE REST OF THE MEL PROC WAS COMPLIED WITH. SUPPLEMENTAL INFO FROM ACN 790544: ACFT RTB DUE TO 'L ENG REV CONT' EICAS MESSAGE. AS LEAD ON DUTY I ASSIGNED 2 AMT'S TO DEFER THE L THRUST REVERSER. I PREPARED THE DEFERRAL ENTRY INTO THE MAINT CPU AS THE WORK PROGRESSED. UPON CONFERRING WITH THE AMT'S INVOLVED I COMPLETED THE ENTRY. I LATER RECEIVED A PHONE CALL FROM LINE MAINT CTL THAT THE CIRCUIT BREAKER PULLED FOR THE DEFERRAL WAS INCORRECT AND HAD CAUSED ANOTHER MESSAGE; 'L OIL SCVG' UPON TKOF. THE ACFT CONTINUED ON ITS TRIP. SUPPLEMENTAL INFO FROM ACN 790545: THE ACFT CAME BACK TO THE GATE WITH A L ENG REV CONT STATUS MESSAGE. WE CONFERRED WITH MAINT CTL AND HE ADVISED US TO LOCK OUT THE L THRUST REVERSER PER THE MEL PROCS. WE WERE TRYING TO DO THIS AS SAFELY AS POSSIBLE BUT ALSO WE WERE WORKING IN A TIME SENSITIVE MANNER. WE READ AND REREAD THE MEL BUT IT IS VERY LENGTHY AND CAN BE SOMEWHAT CONFUSING. ONE OF THE LAST PROCS IS TO LOCK OUT A CIRCUIT BREAKER FOR THE SYNC LOCK ON THE P6-2 PANEL. AS I ENTERED THE FLT DECK I LOOKED UP ON THE P11 PANEL FOR THE BREAKER THINKING IT WAS THERE; THE D12 BREAKER IS A CONT BREAKER WHICH MATCHED THE STATUS MESSAGE WE HAD; SOMEWHAT; AND THIS IS WHAT I BELIEVED WAS THE CORRECT BREAKER. THINKING WE HAD FOLLOWED THE MEL PROC CORRECTLY; WE RELEASED THE ACFT. WE LEARNED LATER; THAT THE CREW GOT A SCAVENGE CONT STATUS MESSAGE AFTER TKOF AND CONTINUED ON TO THEIR DEST. THE REST OF THE MEL PROC WAS ACCOMPLISHED PER THE MEL CORRECTLY.