A319 MECH WAS NOT SURE THAT ALL CIRCUIT BREAKERS WERE RESET AFTER WORKING ON THE YELLOW HYD SYS.

Narrative

IN ADDITION TO MANY OTHER ACFT; I PERFORMED MAINT ON ACFT X. THE ACFT ARRIVED WITH A DEFERRED ITEM FOR THE YELLOW HYD PUMP RUNNING CONTINUOUSLY. I TROUBLESHOT THE SYS PER THE TROUBLESHOOTING MANUAL AND SCHEMATICS AND REPLACED A TIME-DELAY RELAY FOR THE FIX. I THEN PERFORMED A SATISFACTORY FUNCTIONAL CHK OF THE AUX YELLOW HYD SYS THAT WAS FAILING EARLIER. ALL CHKED GOOD AND I THEN SIGNED OFF THE ITEM. ON JUL/TUE/04; A FELLOW AMT IN ZZZ1 FOUND ONE OF THE YELLOW ELECTRIC PUMP CIRCUIT BREAKERS OUT -- ASSUMING THAT IT WAS LEFT OUT WHEN MY DEFERRED ITEM WAS FIXED. IT WAS RESET AND ENTERED INTO THE ACFT HISTORY. THE NIGHT I WORKED ON THAT SYS I DID READ THE MEL DEACTIVATION/REACTIVATION PROCS. HOWEVER; THERE IS A POSSIBILITY THAT I MISSED RESETTING THAT PARTICULAR BREAKER. THIS IS A POSSIBILITY BECAUSE THE BREAKER IN QUESTION ONLY PWRS THE SYS WHEN EXTERNAL PWR IS ATTACHED BUT NOT SELECTED ON THE ACFT. ALL OTHER SITS (I.E. ACFT PWRED NORMALLY) WOULD WORK FINE THROUGH THE OTHER 'NORMAL' CIRCUIT BREAKER. THE FUNCTIONAL CHK WOULD STILL HAVE PASSED WITH THE BREAKER PULLED. THE SYS STILL WORKED SATISFACTORILY AND NO INFLT EVENTS OCCURRED. THE BREAKER WAS FOUND OUT VISUALLY; AND RESET PUTTING THE ACFT BACK IN ITS NORMAL CONFIGN. DOUBTFUL; BUT IF IN FACT I DID INADVERTENTLY LEAVE OUT THIS CIRCUIT BREAKER; I SUPPOSE I WOULD ATTRIBUTE IT TO THE FACT THAT THERE WAS A HVY WORKLOAD AND I OFTEN WORK MANY ACFT AND SYS SIMULTANEOUSLY. I WILL HAVE TO SLOW DOWN A LITTLE AND ENSURE THAT EVERY DETAIL IS COVERED.