A B737-300 WAS DISPATCHED IN NON COMPLIANCE WITH THE STANDBY RUDDER HYD PUMP CB PULLED AND COLLARED FOR MAINT.

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I AM AN A&P MECH EMPLOYED BY ACR AT ZZZ. MY BID LOCATION IS 'C' CHK; WORKING IN THE HANGAR. OUR CREW PERFORMED A 'SEGMENTED C CHK' ON ACFT XYZ ON THE NIGHT/MORNING OF NOV/THU/00. AFTER MAINT WAS COMPLETED AND ACFT HAD BEEN 'PUSHED OUT AND LEAK CHKED;' I PERFORMED THE 'POST DOCK INSPECTION' ON THE ACFT. THIS INSPECTION INCLUDES CHKING FLT CTL LOCKS ARE REMOVED; HYD QUANTITIES; AND COCKPIT CB; AMONG OTHER ITEMS. APPARENTLY; DURING MY CHK OF THE COCKPIT; I OVERLOOKED THE RESETTING OF THE 'STANDBY HYD' CB. THIS CB (ON OUR 300/500 ACFT) IS LOCATED BEHIND AND BELOW THE FO'S SEAT. IN ADDITION; THIS CB (AS WELL AS SEVERAL OTHERS) IS PLACED BEHIND A MIKE INSTALLATION ON THE CB PANEL; WHICH OBSTRUCTS A CLR VIEW OF THE CB'S. FROM THE LIMITED INFO I'VE HAD; AN FAA CHK PLT FOUND THE CB PULLED (WITH A LOCKOUT COLLAR ON IT) DURING A REVENUE FLT ON NOV/XX/00. EVIDENTLY; THIS CB LOCKOUT COLLAR DIDN'T HAVE A 'DO NOT OPERATE' TAG ATTACHED TO IT; SO I ASSUME I MISSED SEEING IT DURING MY INSPECTION DUE TO THE OBSTRUCTED VIEW OF THE PANEL. THE 'STANDBY HYD' CB IS NORMALLY PULLED AND COLLARED DURING THE 'PRE DOCK' PHASE OF THE CHK; WHEN OUR 'FUNCTIONS CREW' PERFORMS OPS CHKS ON VARIOUS SYS. I ALSO THINK THAT THE RUN-UP/LEAK CHK MECH WHO RUNS THE AFT ENGS SHOULD ALSO PERFORM THE 'POST DOCK' INSPECTION IN THE FUTURE; SINCE IT IS ALSO HIS JOB TO ASSURE ALL CB'S ARE RESET. IN THIS PARTICULAR INSTANCE; NOT ONLY MYSELF; BUT THE 'TAXI TO THE GATE' MECH; AS WELL AS THE PLT (ON REVENUE FLT) FAILED TO NOTICE AND RESET THIS CB.