AN AIRBUS 320 WAS DISPATCHED IN NON COMPLIANCE WITH #1 AND #3 IRU'S NOT SECURED AFTER MAINT RESULTING IN A DIVERSION.

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ON FRI/XA/00; KXX WXX APCHED ME AFTER LUNCH ASKING ME IF I COULD HELP OUT DOING THE ATCRBS AND MODE S XPONDER TEST; AS KXX AND THE 3 TECHNICIANS (YT; XZX; AND ZYX) WERE UNFAMILIAR WITH THE TEST AND THE PROCS. DURING THE TEST; KXX ANNOUNCED TO ME THAT THE ADC FAULT WAS ON FOR #1 AND THE SCREEN INFO WAS GONE. I WENT UPSTAIRS TO SEE AND KXX STATED HE THOUGHT WE WERE CLBING TOO QUICKLY AND MAY HAVE TRIPPED THE ADC IN THE ATTITUDE DIRECTIONAL INERTIAL REF UNIT. WE RESET THE BREAKER; PWRED DOWN AND CAME UP AGAIN TO NO AVAIL. I STATED WE NEEDED TO GET THIS GOING; SO I TOLD HIM I WAS GOING TO SWAP #1 AND #3 ATTITUDE DIRECTIONAL INERTIAL REF UNITS TO SEE IF THE PROB MOVED. WENT DOWN TO THE E&E BAY; WHICH WAS OPENED; AND A LADDER ALREADY SET UP. I SWITCHED THE ATTITUDE DIRECTIONAL INERTIAL REF UNITS AND WENT BACK UPSTAIRS TO CHK. WAS TOLD THAT THE LIGHT WAS STILL ON. WAS GOING BACK DOWN TO PUT THEM BACK IN POS WHEN KXX YELLED THAT THE FAULT CLRED(?). I CONTINUED DOWN TO TELL THE TECHNICIANS TO CONTINUE; WHEN I SAW THAT THE PLUMBING FOR THE TEST WAS NOT CORRECT. WENT OVER AND TOLD THE TECHNICIANS TO SET IT THE RIGHT WAY. THE ACFT SUPVR CAME OVER AND ASKED HOW WE WERE DOING. I TOLD HIM OF THE PROB AND WE WERE BACK ON TRACK AND MORE BEHIND. HE SAID COULD WE WORK THROUGH BREAK AND KEEP MOVING. FROM THEN TILL THE END OF THE SECOND TEST I WAS UP AND DOWN FROM THE FLT DECK RUNNING THE TEST AND GIVING INFO TO THE TECHNICIANS WHAT TO SET UP AND WHAT READINGS WERE TO BE SEEN. DURING THIS; WE HAD AN APU CREW DOING THEIR TESTS FROM THE FLT DECK GETTING US MORE BEHIND. WE FINALLY FINISHED THAT TEST AND COMPLETED THE TCASII FUNCTIONAL CLOSE TO THE PUSHBACK TIME. I LET EVERYONE ON THE GND KNOW TO TAKE OFF ALL THE TEST EQUIP; AND LET THE MECHS KNOW WE WERE DONE. KXX AND I THEN TOOK THE PAPERWORK INTO THE OFFICE TO COMPLETE; TO FINISH THE PACKAGE. WHEN I CAME IN THAT EVENING I WAS INFORMED OF THE EVENT AND I REMEMBERED ABOUT THE IRU'S.