Narrative:

Aircraft xyz had a routine overnight layover in ZZZ on feb/tue/01 with the #1 ILS on MEL. Myself and another technician, while troubleshooting the #1 ILS, found an open wire in the frequency tuning circuit from the navigation control panel to the navigation receiver. Unable to locate where the open wire was before shift change. I decided we should leave the system on MEL since it was an open item MEL and had time remaining. Nine days later a pilot wrote up the #1 VOR system inoperative on some frequencys. My error was that while finding a frequency tuning problem with the ILS, it did not dawn on me at the time that the VOR would have a tuning problem also. Although the VOR system had no history in the past 60 days and operations checked normal with tic [hand-held VOR/ILS tester] test set, on local vors and the test vot, while troubleshooting the ILS. The ILS can be MEL'ed, but the aircraft cannot be dispatched with an inoperative VOR, which I should have realized at the time and grounded the aircraft until the open wire was repaired. Aircraft xyz was released for flight with the #1 ILS on MEL. The VOR discrepancy arose nine days later in the form of a pilot write-up. At this time XXX maintenance repaired the open wire, fixing the #1 VOR and #1 ILS system. This was all brought to my attention by maintenance control in abc.

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Original NASA ASRS Text

Title: A B737-400 WAS DISPATCHED IN NON COMPLIANCE WITH THE #1 VOR NAV SYS INOP ON SOME FREQS. CAUSED BY DEFERRAL OF THE ILS SYS.

Narrative: ACFT XYZ HAD A ROUTINE OVERNIGHT LAYOVER IN ZZZ ON FEB/TUE/01 WITH THE #1 ILS ON MEL. MYSELF AND ANOTHER TECHNICIAN, WHILE TROUBLESHOOTING THE #1 ILS, FOUND AN OPEN WIRE IN THE FREQ TUNING CIRCUIT FROM THE NAV CTL PANEL TO THE NAV RECEIVER. UNABLE TO LOCATE WHERE THE OPEN WIRE WAS BEFORE SHIFT CHANGE. I DECIDED WE SHOULD LEAVE THE SYS ON MEL SINCE IT WAS AN OPEN ITEM MEL AND HAD TIME REMAINING. NINE DAYS LATER A PLT WROTE UP THE #1 VOR SYS INOP ON SOME FREQS. MY ERROR WAS THAT WHILE FINDING A FREQ TUNING PROB WITH THE ILS, IT DID NOT DAWN ON ME AT THE TIME THAT THE VOR WOULD HAVE A TUNING PROB ALSO. ALTHOUGH THE VOR SYS HAD NO HISTORY IN THE PAST 60 DAYS AND OPS CHKED NORMAL WITH TIC [HAND-HELD VOR/ILS TESTER] TEST SET, ON LCL VORS AND THE TEST VOT, WHILE TROUBLESHOOTING THE ILS. THE ILS CAN BE MEL'ED, BUT THE ACFT CANNOT BE DISPATCHED WITH AN INOP VOR, WHICH I SHOULD HAVE REALIZED AT THE TIME AND GNDED THE ACFT UNTIL THE OPEN WIRE WAS REPAIRED. ACFT XYZ WAS RELEASED FOR FLT WITH THE #1 ILS ON MEL. THE VOR DISCREPANCY AROSE NINE DAYS LATER IN THE FORM OF A PLT WRITE-UP. AT THIS TIME XXX MAINT REPAIRED THE OPEN WIRE, FIXING THE #1 VOR AND #1 ILS SYS. THIS WAS ALL BROUGHT TO MY ATTN BY MAINT CTL IN ABC.

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.