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.