What was found
IAS DISAGREE ON FINAL, MISSED APPROUCH DUE TO LOC SIGNAL FAILURE, AUTOPILOT DISCONNECTED DURING GEAR RETRACTION. ALL 3 AIRSPEED INDICATORS READ EXACTLY THE SAME. IAS DISAGREE CLEARED ITSELF. 2ND ILS UNEVENTFUL. LOC SIGNAL FAILURE DUE TO GROUND EQUIPMENT FAILURE. REF FAULT REPORTING & FAULT ISOLATION MANUAL, FAULT CODE 34 90 38 00. REF F.I.M. 34-12 FAULT TREE 808,BLOCK 1, 2, AND 14 , BLOCK #2 "ADC-L" RIGHT CHANNEL FAULTED. REMOVED & REPLACED THE LEFT ADC REF M/M 34-12-01-4, ALL TEST PASSED. PERFORMED A TEST 30 & 40 REF M/M 22-00-02-2, ALL TEST PASSED WITH NO FAULTS. TOWER NOTIFIED AND CONFIRMED TO THE FLIGHT CREW THAT THE SLC AIRPORT LOC SIGNAL WAS INOP DURING FIRST APPROACH.