What was found
THIRTY MINUTES ENROUTE, IN WEATHER, THE FMC 2 WENT INDEPENDENT COMMUNICATION. IMMEDIATLY FOLLOWED BY DUAL FMS FAILURE . ALL DATA WAS LOST AND SECONDARY FLIGHT PLAN DATA DUMPED AS WELL, WENT DIRECT TO A FIX, PUT IN AND TRIED TO LATTERAL OFF FOR A NEW DESTINATION TO BUT THE NEW DESTINATION PROMPT WAS NOT THERE . BUILT THE ARRIVAL AND POINTS FOR APPROACH, BUT COULD NOT TUNE THE ILS HEAD PERFORMED. TROUBLESHOT PROCEDURES TO FMS, FOUND THE NR 1 AND 2 VIA'S AT FAULT INTERMITTENT UNDER NR 1 ADIRIU FAULT REVIEW, REMOVED SAME FOR GENERAL VISUAL INSPECTION FOR EVIDENCE OF WATER OR COMPONENTS LOOSE ON RACKS, INSTALLED THE NR 1 ADRIU, FOUND NO EVIDENCE OF DEFECTS, PERFORMED SYS OPS CHECK, SYS OPS CHECKED NORMAL, REMOVED AND REPLACED THE NR 1 AND 2 VIA PRECAUTION, COMPLIED WITH RETURN TO SERVICE, ALL SYSTEMS CHECKED NORMAL IAW FRM/FIM 34-43-00-5, 34-63-00-2, AMM 34-63-00-5, 31-43-01-4, 22-00-00-2, AND 22-00-00-5, AIRCRAFT OK FOR SERVICE.