What was found
AFTER PRESSING A KEY ON MKP THE SVS WAS LOST. MFD WENT BLACK, FMS ILLUMINATED ON PFD1 IN RED, A/P REVERTED TO ROLL AND PITCH MODES. THE MFD SLOWLY CAME BACK ONLINE OVER THE COURSE OF APPROXIMATELY 60 SECONDS. DURING SUCH TIME, TOPO FAIL, PFD COMPARE FAIL, PFD 2 TOPO TERR, MFD TOPO TERR, PFD 1 TOPO TERR, AND FMS 2 INOP WERE DISPLAYED. FMS 1 WAS NOT ABLE TO BE ACCESSED AND XTALK FAIL REMAINED DISPLAYED ON PFD 1& FOR THE DURATION OF THE FLIGHT. MAINTENANCE REMOVED AND REPLACED THE CENTER AFD AND LOADED SOFTWARE. OPERATIONAL CHECKS WERE SUCCESSFUL. AIRCRAFT WAS RETURNED TO SERVICE.