What was found
IN CRUISE, THE CAPTAIN'S FMC FAILED. DISPLAYED VTK ON CAPTAIN'S NAV DISPLAY AND NOT ON F/O'S DISPLAY. IT RESOLVED ITSELF IN A FEW MINUTES. 5 MINUTES LATER ATC GAVE US DIRECT YKM. TRIED TO ENTER THAT ON EITHER FMC AND GOT A SCRATCH PAD MESSAGE INVALID MOD ROUTE. REENTERING THE ARRIVAL ROUTE 2 OR ROUTE 1 WOULD NOT WORK. IT WAS STUCK ON A BEAM WAYPOINT PRIOR TO YKM AND COULD NOT PUT ANYTHING AHEAD OF THAT. SELECTING FMC BOTH ON R ON TRANSFER SWITCHES ON OVERHEAD PANEL FIXED THE PROBLEM. ACFT GROUNDED. SWITCHED FMC TO NORMAL - BOTH OPS NORMAL.