What was found
DURING TAXI, F/O SIDE OTBD DISPLAY UNIT SHOWED MAP LAND ALT AND NO V SPEED. ACFT GROUNDED. ON GROUND VERIFICATION TEST, FOUND THAT RT FMC RESET ON ITS OWN TWO TIMES IN ABOUT A 45 MINUTE PERIOD. FMC PROMPT WENT AWAY FROM MCDU AND MAP AND VTRK FLAGS CAME INTO VIEW. AFTER RT FMC PROMPT REAPPEARED, FMC WOULD OPS NORMAL WITH NO FAULTS LOGGED. REPLACED RT FMC REF MM 34-61-02. MONITORED FOR ABOUT 45 MINUTES WITH NO ISSUES. GROUND VERIFICATION GOOD.