What was found
DURING TWO INSTRUMENT APPROACHES ) LOC AND RNAV GPS)) AT/NEAR FINAL APPROACH FIX FMC DISAGREE SCRATCHPAD MSG DISPLAYED AND AUTO PILOT DISCONNECTED. UNABLE TO FLY EITHER APPROACH, INTERMITTENT HIGH PITCHED ALARM SOUNDED ON SEVERAL OCCASIONS BENEATH CENTER PEDESTAL. FOLLOWED FIM TASK 34-61-00-810-835. THE AIRCRAFT WAS GROUNDED. REMOVED AND REPLACED RIGHT FMC IAW AMM 34-61-02 AND AS PRECAUTIONARY REMOVED AND REPLACED RIGHT MULTI-MODERECEIVER IAW AMM 34-31-42. OPS CHECKED GOOD. COULD NOT DUPLICATE THE ALARM SOUND.