As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PRIOR TO TAKEOFF HEARD A CRACKLING NOISE AND SMELLED ELECTRICAL BURNING RECEIVED A "L FMC FAIL IN EICAS" AND LOST THE R FMC CDU. CDU BREAKER OPENED AND WOULD NOT RESET. IDENTIFIED RT CDU HAD A BURNED ODOR REPLACED CDU PER MM 34-61-02-2. REPLACED LT FMC PER MM 34-61-01-4. OPS GOOD.