As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT PREFLIGHT INFORMED MAINTENANCE LEFT FMC NOT WORKING. SWAPPED COMPUTERS FOR TROUBLESHOOTING PROBLEM FOLLOWED. RE-INSTALLED RT FMC COMPUTER AND REPLACE LT SIDE COMPUTER PER AMM 34 61 02 PERFORMED FMC SYSTEM CROSSLOAD REF AMM 34 61 00. SYSTEM OPS CHECK OK PER AMM 34 61 00.