As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN CRUISE STAB TRIM UNSCHEDULED EICAS MSG. RAN QRH 45 MINUTES LATER 2ND EICAS MSG. RAN QRH DISC AUTO PILOT AND DIVERTED TO SYD. FOUND RIGHT RVDT IN STAB BUZZING AND CRACKING ELECTRICALLY. REPLACED UNIT, OPS CHECK OK. ALSO REPLACED RIGHT FCU AND FCC AS PRECAUTION.