As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LAX - BOTH AC AND DC STANDBY POWER LOST AND EICAS MESSAGE STANDBY BUS OFF DISPLAYED. STANDBY POWER BUS OFF LIGHT ILLUMINATED, BOTH INDICATORS SAME WHEN STANDBY POWER MOMENTARILY SELECTED TO BAT. REPLACED K-109 STANDBY POWER RELAY. PERFORMED STANDBY POWER. TEST OPS NORMAL PER MM 24-33-01. (M)