As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DFW - CREW REPORTED ELECTRIC STANDBY SYSTEM EICAS MESSAGE. EMERGENCY DECLARED FLIGHT RETURNED DFW LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. CHANGED M24406A12 DC STANDBY CARD AND A/M24406A1 POWER SUPPLY. SYSTEM GROUND CHECK NORMAL OPERATION.