As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAKE OFF, ENGAGED AUTO-THROTTLES AT 70 KNOTS. DC BUSS OFF MESSAGE APPEARED ON THE EPCU ANNUNCIATOR PANEL. ALL OTHER SYSTEMS & INDICATIONS NORMAL BEFORE AND AFTER ATO. PERFORMED NO GO ODI PREVENTION CHECK LIST. FOUND DC EMERGENCY POWER TRANSFER RELAY R2-326 FAILED. REPLACED THE RELAY. OPS CHECKED NORMAL.