What was found
(LOG 8567596) UPON REACHING THE GATE, UPON REACHING THE GATE, AND SHUTTING BOTH BOTH ENGINES DOWN WITH BOTH APU POWER AND GROUND POWER THE WHOLE CABIN WENT DARK. RESET POWER AT GATE, OPS NORMAL REF B737 AMM 24-41.
As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
(LOG 8567596) UPON REACHING THE GATE, UPON REACHING THE GATE, AND SHUTTING BOTH BOTH ENGINES DOWN WITH BOTH APU POWER AND GROUND POWER THE WHOLE CABIN WENT DARK. RESET POWER AT GATE, OPS NORMAL REF B737 AMM 24-41.