As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED CLICKING SOUND COMING FROM AROUND P6 3 PANEL. ISOLATED SOUND TO STANDBY POWER CONTROL UNIT. CYCLED STANDBY POWER SOUND STOPPED BUT RETURNED MINS LATER. REMOVED & REPLACED SPCU REF MM 24-34-11-400-801. GROUND VERIFICATION TEST PASSED.