What was found
AFTER HOOKING UP GROUND POWER UNIT (24 VDC), BATTERY CIRCUIT TRANSIENT VOLTAGE SUPPRESSOR BLEW SMOKE AND LOUD POPPING SOUND.
As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
AFTER HOOKING UP GROUND POWER UNIT (24 VDC), BATTERY CIRCUIT TRANSIENT VOLTAGE SUPPRESSOR BLEW SMOKE AND LOUD POPPING SOUND.