As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
REPORTED A PUFF OF SMOKE FROM THE AUXILLARY POWER UNIT CONTROL PANEL WHEN THE GENERATOR SWITCH WAS SELECTED ON.MAINTENANCE CONFIRMED THAT THE CONTROL PANEL WAS AT FAULT AND DISCONNECTED THE PANEL CONNECTOR, ISOLATED THE UNIT, AND COMPLIED WITH MEL PROCEDURES UNTIL PARTS WERE OBTAINED. ONCE PARTS WERE AVAILABLE THE CONTROL PANEL WAS REMOVED AND REPLACED AND THE SYSTEM WAS OPERATIONAL CHECKED. ALL CHECKS WERE GOOD AND THE AIRCRAFT WAS RETURNED TO SERVICE.