As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER GPU CONNECTED ELECTRICAL SMOKE COMING FROM OVER HEAD PANEL, POST INSPECTION REVEALED ELECTRIC PUMP CIRCUIT BREAKER HAD BURNING ODOR. REMOVED AND REPLACED HYDRAULIC CONTROL PANEL IAW EMB AMM 20-13-10. OPERATIONAL CHECK GOOD, RETURNED AIRCRAFT TO SERVICE.