As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT NR 0730 - DCA - THE NR 3 AUDIO SELECT PANEL BEGAN TO SMOKE IN FLIGHT. THE SMOKE CEASED AFTER THE CIRCUIT BREAKERS WERE PULLED AND THE UNIT WAS REMOVED FROM OVERHEAD PANEL. THE NR 3 AUDIO SELECT PANEL WAS REMOVED AND REPLACED. OPERATIONAL CHECKS WERE GOOD. AN INSPECTION OF THE INSIDE OF THE REMOVED UNIT FOUND A BURNED CIRCUIT BOARD. (M)