As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) CREW REPORTED SMOKE COMING FROM BEHIND THE LEFT HAND INSTRUMENT PANEL JUST ABOVE THE TRANSPONDER, ACCOMPANIED BY ELECTRICAL BURNING SMELL. NR 1 TRANSPONDER TURNED OFF AND SMOKE DISSIPATED. CIRCUIT BOARD OF NR 1 TRANSPONDER BADLY BURNED.