As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHEN MOVING THE VOLT/FREQ SELECTOR KNOB IT STARTED SMOKING. THE VOLTS AND FREQ METERS INCREASED A LITTLE THEN DROPPED TO ZERO. THE SMOKE STOPPED. COMPLIED WITH ODI CHECKLIST. INSPECTED ALL WIRING. REPLACED THE SELECTOR SWITCH AND FREQ INDICATOR. CHECKED GOOD IAW AMM 24-00. ACFT OK FOR SERVICE.