As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE FLIGHT, SMOKE WAS NOTED COMING FROM TOP OF CONTROL STAND UNDER AUTOPILOT PANEL. SMOKE STOPPED WHEN 'ALT' HOLD WAS SHUT OFF. ACCOMPLISHED SMOKE EVAC PER ADM, OPENED C/B. REMOVED AND REPLACED AUTOPILOT CONTROL PANEL IAW 22-11-81.