As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PRIMARY TRIM CIRCUIT BREAKER TRIPPED WHILE SETTING TAKEOFF TRIM. WHILE MECHANIC WAS TROUBLESHOOTING PRIMARY TRIM, HEAVY SMOKE PRODUCED THROUGHOUT FRONT & REAR CABIN. CREW CONDUCTED EMERGENCY SHUT DOWN & EVACUATED AIRCRAFT. FOUND RELAY R20-15 BURNT. REPLACED RELAY R20-15 IAW DC9 AMM 27.40.04.