As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ELECTRICAL SMOKE AND STRONG BURNING ODOR IN COCKPIT. THIS SITUATION OCCURRED PRIOR TO FOLLOWING WRITE UP, STICK SHAKER. INSPECTED COCKPIT WIRING, NO EVIDENCE OF BURNING. ODOR CAME FROM PACKS THAT OVERHEATED WHILE A/C WAS IN AIR MODE, OPS CHECK GOOD IAW B727 MM 21-12-0.