As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRTURN BACK, SHORTLY AFTER TAKEOFF FELT A LIGHT VIBRATION AND THEN SMOKE AND FUMES IN COCKPIT. SMOKE SMELLED ELECTRICAL AND DISIPATED ALMOST IMMEDIATELY. VIBRATION ALSO CEASED. FOUND DISCONNECT D970 SHORTED TO GROUND AND WIRES W388-010-20 AND W388-027-20 BURNED IN JUNTION BOX AT BS 720R. SPLICED NEW WIRES AND REPLACED D970 CONNECTOR PER MM. ALSO, REMOVED AND REPLACED P5-2 FUEL SYSTEM MODULE PER MM.