As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAXI OUT BOTH PILOTS SMELLED AN ELECTRICAL BURNING SMELL AND SAW LIGHT SMOKE COMING FROM THE JUNCTION BOX PANEL. THE ACFT WAS STOPPED, ENGINES SHUTDOWN, AND THE CREW SAFELY EGRESSED THE ACFT WITHOUT INCIDENT. A MX REPAIR TEAM WAS FLOWN TO ACFT AND FOUND THAT A BOLT (POST BOLT TO 400 AMP FUSE) HAD LOOSENED, SHORTED OUT A CURRENT LIMITER, AND SINGED INSULATION. MX REPLACED CURRENT LIMITER AND SECURED POST BOLT.