As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
OBSERVED SMOKE UNDER CO-PILOTS INSTRUMENT PANEL. PERFORMED EMER PROCEDURES CHECKLIST & NOTED THAT THE NR 1 N1 INDICATOR CB HAD POPPED. CONFIRMED THAT THE POPPED CB ISOLATED THE ISSUE. IMMEDIATELY RETURNED TO THE BASE OF ORIGINAL DEPARTURE FOR EVALUATION & INSPECTION. ON INSPECTION MX NOTED A WIRE CHAFING AGAINST THE CO-PILOT LT BRAKE HYD B NUT.