As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI-OUT, AN ACRID ELECTRICAL SMOKE DEVELOPED IN COCKPIT. FLUORESCENT LIGHT CIRCUIT BREAKER L-20 POPPED. AIRCRAFT RETURNED TO GATE. MAINTENANCE SUSPECTED SHORT IN BALLAST OR WIRING TO FIRST OFFICER'S FLUORESCENT LIGHTS. DEFERRED LIGHTS PER MEL 33-1.