As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED SMOKE ODOR AND STANDBY INSTRUMENT LIGHTS FLICKERED ON RUN-UP PRIOR TO TAKEOFF. INVESTIGATION REVEALED WIRE BUNDLE WHICH CONTAINS THE POWER WIRE FOR THE STANDBY INSTRUMENT LIGHTS WAS CHAFING ON THE LOWER LEFT CORNER OF THE AUDIO PANEL RACK. MAINT REPLACED A SECTION OF THE AFFECTED WIRE. OPS CK GOOD.