As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE FLIGHT CREW REPORTED A ODOR OF SMOLDERING INSULATION APPEARS WHEN THE AVIONICS MASTER SWITCHES WERE ON. AFTER SHUTTING THE AVIONICS OFF THE ODOR DISSIPATED. MAINTENANCE TRACED THE SMOKEY ODOR TO THE FUEL VALVE ANNUNCIATOR SOCKET AFTER DISCOVERING THAT THE (OPEN) LIGHT DID NOT ILLUMINATE. THE RT FUEL VALVE SWITCH ASSEMBLY WAS REPLACED. OPERATIONAL CHECKS OF THE SYSTEM WERE GOOD AND THE AIRCRAFT WAS RETURNED TO SERVICE.