As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED AVIONICS MASTER SWITCH INOPERATIVE, WHEN BATTERY SWITCH IS TURNED ON, ALL AVIONICS LEFT IN ON POSITION POWER UP REGARDLESS OF AVIONICS MASTER SWITCH POSITION. MAINTENANCE FOUND ONE SIDE OF AVIONICS MASTER SWITCH INOPERATIVE. REPLACED AVIONICS MASTER SWITCH. OPERATIONAL CHECKED SATISFACTORY.