As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(AUS) TRANSPONDER VOLTAGE DROPPING RESISTOR INCORRECTLY MOUNTED. THE RESISTOR IS MOUNTED ON THE REAR OF THE TRANSPONDER MOUNTING RACK. THE INSTALLATION MANUAL STATES THAT IT MUST BE MOUNTED AWAY FROM THE AVIONICS STACK TO AVOID OVERHEATING OF THE POWER SUPPLY.