As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INSTALLED UNIT IN AIRCRAFT AND TURNED ON POWER. THREE OF THE FUNCTION LIGHTS ILLUMINATED THEN WENT OUT AFTER A FEW SECONDS. THE DISPLAY WINDOW NEVER DID LIGHT UP. IT WAS VERIFIED THAT UNIT WAS GETTING POWER. REPLACED 2 EACH REAR TRANSISTORS. REPAIRED PROBLEM. BENCH CHECK GOOD.