What was found
CUSTOMER STATED THAT THE GNS-430 DISPLAY WAS NO LONGER WORKING AND THAT THE CDI WAS PEGGED LT AT ALL TIMES. SENT UNIT OUT FOR REPAIR. ALSO FOUND UPON INSPECTION OF THE GNS-430 INSTALLATION, IT WAS NOTED THAT REPAIR STATION HAD NOT INSTALLED AN AVIONICS COOLING FAN IAW THE INSTALLATION MANUAL. AN AVIONICS COOLING FAN WAS INSTALLED UPON RECEIVING THE GNS-430 BACK FROM REPAIR. THE PROBLEM WITH THE GNS-430 WOULD HAVE BEEN PREVENTED IF AN AVIONICS FAN HAD BEEN INSTALLED IAW THE REQUIREMENTS FOR COOLING AS STATED IN THE INSTALLATION MANUAL.