I got in my 1967 Piper Cherokee 180, started it up, and was looking forward to an after work flight. I noticed the Narco MK-12D was not displaying the correct data. I could hear myself, the unit was getting power, and the Glide Slope/VOR was receiving a signal. The mechanic came out and said everything looking good from behind and he didnt feel any moisture. The display would show 1 or 2 numbers and when I would restart the Narco Nav/Comm it would not show anything. Has anyone else had this issue and does anyone know of a direct replacement for this unit?