I made the cutout in the panel, following the guidelines in the Installation Manual, except I considered that the cutouts around the knobs in the corners were a bit bigger than necessary. So, I tried to make those cutouts a bit smaller, to have a more visually appealing fit. Then I tried to fit the instrument in the panel. I couldn't figure out how to manoeuvre it into place. It was like a Chinese Puzzle. I had removed the Power/Volume knob at the to right corner, as that shaft fit though a corner. But I expected that the other knobs would just slip into the cutouts. Nothing doing. I removed the Course Select knob at the lower left corner, but I couldn't figure out how to remove the Frequency knobs at the lower right corner

I tried to get it in the hole for 30 minutes - no luck. I finally cracked, and posted a request for help to the RV-List and the Aeroelectric-List. Then I decided to try one more time. Of course I figured it out right away, now that I had asked for help.

How do you get the Narco 122D in its hole?

  1. Make the cutout at the top right and bottom right the full size called out in the Installation Manual - don't try for too tight a fit.
  2. Remove the Power/Volume and Course Select knobs (you need a Torx T-5 tool).
  3. Remove the sleeves over the Power/Volume and Course Select shafts.
  4. Slip the Power/Volume shaft into its hole.
  5. Push the unit up against the panel, so the right side of the unit is touching panel.

  6. Twist the unit so the Frequency knobs slip into their cutout. Enlarge the bottom of this cutout if necessary.

  7. Slip the Course Select shaft into its cutout.
  8. Install the two screws, the bushing on the Power/Volume shaft, and the knobs you had removed earlier.
  9. Note: I didn't have screws that were short enough, hence I had to put washers under the screw heads. I need to purchase #6 screws 1/2" long.

Lesson learned - use the cutout dimensions in the Installation Manual, even if they are "obviously" too big. If you want to make a smaller cutout, try it on some scrap first to see whether it will work.