Once or twice a year one of the display units will burn out and die. The five digits displayed in each of these radios are separate display units, so with dual nav/comms, this package has twenty individual display units. Every time I'd bring one in for repair, it costs close to $100 and seemingly without fail, two weeks later a different digit in the same radio would fail!

My avionics shop only charges a half hour labor and usually says "I'll have it done in an hour or so"...so I figured just how hard can it be! The next time it happened I figured I'd give it a shot by doing it myself. The avionics shop agreed to sell me a display unit ($63), but cautioned to be very careful, "there's a trick to getting that face apart without damaging it" (not that they offered to show me what it was!). So I was very careful, figured out the 'trick' without breaking anything, and changed the display.

It took about five minutes, including pulling the radio and reinstalling it in the panel. So with the help of a couple of electrical engineering buddies from Raytheon, I tracked down the manufacturer of the display units in hopes of getting a really economical fix to this recurring problem. I contacted them and they promptly responded with a note saying they'd be happy to sell to me and they'll even accept a credit card!

Remove radio/nav. from aircraft using a standard avionics allen key. Undo the selector switches with a small allen key and gently remove. Undo the two screws that hold the plastic front plate to the frame and remove gently. Carefully pull out the failed display and replace with a new one, taking care not to bend any pins. Reverse the above to re-assemble.