Earlier this year, my 20-year-old Flight Deck stopped working. I replace the batteries and verified the magnet's position. It would read speed up to about 5 MPH then go to zero. It would indicate shifts and gear combinations normally. On a 35-mile loop I ride regularly, I would see one or two miles on the trip distance function. I was pretty much convinced the sender was bad, but couldn't find a replacement. I have been thinking about finally saying "goodbye" to the system. I downloaded a phone app ("Ride with GPS") which looked interesting.
Yesterday in the late afternoon I went out for a ride. The Flight Deck was misbehaving as usual. At some point, I looked at the odometer function, and noticed that the total mileage was changing even though trip distance was not. Then things got *really* strange. It got dark enough for me to turn on my headlight (Light & Motion "Seca 800"). As soon as I turned it on, the Flight Deck came to life! The light head and computer are about 5" apart, and have worked well together in the past (I know that LED lights generate electrical interference that can interfere with wireless computers; this had not happened previously). So it appears that the light now serves as a "pacemaker" or "defibrillator" for the Flight Deck!
Fortunately, the phone app worked well. So, for now anyway, I can still keep stats on my rides, while viewing the gear combination. Plus I now can see elevation gain. It's just a little Rube Goldberg-ish.