This what he said .
In short, it was either buy in bulk of 10's or wait a few days for delivery. Neither appealed to me. To a simpleton like myself, an LED looked like another LED and there wasn't much spec difference from one to another apart from wavelength. No doubt frequency is an important factor.
I decided to take donor parts off a redundant tv remote control and proceeded to replace the shot LED. To my surprise, it worked equally well and a side by side comparison with my other 2 chrono's, it gave virtually identical readings. I left the LED legs long so I can align the LED to the sensor in the roof. Well happy with the results.
I am lucky in having 4 chrono's to double check. On this occasion, this repair worked well and and equalled the other chrono's on accuracy. I may have been lucky to find an LED of exacting spec so the unit performed to design. A quick, cheap and satisfying fix.
Please bear in mind a different LED off a different remote may not work to the same level of accuracy so use another chrono to check your new reading.