I've probably been flying the FlySky/iMax/Turnigy 9X transmitter for longer than almost anyone on the planet.
My original iMax transmitter has seen very regular use for nearly 3 years now and just recently I've noticed that the off/on switch is failing.
I'd have considered this to be just a one-off, except that the Turnigy 9X V2 I purchased recently also has a rather suspicious-feeling switch too.
Clearly these radios are made to a price -- but keep an eye on your transmitter switch.
Mine began showing problems when it simply would not turn on without moving the switch off/on several times.
Then it started showing wildly fluctuating voltage readings on the LCD sometimes -- until the switch was again cycled several times. One time (while I was using it on the bench) it actually stopped working all of a sudden and jiggling the switch slightly bought it back to life.
Clearly the wiper/contact interface is worn or dirty. I'll be pulling it apart soon to see but i suspect this is just a very cheap switch with a low number of use-cycles and it has now come to the end of its useful life.
Just a heads-up for those who are also using these radios and may have a year or two of regular power-cycling already clocked up.