I bought a Nitecore Tube Flashlight a few weeks back and really liked how well it worked, for how small it was. Then, my son was playing with it one day and it stopped working.
So, figured it just needed charging. Which, I did. The battery appears to be about 33mAh btw. Anyway, after charging, it still didn’t work. I started a return with Amazon, and while playing with it, I decided to hold the power button while plugging into USB. It immediately started working again! Unplugged USB, and it still works.
So, there seems to be some type of state the little IC gets into where it refuses to turn on again. Maybe when the battery dies rather suddenly while in a certain state. Anyway, resetting it isn’t covered in the manual. So this seems to do it.
Good luck for anyone if they have this issue. =)