this can be caused by many different problems.
1) battery. The device's battery can be failing to put out the proper current, causing the device to time out.
2) Software. your device could have a software failure, and not understand what to do in order to fully boot.
3) Modular Short. a short circuit in a modular component could cause excess current draw. this would cause issues with the device not being able to boot.
4) motherboard failure. Be it a short circuit, cold circuit, or a fried fried component, the logic board can easily cause this type of issue if it is failing.
Troubleshoot with these 4 components to see which one it is.