I have noticed my Surface Pro 3 power adapter does not charge when I leave the tablet out overnight, and then tries to charge it next morning, the adapter does not charge or lite up on the connected adapter. I have even tried to plug in a usb cable to charge my phone in the 5v usb port, and it does not charge. But if I unplug / plug in the power adapter from my outlet, then it will start charging, both to the Surface Pro 3 and the 5v usb outlet. Does this sound like an power adapter issue? Does the power adapter have a built-in sleep mode? Thanks for any info!