Does anyone else experience the same weird power supply behaviour? If I connect a power bank to the usb port of the unit, the cable starts blinking. After deconnecting it, it goes back to normal ... and then, 5 minutes later, nothing. No more power, neither for the surface, nor for the usb port of the supply unit. It took about 2 days until it started to work again. And now .. it stops functioning every 5 minutes. Then I have to wait, or connect it to another plug socket. Sometimes, this doesn't work either.