# BeagleBone Black won't power up from USB

I have been successfully using BBB powered from the USB adapter until now.

I had to do some restart, and then the board won't power up (the PWR led blinks once when I press the POWER button, then it stays like that, off).

Now I can only start the board using an external power supply (5.0V), and it seems that the board uses around ~0.8A and up to ~1.1A.

What can be wrong?

Why it isn't working now?

L.E. Also, I have noticed that the main chip (AM355) gets very hot, I can't put my finger more than one second on it.

L.E.2. I don't have attached any relevant power-consuming devices to it, only a USB WiFi dongle.

L.E.3. Before restarting the board, I was trying to get a GPIO pin working, the problem was that from the library I've used (BlackLib) when I set one GPIO pin to high, it would only stay high for around 10ms, and then go low again. So for solving what, I have used this tutorial. I only got to the part where I exported some pins to the /sys/class/gpio/export file, and then echoing 1s and 0s to the associated pin (with a LED connected it didn't work), then I rebooted the board and this problem started.

I don't see any hardware mistakes that I may have done, is it possible that this fault is software-related?

• Unplug the wifi dongle and see what happens. – JRE Jun 10 '16 at 9:41
• @JRE Nothing happens, the problem persists. – Marius Marusanici Jun 10 '16 at 9:41
• OK. Then at least you now know that the wifi dongle isn't source of the problem. – JRE Jun 10 '16 at 9:42
• Then sounds like the chip is on the way to its ancestors. – Dmitry Grigoryev Jun 10 '16 at 9:42
• If you killed a GPIO pin, it can cause a short inside the processor. This would consume more current, hence the overheating. – JRE Jun 10 '16 at 10:08