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?

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

Part of the chip on your board is damaged, probably the GPIO pin you were playing with, but not necessarily. Maybe you shorted a pin next to it, or damaged an internal buffer - such issues are almost impossible to diagnose precisely. Here are the options you have:

  • Get a new board. Preferable if money is not a problem, and you need to trust your BBB. Using a damaged board in your projects will make them harder to debug, since you won't be sure whenever a bug is due to your HW or SW, or to the chip fault.
  • Try to disable the pin. If you can reprogram the pin you suspect in a state which stops the overheating, you'll substantially prolong your BBB's life. Try to output 0, 1, configure it as input and see if the excessive current draw stops. Then apply that config on each reboot.
  • Live with it. Since the chip is getting hot, it may not last very long, but you never know.

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