BBB not powering on

[Marco Thome]

Hi,

I was working with a brand new beaglebone black on usb as usual. Everything was fine, until I connect it to the company's network over ethernet and updated the board with apt-get update then apt-get upgrade. In the middle of the upgrade, the beagleboard just died. None of the five leds are on, no matter which usb port or computer it's connected to. I tried the same config with another board and it turned on just fine.

I'm a little worried about it because it isn't the first time this kind of problem occurs. I was working with another board also over usb but on another computer and the same thing happened, though on this board the power led at least blink once when connected.

It may not be so helpful, but I'm attaching a printscreen of what I was doing at the time. I had no chance to upgrade the kernel.

Both boards only turn on when on power plug, but as soon as I connect them to the computer over usb, they die (no led lit).

What am I doing wrong?

Regards,

Marco

[Graham]

Most likely, you are having power supply issues.

The power drain of the BBB will double or triple during boot and update, (relative to idle) so you need a power supply that can handle this.

Many long USB cables are not capable of powering a BBB during peak loads.

Some of the cheap wall supplies can't handle it.

--- Graham

==

[Marco Thome]

Thing is that I'm using only the provided USB cable. What troubles me is that the board turns on when I'm using a power adapter (DC jack), but it dies as soon as I connect it to the computer with an USB cable.

[Graham Haddock]

All of your description points at a power supply problem.

If the USB power, even for a millisecond, drops below 4.5 Volts AT THE BBB, the PMIC (Power Management IC) will shutdown.

If you have a computer with a USB port on the low side of the USB Voltage range (4.5 to 5.5 Volts) then what you describe happens.

So that you have some margin in the system, you should hold the power AT THE BBB between 4.75 and 5.25 Volts, even with heavy loads of booting or updating.

If you put an oscilloscope on the power connector of the BBB, you should be able to see what is happening.

--- Graham

==

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[Marco Thome]

Is this a common issue? I can plug both boards to any computer in the room and they'll have the same behavior everytime..

Anyways, I'll grab an oscilloscope as soon as possible to check what is going on over the board. At least it's still working on a wall power supply.

I'm sorry this subject is taking so long, I'm new on power issues on this board (which I must add that both are old, I guess they could be Rev Bs, since there're still some Rev Bs around here).

Thank you for the help so far.

Marco

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