help with defective bbb wireless

[rogeri...@gmail.com]

Hello everyone,

I need help and would be grateful for any help to understand what happened with a unit of my BBB wireless. I'm not looking for RMA, but only to understand what might have caused the board to burn.

It happened the following:

The board was plugged into an LCD and connected to a 5V - 2A power supply (it came from an IT kit with an am335x) and also connected with a USB cable on my Macbook;

I had been using this board with no problem, and last night I execute a halt on the command line and went to sleep. In the morning I instead of unplugging the USB cable I just turned off the power supplying the 5V source and forgot to disconnect the USB cable, so I stayed for some time connected only by the USB port, but as I was in halt and nothing happened, so I turned on the 5V source again and then the board did not call anymore.

I had plans to create a custom version of the board with a onboard LCD input, a DAC and a few more components, but I'm scared to now. I'm in the middle of a very big project, i do not know what direction I should take now. I'm afraid to continue with the platform as the basis for my project.

I do not know if there was a problem in the power source during the night, I'm very worried because the board just short circuit without using it, I'd be very happy if I knew I did something wrong, but it's not the case.

I would also like recommendations to project a Surge Protection Device. Any help is welcome.

Thanks in advance!

[Jason Kridner]

On Monday, March 11, 2019 at 5:31:56 PM UTC-4, Rogério Lucas wrote:

Hello everyone,

I need help and would be grateful for any help to understand what happened with a unit of my BBB wireless. I'm not looking for RMA, but only to understand what might have caused the board to burn.

It happened the following:

The board was plugged into an LCD and connected to a 5V - 2A power supply (it came from an IT kit with an am335x) and also connected with a USB cable on my Macbook;

I had been using this board with no problem, and last night I execute a halt on the command line and went to sleep. In the morning I instead of unplugging the USB cable I just turned off the power supplying the 5V source and forgot to disconnect the USB cable, so I stayed for some time connected only by the USB port, but as I was in halt and nothing happened, so I turned on the 5V source again and then the board did not call anymore.

Can you say more about this "IT kit"? I'm wondering if it was trying to draw excessive current. The board itself can work off of USB power just as well as the power jack, depending on what external hardware is connected.

Does the power LED come on?

Can you try booting from the image on http://beagleboard.org/latest-images?

[Rogério Lucas]

Can you say more about this "IT kit"? I'm wondering if it was trying to draw excessive current. The board itself can work off of USB power just as well as the power jack, depending on what external hardware is connected.

 basically it was just to say that I'm using a 5V / 2A quality source. It's from an IT development kit.

Does the power LED come on?

  The power led flash fast one time.

  unfortunately the board is dead :|

I made some mistakes and I believe there was some leakage of some peripherals to the GPIOs while the bord was off or early in the power on sequence, since I had an cape powered by the VDD_5V and not by the SYS_5V. Another problem i detected was a incorrent resistor calculation for a transistor that drains between 5ma and 6ma when my limit should be 4ma. It was switch to a BJT or FET transistor with current drain in the order of micro or nano apameres, so I hope to eliminate this problem.