What went wrong?

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RhinoAK
 
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Joined: Fri Mar 28, 2014 7:11 am

What went wrong?

Post by RhinoAK »

I've recently purchased the BBB and over the weekend I went through setting it up. I have to say I'm thoroughly impressed with the setup and the size. I followed the supplied instructions of connecting the device to my computer using the USB cable connecting it from the micro USB port to a port on my laptop, installing the necessary files to communicate with the device. My
issue occurred when I connected the BB in the following manner.

1. From micro HDMI port to HDMI port on monitor.
2. Connected the 5V power source into the BB
3. Connected a USB cable from the USB jack on the BB to my 4 port powered
USB hub.
4. Connected the micro USB cable into the 4 port hub.
5. Inserted wireless keybrd/mouse dongle into the 4 port hub.

When I applied power to the BB within 1 minute of doing so I hear a faint high pitch tone and shortly thereafter I see a spark coming from the board. Based on the setup described what could have gone wrong? Also what's the process for resolving this issue and replacing the BB? At this point I'm no longer able to use the device.

Anthony Kent
MCSE, MCITP-EA

Agent_24
 
Posts: 87
Joined: Thu Feb 23, 2012 6:08 pm

Re: What went wrong?

Post by Agent_24 »

I don't know for sure as I am not familiar with the product but plugging the USB cable from the miniUSB connector into the other USB connector may have caused a short circuit and blown something on the BB.

RhinoAK
 
Posts: 3
Joined: Fri Mar 28, 2014 7:11 am

Re: What went wrong?

Post by RhinoAK »

Just to be clear I didn't plug the micro USB cable back into the beagle Bone. I plugged it directly into my USB hub. Considering that does this look like it could be a RMA return?

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adafruit_support_mike
 
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Joined: Thu Feb 11, 2010 2:51 pm

Re: What went wrong?

Post by adafruit_support_mike »

The makers of the BBB insist that all RMAs be handled through their system: http://beagleboard.org/Support/RMA

If it was a hardware failure, it's something they'll want to know about.

RhinoAK
 
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Joined: Fri Mar 28, 2014 7:11 am

Re: What went wrong?

Post by RhinoAK »

I'll submit my RMA request as suggested. Thanks for the feed back.

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chuckm
 
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Joined: Thu Dec 24, 2009 3:31 am

Re: What went wrong?

Post by chuckm »

This is my guess, you created a ground short. Let me explain ...

Switching power supplies don't have a transformer, instead they take a 'ground' reference and the rectified AC coming from the wall and they switch that into a filter network which becomes the DC output on the other side. If the supply does not use a polarized power cord, it is possible to connect the either the AC 'return' side or the AC 'hot' side to the power supply's 'ground.' You had two such supplies in your setup, one for the Hub and one for the BBB. I'm guessing that one was using 'HOT' as the ground and one was using 'RETURN' (the other half of the AC line, sometimes called ground). That set up a short between the AC wires through the ground plane of your BBB which hummed for a while and then blew. (BTW a ground fault interrupt outlet would have tripped). This was a common problem in the early days of microcomputers when people were using TV's as monitors that didn't have an isolated supply.

You have to do two things, either get an isolated 5V supply for the BBB and/or make sure that you have both supplies connected in the correct way. A simple way to check this (while you wait for your BBB to be processed) is to put a volt meter between the ground of your 5V supply and the ground of the USB plug. If you see 60V you've got a problem. You can trying changing the orientation of *one* of the supplies and see if that 60v goes down to 0. If it does you've got your problem.

Kevin_M
 
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Joined: Sun Apr 20, 2014 4:03 pm

Re: What went wrong?

Post by Kevin_M »

Was the BBB on a metal plate or a different conductor?

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