Hi all, I just run my PocketNC machine today and it suddenly stopped and it seems that my BeagleBoard Black (I think) just died. There is no Blue Light indication any longer. I have tried to unplug / plugin USB again and again several times. No response. I even tried to plug in the USB cable to another computer to make sure that the USB was not damaged on the computer. I also tried the USB cable for another purpose and it worked. So I actually think my BBB died after just 48h. But this must be rare I think. Or does anyone know how I can try if it actually is dead or not, other than plug in and out the USB? Is there any fuse on the board? Any on/off button that might have gone to off? (The BBB is built in so I can not access it easily. But it should not need to power on and off by a switch according to my manual of the machine).
There is no fuse on the board. Sounds like you my have popped the processor via an I/O pin. If the power LED flashes, that means the PMIC has detected an over current condition on one of the power rails and is shutting down.
It doesn't flashes, no light at all.. during operation it went down. The BeagleBoard doesn't show up any longer as a hard drive. I connect via the micro USB port, and that is the only power source for the board.
Thanks Gerald for the support. So just to make sure that I have understood it correctly. If no LED light then no power - got that. Since the power source to the BBB is the USB, the problem could be with the mini USB on the BBB. But since the BBB shutoff during operation probably something on the circuitboard is most probably broken. And you suggested the CPU. Could it be something else or is this the most likely to get broken first? Should I change only the CPU or should I buy a brand new BBB just to make sure all is good?
On Sun, 5 Feb 2017 07:55:47 -0800 (PST),
micael@cyto365.com declaimed the following:
It doesn't flashes, no light at all.. during operation it went down. The BeagleBoard doesn't show up any longer as a hard drive. I connect via the micro USB port, and that is the only power source for the board.
If the unit is driving any other hardware, I'd be concerned about the
power supply... USB is normally only rated for 5V 500mA max (normally that
500mA is distributed among up to four sockets of a hub).
However... "during operation it went down" is too vague to really
comment upon... Failure points could be the USB to PMIC, the PMIC itself,
or something later. A short between almost anything could draw more power
than the USB could provide.
Also, if that unit is running normal Linux (rather than a totally
custom embedded application), then shutdown should NEVER be done by just
pulling the power... Pulling power could lead to a corrupt file system
(though a corrupt file system won't affect the power LED, and maybe not
even the status LEDs.
For good measure, you should be aware that pins that are connected to external hardware. Should be isolated if those pins, and hardware are powered up before the beaglebone. I would think that if the beaglebone it’s self is powering these external circuits, and hardware. Then this would be less of a problem.
Additionally, I’ve had more than one beaglebone come across my “desk” in the last 4 or so years. One in particular is possibly form the first batch sold to the public. e.g. ~4 years old. I have heard people saying that if you pull the power, while the board is running, that the processor can be damaged from this action. I’m not saying to is false, I am just saying that it would probably be a fairly rare issue. As I’ve been in a situation where I’ve had to do exactly that, many times. As far as corrupting the operating system. It is possible, as with any operating system. But again, it’s a fairly rare situation. You’re just as likely to corrupt the system by installing an application, updating the system, or flashing an new image to the eMMC.
So there is one thing I have not seen you mention if you’ve attempted this or not. Sometimes, the board needs to have the reset button pressed, before it will power up again. I’ve run into this a few times myself, and like you I was nearly convinced the board was dead. No power lights coming on. even after completely disconnecting the input power several times. I also power my own personal beaglebones the same way you do. Via USB. Anyway, I’m not saying this will fix your problem. but it is worth looking into. If in doubt which button is reset, it probably would not hurt for you to just press both of the button to the right of the ethernet jack, with ethernet jack oriented at the top of the board.
Anyway, if you care for a much better “analysis” of what happened, and how to avoid the same in the future. It would behoove you to tell us exactly how many pins you had connected to your external hardware. What kind of periphery, and how much current source/sink + voltage levels. As the beaglebone is only 3.3v tolerant, and the ADC pins have a max tolerance of 1.8v.
Thanks all for great posts. Tomorrow I will start by cleaning the machine from all potential leftover aluminium chips from previous milling carefully. I believe that this is the most promising lead so far, a short circuit in a connector somewhere. I will keep you posted here of the result.
On Mon, 6 Feb 2017 13:05:35 -0800 (PST),
micael@cyto365.com declaimed the following:
Thanks all for great posts. Tomorrow I will start by cleaning the machine from all potential leftover aluminium chips from previous milling carefully. I believe that this is the most promising lead so far, a short circuit in a connector somewhere. I will keep you posted here of the result.
That is also the most likely killer... A short between 5V and ground
could overload the current capability of the regulators. A short between 5V
and any GPIO pin could kill the main processor (3.3v except for ADC pins
which are 1.8V).
So I have now removed the board from the machine and plugged it in to the computer USB again. One fast LED blink happens when it is connected. I have pressed reset button, I have pressed power off. Nothing more happens. So is the board dead or not? There is nothing connected to the board itself only the USB to power it.
