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Beaglebone Black unable to power on

chienandrew

Hi everyone,

 

We have been using several units of the Beaglebone Black for the past 2 years. We have found 5 units out of 13 units had some problems that required RMA to Element14 after using them for 3 months or more. We are trying to identify the root cause of the issue.

 

3 units had this symptom: Unable to power up. When connected to power, the Power LED does not turn ON. Flashing the eMMC does not help resolve the issue.

1 unit had this symptom: eMMC was not working.

 

Any ideas what can cause such failures? Please advise. We are trying to find the root cause, so to avoid having such failures in the future.

 

Thanks,

Andrew

  • 0

    Hi Andrew,

     

    If the power LED briefly flashes but does not remain on, this could be related to damage caused by the power supply, see the elinux page with list of all known issues. It could be worth trying the actual power supplies (i.e. don't mix them with new ones) you had with the boards that failed, with a BBB connected to a scope as close as possible to the supply rail into the PMIC IC (you'll need to inspect the schematics and board files to find a suitable location to probe this) to see if there are spikes or sag. It would be important to use the same power supplies for this test, in case there is any variation or issues with them after 3 months or more.

  • 0 in reply to shabaz

    I'd suspect the power supplies too.

    Having them all failed in the same environment may point to something in that environment itself.

  • 0

    I had same issue like you had on those 3 BBB that does not power anything up. Mine also was not shortly flickering blue power led. Just nothing.

    How i solved it:

    Measure the power consumption at first connection to mini-usb. I have a usb power meter. I could see that in the first second it was consuming a tiny bit and then 0. Also when pressing a reset or power button, the power consumption went up.

    Conclusion: The TPS65217C is probably working. This was an error i did. I replaced the TPS65217C but my issue was still there with the new chip.

    Then i asked a friend to borrow his working BBB and compared them.

    Measure how much resistance you have on the analog pins to ground. My issue was that AIN0 was broken. Probably broke because more then 1.8V had been connected to the pin. This breaks the internal analog measuring connectors in the CPU.

    Prove it once again by measuring at capacitor C14. If you also have there a short, then you have to disable the analog power input (VDDA_ADC) to get a BBB without analog connectors. This is been done by removing the "FB2".

     

    Reason why it does not start up:

    The VDD_1V8 is shorted. When VDD_1V8 is shorted, the TPS65217C does not power up the rail thanks to its protection to not melt down things. This is how the powerup-sequence looks like: https://raw.githubusercontent.com/wiki/beagleboard/beaglebone-black/media/image40.png

    Without VDD_1V8  VDDS_SRAM_CORE_BG and VDDS_PLL_MPU are not working and thats why nothing works(also not the LED).

     

    Good help for understanding : https://raw.githubusercontent.com/beagleboard/beaglebone-black/master/BBB_SCH.pdf

     

    Huge thanks to user zmatt from https://web.libera.chat/#beagle