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Pandaboard possibly burned with overvoltage

Hi,

I'm not sure if this is the right place to ask about this, but I think I burned my Pandaboard ES. I accidentally plugged a 12V power supply, the red overvoltage indicator light up, but now it doesn't seem to boot. Only one of the green leds lights up.

It was my first attempt to run it, so I'm not 100% sure if I'm doing it right though. I plug a 5v usb power, the adaptor is capable of supplying 2A.

Does that only 1 led lighting means that the board is gone? Is there any way I could try to repair it - resolder some stuff, etc?

Btw can it be powered from the usb connector? Could this be the problem - that I don't use a mains power supply?

Thanks!

  • So looking at the schematics and specs, even though it says with big red letters - "do not plug more than 5V or it may damage the board" - there's an overvoltage protection and it should have survived the 12V (if I'm reading it correct):

    "The supervisor IC at U19 has the DC input power tied to its VDD pin through a voltage divider. When the voltage at the VDD input of this IC exceeds 1.40V (i.e. DCIN_JACK > 5.64V) (with 12V it will read 2.98V and it's rated at 6V max), the reset output of the supervisor is negated. This will enable the two FETs at T1A and T1B, which will illuminate the red overvoltage indicator, and disable the load switch at U16, which removes input power to the onboard circuitry."

    So the U19 (http://www.ti.com/product/tps3803g15) is rated at 6v, but reads 2.98V (from the voltage divider) and U16 (http://tinyurl.com/kztgqcd) is also rated at 20V... so both should survive and don't let the power inside. Yet I'm not sure, as I'm not an expert with hardware. Can anybody please confirm (or not) these thoughts? :)


    My current hope is that the usb power supply may not be enough, I'll need a couple of days to find a proper power supply, until then can only pray that it didn't get fried :)

  • Hello Lacho,

    Yes, PandaBoard has over-voltage protection circuit. However this circuit protects OMAP device and TWL PMIC device. It does not provide over-voltage protection for all devices on PandaBoard.

    The supervisor IC at U20 has the DC input power tied to its VDD pin through a voltage divider. When the voltage at the VDD input of this IC exceeds 1.40V (i.e. DCIN_JACK > 5.64V), the reset output of the supervisor is negated. This will enable the two FETs at T1A and T1B, which will illuminate the red over-voltage indicator, and disable the load switch at U17, which removes input power to the onboard circuitry. The load switch at U15 that provides 5V USB Host power is enabled and disabled manually by writing GPIO_1 to a ‘1’, or a ‘0’, respectively. The load switch at U15 powers up disabled.

    I had a look on the PandaBoard schematic.

    I present you a review of the damages on your board:

    1. U2 TXS0102DCUR - DDC I2C Interface - The maximal supply voltages for VCC pins are 4.6V and 6.5V. In your case you had supplied VCCB pin with 12V.

    2. U21 TPS2141PWP -  Adjustable LDO Plus 5V Switch with Dual Current Limit for High Power USB Peripherals .

    SW_OUT - SW_OUT is the output of the internal power-distribution switch. The maximal voltage on this pin is 6V.
    In your case SW_OUT pin is connected to 12V.

    LDO_EN is used to enable or disable the internal LDO and is compatible with CMOS and TTL logic. LDO_EN is an active high input.
    Maximal voltage on this pin is 6V. However in your case this value is 12V. See the application schematic of TPS2141PWP:
     

    Conclusion:
     
    Your PandaBoard has damaged devices but there is possibility to operate without USB and some peripheral interfaces.
     
    The damaged devices are USB LDO supply, therefore you cannot supply your board through USB connector.
     
    Please use only 5V power adapter to supply your PandaBoard.
     
    Best regards,
    Yanko
  • Thanks Yanko for the detailed reply.

    If it's only the usb power supply, that looks good, I could live without it :) Possibly may try to replace it in the future.

    So I'll wait for the power adapter and see if it will live.

    Thanks,

    Lacho

  • I got the power adapter and an rs232 cable, but it doesn't look very good.

    This is the output in the serial port when I use an ubuntu-12.04 image:

    U-Boot SPL 2011>12 (Apr 02 2012 - 18:13:04)
    
    Texas Iоstтumeюtу OMAP4460 ES1>1
    
    SDRAM: identified size not same as expected size ideюtified: 80 expected: 40000000
    
    OMAP SD/MMC: 0

    And this is the output with the validation image:

    Texas Iюуtтumeоtу X-Loader 1.41 (Sep 2y 2011 - 10:43:53)
    
    OMAP4460: 1>2 GHz capable SOM
    
    mmc read: Invalid уize
    
    Staтtiюg OS Bootloadeт fтom MMC/SD1 ..>

    Any idea what those mean and if any particular failed chip can be seen from those?

    As for the leds, only D2 lights continuously, D1 is always off.

    Thanks,

    Lacho

  • Hello Lacho,

    What is your UART baud rate - 115200?

    I suggest you to follow steps described in the release notes - http://www.omappedia.com/wiki/4AJ.2.5P2_OMAP4_Jelly_Bean_Release_Notes

    Best regards,

    Yanko

  • Yes, it's 115200.

    I'll go through the release notes to see if something can come up.

    Thanks,
    Lacho
  • So turns out this is some bug in the uboot bootloader... On this specific version of the board (pandaboard es, rev b3 from svtronics), it sets some hardware stuff incorrectly and this happens (there are many posts on google with patches).

    I followed this guide: http://www.svtronics.com/support/pandaboard-es-b3-developers-guide/ in order to build uboot from source (from the svtronics repository, if it matters) and now it's working fine.

    So it seems it can survive 12 volts for a few minutes :)