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820-3332 suddenly shuts off with kernel panic

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  • 820-3332 suddenly shuts off with kernel panic

    Hi guys, I have this 820-3332 that shuts off when I try to install a new OS (I'm doing it in an external ssd with usb adapter because internal doesn't work, I don't know if this is because ssd is faulty or because the board) I can boot from usb, and I can say "install" choosing the ssd, but when it starts to install with black screen and white apple logo, it shuts off.

    I ran EFI ASD and one sensor readings is much higher than it should do. It says:

    Location : IHSC
    Type: Current
    low-limit: 0.0 A
    high-limit: 0.05A
    description: Debug TBT T29 current
    reading 0.825 (more or less, sometimes 0.832, sometimes 0,822...)
    noise-tolerance: 1.0

    So I supposed this sensor is the cause of kernel panics, but I can't find why it gives me that value. I have looked for any broken trace or something strange near UD250 but can't find anything.. What should I look? Thank you!

  • #2
    Remove Q3880 and try again.
    Do not forget to reflow/resolder/change U8900, just in case.


    • #3
      Originally posted by 2informaticos View Post
      Remove Q3880 and try again.
      Do not forget to reflow/resolder/change U8900, just in case.
      I'll try it, but, will this disable thunderbolt I guess. Am I right? I'm still learning, and I have so much to learn,.. I already reflowed u8900. If I remove q3880, what should happen?
      I'll do it ASAP


      • #4
        Thunderbolt will remain without power.
        Do that only for test.
        You can also reflow GMUX...


        • #5
          Where is gmux? Schematics say u9600 but I can't find it on brd. I already removed Q3880 and EFI hardware profile reads the same. 0,819A on that sensor. Something that I forgot to say is the board starts always, but when I shutdown it, it won't turn on again at the moment, I have to wait a few minutes.. but if I disconnect battery it seems to turn on faster. It's very strange..
          Last edited by rferruses; 03-15-2019, 07:19 AM.


          • #6
            Ooops, I just saw ISHC sensor on the schematic.
            Change all RD251-254.
            You can also change UD250.
            Be sure to have good continuity to RD259; does it have correct value (10 miliohms)?
            Short (for test) CD250 and see if machine still turns off.


            • #7
              I have shorted cd250 but it continues turning off after logo appears... I will replace all components and try again. Reading now is 0.00 of course.


              • #8
                Did you resolder U8900 yet..?


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