How to find shorted rail

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  • samanthban
    Badcaps Veteran
    • Feb 2014
    • 253
    • Sri lanka

    #1

    How to find shorted rail

    I got this motherboard few days back when plug in to dc it goes up to 0.7amp and stuck .

    later i found that PL30, PL32,PL34,PL35,PL37 coils are shorted to ground.

    I,m sure all these coils are not shorted to ground due to cpu on board.

    its a bga chip.one of above shorted to ground.

    if i can remove the cpu its easy to find and here iam stuck due to cpu on board .

    please give me a solution to find the genuine shorted rail.

    schematic is attached ..Thank you very much
    Attached Files
    Last edited by samanthban; 01-03-2017, 11:20 PM. Reason: na
    sigpic
  • subroto
    Badcaps Veteran
    • Oct 2015
    • 230
    • Bangladesh

    #2
    Re: How to find shorted rail

    Find out the culprit with Vin of core voltage generator ic or graphics voltage generator ic. Actually most of the short is occurred by ceramic capacitor with Vin of stepdown regulator IC.

    Comment

    • samanthban
      Badcaps Veteran
      • Feb 2014
      • 253
      • Sri lanka

      #3
      Re: How to find shorted rail

      Originally posted by subroto
      Find out the culprit with Vin of core voltage generator ic or graphics voltage generator ic. Actually most of the short is occurred by ceramic capacitor with Vin of stepdown regulator IC.
      Thanks for your idea
      sigpic

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      • samanthban
        Badcaps Veteran
        • Feb 2014
        • 253
        • Sri lanka

        #4
        Re: How to find shorted rail

        any other suggestions please welcome!!
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        • samanthban
          Badcaps Veteran
          • Feb 2014
          • 253
          • Sri lanka

          #5
          Re: How to find shorted rail

          when I inject 0.9v to PL34 cpu warming up
          sigpic

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          • raajkumar
            Badcaps Veteran
            • Mar 2015
            • 354
            • Srilanka

            #6
            Re: How to find shorted rail

            Originally posted by samanthban
            when I inject 0.9v to PL34 cpu warming up
            Did you solved this problem ? I got a laptop with same problem yesterday. I looked with a magnifier for broken ceramic capacitor, Finally i found a cap on PL32 line +VCCSA area. I replaced it and the laptop working now.
            Last edited by raajkumar; 06-06-2017, 12:48 AM.

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