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
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    • 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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