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Dead Lenovo V-15 ADA

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    Dead Lenovo V-15 ADA

    Hello,
    Need help. I‘m working with dead Lenovo V-15 ADA (motherboard GV451&GV551 NM-D151). The laptop is quite new, mfg date 2020-10. Can‘t find any schematics for it. One of the chip LV5028 had a burned spot on it. Before ordering it from China, decided to do some measurements with chip removed. And now I‘m not sure will the new chip solve the problem. There are suspicious readings (chip desoldered):
    Pin 5 – 0.4Ohm
    Pins 7+8 – 5Ohm
    Pins 17+18 – 0.5Ohm
    Pins 12+13+14+15 - 4.6Ohm
    Found some datasheet of this chip (attached). Are theese readings normal? Or the problem is not only the chip?
    Attached Files

    #2
    Re: Dead Lenovo V-15 ADA

    Any thoughts?

    Comment


      #3
      Re: Dead Lenovo V-15 ADA

      Remove PL500 & PL502 and re-measure the resistance on pins you mentioned. If resistance improves significantly, the ic is likely ok and problem is on the load side.

      Comment


        #4
        Re: Dead Lenovo V-15 ADA

        Originally posted by mcplslg123 View Post
        Remove PL500 & PL502 and re-measure the resistance on pins you mentioned. If resistance improves significantly, the ic is likely ok and problem is on the load side.
        Nothing changes with 500 and 502 removed. These lines are feeding the CPU, right? Maybe then such a low resistance is normal?

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          #5
          Re: Dead Lenovo V-15 ADA

          Originally posted by doncius85 View Post
          Nothing changes with 500 and 502 removed. These lines are feeding the CPU, right? Maybe then such a low resistance is normal?
          By saying nothing changes I mean there is low resistance on the load side.

          Comment


            #6
            Re: Dead Lenovo V-15 ADA

            Post the measured resistance values from your testing.

            Comment


              #7
              Re: Dead Lenovo V-15 ADA

              All values are at the first post. Measured with chip removed:
              Pin 5 – 0.4Ohm
              Pins 7+8 – 5Ohm
              Pins 17+18 – 0.5Ohm
              Pins 12+13+14+15 - 4.6Ohm
              Removing jumpers doesn't change anything all values remain the same to the load side.

              Comment


                #8
                Re: Dead Lenovo V-15 ADA

                When I see a simultaneous short on +1V and +3V rails, the PCH section of the CPU is usually the cause. Confirm with 1V voltage injection and thermal camera. Board will be good as a donor only.

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                  #9
                  Re: Dead Lenovo V-15 ADA

                  @reformatt is 100% right in assuming that.

                  Comment


                    #10
                    Re: Dead Lenovo V-15 ADA

                    Injected 1V, it draws 1.8Amps and one corner of the CPU gets slightly warm (only visible with thermal cam, can't feel with the finger). So, it's dead CPU

                    Comment


                      #11
                      Re: Dead Lenovo V-15 ADA

                      Hi,

                      working on v14-ADA (same MOBO as this post)

                      it turns on include fan but no post, try to flash bios from the bios forum but still same.

                      any one can advise ?

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