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Help problem lenovo yoga 500 lt41 state vegetal plt_rts# off

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    #1

    Help problem lenovo yoga 500 lt41 state vegetal plt_rts# off

    I have a Lenovo Yoga 500-14IBD LT41 laptop with power-on issues. It turns on, reacts to the 3.3v button. Its consumption is only 37mA, in the OFF state it consumes 8mA. remains in a vegetable state. The measures I have taken are:

    AC_PRESENT:3.3V
    ECRST# : 3.3V
    LID_CLOSE# : 3.3V
    1D05V_VTT : 1.05V
    RTC_RST#:3.3V
    5V_S5: 5V
    3D3V_PWR: 3.3V
    1D05V_LX : 1.05V
    1D35V_S3 :1.35V it ram
    VCC_CORE : 0V
    PLT_RTS: 0V
    OSCILLATORS ALL OK

    What other measurements can I take to check that pch if it is healthy?
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    #2
    Re: Help problem lenovo yoga 500 lt41 state vegetal plt_rts# off

    with this I am reviewing.
    Attached Files

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      #3
      Re: Help problem lenovo yoga 500 lt41 state vegetal plt_rts# off

      You have power sequence listed on Page99 of schematic. Check which rail is not coming up in order of sequence. PLT_RST# doesnt makes sense at this stage when even cpu is not powered on. This will come up at the very last stage of posting.

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        #4
        Re: Help problem lenovo yoga 500 lt41 state vegetal plt_rts# off

        Hello sir mcplslg123, thank you for your comment. reviewing the sequence I have stayed in the vcore, there is no voltage. I have checked the ic PU4601, the Svid measurements are ok, although the PGOOD is low. it can be a bad sign. In the ohm test it gives a score of 1.7ohm and it is the absolute zero of my multimeter, detecting a possible short in PU4701 O in the processor. will it be true? what else can i try?

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          #5
          Re: Help problem lenovo yoga 500 lt41 state vegetal plt_rts# off

          These are some measurements of the PU4701 when turned on.
          Vin : 20v
          Boot_R: 0v
          PWR_VCC_BOOT1: 4.88v
          PWR_VCC_PWM1:1.56v
          PWR_VCC_VSW1 : 0v
          5v_S5 : 5v
          PWR_VCC_SKIP#1 : 1.58v

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            #6
            Re: Help problem lenovo yoga 500 lt41 state vegetal plt_rts# off

            Again on a wrong track. Why you are probing Vcore when you are even not aware which rails are not coming up. Measure the rail in power sequence and see where it stops. Vcore will rise after all its requirements are fulfilled. So focus on the power sequence for now.

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