LENOVO G50 -70 power on No screen

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  • ghost73
    Member
    • Feb 2020
    • 28
    • GREECE

    #21
    Re: LENOVO G50 -70 power on No screen

    Originally posted by lapfix
    3Vs appear after switshing power button ,this is your S0 satate.It supply many others IC's .
    why you don't have it on pin 20/23 !!
    can you take the measue of Q24 ( D/G/S) and see like Kiraro says if thers is a short on it !
    In the Q24 i have .... the 17.6 v is OK ???
    Attached Files

    Comment

    • lapfix
      Badcaps Legend
      • Mar 2020
      • 2715
      • my workshop

      #22
      Re: LENOVO G50 -70 power on No screen

      Nice Q24 is OK ,you have 17.6v on gate because it's N-channel , the gate must be equal or higher than the voltage on Drain .
      I really don't understand what you make! do you have 3V on pin 23 and no voltage on pin 20!

      Comment

      • ghost73
        Member
        • Feb 2020
        • 28
        • GREECE

        #23
        Re: LENOVO G50 -70 power on No screen

        yes .. i have 3v on pin 23 but in pin 20 no ... (now i have with the bringe)

        Comment

        • lapfix
          Badcaps Legend
          • Mar 2020
          • 2715
          • my workshop

          #24
          Re: LENOVO G50 -70 power on No screen

          Something is wrong/not clear !
          first what do you mean by : I put a ligth in screen and i see activite .!

          second at jedp connecter we have :
          pin 1/2 = 20v
          pin 21/22 = 3.3v
          pin 20 = 0v
          pin 23 = 3v
          can you complete the measurements for : pin 14/16 /19 /30

          UE1:
          Pin 81 = ENBKL
          Pin 22 =PLT_RST

          JDDR1 :
          Pin 30 =CPU_DRAMRST

          JPWRB1:
          Pin4 = LID_SW

          PL9=CPU_CORE

          Comment

          • ghost73
            Member
            • Feb 2020
            • 28
            • GREECE

            #25
            Re: LENOVO G50 -70 power on No screen

            Originally posted by lapfix
            Something is wrong/not clear !
            first what do you mean by : I put a ligth in screen and i see activite .!

            second at jedp connecter we have :
            pin 1/2 = 20v
            pin 21/22 = 3.3v
            pin 20 = 0v
            pin 23 = 3v
            can you complete the measurements for : pin 14/16 /19 /30

            UE1:
            Pin 81 = ENBKL
            Pin 22 =PLT_RST

            JDDR1 :
            Pin 30 =CPU_DRAMRST

            JPWRB1:
            Pin4 = LID_SW

            PL9=CPU_CORE
            I try to take a picture ...to see what i mean

            pin 30 = 3.4 v
            pin 14 = 0
            pin 16 = 0
            pin 19 = 0

            Comment

            • lapfix
              Badcaps Legend
              • Mar 2020
              • 2715
              • my workshop

              #26
              Re: LENOVO G50 -70 power on No screen

              i m waiting for the other mesearments that i'm saking for !!

              Comment

              • ghost73
                Member
                • Feb 2020
                • 28
                • GREECE

                #27
                Re: LENOVO G50 -70 power on No screen

                UE1:
                Pin 81 = ENBKL = 50Ω
                Pin 22 =PLT_RST = 3.4 V

                JDDR1 :
                Pin 30 =CPU_DRAMRST = 0V

                JPWRB1:
                Pin4 = LID_SW : 6.6 V

                PL9=CPU_CORE
                Attached Files

                Comment

                • ghost73
                  Member
                  • Feb 2020
                  • 28
                  • GREECE

                  #28
                  Re: LENOVO G50 -70 power on No screen

                  This line blink in the screen
                  Attached Files

                  Comment

                  • lapfix
                    Badcaps Legend
                    • Mar 2020
                    • 2715
                    • my workshop

                    #29
                    Re: LENOVO G50 -70 power on No screen

                    Ghost , take again the measures , in voltage please !

                    Pin 81 = ENBKL = 50Ω
                    Pin4 = LID_SW : 6.6 V..are you sure !!

                    DRAMRST must be 1.35v ,without it no display.

                    Since you are getting PLt_RSt means almost everything is ok in power sequence.

                    there's a a resistance and capacitor between CPU and Pin 30 (JDDR) , what's the voltage for both side of RC22, and is CC1 short to ground.

                    Make sure your problem NOT on LVDS cable or LED panel. Make sure you're using known good DDR3L

                    At last flash a known good bios ,it is very likely to solve your problem.

                    Comment

                    • ghost73
                      Member
                      • Feb 2020
                      • 28
                      • GREECE

                      #30
                      Re: LENOVO G50 -70 power on No screen

                      Originally posted by lapfix
                      Ghost , take again the measures , in voltage please !

                      Pin 81 = ENBKL = 50Ω
                      Pin4 = LID_SW : 6.6 V..are you sure !!

                      DRAMRST must be 1.35v ,without it no display.

                      Since you are getting PLt_RSt means almost everything is ok in power sequence.

                      there's a a resistance and capacitor between CPU and Pin 30 (JDDR) , what's the voltage for both side of RC22, and is CC1 short to ground.

                      Make sure your problem NOT on LVDS cable or LED panel. Make sure you're using known good DDR3L

                      At last flash a known good bios ,it is very likely to solve your problem.
                      Sorry
                      Pin 81 = ENBKL = 0V I try to test it again
                      I found the RC22 and i send you the measures.

                      i dont have programmer
                      I have 2 cable for LVDS ,, and two panel i am sure about this ...
                      The DDR3L test OK ..
                      Attached Files

                      Comment

                      • ghost73
                        Member
                        • Feb 2020
                        • 28
                        • GREECE

                        #31
                        Re: LENOVO G50 -70 power on No screen

                        well
                        i take new measures .. In JDDR1 the number is 2-4-6
                        the last measures is wrong

                        This is correct
                        JDDR1 30 = 1.37 V
                        in the image u see the RC22 and CC1 .
                        Attached Files

                        Comment

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