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Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

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    Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

    Hello everyone, I have attached a diagram for Lenovo C340. I got one in the service with spilled fluids. Initially it was taken to another service where the BIOS was changed, of course it didn't work. The problem is that, although I bought the electronic schematic, I can't figure out why I'm missing + VCC_GT, 0V. If anyone can help me, I would appreciate it. Thanks.

    Schematic - https://www.badcaps.net/forum/showthread.php?t=91821

    .
    Last edited by SMDFlea; 01-07-2021, 06:56 AM.

    #2
    Re: Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

    If ram section is ok check pin 20 of Pu 501

    Check vcc_sa voltage then
    vcc_core

    Vcc_gt is s0 state high voltage means full on laptop

    Comment


      #3
      Re: Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

      vcc_sa = 1.010 v
      vcc_core = 0.890 v

      Comment


        #4
        Re: Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

        Have you checked PUG1 and PQG1
        All donations to badcaps are welcome, click on this link to donate. Thanks to all supporters

        Comment


          #5
          Re: Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

          Check enable pin1 2.5 and pin 8 vcc 5v is coming at RT9610CGQW_WDFN8_2X2 which is generating vcc GT pug1

          En pin and vcc both are connected to power on reset logic inside ic and if one goes low output will be low


          If enable is low check driven_set is coming out correctly at voltage divider pr272 and pr275
          Last edited by stingerchamp; 01-07-2021, 10:16 AM. Reason: Read schematic found ic and read it's requirements

          Comment


            #6
            Re: Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

            Picture
            Attached Files

            Comment


              #7
              Re: Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

              First check driven_ set at voltage divider pr275 and pr272

              Driven_set must be 2.5v check


              Then at core ic puz1 carefully check pin 35 voltage it is driven coming here


              Ic will start working when driven is available in threshold
              Last edited by stingerchamp; 01-07-2021, 10:35 AM.

              Comment


                #8
                Re: Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

                pin 35 = 5V

                Comment


                  #9
                  Re: Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

                  Check drven_,set at voltage divider
                  correction
                  prz72 and prz75

                  If 5v then floating is enabled to ps4
                  Last edited by stingerchamp; 01-07-2021, 11:12 AM.

                  Comment


                    #10
                    Re: Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

                    Check prg1 which is 2.2 ohm with 5 percent tolerance
                    Check pcg1 boot capacitor which is 0.1uf

                    Enable is ok , vcc ok but pqg1 gate is disabled because ugate supply is missing , boot is the supply for ugate mosfet ,boot supply is not reaching ugate .
                    Last edited by stingerchamp; 01-07-2021, 11:24 AM.

                    Comment


                      #11
                      Re: Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

                      What is the actual issue with the machine?
                      OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

                      Comment


                        #12
                        Re: Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

                        No video signal, some liquid was spilled.

                        PRG11 - 2.5 ohm
                        PCG12 - 0.1 uF
                        prz72 and prz75 - I don't know where is on the board.
                        So, the conclusion is the PUG3 is defective because boot supply is not reaching ugate?

                        Comment


                          #13
                          Re: Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

                          Originally posted by A1yn88 View Post
                          prz72 and prz75 - I don't know where is on the board.
                          Try to Follow Pin 18 of PUZ1 to find them. They are connected on +5VALW/ Rail.
                          Last edited by Sephir0th; 01-08-2021, 02:43 AM.
                          FairRepair on YouTube

                          Comment


                            #14
                            Re: Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

                            Did you check if it's POSTing at least?
                            If it was liquid damaged you have hints to follow…
                            OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

                            Comment


                              #15
                              Re: Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

                              How to check if it's POSTing?

                              Comment


                                #16
                                Re: Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

                                Originally posted by A1yn88 View Post
                                No video signal, some liquid was spilled.

                                PRG11 - 2.5 ohm
                                PCG12 - 0.1 uF
                                prz72 and prz75 - I don't know where is on the board.
                                So, the conclusion is the PUG3 is defective because boot supply is not reaching ugate?
                                Sorry
                                PRG1 / PCG1 / PUG1

                                Comment


                                  #17
                                  Re: Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

                                  Originally posted by A1yn88 View Post
                                  How to check if it's POSTing?
                                  Put external Keyboard and Test If CapsLock works.
                                  FairRepair on YouTube

                                  Comment


                                    #18
                                    Re: Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

                                    Not working

                                    Comment


                                      #19
                                      Re: Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

                                      Originally posted by stingerchamp View Post
                                      First check driven_ set at voltage divider pr275 and pr272

                                      Driven_set must be 2.5v check


                                      Then at core ic puz1 carefully check pin 35 voltage it is driven coming here


                                      Ic will start working when driven is available in threshold
                                      Driven_set = 0V

                                      Comment


                                        #20
                                        Re: Lenovo C340 El5c3 el531 el431 la-h101p_lo2 problem

                                        Driven_set 0 is ok because look in schematic @ sign at prz72 means resistor is not populated, only prz75 populated which is connected to ground

                                        Correct me if I am wrong

                                        Core voltage is ok , vccsa is ok

                                        Fault is around pug3

                                        Comment

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