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    nm-a273 / lenovo z 50/70 No post

    I've got an nm-a273 / lenovo z 50/70 here and the centre pin of the charger touched positive and blew up the super io. Iv replaced the charge port and the super io and the bios chips. Bios and super io were programmed by the supplier for this board.

    The board now turns on and the leds come on when the power button is pressed, but the hard drive doesn't spin up and Lcd does not power on and fan doesn't spin.

    I have tested voltages and +5valw is present and so is +valw , but +5vs and +3vs isn't present.

    I checked the mosfets q23 and q24 and power is coming into one side but not out of the other.

    I have checked the gate on both and there is zero volts on the gate on both.

    The gate of the 5vs mosfet is connected to +20vsb, this is zero volts, but if I check pj201 +20vsb is present, it's just not at the gate of q23 and q24

    pu301
    1-20.17
    2-20.17
    3-0
    4-0.104
    5-0.004
    6-2.633
    7-0.005
    8-3.385
    9-3.384
    10-0.807
    11-1.214
    12-1.862
    13-1.862
    14-0
    15-0
    16-6.00
    17-5.79
    18-1.856
    19-1.8
    20-20.17
    21-

    #2
    Re: nm-a273 / lenovo z 50/70 No post

    SUSP is missing that’s why GATE Is not operating check the voltage on PQ25 26 Gate if not trace it back up to SIO pin 124
    Last edited by Techtiger; 12-11-2019, 02:47 AM.

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      #3
      Re: nm-a273 / lenovo z 50/70 No post

      Thanks, il try that, what should output of pq202 be ?, as on pin 1 I have 20v.

      Comment


        #4
        Re: nm-a273 / lenovo z 50/70 No post

        If it’s from dc jack +19V if it’s from +B battery approximately 13-14V
        Last edited by Techtiger; 12-11-2019, 05:23 AM.

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          #5
          Re: nm-a273 / lenovo z 50/70 No post

          Ok so Iv tested pq202 and suspend seems to be present. On the gate I have 3.6v and pin 1 and 3 is 20v. Its just the 20v isht getting to the gate of the 5vs mosfet. Shall I trace a wire from the output of pq202 to the gate of the Q23 ?.

          Comment


            #6
            Re: nm-a273 / lenovo z 50/70 No post

            Originally posted by crea2k View Post
            Ok so Iv tested pq202 and suspend seems to be present. On the gate I have 3.6v and pin 1 and 3 is 20v. Its just the 20v isht getting to the gate of the 5vs mosfet. Shall I trace a wire from the output of pq202 to the gate of the Q23 ?.
            That’s not SUSP PQ202 +B line is connected with 2 resisters 100k 22k PQ202 GATE voltage come from this voltage Divider

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              #7
              Re: nm-a273 / lenovo z 50/70 No post

              you have not responded to POST 2
              "check the voltage on PQ25 26 Gate if not trace it back up to SIO pin 124"

              test the Voltage SIO pin 93 2 128 14 72 109 18 21
              Last edited by Techtiger; 12-11-2019, 08:43 AM.

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                #8
                Re: nm-a273 / lenovo z 50/70 No post

                Q25 has a hole in it, so il order a replacement and again then.

                Comment


                  #9
                  Re: nm-a273 / lenovo z 50/70 No post

                  Originally posted by crea2k View Post
                  Q25 has a hole in it, so il order a replacement and again then.
                  Upload a pic

                  Comment


                    #10
                    Re: nm-a273 / lenovo z 50/70 No post

                    https://www.badcaps.net/forum/attach...1&d=1576086162
                    Attached Files

                    Comment


                      #11
                      Re: nm-a273 / lenovo z 50/70 No post

                      Clean it up with Alcool Isopropylique and remove Q25

                      Comment


                        #12
                        Re: nm-a273 / lenovo z 50/70 No post

                        Ok so Iv replaced q25 and pq202. Now I have 20v on two legs of pq202 and the 3.6 on the other, this seems to be working as at R149 I am getting 20v on pin 1 and 1.685v on pin 2. This means that the gate of q25 is getting 1.685v. On the output of q25 I’m getting 1.6v.

                        On the gate of q23 I’m getting 0.9v , which means the output is only 1.5v, with the input being 5v

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                          #13
                          Re: nm-a273 / lenovo z 50/70 No post

                          1.68v seems rather low, is it supposed to be like that the other side of that first resistor ?.

                          Comment


                            #14
                            Re: nm-a273 / lenovo z 50/70 No post

                            SUSP suppose to be approximately 3.3V From SIO to Gate of Q25 the Voltage you are getting is low, on working conditions when SUSP hits Q25 it will pull up +20V from R149
                            To Gate of Q23

                            Comment


                              #15
                              Re: nm-a273 / lenovo z 50/70 No post

                              I tested the resister and it is within spec, so wasn't sure why the voltage was so low ?, as I have changed the mosfet itself.

                              Comment


                                #16
                                Re: nm-a273 / lenovo z 50/70 No post

                                What voltage on the pin 124 SIO before power up and after power

                                Comment


                                  #17
                                  Re: nm-a273 / lenovo z 50/70 No post

                                  124 - 0v when on or off

                                  Comment


                                    #18
                                    Re: nm-a273 / lenovo z 50/70 No post

                                    Originally posted by crea2k View Post
                                    124 - 0v when on or off
                                    So you confirm test the voltage on pin 124 as you press the power btw ?

                                    test the Voltage SIO pin 93 2 128 14 72 109 18 21

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