Component identification

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  • reaper57
    Badcaps Veteran
    • Sep 2014
    • 216
    • Norway

    #1

    Component identification

    Hi, I'm trying to fix a laptop that doesn't want to power on and I suspect what might be causing the problem, but I can't find a datasheet for it. A picture of the component is in the attachments. I've also included a picture of the motherboard model.
    Thank you in advance!
    Attached Files
    Keyboard not detected, press F1 to continue...
  • selldoor
    Slow Learner
    • Dec 2010
    • 7870

    #2
    Re: Component identification

    Not looked for it yet but the component with a Q on it could be a fuse?
    Please upload pictures using attachment function when ask for help on the repair
    http://www.badcaps.net/forum/showthread.php?t=39740

    Comment

    • trebo
      Badcaps Veteran
      • Feb 2010
      • 514
      • Wales, UK

      #3
      Re: Component identification

      Check this out,
      https://cdn.badcaps-static.com/pdfs/...7cd1a0ca35.pdf

      Comment

      • dj_ricoh
        Badcaps Legend
        • Jan 2013
        • 2073
        • uk

        #4
        Re: Component identification

        that Q component maybe a diode.

        its connected from + to ground and you only do that when you want to protect from short.

        as for the component in the red square make a picture and draw how everything its connected. Drain Source and gate.

        you can pin point what is not working if you start to draw by hand and see where is stops.

        my money its on that fet with no voltage on gate and a small chance that the Q component its a diode and its open with ground and it stops the + line to power up.

        lift it up and see what happens.
        Just cook it! It's already broken.

        Comment

        • reaper57
          Badcaps Veteran
          • Sep 2014
          • 216
          • Norway

          #5
          Re: Component identification

          The component with a Q on it is indeed a fuse, but that's not what I was asking about. On the N-channel Mosfet I get 20V input on all of the pins on one side and 0.9 on all of the pins on the other side. So if it's used for the CPU power it should be ok right? If this is true can someone point me to the standby voltages on the motherboard?
          Thanks!
          Keyboard not detected, press F1 to continue...

          Comment

          • reaper57
            Badcaps Veteran
            • Sep 2014
            • 216
            • Norway

            #6
            Re: Component identification

            Originally posted by dj_ricoh
            that Q component maybe a diode.

            its connected from + to ground and you only do that when you want to protect from short.

            as for the component in the red square make a picture and draw how everything its connected. Drain Source and gate.

            you can pin point what is not working if you start to draw by hand and see where is stops.

            my money its on that fet with no voltage on gate and a small chance that the Q component its a diode and its open with ground and it stops the + line to power up.

            lift it up and see what happens.
            I think that it's a fuse, since it's reading 0 ohms in both directions.
            Keyboard not detected, press F1 to continue...

            Comment

            • tibd
              Senior Member
              • Oct 2014
              • 189
              • Sweden

              #7
              Re: Component identification

              N-channel mosfet, best way to check is to take off board and check. The DS voltage follow is controlled/ opened by gate(G) voltage . Not always possible to test on board specially applying the voltage to G to see if it opens drain D to source S.

              Comment

              • paulstef
                Badcaps Veteran
                • Dec 2013
                • 724
                • Canada

                #8
                Re: Component identification

                Originally posted by reaper57
                The component with a Q on it is indeed a fuse, but that's not what I was asking about. On the N-channel Mosfet I get 20V input on all of the pins on one side and 0.9 on all of the pins on the other side. So if it's used for the CPU power it should be ok right? If this is true can someone point me to the standby voltages on the motherboard?
                Thanks!
                On what pins you get what voltage?

                Since gate and source are on the same side and you measured from all pins of each side to ground the same voltage I'd say that this MOSFET was in the OFF state when you measured it. The best though is to measure from gate to source.
                Last edited by paulstef; 04-13-2015, 07:08 AM.

                Comment

                • Djosla
                  Badcaps Veteran
                  • Dec 2012
                  • 246
                  • Montenegro

                  #9
                  Re: Component identification

                  Q is fuse...this is your problem:

                  https://www.badcaps.net/forum/showpos...79&postcount=3

                  Comment

                  • newtothis
                    Badcaps Legend
                    • Mar 2013
                    • 1556
                    • england

                    #10
                    Re: Component identification

                    Originally posted by Djosla
                    That is a broken link, And its already been established that its a fuse

                    Comment

                    • budm
                      Badcaps Legend
                      • Feb 2010
                      • 40746
                      • USA

                      #11
                      Re: Component identification

                      For that MOSFET to be on, the Vgs has to be at least 1.2VDC (the Vgs-threshold is 1.2V min).
                      Never stop learning
                      Basic LCD TV and Monitor troubleshooting guides.
                      http://www.badcaps.net/forum/showthr...956#post305956

                      Voltage Regulator (LDO) testing:
                      http://www.badcaps.net/forum/showthr...999#post300999

                      Inverter testing using old CFL:
                      http://www.badcaps.net/forum/showthr...er+testing+cfl

                      Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                      http://s807.photobucket.com/user/budm/library/

                      TV Factory reset codes listing:
                      http://www.badcaps.net/forum/showthread.php?t=24809

                      Comment

                      • rievax_60
                        Badcaps Veteran
                        • May 2012
                        • 897
                        • australia

                        #12
                        Re: Component identification

                        If that MOSFET is used to switch the AC adapter voltage to he VBAT rail, its control circuit usually wont try to turn it on if there is a short to ground on the VBAT rail. Also check the Gate to Source resistance while no power is supplied.

                        Comment

                        • tata123
                          Senior Member
                          • Nov 2013
                          • 104
                          • Germany

                          #13
                          Re: Component identification

                          Its a SMD N-CHANNEL MOSFET.

                          Comment

                          • dj_ricoh
                            Badcaps Legend
                            • Jan 2013
                            • 2073
                            • uk

                            #14
                            Re: Component identification

                            Find the QFN that is near .

                            Maybe you get lucky and find the charging Ic.

                            There you will see whats wrong.
                            Just cook it! It's already broken.

                            Comment

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