Name that component

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  • dood
    Deputy dood
    • Mar 2004
    • 2462
    • USA

    #1

    Name that component

    On a laptop motherboard... red circled component. Is quite broken. When the power adaptor is unplugged, I get the correct voltage from the adaptor. When I plug it into the laptop, it keeps bumping from 0v to 0.20v and back, as if it's trying to start but not getting anywhere.

    Attached Files
    Ludicrous gibs!

  • Topcat
    The Boss Stooge
    • Oct 2003
    • 16955
    • United States

    #2
    Re: Name that component

    Its a transistor that blew up, and is shorted. This would explain why the PSU goes into safety/shutdown when connected.
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    • dood
      Deputy dood
      • Mar 2004
      • 2462
      • USA

      #3
      Re: Name that component

      Originally posted by Topcat
      Its a transistor that blew up, and is shorted. This would explain why the PSU goes into safety/shutdown when connected.
      Any way to fix? I'm guessing if I just remove it, the board will still be dead. You hired on a mod that doesn't know much about transistor-level circuit designs. I've always drawn the line at caps. But, to fix this, instead of paying $200 for a new motherboard, will make me a hero I promise you'll get a cut :P
      Ludicrous gibs!

      Comment

      • Topcat
        The Boss Stooge
        • Oct 2003
        • 16955
        • United States

        #4
        Re: Name that component

        You have to find out what it is. Look for the same model motherboard (or a good high-res pic of one) from a working unit. The transistor will have tiny numbers on it, and from there it can be identified, and most likely someplace like digikey will have a replacement for mere pennies.
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        • Toasty
          Badcaps Legend
          • Jul 2007
          • 4171

          #5
          Re: Name that component

          If you gave all the laptop's information up front (and in the thread title... *hint*), there might be a member with the same board.

          Also, a backed-off shot helps people locate it on their board.

          Can you find the blown-off top piece to it? Could have viable numbers on it...
          veritas odium parit

          Comment

          • PCBONEZ
            Grumpy Old Fart
            • Aug 2005
            • 10661
            • USA

            #6
            Re: Name that component

            Take it off and see if the adapter is still shorted by the board.
            Mann-Made Global Warming.
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            Comment

            • Per Hansson
              Super Moderator
              • Jul 2005
              • 5895
              • Sweden

              #7
              Re: Name that component

              Originally posted by Toasty
              If you gave all the laptop's information up front (and in the thread title... *hint*), there might be a member with the same board.
              Hahaha, awsome quote of the day!
              These mods I say

              Seriously a service manual would tell you too, look for Q23 in it...
              "The one who says it cannot be done should never interrupt the one who is doing it."

              Comment

              • dood
                Deputy dood
                • Mar 2004
                • 2462
                • USA

                #8
                Re: Name that component

                I guess I shouldn't post so late at night. I was kind of out of it. Anyway, I'll get the requested information when I get home after work today.
                Ludicrous gibs!

                Comment

                • Dgtech
                  E. Technician
                  • Apr 2009
                  • 1462
                  • Steeler

                  #9
                  Re: Name that component

                  There are a few ways of correctly finding this part is:

                  1. Looking into a service manual for Q23 on this board.
                  2. Find a parts list for the board that has Q23 listed.
                  3. Draw out the circuit of parts before and after this component to determine its use - then cross reference.

                  There really is no simple way. You might find out that it is nothing but a general purpose transistor. In that case, you can find them almost anywhere. The service manual would be the best though. I would search for one but we dont have any model numbers yet.
                  The strong-minded rise to the challenge of their goals,the weak-minded BECOME HATERS

                  Comment

                  • Topcat
                    The Boss Stooge
                    • Oct 2003
                    • 16955
                    • United States

                    #10
                    Re: Name that component

                    I'd like to know where you guys are getting service manuals!! Last I ever knew, motherboard manufacturers don't release schematics and whitepapers for their boards.....so this would be a new wrinkle!
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                    • PCBONEZ
                      Grumpy Old Fart
                      • Aug 2005
                      • 10661
                      • USA

                      #11
                      Re: Name that component

                      I've never seen a component level service manual for any mobo, let alone a laptop.
                      Intel server boards have docs that come close for some specific circuits [not the whole board] but that about as good as it gets.
                      Mann-Made Global Warming.
                      - We should be more concerned about the Intellectual Climate.

                      -
                      Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.

                      - Dr Seuss
                      -
                      You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                      -

                      Comment

                      • dood
                        Deputy dood
                        • Mar 2004
                        • 2462
                        • USA

                        #12
                        Re: Name that component

                        Okay, Laptop is an HP G60, and the motherboard is HP PN 578999-001
                        Ludicrous gibs!

                        Comment

                        • dood
                          Deputy dood
                          • Mar 2004
                          • 2462
                          • USA

                          #13
                          Re: Name that component

                          So, I removed the broken transistor, and there's no change in the behavior of the voltage.

                          I pulled the processor to make sure it's not shorted... still no luck. Would this require there be a battery present to kick over the charging/power circuit?
                          Ludicrous gibs!

                          Comment

                          • Toasty
                            Badcaps Legend
                            • Jul 2007
                            • 4171

                            #14
                            Re: Name that component

                            Could be something else shorted. A diode across input for reverse polarity protection?

                            What voltage are you reading with it disconnected from laptop?

                            When plugged in, are you measuring at the input jack to the laptop?

                            Is this the correct power pack for this computer? NW199AA
                            veritas odium parit

                            Comment

                            • dood
                              Deputy dood
                              • Mar 2004
                              • 2462
                              • USA

                              #15
                              Re: Name that component

                              Power pack is showing 18.5v when disconnected from the laptop.

                              When plugged in, I'm measuring from the input jack.

                              The power pack I have is the original. PN 463552-004
                              Ludicrous gibs!

                              Comment

                              • Toasty
                                Badcaps Legend
                                • Jul 2007
                                • 4171

                                #16
                                Re: Name that component

                                Power pack (per HP) has built in overload protection. So, the jumping you're seeing is the PSU trying to come up, seeing the short, and cycling.

                                You're going to have to trace the input and find the component(s) that shorted. With the removal of the obvious bad transistor, the short (most likely) lies between it and the input.

                                I'm assuming this is your laptop and you've never used any other PSU except the HP one you have, correct?
                                veritas odium parit

                                Comment

                                • dood
                                  Deputy dood
                                  • Mar 2004
                                  • 2462
                                  • USA

                                  #17
                                  Re: Name that component

                                  This is not my laptop... Working on it for a friend. I do not know its history, other than she said she left for a week and when she came back it didn't work anymore. I don't even have another similar laptop to be able to charge the battery and see if it runs off batt. In the meantime, I'm loaning her my spare laptop, and we'll go through the options of repairing (replace motherboard) or just buying a new one. Motherboard is around $225 off eBay.
                                  Ludicrous gibs!

                                  Comment

                                  • Per Hansson
                                    Super Moderator
                                    • Jul 2005
                                    • 5895
                                    • Sweden

                                    #18
                                    Re: Name that component

                                    Try measuring the voltage at the pads where you removed the transistor
                                    To see if the voltage reaches this point or is blocked by something in the path to it
                                    "The one who says it cannot be done should never interrupt the one who is doing it."

                                    Comment

                                    • dood
                                      Deputy dood
                                      • Mar 2004
                                      • 2462
                                      • USA

                                      #19
                                      Re: Name that component

                                      I only got 0.01 volt at the top two pads.
                                      Ludicrous gibs!

                                      Comment

                                      • Per Hansson
                                        Super Moderator
                                        • Jul 2005
                                        • 5895
                                        • Sweden

                                        #20
                                        Re: Name that component

                                        Then try tracing the circuit back from there untill you find whatever it is that stops the current from flowing
                                        "The one who says it cannot be done should never interrupt the one who is doing it."

                                        Comment

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