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HP DV6 1120ef won't start - power LED on

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    #1

    HP DV6 1120ef won't start - power LED on

    Hi,

    I just got four laptops from the dump.

    One of them caught my attention because it's the newest and it doesn't have that crap nVidia GPU problem...it's a HP DV6 1120f with a Intel Pentium T4200 and a AMD HD4530. There was no RAM or HDD in it. I put 2x512Mb I've got in my lot of RAM.

    What surprised me is that the power connector is the same as the Dell connector from a Dell power brick I have...
    So when I plug it in, the power led next to the connector is on, but it won't start. No sign of life (no front led, no fan movement, no screen lighting on).
    Power is obviously coming to the board since when I short two pins from the power button board connector, the FRONT power led lights up.

    I was thinking it could be a power button board problem (very basic board : the button, a led, a CMS capacitor and a connector). I've removed the CMOS battery but it didn't change anything.

    Could there be something missing on the Dell brick connector that would prevent the HP from starting ?

    Thanks !
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    #2
    Re: HP DV6 1120ef won't start - power LED on

    Had this problem the other day when a HP G61 I was working on wouldn't turn on anymore. Turns out HP have unique chargers, much like the central communication pin on a Dell charger, and they don't work without the exact charger.

    I tried to use a Dell charger on the G61, charge light showed but no response to the power button. Found a replacement HP adapter and it worked flawlessly.

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      #3
      Re: HP DV6 1120ef won't start - power LED on

      Mmh, very interesting then. I might have a chance to save this one. I'll try to get a HP charger.

      Comment

        #4
        Re: HP DV6 1120ef won't start - power LED on

        I've tried with two different HP chargers from around 2008-2009, it doesn't change anything. Nothing lights up, apart from the little LED next to the jack. Could it be a problem with the jack or the wires from the jack to the motherboard ?

        Comment

          #5
          Re: HP DV6 1120ef won't start - power LED on

          Originally posted by SuperDuty View Post
          I've tried with two different HP chargers from around 2008-2009, it doesn't change anything. Nothing lights up, apart from the little LED next to the jack. Could it be a problem with the jack or the wires from the jack to the motherboard ?
          only way to find out is do a continuity test on it with a dmm...being an hp it could be all sorts of probs ranging from corrupted bios to reflow to bad power fets, etc .....it will most likely need to be torn apart...

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            #6
            Re: HP DV6 1120ef won't start - power LED on

            Ok I may have found a faulty transistor near the battery connector. I'm not very electronics savvy, but if I follow this tutorial :http://www.allaboutcircuits.com/vol_3/chpt_5/3.html
            And the datasheet of the N-channel transistor in question :

            I get no continuity on any of the prongs of the transistor.

            Am I doing it right ?

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              #7
              Re: HP DV6 1120ef won't start - power LED on

              Did you ever figure this one out. I've got an HP G71 G71-442. No boot - no power. Intel cpu chipset graphics. Same N channel with no reading. Tried to locate on the net (digikey et.), but found nothing. Thanks

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                #8
                Re: HP DV6 1120ef won't start - power LED on

                Well I'm back at this laptop, changed the transistor as said above, and no improvement. I have no light at the power connector, but I'm getting power at the board. I'm getting power at the battery connector too. The power on cable has power to it, mostly 3.3V. When I connect the 5 and 6 pins at the mainboard connector that goes to the power switch cable, the power light of the motherboard remains on as long as I keep them connected but nothing happens.

                Anyone has a schematic for this board, or at least for the power on only ? I'm not sure what to do now...there's no visual damage I can see. I've tried a reflow with no sign of improvement.

                Comment

                  #9
                  Re: HP DV6 1120ef won't start - power LED on

                  I have one of these laptops. A dell charger works fine with it.

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                    #10
                    Re: HP DV6 1120ef won't start - power LED on

                    I have a schematic that might the one for your board.. check it out here http://www.4shared.com/office/seVmTp1i/QUANTA_R18D.html
                    if you look at pag. 39 you can see that the dc connector has an AD_ID pin. In some cases this could prevent the computer from starting without the original adapter, this isn't always the case. sometimes the system will power on but won't charge the battery ( as in many dell laptops) since you are already testing the board you can try taking other measurements (+VAD, +PRWSRC, +VIN, etc) and post your results to narrow down your problem.
                    greetings

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