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HP NX6710b shorted capacitor value. Please help ASAP...

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    HP NX6710b shorted capacitor value. Please help ASAP...

    Hi,

    Yesterday after three weeks of absence I plugged PSU to my laptop and it refuses to power on while power LED is barely blinking periodically. PSU is squeaking periodically when it's plugged in to laptop like secondary is shorted. Tried another PSU, same.

    After inspection I found one shorted SMD capacitor C77 (see pic) on laptop motherboard. Shortly after PSU is plugged in it get's very hot and I believe it's the reason of the problem.

    What replacement capacitor shall I use on it's place? What value? Does anybody have schematics to check this?

    Is it logical it's same value like C139 located under? Would I take out C139 to measure capacitance?

    Original bipolar SMD capacitor is not available in local shops. What substitute can I use for it? Can I use standard polarized aluminum or tantal caps? What do you think is best? I guess original cap is 10uF/6V bipolar ceramic or similar...

    I must use the laptop ASAP as all my work is there, I need quick solution.

    Thanks in advance!!!

    Suad
    Attached Files

    #2
    Re: HP NX6710b shorted capacitor value. Please help ASAP...

    C77= 10UF/25V
    you can download the schemativ diagram;
    Attached Files

    Comment


      #3
      Re: HP NX6710b shorted capacitor value. Please help ASAP...

      Originally posted by mabroukmedal View Post
      C77= 10UF/25V
      you can download the schemativ diagram;

      Thank you mabroukmedal for quick and detailed answer. What do you think should I use standard low ESR 10uF/25V aluminum cap? There is enough space for it.

      Thanks again!

      Suad

      PS. thanks for the schematics!

      Comment


        #4
        Re: HP NX6710b shorted capacitor value. Please help ASAP...

        Use a ceramic of the same size. The value is not critical. An electrolytic is not recommended, but it will work.
        Originally posted by PeteS in CA
        Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
        A working TV? How boring!

        Comment


          #5
          Re: HP NX6710b shorted capacitor value. Please help ASAP...

          You could also get some on eBay:
          http://www.ebay.com/itm/MULTICOMP-MC...-/271177853382

          I assume it's 1206 size.
          "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
          -David VanHorn

          Comment


            #6
            Re: HP NX6710b shorted capacitor value. Please help ASAP...

            Solved! I used standard low ESR 10uF/35V electrolytic cap for now. It's a quick fix because I must use the laptop. When I find better substitute or original I'll replace it.

            Btw, why do you think electrolytic cap is not recommended? What is difference in this particular situation?

            Thank you for all your help!!!

            Suad
            Attached Files

            Comment


              #7
              Re: HP NX6710b shorted capacitor value. Please help ASAP...

              Because of ESR and lead inductance. The SMD ceramic cap has vastly lower ESR and inductance due to its construction. That ceramic is just one of the many filtering caps on that power rail, so in this case it works just as fine with it or without it.
              Originally posted by PeteS in CA
              Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
              A working TV? How boring!

              Comment

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