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HP Envy 17, LA-C991P, Burned components

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    HP Envy 17, LA-C991P, Burned components

    does anyone have a hp envy 17 board? model is LA-C991P. I need to know what mosfet is PQB03 and PQB01 (the main 19V mosfets). couldnt find schematics. the one on the board I'm working was completely charred, the whole area was carbonized. I replaced it a couple months back but it came back with it almost desoldered from the board. so I think maybe it is too weak for the job or maybe I didnt scrape enough the burned traces when I first did the job
    Attached Files

    #2
    Re: HP Envy 17, LA-C991P, Burned components

    Locate the DC in connector -> are these mosfets near that connector ? Then locate the charger IC that should be also close to these mosfets.

    What are the SMD topside markings ? Probably a 'BQ' = TI (texas instruments) charger IC?

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      #3
      Re: HP Envy 17, LA-C991P, Burned components

      Originally posted by mon2 View Post
      Locate the DC in connector -> are these mosfets near that connector ? Then locate the charger IC that should be also close to these mosfets.

      What are the SMD topside markings ? Probably a 'BQ' = TI (texas instruments) charger IC?
      They are the 'main' mosfets right out of the dcin.
      the charger ic is an intersil ISL95520
      Last edited by Fontana; 09-23-2022, 01:31 PM.

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        #4
        Re: HP Envy 17, LA-C991P, Burned components

        See attached - found another schematic with this part.

        Now - review if you see a connection from the charger IC to the mosfet like this schematic.

        Then review the mosfet they have used in this attached schematic -> your case should be similar.

        That is, if it is a n-channel mosfet and it connects directly to the charger IC then you will be the same for your logic board.

        Need to nail down the physical size of the mosfets but first confirm if you have a trace from the GATE pin of the mosfet like the attached.
        Attached Files

        Comment


          #5
          Re: HP Envy 17, LA-C991P, Burned components

          they go straight to the charger, yes. Seems to be a very similar circuit. Mind telling me what board your picture is from?
          this one I'm working is a i7 6700HQ + gtx950, powerbrick is 150w

          also they seem to be the same package as the ones I need.

          If it isn't too much to ask, care to give me a quick explanation on how would I go about choosing a replacement? what specs in the datasheet would I need to look for? drain current and power dissipation?
          I noticed the specs of the 2 mosfets differ a lot, despite them being in-line. what's the purpose of that? the first one being on paper much more powerful.
          Last edited by Fontana; 09-23-2022, 01:58 PM.

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            #6
            Re: HP Envy 17, LA-C991P, Burned components

            Hi. See attached for the name of the board & schematic that has the same part onboard. We can continue to debug your board using this example since it is similar for this DCin side of the design.

            It is from a locked (paid) database so unable to post it - since we have not figured out how to break the lock (yet). The schematic may be already on this forum as well.

            For the repair of your board - it will be very helpful to have a micrometer (prefer digital) so we can have a physical size of the part that is onboard your logic board. Even better, if you have a mosfet that fits the SMD pads for soldering - post the part number here on this forum.

            Then from the datasheet -> we will know the x * y mm size of the mosfet.

            Next, if you can agree that the charger IC is driving the mosfet like the sample schematic -> we can source a similar mosfet for your board. We only need to be similar to the recommended mosfets in the sample schematic to proceed.

            Attached is a datasheet for the mosfet used in the other logic board (MDU1512) = N-channel mosfet. This is the first mosfet and is 5*6 mm in size.

            Next is the AON7506 - datasheet is attached = also N-channel mosfet. This is the 2nd mosfet in the DCin power chain @ 3*3mm in size.

            Are the mosfets on your board similar in the noted sizes ? If yes, the same part numbers could be used, if the mosfets need to be replaced.

            With the meter in DC volts scale of 20V or higher, measure the voltage on each pin of the mosfets so we know what the charger is doing to enable / disable these parts.

            Source (1-2-3)
            gate (4) ; being N-channel - to ENABLE this mosfet, the gate voltage should be ~6 volts higher than the voltage it is passing. So ~24-25V to enable.
            drain (5-6-7-8)


            If the gate is at the same voltage as the source / drain - mosfet will be OFF.

            Moreso, the charger IC has to be powered to allow for the above actions.

            ----

            Yeah, noticed that the first mosfet is rated @ 100A - must be an impulse current rating before damage.
            Attached Files

            Comment


              #7
              Re: HP Envy 17, LA-C991P, Burned components

              Originally posted by mon2 View Post
              Hi. See attached for the name of the board & schematic that has the same part onboard. We can continue to debug your board using this example since it is similar for this DCin side of the design....

              ...Yeah, noticed that the first mosfet is rated @ 100A - must be an impulse current rating before damage.
              thanks for the help. the mosfets are the same packages. I'll order them and scrape the board a bit more and replace them. I think with the appropriate mosfets the issue will be solved.

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