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Dell latitude 5440 does not turn on after a short 5v

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    Dell latitude 5440 does not turn on after a short 5v

    La-m401p
    The board after a short circuit of 5v, everything was done and replaced the faulty components, the duty voltage rose, the board turned on from the battery, but the power supply does not see, or rather from 5 yuv does not raise to 20v
    t was replaced by tps65994, but it did not lead to a positive result, I did not find any schemes for this board, maybe someone has already encountered such a malfunction
    Attached Files

    #2
    check all coil for short and all power rail is present

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      #3
      I repeat, it turns on from the battery, and so there is no short circuit anywhere else

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        #4

        Board number: VAW30 LA-9832P Rev1.0 (A00)
        ?

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          #5
          Originally posted by kalilinux25 View Post
          Board number: VAW30 LA-9832P Rev1.0 (A00)
          ?
          no!
          La-m401p

          Comment


            #6
            Maybe someone has a scheme for a board or at least a similar one? I would be very grateful

            Comment


              #7
              I have this motherboard available outside the computer. If you need me to take measurements in certain areas of the motherboard, let me know.

              You mentioned tps65994 chip. I would try to see whether all pins make a good connection with the motherboard. Remove the chip, tin the pins again, use good amount of flux, then resolder the chip. After you do that, get the schematics on the tps65994 chip. See if the voltage reaches the chip, check all caps around it.

              Comment


                #8
                Also, make sure the battery is attached. These Latitudes are notorious for misbehaving when batteries are nowhere to be found.

                Comment


                  #9
                  Originally posted by trepachka View Post
                  I have this motherboard available outside the computer. If you need me to take measurements in certain areas of the motherboard, let me know.

                  You mentioned tps65994 chip. I would try to see whether all pins make a good connection with the motherboard. Remove the chip, tin the pins again, use good amount of flux, then resolder the chip. After you do that, get the schematics on the tps65994 chip. See if the voltage reaches the chip, check all caps around it.
                  I changed 65994 several times, tried different ones, the voltage coming to it is 5v, 3.3v, 1.5v, but 19v never rises, the laptop turns on from the battery

                  Comment


                    #10
                    Originally posted by trepachka View Post
                    Also, make sure the battery is attached. These Latitudes are notorious for misbehaving when batteries are nowhere to be found.
                    with or without battery, it doesn't raise 19v, battery starts it up

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                      #11
                      Here are my measurements
                      Attached Files

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                        #12
                        Measure who is what voltage with the connected type-c at this point
                        Attached Files

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                          #13
                          Were you able to figure out the issue with the motherboard? I am in a similar predicament. Computer is stuck @ 5V, drawing 0A current. Everything appears to be fine. I replaced both the PD chip and the ISL chip just in case to no avail.

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