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Dell E5440 completely dead

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    #21
    Re: Dell E5440 completely dead

    Originally posted by Andreasbest View Post
    Hello again.
    PL5 one side is indeed grounded but i think is normal, all rest coils are fine, no shortcircuits to ground.
    Indeed both sides are grounded, wrong measure before (probably probe needed some more pressure on lead)

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      #22
      Re: Dell E5440 completely dead

      Ok. So it seems most of the parts on the supicious rail were checkd, except PQ5 and PU701, right?
      FairRepair on YouTube

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        #23
        Re: Dell E5440 completely dead

        Originally posted by Sephir0th View Post
        Ok. So it seems most of the parts on the supicious rail were checkd, except PQ5 and PU701, right?
        Seems so, what do you suggest?

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          #24
          Re: Dell E5440 completely dead

          Unfortunately i can't find datasheet right no for PU701, but you can at least check whether 19V reach Pin1 and of course, you can check each pin for short to GND
          FairRepair on YouTube

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            #25
            Re: Dell E5440 completely dead

            How many amps is the board taking?

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              #26
              Re: Dell E5440 completely dead

              5 6 7 14 15 & 32 are grounded
              Pin #1 receives 19.5v

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                #27
                Re: Dell E5440 completely dead

                How many amperes? Do you have a bench power supply? If yes, set it to 19.5V and power the board from it.

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                  #28
                  Re: Dell E5440 completely dead

                  Originally posted by Spider1211 View Post
                  How many amps is the board taking?
                  You mean if i apply 19v directly to DC_IN?

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                    #29
                    Re: Dell E5440 completely dead

                    Check where the DC adaptor connects to the motherboard. Apply power from your power supply on the DC connector pins, just make sure which is +ve and -ve first.

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                      #30
                      Re: Dell E5440 completely dead

                      PU701 Pin 6 & 15 short to GND means Main Power Rail short to GND. How could that Be missed before?
                      Last edited by Sephir0th; 10-19-2021, 07:23 AM.
                      FairRepair on YouTube

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                        #31
                        Re: Dell E5440 completely dead

                        Originally posted by Sephir0th View Post
                        PU701 Pin 6 & 15 short to GND means Main Power Rail short to GND. How could that Be missed before?
                        Yes i can confirm pin 6 and 15 of PU701 are both grounded.
                        What do you suggest?

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                          #32
                          Re: Dell E5440 completely dead

                          Do a visual check first to identify if something is physically damaged, otherwise Inject voltage on that line and see what gets hot. As always, start with 1V 1A then increase amp slowly if needed.

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                            #33
                            Re: Dell E5440 completely dead

                            Did visual inspection before, totally clean mb.
                            Gonna inject voltage and report in 2 mins

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                              #34
                              Re: Dell E5440 completely dead

                              First, Share exact RĂ©sistance to GND there in Ohms Mode, Range 200 or Auto-Range to exclude a Short with a step down Circuit.
                              FairRepair on YouTube

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                                #35
                                Re: Dell E5440 completely dead

                                When i set it to Ω shows 20Ω not 0.

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                                  #36
                                  Re: Dell E5440 completely dead

                                  20 Ohms are probably Bad News. Now you have to Check Resistance to GND of each coil. Look for a similar value...
                                  FairRepair on YouTube

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                                    #37
                                    Re: Dell E5440 completely dead

                                    I see same value only on PL400 (both pins) all other coils have values way beyond this.

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                                      #38
                                      Re: Dell E5440 completely dead

                                      That's fine then. So Voltage injection Like mentioned before. Pay Attention especially To PU401 and PU701.
                                      FairRepair on YouTube

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                                        #39
                                        Re: Dell E5440 completely dead

                                        I inject voltage on pin 6 (+) and GND (-), 1v 1a and drown only 0.4A, no shortcircuit indication.

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                                          #40
                                          Re: Dell E5440 completely dead

                                          They both share a common line through PR400. You could try removing PR400 to see which side is 20Ohms.

                                          I suspect it might be a faulty PU701. These are fairly easy to remove and resolder. I'd try removing it and see if the 20Ohms is still there. Or you could just inject voltage, but with 20Ohms at 1V, I doubt anything will get hot (expected 0.05A flow).

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