Dell Latitude E5440 Power Issue

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  • dspok
    Badcaps Veteran
    • Jan 2014
    • 553
    • Nepal

    #1

    Dell Latitude E5440 Power Issue

    Hello,

    I have above said model with power issue. Power LED turns on for 5sec and off, battery LED blinking for 1sec continuously after power LED turns off. No power on B+ but all SCL SDA are 3.3v on battery connector.

    3v, 5v is ok but I'm getting 13v on +PWR_SRC. I have changed charger IC no effect. No shorting and No leakage found. BIOS reprogramming may not help in this case in my opinion.

    Can anybody help?

    Thanks in advance.
    Attached Files
  • dspok
    Badcaps Veteran
    • Jan 2014
    • 553
    • Nepal

    #2
    Re: Dell Latitude E5440 Power Issue

    anybody?

    Comment

    • khaahk
      Badcaps Veteran
      • Dec 2013
      • 751
      • Estonia

      #3
      Re: Dell Latitude E5440 Power Issue

      Battery led blinking - is the battery connected or not?
      Why do you rule out bios?
      13V on PWR_SRC should be ok.
      Which power rails come on when power button pressed?

      Comment

      • Duranitron
        Badcaps Veteran
        • Jul 2014
        • 544
        • Philippines

        #4
        Re: Dell Latitude E5440 Power Issue

        Originally posted by dspok
        Hello,

        I have above said model with power issue. Power LED turns on for 5sec and off, battery LED blinking for 1sec continuously after power LED turns off. No power on B+ but all SCL SDA are 3.3v on battery connector.

        3v, 5v is ok but I'm getting 13v on +PWR_SRC. I have changed charger IC no effect. No shorting and No leakage found. BIOS reprogramming may not help in this case in my opinion.

        Can anybody help?

        Thanks in advance.
        check these power table .. check the alw voltages.. those voltages must be present in order for it to turn on
        Attached Files
        Never stop LEARNING because life never stops TEACHING!

        Comment

        • ktmmotocross
          Boardkiller
          • Feb 2014
          • 3574
          • slovakia

          #5
          Re: Dell Latitude E5440 Power Issue

          that 13V is way low. it is ok for stepdown circuits but not for logic.

          check why u have 13V. i have this problem when have one of first two mosfets blown but everything works. blown mosfet have bigger resistance wich pulls 19V down and mosfet was heating

          and remove battery until u solve that low voltage

          Comment

          • piernov
            Super Moderator
            • Jan 2016
            • 4435
            • France

            #6
            Re: Dell Latitude E5440 Power Issue

            +PWR_SRC is battery charging rail (before current sensing resistor). 13V sounds ok there.
            OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

            Comment

            • ktmmotocross
              Boardkiller
              • Feb 2014
              • 3574
              • slovakia

              #7
              Re: Dell Latitude E5440 Power Issue

              Originally posted by piernov
              +PWR_SRC is battery charging rail (before current sensing resistor). 13V sounds ok there.
              looks like, but it is main power rail for every stepdown circuit when u check schematic.

              that charging circuit looks weird

              Comment

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