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Dell E6440 laptop - Powers on, no display. Keyboard lights up. Fan spins.

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    #1

    Dell E6440 laptop - Powers on, no display. Keyboard lights up. Fan spins.

    As per the description, there is some life but it seems like the important power rails are not getting any juice. How can I test that the power management chip (UH1) is not at fault? My tests show that I get power to the various power chips but then the enable triggers are not there to switch them on? Are there any other tests I should be doing to pinpoint the issue?

    Board: VAL91 LA-9932P Rev 1.0 (A00) 2013-09-11

    PJP101/103 = 5.04v
    PJP100/102 = 3.32v

    PJP200 = 13.5v
    PJP201 = 0v
    PJP202 = 0v
    PJP203 = 0v
    PJP204 = 0v

    PJP300 = 13.5v
    PJP301 = 0v

    PJP400 = 3.3v
    PJP401 = 0v

    PL700 battery/charger coil 13.5v
    PL701 coil 19.89v
    PL600/PL601 (PWR_+GPU_CORE) 0v

    PL 502/503 (+VCC_CORE) 0v
    PU500 is not turning on because no 3.3V_RUN / IMVP_Pwrgd. +3.3V_ALW is okay.

    PL301 (PWR_+1.05V_MP) 0v
    PL201 (+1.35V_MEN_P) 0v
    PU603 (+1.8V_RUNP) 0v
    U52/U53 (Flash ROMs) pin 8, 0v
    Tags: None
    #2
    Re: Dell E6440 laptop - Powers on, no display. Keyboard lights up. Fan spins.

    Save! friend, have you checked the bios? if not try to perform a clear me bios. or try another bios!

    Comment

      #3
      Re: Dell E6440 laptop - Powers on, no display. Keyboard lights up. Fan spins.

      Thanks, this morning I actually ordered a EZP2019 programmer as I see it supported the BIOS chips on this board (Winbond 25Q64F & Winbond 25Q32F).
      I am planning on removing these chips from the board, dumping what is on them as a backup and then writing a copy of the BIOS detailed in this post (https://www.badcaps.net/forum/showth...t=e6440&page=2).

      Does this sound like the right idea?

      I'll look into the "ME cleaning" but it sounds like the BIOS images in the above post have already been "cleaned".

      Comment

        #4
        Re: Dell E6440 laptop - Powers on, no display. Keyboard lights up. Fan spins.

        This is simply not a bios issue and dont mess with it for now. You dont even have RAM voltage and you are probing PU500 for Vcore? Go step by step and check basics first-you need to know what is missing and then try to get to the root cause of missing rail/signal.

        Suggest to probe U146 pin3/5/8-9/13-14. Note that pin 8-9 and 13-14 are together.You need to trigger the mb and measure voltage on these pins.
        Since you know +3.3V_RUN is miising,we're simply trying to go backward and see where it is stuck.

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          #5
          Re: Dell E6440 laptop - Powers on, no display. Keyboard lights up. Fan spins.

          I've measured the following:

          U146
          pin 3 = 3.3v
          pin 5 = 0v
          pin 8/9 = 0v
          pin 13/14 = 3.3v

          Interestingly, a shortly while after my original post the board did power on (_all_ rails had power), however I never got any display on the LCD or the HDMI.

          Today when coming back to this issue and measured U146, the board is back to how it was a few days ago, no triggering power on the IC's.
          Bit of a strange one. How do you suggest I continue with the debugging following the measurements on U146?

          I believe the voltage missing is from U46 "RUN_ON", but Im not sure why this chip isn't supplying the voltage.
          I went as far as checking that U46 is getting supply voltage via "+3.3V_ALW_5048"

          Note, I have not yet touched the BIOS chips (still waiting on delivery)

          Comment

            #6
            Re: Dell E6440 laptop - Powers on, no display. Keyboard lights up. Fan spins.

            Quick update!
            After toying around a bit and measuring various components, the board now powers up as it did a few days ago. Part of me thinks maybe this is heat related, as I have had the board "on" for about 30 min now? I will let the board cool down and then try power it on again.

            Sadly though, even in this state I still do not get any output on HDMI (external monitor). I have checked U19 and it seems to be getting power via +3.3V_RUN and +1.5V_RUN_HDMI.

            +VDISPLAY_VCC is also getting 5v

            Could this still be an issue with the BIOS? Where should I be looking now if _everything_ is getting power?
            Last edited by elfelvin; 07-24-2023, 01:57 PM.

            Comment

              #7
              Re: Dell E6440 laptop - Powers on, no display. Keyboard lights up. Fan spins.

              Here are some voltage readings while getting power to the rails but no display. (Still not sure why it doesn't power on initially, will let the motherboard cool down and try again tomorrow).

              PJP101/103 = 5.04v
              PJP100/102 = 3.32v

              PJP200 = 13.5v
              PJP201 = 1.34v
              PJP202 = 0.67v
              PJP203 = 1.34v
              PJP204 = 1.34v

              PJP300 = 13.5v
              PJP301 = 1.07v

              PJP400 = 3.3v
              PJP401 = 1.5v

              PL 502/503 (+VCC_CORE) = 1.75v

              PL301 (PWR_+1.05V_MP) = 1.11v
              PL201 (+1.35V_MEN_P) = 1.34v
              PU603 (+1.8V_RUNP) = 1.79v
              U52/U53 (Flash ROMs) pin 8 = 3.31v

              QV1 +1.35V_MEM_GFX = 1.35v
              Q63 +1.05V_RUN = 1.07v
              PL603 +VGA_PCIEP = 1.0v

              Comment

                #8
                Re: Dell E6440 laptop - Powers on, no display. Keyboard lights up. Fan spins.

                The readings at post#7 seems good. Check DRAMRST# present or not. With this kind of reading, it may be bios issue now.

                Comment

                  #9
                  Re: Dell E6440 laptop - Powers on, no display. Keyboard lights up. Fan spins.

                  Thank you all for the help. I flashed both BIOS chips using a EZP2019 and images from post #49 of https://www.badcaps.net/forum/showth...t=e6440&page=3

                  Now the laptop is alive again! Thanks again

                  Comment

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