Complex Backlight Issue. Please advise Asus DA0BKXMB8D0

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  • IamPritesh
    Badcaps Veteran
    • Aug 2017
    • 356
    • India
    #1

    Complex Backlight Issue. Please advise Asus DA0BKXMB8D0

    So I have this Asus TUF laptop ( BOARD ID : DA0BKXMB8D0 ) which has no backlight. tested this with multiple screens and each has different result.

    Original Screen ( FULL HD ) :
    Has Data
    No Backlight
    0V on EDP connector Pin 39,40
    Backlight Enable has 3.3V

    TEST Screen 1 (ONLY HD)

    No data
    No Backlight
    8V on EDP connector Pin 39,40

    TEST Screen 2 (ONLY HD)

    No data
    No Backlight
    5V on EDP connector Pin 39,40

    LDVS CONNECTED TO MB BUT NOT TO LED SCREEN

    19V on EDP connector Pin 39,40 and also on the display cable ( So probably not a cable issue I think )

    Attaching schematic .Would love to know what exactly is causing the drop in 19V Vin that is connected to the LDVS .
    Attached Files
    Last edited by SMDFlea; 02-16-2022, 07:29 AM.
    Tags: None
    • mcplslg123
      Badcaps Legend
      • Jun 2015
      • 7262
      • india
      #2
      Re: Complex Backlight Issue. Please advise Asus DA0BKXMB8D0

      Display cable is likely burnt.

        Comment

        • IamPritesh
          Badcaps Veteran
          • Aug 2017
          • 356
          • India
          #3
          Re: Complex Backlight Issue. Please advise Asus DA0BKXMB8D0

          Originally posted by mcplslg123
          Display cable is likely burnt.
          If I dont connnect the led screen I get full 19V on the both the ends of display cable.

            Comment

            • mon2
              Badcaps Legend
              • Dec 2019
              • 14088
              • Canada
              #4
              Re: Complex Backlight Issue. Please advise Asus DA0BKXMB8D0

              Does the original screen work on another logic board?

              You can see the text / graphics with a flashlight?

              Remove all power. Meter in resistance mode. Check the resistance to ground for the lcd pin 39,40.

              Then check the same in diode mode. Meter in diode mode, red probe to ground. Black probe to pin 39,40.

              Post the readings.

                Comment

                • piernov
                  Super Moderator
                  • Jan 2016
                  • 4435
                  • France
                  #5
                  Re: Complex Backlight Issue. Please advise Asus DA0BKXMB8D0

                  Of course fuse is good…?
                  OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

                    Comment

                    • mcplslg123
                      Badcaps Legend
                      • Jun 2015
                      • 7262
                      • india
                      #6
                      Re: Complex Backlight Issue. Please advise Asus DA0BKXMB8D0

                      Originally posted by IamPritesh
                      If I dont connnect the led screen I get full 19V on the both the ends of display cable.
                      This doesnt proves cable is not bad.

                        Comment

                        • IamPritesh
                          Badcaps Veteran
                          • Aug 2017
                          • 356
                          • India
                          #7
                          Re: Complex Backlight Issue. Please advise Asus DA0BKXMB8D0

                          Originally posted by mon2
                          Does the original screen work on another logic board?

                          You can see the text / graphics with a flashlight?

                          Remove all power. Meter in resistance mode. Check the resistance to ground for the lcd pin 39,40.

                          Then check the same in diode mode. Meter in diode mode, red probe to ground. Black probe to pin 39,40.

                          Post the readings.
                          Originally posted by piernov
                          Of course fuse is good…?
                          Originally posted by mcplslg123
                          This doesn't proves cable is not bad.
                          The original screen was bad and only specific screen works on this asus machine. Something to do with the panel_id signal maybe ?

                          The machine is no more with me. Since I could not source the new compatible screen, had no choice but to return the laptop.

                            Comment

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