Announcement

Collapse
No announcement yet.

dead samsung 940bw

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    dead samsung 940bw

    Hi all,

    I'm new to this forum and I've got a dead samsung 940bw monitor that went completely dead a few weeks ago, and I was hoping not to give up on it just yet and hopefully bring it back to life.

    When I turn the power switch on then hit the frontal power button, a blue led lites and I get a faint grey on the screen, almost unnoticeable.

    If it hit the frontal power button again, the blue led shuts off and the screen goes completely black.

    I already changed: (2) 1000uf/16v and (2) 1000uf/25v capacitors on the power board with no avail.

    I don't want to spend any more money on parts without having a more clear direction where to start from.

    Could you help me troubleshoot it?

    Regards,

    Paulo

    #2
    Re: dead samsung 940bw

    Hi blasteroo,

    Can you see an image on your screen if you shine a flash light at it?

    Does the screen come on normally for a few seconds before turning off?

    And welcome to the forum.
    Fixed so far : 1 Home cinema system, 16 LCD Monitors, 4 LCD TV's

    How to resize your pictures guide click HERE
    Retiredcaps Ideal post example click HERE

    Comment


      #3
      Re: dead samsung 940bw

      Jasgriff,

      Thank you for the reply and for the welcoming message.

      Regarding your questions, the faint grey image (without graphics) is only noticed in a really dark environment. In a well-lit room you can hardly see a change.

      The screen doesn't come on at all, except for the faint grey image.

      When I press the frontal power button I either get:

      - No image + no led light

      - Faint grey image with no graphics + continuous blue led light

      Best,

      Paulo

      Comment


        #4
        Re: dead samsung 940bw

        Jasgriff,

        I think I understood what you meant when you asked "Can you see an image on your screen if you shine a flash light at it?".

        Yes, I can see windows desktop if I shine a flash light really close to the screen.

        Any advice?

        Thank you,

        Paulo

        Comment


          #5
          Re: dead samsung 940bw

          If the backlights don't come on, check for

          1) blown fuse in the inverter section
          2) shorted mosfets in the inverter section

          Both components could be on the back side.
          --- begin sig file ---

          If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

          We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

          Please do not post inline and offsite as they slow down the loading of pages.

          --- end sig file ---

          Comment


            #6
            Re: dead samsung 940bw

            that's good it tells us that its your back light not coming on or not staying on that's the issue.

            If you are not even getting a flash of light then this looks like the inverters which drive your back lights are not getting any power at all. This is why retired caps is asking you to check for a blown fuse or mosfet. As he explains these will be on the underside of you main board.

            This is difficult to point out without really good clear pics of the top and the bottom of you board.
            Fixed so far : 1 Home cinema system, 16 LCD Monitors, 4 LCD TV's

            How to resize your pictures guide click HERE
            Retiredcaps Ideal post example click HERE

            Comment


              #7
              Re: dead samsung 940bw

              Thank you so much for your help!

              Please see attached pic of power board.

              I've checked the FH602 and FH601 fuses for continuity with a multimeter
              and it seems to be ok.

              Could you assist me in testing the mosfets?

              Paulo
              Attached Files

              Comment


                #8
                Re: dead samsung 940bw

                http://www.youtube.com/watch?v=fsdQtcd9tDs

                Você fala português.

                Or

                http://www.youtube.com/watch?v=YsJXFLnA62s

                PS: Is it me or the plastic BN26-00012A is fried? It look to me that the plastic has been exposed to really high temperatures.

                Comment


                  #9
                  Re: dead samsung 940bw

                  Originally posted by blasteroo View Post
                  I've checked the FH602 and FH601 fuses for continuity with a multimeter
                  and it seems to be ok.
                  I don't recommend using continuity as a good way to reliably see if a fuse is good or not. A good fuse should measure less than 1.0 ohms.

                  Some multimeters will beep continuous if the resistance is less than 1800 ohms. No fuse is good when the multimeter beeps and the resistance reading is 1795 ohms.

                  Could you assist me in testing the mosfets?
                  As I mentioned, the mosfets could be on the backside. A procedure for testing is at

                  https://www.badcaps.net/forum/showpo...4&postcount=19
                  Last edited by retiredcaps; 04-03-2012, 02:42 PM.
                  --- begin sig file ---

                  If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

                  We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

                  Please do not post inline and offsite as they slow down the loading of pages.

                  --- end sig file ---

                  Comment


                    #10
                    Re: dead samsung 940bw

                    Hi guys,

                    thank you so much for the help you provided.

                    I've decided to order a used powerboard from ebay, I've received and installed it today and the monitor came back to life.

                    All is good now.

                    It cost me around 19 euros and it solved the issue.

                    Thanks again for your selflessness and support.

                    Best,

                    Paulo

                    Comment


                      #11
                      Re: dead samsung 940bw

                      Hi Paulo,

                      Glad you got it up and running. Shame we didn't manage to get the olf board up and running.
                      Fixed so far : 1 Home cinema system, 16 LCD Monitors, 4 LCD TV's

                      How to resize your pictures guide click HERE
                      Retiredcaps Ideal post example click HERE

                      Comment

                      Working...
                      X