Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

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  • tom66
    EVs Rule
    • Apr 2011
    • 32560
    • UK

    #1

    Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

    About 3 years ago I fixed an LE40A656 for my parents with the common bad capacitors issue.

    Now the TV exhibits another fault, which is rather odd. Essentially any bright part of the image will bleed vertically across the panel although it's more predominant near the top of the panel. Turning the contrast down below about 85 hides the lines except on the menus, which seems to have a fixed brightness.

    I have a theory that the panel itself might be aging, rather than this being a tab bonding issue. The bulbs emit UV light which might be damaging the pixel TFTs requiring a stronger or weaker drive voltage. Or it could be related to heat over time - perhaps temperature related.

    I am going to investigate changing the VGL voltage (this turns pixels off, I suspect it may be too marginal), if this is not possible I will try reducing AVDD.
    Last edited by tom66; 07-02-2014, 11:48 AM.
    Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
    For service manual, schematic, boardview (board view), datasheet, cad - use our search.
  • stj
    Great Sage 齊天大聖
    • Dec 2009
    • 30950
    • Albion

    #2
    Re: Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

    i'v seen ghosting / trailing too.
    i would check the panel for bad or missing bias voltages.

    Comment

    • tom66
      EVs Rule
      • Apr 2011
      • 32560
      • UK

      #3
      Re: Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

      Thing is the picture is OK mostly - only bright lines cause the bleeding. If you set the contrast low they never occur. Apparently the issue occurred slowly and got worse over time, which is interesting.
      Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
      For service manual, schematic, boardview (board view), datasheet, cad - use our search.

      Comment

      • martino
        Not so "senior"
        • Aug 2013
        • 997
        • canada

        #4
        Re: Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

        Pictures of fault,boards front/back,ID off all boards etc.. Do you have a DMM? Any knowledge of electrical/wood/metal? Cooking?.... lmao.........
        Proud owner of dozens of broken TV's and many,many,many boards.


        Our website and passion:http://hollenhundshepherds.com/

        Comment

        • stj
          Great Sage 齊天大聖
          • Dec 2009
          • 30950
          • Albion

          #5
          Re: Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

          lol

          Comment

          • tom66
            EVs Rule
            • Apr 2011
            • 32560
            • UK

            #6
            Re: Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

            Long delay in posting.
            Going to have a look at this thing soon.
            Found that increasing AVDD (by loading feedback point) made fault worse.
            Going to try decreasing it.
            Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
            For service manual, schematic, boardview (board view), datasheet, cad - use our search.

            Comment

            • cliff_hootarski
              Badcaps Veteran
              • Jul 2006
              • 411
              • USA

              #7
              Re: Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

              Too funny, Martino!

              Comment

              • debugger
                Member
                • May 2014
                • 47
                • usa

                #8
                Re: Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

                I have a LG LN40A630M with the same symptoms. It gets a decent picture with the contrast turned down. Do these pictures look like your fault.
                Attached Files

                Comment

                • tom66
                  EVs Rule
                  • Apr 2011
                  • 32560
                  • UK

                  #9
                  Re: Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

                  Yep, that's the same as what I'm seeing. Haven't had a chance to hook it up to a source properly yet.
                  Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                  For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                  Comment

                  • Flipk614
                    Member
                    • Oct 2014
                    • 12
                    • United states

                    #10
                    Re: Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

                    ...
                    Last edited by Flipk614; 10-06-2014, 09:44 AM. Reason: Delete post

                    Comment

                    • Flipk614
                      Member
                      • Oct 2014
                      • 12
                      • United states

                      #11
                      Re: Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

                      Okay here are some pictures of mine.

                      1-Tv right at startup
                      2-After about a minute in PC mode
                      3-Close up of lines in PC mode after 1 minute
                      4-Xbox guide Hdmi after 3-5 minutes
                      5-Cable after 3-5 minutes
                      6-Back of tv
                      7-Tcon board LJ94-02853
                      Attached Files

                      Comment

                      • debugger
                        Member
                        • May 2014
                        • 47
                        • usa

                        #12
                        Re: Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

                        Tom, Badcaps veteran truep told me he fixed a sony with similar problem, with a main bd.

                        Comment

                        • tom66
                          EVs Rule
                          • Apr 2011
                          • 32560
                          • UK

                          #13
                          Re: Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

                          Different fault, I think. These are panel faults.
                          Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                          For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                          Comment

                          • Alastair E
                            Chief Womble
                            • Mar 2013
                            • 1963
                            • U.K.

                            #14
                            Re: Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

                            Hey,--Tom.....

                            You know what you need to do.....

                            Take the set to a TV Repair shop! Haha!

                            Have you tried a T-Con out of curiosity.....?
                            TELEFIX

                            How PLASMA SCREENS WORK, X-SUS and Y-SUS what they do--
                            http://www.irf.com/technical-info/appnotes/an-1088.pdf
                            PLEASE DO NOT EMAIL ME PRIVATELY FOR REPAIR ADVICE. QUESTIONS BELONG ON THE FORUM!

                            Comment

                            • tom66
                              EVs Rule
                              • Apr 2011
                              • 32560
                              • UK

                              #15
                              Re: Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

                              Not going to bother with a t-con. I know it's panel related but maybe I can get some life out of it.
                              Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                              For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                              Comment

                              • debugger
                                Member
                                • May 2014
                                • 47
                                • usa

                                #16
                                Re: Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

                                A t-con did not fix my set.

                                Comment

                                • Shinju
                                  Badcaps Legend
                                  • Mar 2014
                                  • 1239
                                  • USA

                                  #17
                                  Re: Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

                                  Service menu, run the test patterns and see if this happens there.

                                  Comment

                                  • tom66
                                    EVs Rule
                                    • Apr 2011
                                    • 32560
                                    • UK

                                    #18
                                    Re: Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

                                    Can't do that on A656. But it is panel failure, no way for it to be anything else. After a few TVs, you can tell when a Samsung panel has died!
                                    Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                                    For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                                    Comment

                                    • Flipk614
                                      Member
                                      • Oct 2014
                                      • 12
                                      • United states

                                      #19
                                      Re: Samsung LE40A656 vertical line bleed, ideas about fix (panel ageing?)

                                      Tcon didn't help mine. Helped a little. I'm gonna tear it down again and check out the tabs this weekend with the help of component cooler and hair dryer. Any way you can rule out the bad panel. Still got my hopes up on this one. Hate to see it go.

                                      Comment

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