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    Samsung 40" LCD tv model LN40B610A5FXZA new problem

    Trying to keep this TV going for my sister. About a month ago I posted when the set would not turn on. See thread here:
    https://www.badcaps.net/forum/showthread.php?t=75358
    It seems to have an inverter or back light problem now.
    The TV turns on fine now but yesterday the top 1/3rd of the screen turned pink. At times the back light would flicker and then turn off, had sound and a flashlight test showed the pic was still there. Turning it off and on would bring back the back light.
    I picked it up today. Plugged it in and the top 1/3rd was indeed pink. I pulled the power plug a few times and the whole screen returned to normal, no pink. After a while it started to flicker then back light turned off. It did that a few times but it's been running flawlessly for a couple of hours now. Hard to figure out when it's working.
    Visually there are no signs of a problem. Transformers look normal. Tapping or pressing around on the board doesn't make it stop or start to flicker.
    Anyone have any thoughts or tips for where I might start looking?

    The power/inverter board is number BN44-00264A. The schematic is here: https://www.badcaps.net/forum/attach...3&d=1434074295

    #2
    Re: Samsung 40" LCD tv model LN40B610A5FXZA new problem

    If the transformers are all the same, I would first exchange the top transformer with one of the other ones, if the top is still pink I would start to suspect either a worn out ccfl or maybe a poor connection on the clips on the end of the lamps.

    Comment


      #3
      Re: Samsung 40" LCD tv model LN40B610A5FXZA new problem

      Thanks, R_J
      The pink went away on its own, before I had a chance to do anything and hasn't returned...yet. The back light hasn't shut off or flickered again or shown any sign of a problem for the past 4 hours. An intermittent somewhere, just have to wait for if it reappears I guess. Hoping it's not the back light.

      Comment


        #4
        Re: Samsung 40" LCD tv model LN40B610A5FXZA new problem

        I have seen poor connections in these panels before, you would need to get to the ccfl's and then remove the plastic covers that are over the ends of the lamps.

        Comment


          #5
          Re: Samsung 40" LCD tv model LN40B610A5FXZA new problem

          Originally posted by R_J View Post
          I have seen poor connections in these panels before, you would need to get to the ccfl's and then remove the plastic covers that are over the ends of the lamps.
          I was hoping any poor connection would be on the Power/Inverter board and preclude the need to open the panel. The TV has now been operating perfectly for over 9 hours, through power cycles and on/off commands with the remote.
          One thing I just discovered is the top 2 screws holding down the black connector that the Power/Inverter board plugs into were a little loose. Not sure if it would make any difference to the ccfl's on the other side but I tightened them up.

          Comment


            #6
            Re: Samsung 40" LCD tv model LN40B610A5FXZA new problem

            Damn, lasted about 17 hours then began flickering, no pink. I found if I pried up under the top of the Power/Inverter board I could make it flicker more or less to the point the back light turned itself off. I took the board out and cleaned up the edge connections that feed the ccfl's and re-soldered component connections in the area I was prying. Been on for over 8 hours with no flickering...here's hoping that was it.

            Comment


              #7
              Re: Samsung 40" LCD tv model LN40B610A5FXZA new problem

              Lasted over 24 hours this time. Took it back to my Sister's house. After turning it on the top of the screen was pink for about 30 seconds, then cleared up. I guess we'll see how long it lasts.

              Comment


                #8
                Re: Samsung 40" LCD tv model LN40B610A5FXZA new problem

                Sister's TV back light finally quit today.
                Took the panel apart. Found one of the tubes finally snapped. Two others glowed pink until they warmed up.
                I jumped in some tubes from a monitor to replace the defective ones as you can see in the pics.
                Can somebody suggest a source for replacements? They are 4.0mm X 900mm
                Attached Files

                Comment


                  #9
                  Re: Samsung 40" LCD tv model LN40B610A5FXZA new problem

                  https://www.badcaps.net/forum/attach...0&d=1558561106
                  How many of the lamps have blackened ends like that? Blackened = worn out lamps.
                  Never stop learning
                  Basic LCD TV and Monitor troubleshooting guides.
                  http://www.badcaps.net/forum/showthr...956#post305956

                  Voltage Regulator (LDO) testing:
                  http://www.badcaps.net/forum/showthr...999#post300999

                  Inverter testing using old CFL:
                  http://www.badcaps.net/forum/showthr...er+testing+cfl

                  Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                  http://s807.photobucket.com/user/budm/library/

                  TV Factory reset codes listing:
                  http://www.badcaps.net/forum/showthread.php?t=24809

                  Comment


                    #10
                    Re: Samsung 40" LCD tv model LN40B610A5FXZA new problem

                    Originally posted by budm View Post
                    https://www.badcaps.net/forum/attach...0&d=1558561106
                    How many of the lamps have blackened ends like that? Blackened = worn out lamps.
                    There are 3 or 4 that are blackened but not nearly as bad as that one.
                    I'd replace all 14 if it wasn't cost prohibitive. Only tube sources I've found so far want $20USD plus shipping each so wouldn't really be worth it. Going to keep looking for a cheaper source.

                    Comment


                      #11
                      Re: Samsung 40" LCD tv model LN40B610A5FXZA new problem

                      What do you think about converting the panel from CCFL to LED using this:
                      https://www.aliexpress.com/item/32844580758.html?storeId=2632040&spm=2114.12010612.8148356.59.57de7
                      The screen viewing area measures 870mm X 500mm
                      Since the LED strips are 500mm long I was thinking of mounting them vertically.
                      That would allow for 10 strips spaced in the horizontal, equating to 5 rows of 10 LEDs. Do you think 50 LEDs is enough light?
                      I would kill the CCFL power supply and pick up the inverter on/off, Dim and power for the LED inverter on the power/inverter board or use the included circuit board to manually adjust the back light brightness.
                      Be a cheap fix if it provides enough light output.
                      Worth trying?

                      Comment


                        #12
                        Re: Samsung 40" LCD tv model LN40B610A5FXZA new problem

                        For $28 is worth a try, you try arranging them to get even lights without the LCD glass in place first.
                        Never stop learning
                        Basic LCD TV and Monitor troubleshooting guides.
                        http://www.badcaps.net/forum/showthr...956#post305956

                        Voltage Regulator (LDO) testing:
                        http://www.badcaps.net/forum/showthr...999#post300999

                        Inverter testing using old CFL:
                        http://www.badcaps.net/forum/showthr...er+testing+cfl

                        Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                        http://s807.photobucket.com/user/budm/library/

                        TV Factory reset codes listing:
                        http://www.badcaps.net/forum/showthread.php?t=24809

                        Comment


                          #13
                          Re: Samsung 40" LCD tv model LN40B610A5FXZA new problem

                          https://www.badcaps.net/forum/showth...led+conversion

                          Comment


                            #14
                            Re: Samsung 40" LCD tv model LN40B610A5FXZA new problem

                            Thanks for that link. In all likelihood it will show 50 bright spots but I suppose it will be somewhat dependent on the type of lenses on the strips and the strip positioning and the backlight brightness setting. I'll post some pics after it's done.

                            Comment


                              #15
                              Re: Samsung 40" LCD tv model LN40B610A5FXZA new problem

                              Looks like in a lot of these conversions they don't need lenses, which makes sense because the original ccfl tubes don't have lenses.
                              Last edited by nomoresonys; 05-23-2019, 08:46 AM.

                              Comment


                                #16
                                Re: Samsung 40" LCD tv model LN40B610A5FXZA new problem

                                One example there's lots more. https://www.youtube.com/watch?v=MrX9Sw-ug64

                                Comment


                                  #17
                                  Re: Samsung 40" LCD tv model LN40B610A5FXZA new problem

                                  I've converted a few computer monitors. The strips had LEDs closely spaced to simulate the fluorescent tube using 5 LEDs per inch. Worked good.
                                  I think lenses become more of a necessity, to spread the light, when the LEDs are in a direct backlight configuration, are higher power and spaced few inches apart.
                                  Simulating the tube with LEDs surely works but takes more LEDs, more LEDs equal more points of failure. I expect that's why we don't see them in mass production.

                                  Comment


                                    #18
                                    Re: Samsung 40" LCD tv model LN40B610A5FXZA new problem

                                    Just coming back to close out this thread.
                                    I received the led strips and inverter about a month ago. Unfortunately the smoke got out of the MOSFET on the inverter a couple of minutes after it was powered on. The seller was excellent and sent a replacement right away. I installed it today. It's plenty bright but on certain screens you can see the leds, just a little bit...but it works.
                                    Attached Files

                                    Comment


                                      #19
                                      Re: Samsung 40" LCD tv model LN40B610A5FXZA new problem

                                      So it is the kit you bought in your post #11?
                                      Never stop learning
                                      Basic LCD TV and Monitor troubleshooting guides.
                                      http://www.badcaps.net/forum/showthr...956#post305956

                                      Voltage Regulator (LDO) testing:
                                      http://www.badcaps.net/forum/showthr...999#post300999

                                      Inverter testing using old CFL:
                                      http://www.badcaps.net/forum/showthr...er+testing+cfl

                                      Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                      http://s807.photobucket.com/user/budm/library/

                                      TV Factory reset codes listing:
                                      http://www.badcaps.net/forum/showthread.php?t=24809

                                      Comment


                                        #20
                                        Re: Samsung 40" LCD tv model LN40B610A5FXZA new problem

                                        Originally posted by budm View Post
                                        So it is the kit you bought in your post #11?
                                        Yes it is that kit.
                                        My original intent was to mount the strips vertically but they were too long.
                                        I thought where the leds are doubled up in the middle might have an adverse effect but it's not particularly noticeable.
                                        It was lucky that the 13 volt supply to the inverter section of the Samsung power supply board was fed through a jumper so it was easy to snip and connect the 13 volts to the LED inverter. I took the inverter on/off pin out of the power supply board connector and hooked it to the on/off of the led inverter. So the leds turn on/off with the set. I didn't connect the TV dim control to the led inverter. The led inverter uses an analog signal to control brightness and I didn't want to take a chance connecting it to the PWM dim control that the TV uses. I set the led brightness using the trim pot on the little control board included in the kit.
                                        Attached Files

                                        Comment

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