Samsung LN32A550 Backlight Issue

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • stith
    Member
    • Oct 2012
    • 24
    • usa

    #1

    Samsung LN32A550 Backlight Issue

    Hello and first of all thanks for reading this post. My LN32A550 P3F Samsung TV is having a backlighting issue.

    I was getting ready to watch a movie through HDMI. Everything was good and so I left the room. I come back about 5 minutes later, the screen is nearly completely faded out. There was nothing I could do to get the backlights to come on (as if power save had came on) through the remote or turning the TV off and on again.

    What I noticed was, only the top right corner was being slightly lit by the backlights. Everything else was black but there was still a picture on the LCD (static when I selected antenna input).

    I proceeded to the internet and eventually found these forums and these posts...

    "2 seconds to black trouble shooting"
    https://www.badcaps.net/forum/showthread.php?t=10419

    "Samsung LN32A550 P3F"
    https://www.badcaps.net/forum/showth...light=ln32a550

    So far I have...
    Taken the back off the LCD and examined the caps for bulges and other damages. Tested the transformer resistance on the inverter card and they all seem similar in value. Tested the fuses (on the inverter card and power board) and are OK. Tested for 24volts on the power to inverter connection and it's also OK.

    I'm not sure what to do now and help is appreciated. I'm thinking it could be a bad CCFL and I don't have access to a spare at the moment and not sure if there is a way to test this without having one.

    Thanks for your help!
    Last edited by stith; 10-06-2012, 08:11 PM.
  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA

    #2
    Re: Samsung LN32A550 Backlight Issue

    "What I noticed was, only the top right corner was being slightly lit by the backlights"
    That does not sound right, since the backlights will either be on or off. If you look at the back of the panel, do you see any lights glowing on the back side of the panel? Try looking at it in the dark room.
    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

    • stith
      Member
      • Oct 2012
      • 24
      • usa

      #3
      Re: Samsung LN32A550 Backlight Issue

      Here is an image of the screen. The camera takes a really long exposure and captures more light but the screen is not this bright. I can adjust the image to resemble how dark it really is. Also, I notice a high pitch squeal near that same corner on the back of the TV.
      Attached Files
      Last edited by stith; 10-07-2012, 07:27 AM.

      Comment

      • drpj23
        Badcaps Veteran
        • May 2012
        • 528
        • USA

        #4
        Re: Samsung LN32A550 Backlight Issue

        Could you take a long exposure of just the CCFl tubes?

        If the tubes are blackened significantly more than others, that can be a sign of bad tubes.

        The picture makes it seem only the top portion are lighting half way. When bulbs light half way that usually means not enough power is there. (Im also assuming the exposure setting made it really bright at the edge or side too).

        Comment

        • budm
          Badcaps Legend
          • Feb 2010
          • 40746
          • USA

          #5
          Re: Samsung LN32A550 Backlight Issue

          Can you post good clear pictures of the boards? There are more than one version/manufacturer of the same model.
          drpj23 may be correct about the power supply may not be supplying full voltage to the inverter board.
          The power supply has PFC Voltage booster, it may not be working.
          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

          • stith
            Member
            • Oct 2012
            • 24
            • usa

            #6
            Re: Samsung LN32A550 Backlight Issue

            Originally posted by budm
            Can you post good clear pictures of the boards? There are more than one version/manufacturer of the same model.
            drpj23 may be correct about the power supply may not be supplying full voltage to the inverter board.
            The power supply has PFC Voltage booster, it may not be working.
            Here are pictures of the two boards. If you need better pictures or zooms of portions of the board let me know and I can do that. I can work on getting a shot of the CCFLs only but it's a bit harder to get all the screens off and not damage them (that's more of a personal defect of mine that I like to destroy objects when taking them apart).

            If it could be the power supply, what should I test? I tested the volt at the connector to the inverter board and it came out to 24volts. Let me know what you think. Oddly, I might believe its either one of the two boards if anything.

            Thanks for the quick help guys!
            Attached Files

            Comment

            • budm
              Badcaps Legend
              • Feb 2010
              • 40746
              • USA

              #7
              Re: Samsung LN32A550 Backlight Issue

              OK, the 24V is OK then. Can I get the LCD panel number so I can look up the spec to see if the lamps inside are U shape or straight type since I do not see any lamp return wires back to the inverter board. I also do not see any ballast caps on the inverter board, that mean they are inside the panel assembly.
              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

              • stith
                Member
                • Oct 2012
                • 24
                • usa

                #8
                Re: Samsung LN32A550 Backlight Issue

                LN32A550 P3F is the LCD TV I have. I'm pretty sure the CCFL's are straight (took a look after taking the frame off and peeking behind the layers of panels). I believe the lamp return wires are the white connectors on the inverter board. 2 per connector.
                Attached Files
                Last edited by stith; 10-07-2012, 09:00 PM. Reason: attachments

                Comment

                • budm
                  Badcaps Legend
                  • Feb 2010
                  • 40746
                  • USA

                  #9
                  Re: Samsung LN32A550 Backlight Issue

                  I am not so sure how your lamps are setup inside your panel yet, that is why I need the spec to see, as you can see in the attached PDF of the two type of lamp setup: Straight and U-Shape setup. I still do not see any ballast caps any where on the inverter board or they may inside the PCB connected to the lamps.
                  http://s807.photobucket.com/albums/y...nt%20FLX-3210/
                  I need the panel number as printed on the sticker on the panel itself.
                  Attached Files
                  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

                  • stith
                    Member
                    • Oct 2012
                    • 24
                    • usa

                    #10
                    Re: Samsung LN32A550 Backlight Issue

                    I understand now. Here is a pic of the label.
                    Attached Files

                    Comment

                    • budm
                      Badcaps Legend
                      • Feb 2010
                      • 40746
                      • USA

                      #11
                      Re: Samsung LN32A550 Backlight Issue

                      Sorry, we need the sticker on the LCD panel, not the sticker for the model of the TV.
                      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

                      • stith
                        Member
                        • Oct 2012
                        • 24
                        • usa

                        #12
                        Re: Samsung LN32A550 Backlight Issue

                        Where is it located?

                        Comment

                        • budm
                          Badcaps Legend
                          • Feb 2010
                          • 40746
                          • USA

                          #13
                          Re: Samsung LN32A550 Backlight Issue

                          On the back of the LCD panel. Can you post the pictures of the whole backside of the TV so we can see all the board.
                          Example: http://s807.photobucket.com/albums/y...t=DSC02776.jpg
                          Last edited by budm; 10-08-2012, 09:16 AM.
                          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

                          • stith
                            Member
                            • Oct 2012
                            • 24
                            • usa

                            #14
                            Re: Samsung LN32A550 Backlight Issue

                            OK I think this will help. Thanks again for your quick help!
                            Attached Files

                            Comment

                            • budm
                              Badcaps Legend
                              • Feb 2010
                              • 40746
                              • USA

                              #15
                              Re: Samsung LN32A550 Backlight Issue

                              OK, let me Google it and see if the info is out there for this panel.
                              AU Opto T315HW01 Version 0.
                              Funny how Samsung does not use its own panel in its TV, but use the cheaper one by other manufacturer instead in their low end model.
                              Here it is:
                              Last edited by budm; 10-08-2012, 09:29 AM.
                              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

                              • stith
                                Member
                                • Oct 2012
                                • 24
                                • usa

                                #16
                                Re: Samsung LN32A550 Backlight Issue

                                Interesting information. But I'm not 100% sure what I should do with this or the next step of testing to do.

                                Comment

                                • budm
                                  Badcaps Legend
                                  • Feb 2010
                                  • 40746
                                  • USA

                                  #17
                                  Re: Samsung LN32A550 Backlight Issue

                                  Well, it does not show the lamps info.
                                  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

                                  • stith
                                    Member
                                    • Oct 2012
                                    • 24
                                    • usa

                                    #18
                                    Re: Samsung LN32A550 Backlight Issue

                                    Originally posted by budm
                                    Well, it does not show the lamps info.
                                    LOL yah I noticed that...

                                    What would be the probability that it's the Inverter or CCFLs or Power Supply?
                                    Last edited by stith; 10-08-2012, 09:44 AM. Reason: more questions

                                    Comment

                                    • tom66
                                      EVs Rule
                                      • Apr 2011
                                      • 32560
                                      • UK

                                      #19
                                      Re: Samsung LN32A550 Backlight Issue

                                      Originally posted by budm
                                      Funny how Samsung does not use its own panel in its TV, but use the cheaper one by other manufacturer instead in their low end model.
                                      I noticed this originally with older TVs. But newer Samsung TVs - even small 22" ones - seem to be going back to Samsung panels. I even got a look at a Vestel chassis (from Sienoki) and it had a Samsung panel in it - and it was a recent 32 inch TV (about 2 years old.) So I guess Samsung are bringing back their panels, that is good, as they are decent LCD screens (good picture quality.)
                                      Last edited by tom66; 10-08-2012, 09:51 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.

                                      Comment

                                      • budm
                                        Badcaps Legend
                                        • Feb 2010
                                        • 40746
                                        • USA

                                        #20
                                        Re: Samsung LN32A550 Backlight Issue

                                        The symptom he has looks like it does not get enough drive even thogh the inverter does get 24V feeding it, since it looks like ALL the lamps are halfway lit, it gotta be some thing common to all. I need to figure out how to properly test the inverter, and I still do not see any ballast caps yet.
                                        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

                                        Related Topics

                                        Collapse

                                        • Document Archive
                                          Samsung Galaxy Book 2 Notebook Specification for Upgrade or Repair
                                          by Document Archive
                                          This specification for the Samsung Galaxy Book 2 Notebook can be useful for upgrading or repairing a laptop that is not working. As a community we are working through our specifications to add valuable data like the Galaxy Book 2 boardview and Galaxy Book 2 schematic. Our users have donated over 1 million documents which are being added to the site. This page will be updated soon with additional information. Alternatively you can request additional help from our users directly on the relevant badcaps forum. Please note that we offer no warranties that any specification, datasheet, or download...
                                          09-07-2024, 05:50 AM
                                        • x_orange90_x
                                          Vizio E55-E1 bad backlights or bad inverter?
                                          by x_orange90_x
                                          I just got this tv today and it appeared to have no backlight on. After taking off the rear cover and checking again in the dark I can see that MAYBE one quadrant is lit.. But still it's quite dim. I was going to check the LEDs with my tester, and I found LED 1 and LED 2 + pins on the wire from the inverter, but I couldn't identify a ground. Nonetheless I tried using a mounting screw on the inverter board and also the chassis as ground but regardless my tester reads 300 which is what it reads when there is no voltage draw.

                                          I don't know how exactly to test the inverter itself. Is it...
                                          01-29-2025, 09:24 PM
                                        • max789
                                          Samsung UE48H6410 replaced Mainboard but backlights doesnt go on
                                          by max789
                                          Hello, I have a problem with my Samsung UE48H6410SSXZG with the main board BN41-02156A and the power board BN44-00709A. Everything seemed like this, the TV could no longer be switched on, the standby LED always flashed 5x2 times. Backlight was off and no sound from TV. Also made the flashlight test and there was no picture.

                                          I made the following tests:
                                          1. Disconnected the main board from Power Board = backlight works.
                                          2. Connected the main board and disconnected the T-Con = backlights does not work.

                                          So I ordered a main board from Ebay also BN41-02156A but from...
                                          01-18-2024, 06:56 AM
                                        • vincentedel
                                          Samsung SyncMaster 740n Phase Control Issue
                                          by vincentedel
                                          Hello,
                                          I'm having an issue with the Samsung 740n's phase control setting. When I use the automatic adjustment, it sets the value to around 54 (with a range of 0-100), and the picture looks clear and sharp. However, after some timeβ€”like after playing a gameβ€”the text starts to look blurry. When I auto-adjust again, it may increase the value to 80, and everything becomes sharp once more. Yet, after a while, whether it's a few hours or a day later, the same blurriness returns, and I have to adjust it again.

                                          I'm using the Samsung 740n monitor drivers instead of the default plug-and-play...
                                          04-22-2025, 12:33 AM
                                        • Manucsl
                                          QE65Q800TATXXC Samsung TV Issue
                                          by Manucsl
                                          Hello.

                                          My TV is a QE65Q800TATXXC Samsung TV.

                                          Issue : When you plug the 220V, voltages are OK on the power board and you can hear the click from the relay, but TV is not starting when power button is pressed. Red led is blinking when you press power button. But no images or sound ( Back-light is off )
                                          Then if you disconnect the cable from the main board to the power supply, the TV back-light turns on.
                                          Any ideas to check would be very appreciated 😊

                                          After reading some posts on this forum, I suspect an eeprom issue so I bought a CH341A to dump...
                                          02-19-2025, 07:47 AM
                                        • Loading...
                                        • No more items.
                                        Working...