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Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

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    #21
    Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

    When I got it opened, there was one bulb out, and two dim bulbs. I don't have any 900MM bulbs, so I soldered a lead on each end of a 840MM bulb for test purposes. I replaced the failed bulb with the new one and fired it up. They all lit. I pulled the jumper from CI806 and tried again. The lights still cut off after a second. At this point, I don't know if the modified bulb is still drawing too much current and sending the inverter section into protection or if there is another bulb causing the problem. I saw a youtube video where the maker of the video was able to determine which lamp was causing the problem on a differeent Samsung with a different configuration by probing something on the backside of the inverter. Looking at the IP board via the link to ShopJimmy that I posted earlier, do you see anywhere I could probe to look for an abnormality?
    Attached Files
    Last edited by johnboy1313; 06-19-2013, 05:52 AM.

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      #22
      Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

      Link to the video I was referring to.

      http://youtu.be/oE6K4xBVweA

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        #23
        Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

        If the bulbs are dim, it is more likely to be due to a bad transformer than a bad bulb.
        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.

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          #24
          Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

          Is there a test procedure?

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            #25
            Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

            Budm has a method for testing inverter output using old energy saving CFL:
            https://www.badcaps.net/forum/showthread.php?t=19987

            I have not personally done this but it looks like it may work.

            I am tempted at some point to make a high voltage multimeter jig for measuring CCFL inverter output voltages. It would need to measure up to 5kV.
            Last edited by tom66; 06-19-2013, 07:43 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.

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              #26
              Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

              There are four transformers on the IP board. The top three each power four lamps. The bottom one powers just two lamps with pins 2 and 3 jumpered. The top transformer was the questionable one. I swapped the top and bottom transformers this afternoon. All bulbs lit brightly but they still cut off after a second. I used this link to verify that the one transformer is definitely bad.

              http://www.lcdparts.net/TransformerD...ProductID=3991

              A new transformer is $25. I got on eBay and found a used IP board for $20 shipped. The seller has a no returns policy, but if need be, I can always pull one of the transformers from that board and put it in this one. I'll keep you posted.
              Last edited by johnboy1313; 06-24-2013, 09:05 PM.

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                #27
                Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

                For $20 for the board is pretty good deal, even if you get two good transformers out of it.
                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

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                  #28
                  Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

                  Once in a while, the entire board is cheaper than a single transformer. A no brainer decision and you can resell the good transformers.
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                  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.

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                    #29
                    Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

                    With the transformer removed, the backlights don't light at all. Can any of you tell from the pics if I can jumper somewhere to at least get the upper 12 bulbs to fire and stay lit? I'd like to at least see if there's anything else going on with this PSU.

                    http://www.shopjimmy.com/samsung-bn4...t-inverter.htm
                    Attached Files

                    Comment


                      #30
                      Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

                      The transformers are wired in series (primary to primary), so it's not possible to run it with a missing transformer. If you jumpered the primary across it would probably be like christmas lights without fuse bulb (another transformer or the inverter circuit would fail.)
                      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.

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                        #31
                        Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

                        thanks

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                          #32
                          Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

                          The new IP board arrived today. I put it in and the bulbs are still shutting off. All four transformers on the new board test good. Short of replacing every bulb in the panel, any ideas how I might be able to determine which bulb(s) is/are causing the shut down?

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                            #33
                            Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

                            The dim ones, assuming you have some still?
                            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


                              #34
                              Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

                              They all seem to be equally bright. I'll post a pic later this afternoon.

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                                #35
                                Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

                                Here's a pic. I really don't want to bypass the protection circuit on this new IP board. This is the best pic I could get before the lights shut off.
                                Attached Files

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                                  #36
                                  Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

                                  Looks very bright, is that normal?
                                  Also is one tube a little short?
                                  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


                                    #37
                                    Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

                                    I think it's just that the camera didn't have time to adjust to the light. See post #21 regarding the length of the one bulb.

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                                      #38
                                      Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

                                      It is possible the bulb is too short and this will stop it working properly.
                                      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


                                        #39
                                        Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

                                        You're probably right, though the resistance from the connector in the panel to the end of the bulb is exactly the same at each end as the normal bulbs. I might have to toss this one under the bench with the others until I can find another set with the correct bulbs in it. I don't want to pay for a new bulb just to have it show up broken or not fix the problem.
                                        Last edited by johnboy1313; 06-27-2013, 03:31 PM.

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                                          #40
                                          Re: Samsung LN40B630N1FXZA, brief backlight, power up chime, then nothing.

                                          Out of curiosity, does the circuit go into protection because the one (or more) bulb is different than the rest or because the entire assembly is abnormal?

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