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Please help Identifying this CCFL transformer and answering few questions

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    Please help Identifying this CCFL transformer and answering few questions

    Hello everyone,

    I am trying to repair a Samsung Syncmaster 2333SW. I need help in identifying a transformer, finding a replacement, and a couple of questions answered and I am hoping some of forum members will point me in the correct direction. I will post a picture of the CCFL transformer and the schematics of a board that is really close in design to what I am repairing. I cannot find a datasheet on the transformer so I do not know how to find an equivalent if there is such a thing. I am open to any suggestions on identifying this one and possible sources or replacements.

    I also have a few capacitor questions that I hope can be easily answered. I apologize if the following questions belong in another thread I am not sure if they will be considered off topic for computer monitor troubleshooting. If these questions are covered elsewhere in this forum I apologize but I could not find them.

    First, my only test equipment is a Fluke 26III which does test capacitance. I know I need more tools, hopefully I will have them in the future, but for now I have to make due.

    Why would a capacitor test at a much higher capacitance than what it is rated? I sometimes find electrolytic capacitors that do this but almost all the solid capacitors test at double their rating. I do not think it is the meter because new capacitors test in spec and this meter is regularly calibrated to ISO standards. (I borrow it from work when I need it.)

    I understand that to truly test a capacitor it must be removed from the circuit and an ESR meter should be involved. With that being said, when I start troubleshooting I like to test the capacitance on the different power busses to get an idea of what the board is “seeing”. Usually what I get is basically the sum capacitance of all the capacitors in parallel. Unless I see something physically wrong with these capacitors I usually will not bother with them. Sometimes I get no capacitance reading without the bus being shorted, does this mean that one or more of the parallel capacitors are bad or does it point to another component being bad or is it 50/50? In this same testing scenario I sometimes get readings that vary greatly, for example the reading goes from 600uF to 1100uF and back every few seconds and will not stabilize. Does this indicate bad capacitors or is it most likely caused by other devices in the circuit? (Trying to test this way may be wrong, but I want to avoid “fixing” or removing something that is not broken if possible.)

    I will grateful for any assistance, pointers or links that can be provided. I will be more than willing to answer any questions. I also want to say I really love all the great information on this site as it has helped me learn a lot and fix some things that would have went into the landfill.





    Attached Files

    #2
    Re: Please help Identifying this CCFL transformer and answering few questions

    First of all, what is the monitor not doing?
    I never trust testing capacitor still in the circuits, since it may have resistance circuits in parallel with the caps, that can give you wrong reading.
    Bad cap can look normal but can have high ESR.
    Did you do any resistance reading of the secondary widings of all the inverter transformers to see if one or two are way out of range (+/- 3%)?
    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


      #3
      Re: Please help Identifying this CCFL transformer and answering few questions

      This set has appeared before but possible with different boards and transformers.
      We can help a lot more if you please post good clear pictures of the whole chassis, and then pictures of each board, front and back and close up of connectors, (max resolution 2000x2000 and 2MB) using the manage attachments button, which is found by clicking "go advanced" under quick reply.

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

      Examples of what is needed
      https://www.badcaps.net/forum/attach...1&d=1290283049

      https://www.badcaps.net/forum/attach...7&d=1280167246

      It will be useful if you can say what the supposed fault was
      Please upload pictures using attachment function when ask for help on the repair
      http://www.badcaps.net/forum/showthread.php?t=39740

      Comment


        #4
        Re: Please help Identifying this CCFL transformer and answering few questions

        The fault is two seconds to black. The primary windings on both transformers are shorted. They read the same as putting the two multimeter leads together. I have used this forum (reading not posting) to fix other monitors doing this same thing. I realize there is most likely more wrong with it than just this but if I cannot find replacement for the transformers more troubleshooting will be a waste of everyone's time which I want to avoid.

        I posted the best pictures that the camera I have available could take. I am sorry the camera is crappy but it was all that I had to use. I can post pictures of the boards later if it will help but without working transformers I do not see the point.

        I really appreciate the quick responses and I apologize if I did not include enough information in my original post.

        Comment


          #5
          Re: Please help Identifying this CCFL transformer and answering few questions

          Primary should always read shorted. Secondary should be high ohms from 500 ohms to 5k ohms.
          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


            #6
            Re: Please help Identifying this CCFL transformer and answering few questions

            That reading is normal for primary because you are reading DC resistance (will be less than than one Ohm) not Reactive resistance that the drive circuits will see.
            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


              #7
              Re: Please help Identifying this CCFL transformer and answering few questions

              I knew the resistance should be low but it is less than 0.1 ohms. The meter with leads together reads 0.2 ohms and the primary's read 0.2 -0.3 ohms. Since the primary's are driven at ~25V this resistance seemed low to me which made me think they are bad. If this is a normal reading then I will have to go back to square one of my troubleshooting.

              Comment


                #8
                Re: Please help Identifying this CCFL transformer and answering few questions

                It is driven by 50~70KHz AC switching circuits. At that frequency, the inductive reactance will be very high.
                Please read this guide:
                https://www.badcaps.net/forum/showthread.php?t=10419
                Last edited by budm; 08-12-2012, 06:26 PM.
                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


                  #9
                  Re: Please help Identifying this CCFL transformer and answering few questions

                  I had read that guide before posting. I used that guide as best as I could to test the board with the tools I have. I just read back through it. It mentions very little about the primary windings, mostly it involves the secondary windings. The secondary windings were good, they had way less than a 3% difference. I suppose to truly test the primary windings you need a ring tester? I am not used to working with electricity at such high frequency, anything I normally work with would be considered shorted with 0.1 Ohms of resistance. This value is also 5 times (500%) lower than the example from the troubleshooting guide. That is why I assumed that the ones I have are bad. The good thing out of all of this is I have learned something new and know I have another tool to add to my wish list.

                  Comment


                    #10
                    Re: Please help Identifying this CCFL transformer and answering few questions

                    Originally posted by LDSisHere View Post
                    It mentions very little about the primary windings, mostly it involves the secondary windings.
                    In 2+ years of participation, I have never seen a bad primary winding on the inverter transformer. 100% of the time it is the secondary winding that is bad.

                    I suggest you start testing your ccfl lamps as per my guide.

                    Also, see budm's Inverter tester using old CFL

                    https://www.badcaps.net/forum/showthread.php?t=19987
                    --- 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.

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                    Comment


                      #11
                      Re: Please help Identifying this CCFL transformer and answering few questions

                      Thanks for the help guys. I thought I was at a dead end because I had a bad part that I could not replace, but I now still have hope that it will live again. I definitely learned something new and I have shown the world what assuming will do for you. I am going to start my troubleshooting over from the beginning and see what I can figure out. I am going to have to get an ESR meter, I know that. The more I read about them the more blind I feel working without one and I have a feeling that my tool set may be a big hindrance in proper troubleshooting. I have a very long wish list for tools / test equipment and a very teeny tiny budget as this is just a hobby. The help you guys provide is a great service, these forums have help me learn a tremendous amount about electronics and capacitors in particular.

                      The questions I was asking about the testing of capacitors in circuit were not about this project directly. I have several different dead devices that I am not sure if they are even worth attempting to fix by recapping. I now realize I just need to bite the bullet and get an ESR meter to better help me decide.

                      Comment


                        #12
                        Re: Please help Identifying this CCFL transformer and answering few questions

                        As a hobby I am not sure an ESR meter is the way to go - you have to save a lot of used caps to buy a meter and the results do not always seem to be conclusive . The caps still need to be removed to test properly and a lot of makes/series are known to be likely to be bad. Many problems are not even cap related but replacing them at the time can increase the life expectancy of the set. Some very basic tests can be done with a multimeter - you may find this link helpful
                        http://www.repairfaq.org/sam/captest.htm#cttcm
                        Please upload pictures using attachment function when ask for help on the repair
                        http://www.badcaps.net/forum/showthread.php?t=39740

                        Comment


                          #13
                          Re: Please help Identifying this CCFL transformer and answering few questions

                          Retiredcaps, thanks for the inverter tester link, I will work on making my own tester.
                          Selldoor, thanks for the link, there was a lot of information that I have not seen elsewhere and was very informative. I may give a home-brew ESR meter a shot as an experiment. If anyone has links like the ones posted so far in this thread for working with solid capacitors I would really appreciate it.

                          I understand your point that if you are going to the trouble of fixing a device that you might as well replace the capacitors and make it last a while. I am just trying to find the most time saving way to determine if what I am working is repairable. (I am sure everyone feels this way.) The dilemma I run into is troubleshooting devices with known defects. For example I have an original style Xbox360, which is notorious for having failure due to solder cracking, that has some bulging capacitors and I do not know its' history. If it only had a handful of caps like a monitor supply then I would not hesitate to just change them all and see if it works. However this 360 has 44 electrolytic capacitors, around 30 of them are “large” ones. If I was reasonably sure that changing caps would fix it like a normal mother board then I would not hesitate, but the Idea of replacing them all just to see if it may possibly work is less than appealing. For this kind of situation I would like to change only the truly “bad” caps leaving the old working ones to prove it could work, and then if it does work, a full proper recap could be done. It is my lack of experience and knowledge for working with caps in this kind of situation that makes me unsure how to proceed. I am thinking an ESR meter would help in this kind of situation as you are supposed to be able to do some checking of capacitors in circuit. I know that this is not ideal, but would it help someone separate working capacitors from dead bad ones, at least enough to see if a device may work and be worth recapping? What would other forum members do in a situation like this to see a device will work? (I am not asking for “help” fixing the Xbox, I am asking for help with generic device / capacitor troubleshooting strategy in situations like the one I described using the Xbox as an example.)

                          Comment


                            #14
                            Re: Please help Identifying this CCFL transformer and answering few questions

                            Originally posted by LDSisHere View Post
                            What would other forum members do in a situation like this to see a device will work? (I am not asking for “help” fixing the Xbox, I am asking for help with generic device / capacitor troubleshooting strategy in situations like the one I described using the Xbox as an example.)
                            Obviously having the "right" tools helps troubleshoot problems quickly and accurately. What selldoor is pointing out is that if you are a "one time" DIY fixer, it is cheaper to swap out all the caps versus buying an ESR meter.

                            If you plan to fix a lot of future electronics, then spending $70+ on an ESR meter is potentially justified.
                            --- 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 ---

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