Samsung Syncmaster T240 - Bad Inverter Transformer?

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • meths
    New Member
    • Jan 2013
    • 8
    • Scotland

    #1

    Samsung Syncmaster T240 - Bad Inverter Transformer?

    My monitor has developed the 2 seconds to black fault. I've never tried to fix anything like this before but thought I'd give it a go just for the fun of it rather than pay someone else to do it and you guys make it sound really easy.

    I removed the power board from the monitor on from a quick visual inspection all appears well with the capacitors.

    Testing the secondary coils on the inverter transformer give reading of 952 and 918. I've read that 3 or 4% variance is enough to suggest a faulty transformer but mine seems to be borderline. Other threads I've read on here show much more dramatic differences in the coils, e.g. 950 and 600.

    So I'm wondering:
    1) In a new Inverter Transformer would both coils measure 950 or will there always be a bit of variance?

    2) Is the difference in mine enough to suggest a faulty component?
  • retiredcaps
    Badcaps Legend
    • Apr 2010
    • 9271

    #2
    Re: Samsung Syncmaster T240 - Bad Inverter Transformer?

    Originally posted by meths
    So I'm wondering:
    1) In a new Inverter Transformer would both coils measure 950 or will there always be a bit of variance?

    2) Is the difference in mine enough to suggest a faulty component?
    Close enough for now until you rule out the lamps/wiring.

    2 seconds to black can be

    a) bad caps
    b) bad ccfls
    c) bad ccfl wiring (especially the return wiring)
    d) bad secondary windings on the inverter transformer

    More details starting with post #19 at

    https://www.badcaps.net/forum/showthread.php?t=10419

    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.

    --- end sig file ---

    Comment

    • meths
      New Member
      • Jan 2013
      • 8
      • Scotland

      #3
      Re: Samsung Syncmaster T240 - Bad Inverter Transformer?

      Thanks for the reply. I'll have a look at the CCFLs later but in the meantime here's a few pics of the board.
      Attached Files

      Comment

      • meths
        New Member
        • Jan 2013
        • 8
        • Scotland

        #4
        Re: Samsung Syncmaster T240 - Bad Inverter Transformer?

        Okay, so I've not got a spare CCFL to test with and I've not taken the panel apart to look at them so I did the following test:

        1) Plugged the bottom set of lights into the bottom connector (rightmost in the picture) and powered up. No image at all.

        2) Plugged the top set of lights into the bottom connector. No image at all.

        3) Plugged the top set of lights into the top connector. 2 seconds to black.

        4) Plugged the bottom set of lights into the top connector. 2 seconds to black.

        With my limited knowledge this suggests that it's likely that the CCFLs are fine as both gave exactly the same results and lit up in the top connector before going black. If one set was dodgy I'd have expected no light at all from it.

        When I noticed that the bottom connector didn't cause the lamps to light up at all I looked at the back of the pcb to try to see if there was anything up with it. It looks to me that power for this connector is routed through the secondary coil with lowest resistance (918) which seems to suggest that the inverter transformer is in fact the problem.

        So, what do you guys think? Have I solved the mystery?
        Attached Files

        Comment

        • retiredcaps
          Badcaps Legend
          • Apr 2010
          • 9271

          #5
          Re: Samsung Syncmaster T240 - Bad Inverter Transformer?

          Originally posted by meths
          It looks to me that power for this connector is routed through the secondary coil with lowest resistance (918) which seems to suggest that the inverter transformer is in fact the problem.

          So, what do you guys think? Have I solved the mystery?
          I can't tell from the picture, but try reflowing/resoldering all the joints regardless how they look in that section you highlighted in red.

          If that doesn't help, then the inverter transformer is the likely suspect.
          --- 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 ---

          Comment

          • retiredcaps
            Badcaps Legend
            • Apr 2010
            • 9271

            #6
            Re: Samsung Syncmaster T240 - Bad Inverter Transformer?

            A replacement is less than $4 USD + free shipping on ebay.

            http://www.ebay.com/sch/i.html?_from...-10160&_sop=15
            --- 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 ---

            Comment

            • retiredcaps
              Badcaps Legend
              • Apr 2010
              • 9271

              #7
              Re: Samsung Syncmaster T240 - Bad Inverter Transformer?

              I forgot to have you check those blue caps.

              With power off, measure the resistance of C301, C302 and C305. Also measure R302. Report all your readings.
              --- 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 ---

              Comment

              • meths
                New Member
                • Jan 2013
                • 8
                • Scotland

                #8
                Re: Samsung Syncmaster T240 - Bad Inverter Transformer?

                I can't get a reading on C301 and C302. My meter only has up to 2M range and it's showing 1. for those two.

                C305 shows 931 ohms and R302 shows 149.7k ohms.

                Comment

                • retiredcaps
                  Badcaps Legend
                  • Apr 2010
                  • 9271

                  #9
                  Re: Samsung Syncmaster T240 - Bad Inverter Transformer?

                  Originally posted by meths
                  I can't get a reading on C301 and C302. My meter only has up to 2M range and it's showing 1. for those two.

                  C305 shows 931 ohms and R302 shows 149.7k ohms.
                  Desolder C305 and remeasure the resistance. If it still reads 931 ohms, it is likely bad. These blue caps should read open circuit.

                  Even though the "top connector" works, you might as well measure those blue caps and verify they should read open circuit.

                  Check the color code of R302 and see if it matches your reading.
                  --- 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 ---

                  Comment

                  • meths
                    New Member
                    • Jan 2013
                    • 8
                    • Scotland

                    #10
                    Re: Samsung Syncmaster T240 - Bad Inverter Transformer?

                    So just to be clear, when the meter is showing 1 is that it reading open circuit?

                    I'll need to go and buy a soldering iron now I guess.

                    Comment

                    • newbie1
                      Badcaps Veteran
                      • Apr 2010
                      • 269

                      #11
                      Re: Samsung Syncmaster T240 - Bad Inverter Transformer?

                      Originally posted by retiredcaps
                      A replacement is less than $4 USD + free shipping on ebay.

                      http://www.ebay.com/sch/i.html?_from...-10160&_sop=15
                      I am inclined to agree with this course of action. However, i am not sure about the quickness of the shipping though.

                      Comment

                      • retiredcaps
                        Badcaps Legend
                        • Apr 2010
                        • 9271

                        #12
                        Re: Samsung Syncmaster T240 - Bad Inverter Transformer?

                        Originally posted by meths
                        So just to be clear, when the meter is showing 1 is that it reading open circuit?
                        "1" in the left hand side means out of range on a manual multimeter.
                        Last edited by retiredcaps; 03-11-2013, 07:36 PM. Reason: typo
                        --- 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 ---

                        Comment

                        • meths
                          New Member
                          • Jan 2013
                          • 8
                          • Scotland

                          #13
                          Re: Samsung Syncmaster T240 - Bad Inverter Transformer?

                          Thanks for all the help guys!!!

                          I ordered the inverter transformer from Hong Kong and bought a cheap 40w soldering set and I fixed the monitor tonight.

                          I've never soldered anything before and am quite pleased with my work - shiny joints and quite neat.

                          Now I need to go and find something else to solder...

                          Comment

                          • retiredcaps
                            Badcaps Legend
                            • Apr 2010
                            • 9271

                            #14
                            Re: Samsung Syncmaster T240 - Bad Inverter Transformer?

                            Originally posted by meths
                            I ordered the inverter transformer from Hong Kong and bought a cheap 40w soldering set and I fixed the monitor tonight.
                            Good fix for $4.
                            --- 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 ---

                            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
                            • soopacrucial
                              Samsung Syncmaster 740BF repair
                              by soopacrucial
                              Hi folks,

                              I'm new here and was wondering whether you might be kind enough to give me some advice on troubleshooting the following problem:

                              Quite a few years ago now, a couple of years from new, my Samsung Syncmaster 740BF LCD monitor starting playing up by making a buzzing noise and then the display would go blank. I seem to remember the blue power led would also go off when this happened but that I'm not 100% sure of. By pressing the power button I do remember I could at first get it working again but eventually the problem would come back. At the time I had read about...
                              10-29-2024, 02:40 PM
                            • Document Archive
                              Samsung Galaxy Book Ion NP930XCJ Notebook Specification for Upgrade or Repair
                              by Document Archive
                              This specification for the Samsung Galaxy Book Ion NP930XCJ 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 NP930XCJ boardview and NP930XCJ 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...
                              09-06-2024, 11:40 PM
                            • Document Archive
                              Samsung Galaxy Book Ion NP950XCJ Notebook Specification for Upgrade or Repair
                              by Document Archive
                              This specification for the Samsung Galaxy Book Ion NP950XCJ 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 NP950XCJ boardview and NP950XCJ 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...
                              09-06-2024, 11:40 PM
                            • Document Archive
                              Samsung Galaxy Book Ion NP950XCJ Notebook Specification for Upgrade or Repair
                              by Document Archive
                              This specification for the Samsung Galaxy Book Ion NP950XCJ 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 NP950XCJ boardview and NP950XCJ 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...
                              09-06-2024, 08:40 PM
                            • Loading...
                            • No more items.
                            Working...