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    #1

    Samsung 215tw still dead :(

    Got this monitor from somone who had evidently tried to repair it. The caps on the powerboard were already replaced with Sanyo WX. The fuse was blown and i replaced it with a new one of same value as the old one. The monitor would then blink the back light on and off again.

    Same powerboard as this thread https://www.badcaps.net/forum/showthread.php?t=11012

    Searched for forum threads on the issue and found another thread where it was concluded it might be due to shorts at the CCFL tubes. Took the thing apart and sure enough, a big scorch mark at the upper CCFL assembly. I shortened the leads a tad and resoldered them. Put on some heatshrink to isolate the ends.

    Now the backlight works however still no picture, doesnt say samsung or anything else on it. If i have the monitor hooked to a computer it will show the EDID info on the computer. While hooked up the backlight will turn on and then after a few seconds turn off again as if it goes to powersave mode or similar. If its not hooked up the backlight will stay on for much longer.

    Im starting to think its a logic board issue of some kind, or could it be the caps on the powerboard are too good/bad (ESR/Ripple wise) compared to originals?

    I will add some pics later if noone can come up with anything else i could check. Just need to charge batteries of camera, only have semi bad pics atm.
    Last edited by digge; 05-30-2011, 12:20 PM.
    Tags: None
    #2
    Re: Samsung 215tw still dead

    Try turning on the computer on in the safe mode,see if anything changes
    Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

    Comment

      #3
      Re: Samsung 215tw still dead

      I would check the transformers had this issue on a 215t
      turned out to be top one of the six

      Comment

        #4
        Re: Samsung 215tw still dead

        Originally posted by sabre504 View Post
        I would check the transformers
        Picture of secondaries for reference

        http://lcdparts.net/TransformerDetai...ProductID=3355
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          #5
          Re: Samsung 215tw still dead

          So you think it might be the transformers? But if it was wouldn't it turn of the backlight when no computer connected as well as when connected?

          And what would be a good way to check them?
          Last edited by digge; 05-30-2011, 01:24 PM.

          Comment

            #6
            Re: Samsung 215tw still dead

            Mine would stay on for a while then flicker and shut off

            Do a resistance test between pins S1 and S2 should be approx 950 ohm

            See pics
            Attached Files

            Comment

              #7
              Re: Samsung 215tw still dead

              Originally posted by digge View Post
              Got this monitor from somone who had evidently tried to repair it. The caps on the powerboard were already replaced with Sanyo WX.
              I had a customer give me two identical monitors that had caps replaced by them. They turned out to not have all been replaced. I took caps off one by one and replaced them until my monitors powered back up. Turned out to be the startup caps on the 5v standby.

              Also I have a Hyundai 24inch monitor with similar issues to yours. I have not checked if it is due to a short at all. But I know those hyundai's have logic board issues.

              Comment

                #8
                Re: Samsung 215tw still dead

                Originally posted by sabre504 View Post
                Mine would stay on for a while then flicker and shut off

                Do a resistance test between pins S1 and S2 should be approx 950 ohm

                See pics
                That is not the same ones i have on my board. Mine have only 5 pins total.

                Ill attach more pictures below, hope that helps any.
                Attached Files

                Comment

                  #9
                  Re: Samsung 215tw still dead

                  Please explain: dose your monitor power led indicate a signal [green or blue light] when the computer is posting, and it indicates no signal [amber led ] when it gets into the operating system? Or did I misunderstand your problem?
                  Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

                  Comment

                    #10
                    Re: Samsung 215tw still dead

                    Originally posted by digge View Post
                    That is not the same ones i have on my board. Mine have only 5 pins total.

                    Ill attach more pictures below, hope that helps any.

                    Good focused pictures are ALWAYS a help. In the photo, measure resistance across the points outlined in yellow. You may be able to do your measurements on top of the board, otherwise you'll have to scrape off the white adhesive. Also, measure the other 3 transformers on the other side the same way.

                    Since you say there was a scorch mark in the upper CCFL assembly, I'm assuming the wiring was shorting out? If the transformer powering that assembly checks good, then check all components connected to that transformer for shorts.

                    If you have a spare ccfl, then try substituting it for the one that was shorting out.
                    Attached Files
                    Last edited by jetadm123; 05-31-2011, 11:37 AM.

                    Comment

                      #11
                      Re: Samsung 215tw still dead

                      Originally posted by digge View Post
                      Mine have only 5 pins total.
                      I *think* the secondaries on this inverter transformer are the two feeding into the blue caps.
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                        #12
                        Re: Samsung 215tw still dead

                        Originally posted by alexanna View Post
                        Please explain: dose your monitor power led indicate a signal [green or blue light] when the computer is posting, and it indicates no signal [amber led ] when it gets into the operating system? Or did I misunderstand your problem?
                        Didnt try it during post yet. What i tried is not connected to compute = always blue and connected to computer = always blue i think, i will restest and make sure. Difference was that when connected to computer the backlight would go of quite soonish, while not connected it would stay lit for much longer.

                        Comment

                          #13
                          Re: Samsung 215tw still dead

                          Originally posted by jetadm123 View Post
                          Good focused pictures are ALWAYS a help. In the photo, measure resistance across the points outlined in yellow. You may be able to do your measurements on top of the board, otherwise you'll have to scrape off the white adhesive. Also, measure the other 3 transformers on the other side the same way.

                          Hmmm... looking a little more closely, it looks like one of the test points (the one without adhesive over it) MAY NOT be connected to anything. Try putting one test probe on the point with adhesive and test the other pins of the transformer with the other probe. Pin 1 (lower left) of the transformer appears connected to ground.

                          Comment

                            #14
                            Re: Samsung 215tw still dead

                            Looks like there is a scorch mark under one of the transformers
                            Attached Files
                            Last edited by sabre504; 05-31-2011, 12:31 PM.

                            Comment

                              #15
                              Re: Samsung 215tw still dead

                              As i remember on mine and on the neovo i did (used these transformers)

                              The 2 yellow areas were the secondaries (Think)
                              Attached Files

                              Comment

                                #16
                                Re: Samsung 215tw still dead

                                Originally posted by jetadm123 View Post
                                Good focused pictures are ALWAYS a help. In the photo, measure resistance across the points outlined in yellow. You may be able to do your measurements on top of the board, otherwise you'll have to scrape off the white adhesive. Also, measure the other 3 transformers on the other side the same way.

                                Since you say there was a scorch mark in the upper CCFL assembly, I'm assuming the wiring was shorting out? If the transformer powering that assembly checks good, then check all components connected to that transformer for shorts.

                                If you have a spare ccfl, then try substituting it for the one that was shorting out.
                                Measured all of them, yellow marked in your pic. Gives no connection on any of them. My dmm only goes to 20M but im guessing its not supposed to be higher then that?

                                Dont have any extra tubes to try with, but at least the short should be fixed since my fix made the failsafe stop turning the backlight of at least?
                                Last edited by digge; 05-31-2011, 12:44 PM.

                                Comment

                                  #17
                                  Re: Samsung 215tw still dead

                                  Supposed to be ~1k. Either your transformers have failed open (but that's a no since your backlights work) or they have a different pinout.
                                  Originally posted by PeteS in CA
                                  Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
                                  A working TV? How boring!

                                  Comment

                                    #18
                                    Re: Samsung 215tw still dead

                                    Originally posted by sabre504 View Post
                                    As i remember on mine and on the neovo i did (used these transformers)

                                    The 2 yellow areas were the secondaries (Think)
                                    On those pins i measure about 900-910 ohms on all but the one where the suspected scorch is, that one measures 855ohms.

                                    Comment

                                      #19
                                      Re: Samsung 215tw still dead

                                      Turned out the same on mine
                                      Either bad wiring on the CCFL have caused transformer to start to fail or
                                      vice versa .
                                      Without a spare tube the only option i can suggest is a new trans or a good second hand one

                                      Comment

                                        #20
                                        Re: Samsung 215tw still dead

                                        Originally posted by digge View Post
                                        On those pins i measure about 900-910 ohms on all but the one where the suspected scorch is, that one measures 855ohms.
                                        PlainBill suggests that these inverter transformers should be within 3% of each other. Details at

                                        https://www.badcaps.net/forum/showpo...7&postcount=18

                                        So 900 x 0.97 = 873 ohms.

                                        This suggests the inverter transformer is out of spec and bad.
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