Another SAMSUNG 2493HM !

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  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA

    #41
    Re: Another SAMSUNG 2493HM !

    Vcc at the IC pin is 12.48VDC?
    Per post 23:
    "C) checked the operation of the MC33067P ICM801
    pin 14 was always high and pin 12 alway low...check the oscillator (pin 2 ) and their was no oscillations there, so I started looking at reasons for not startup of the IC in the datasheet...
    pin15 12V was ok (power supply)"
    If I rememember corectly, it should be around 15VDC.
    By the way, which schematic diagram you are using?
    The diagram of the 192A is real close to 195A, only the designators are not the same, but the connections wise are the same.
    Attached Files
    Last edited by budm; 08-07-2013, 01:49 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

    • Behemot
      Badcaps Legend
      • Dec 2009
      • 4845
      • CZ

      #42
      Re: Another SAMSUNG 2493HM !

      I looked into datasheet of the MC33067P and it says 20 V, but reading it carefoully reveals it is *maximum* ratings

      I more like read old threads because what I have found, there is only diagram for another version of this board and it seems there are some differences.

      As for the oscillation, is it safe to just wire o-scope to that? McEugene had double separation transformer for that. All I have at my disposal is 2kVA mains separation transformer.
      Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

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      • budm
        Badcaps Legend
        • Feb 2010
        • 40746
        • USA

        #43
        Re: Another SAMSUNG 2493HM !

        The board you are working on should be connected to the Isolation transformer so the primary side of the primary side will be floated. The scope can then be connected directly to the AC outlet.
        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

        • Behemot
          Badcaps Legend
          • Dec 2009
          • 4845
          • CZ

          #44
          Re: Another SAMSUNG 2493HM !

          Pin 12 (drive output B) is high (11,5 V or so), pin 14 (drive output A) is low (under 0,3 V). Pin 10 is 0 V.

          Here are shots from pin 2 (osc) and pin 10 (fault).

          I think the driver is working fine, isn't it? Unfortunatelly I cannot directly connect my scope to the SMPS transformer primary as it is CAT I/300 V max. But if the driver circuit is OK and transistors are being driven, than I think there is only one conclusion - transformer winding is shorted.
          Attached Files
          Last edited by Behemot; 08-08-2013, 11:29 AM.
          Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

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          Hardware Insights - power supply reviews and more!

          Comment

          • Behemot
            Badcaps Legend
            • Dec 2009
            • 4845
            • CZ

            #45
            Re: Another SAMSUNG 2493HM !

            OK those images are useless, I know These are DC coupling from pin 14, the same is on pin 12 just on lower potential. So far this is OK I think, right? Saw tooth wave, that seems OK to me. It goes well all the way to resonant transformer primary legs.

            On the other side of resonant transformer, I got this output on the second image. Not sure, should it be driven this way? I find it somewhat difficult to drive 500V MOSFET with 50 mV pulses, right??
            Attached Files
            Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

            Exclusive caps, meters and more!
            Hardware Insights - power supply reviews and more!

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            • Behemot
              Badcaps Legend
              • Dec 2009
              • 4845
              • CZ

              #46
              Re: Another SAMSUNG 2493HM !

              I am taking appart that old HP P1130 CRT which died and besides all the huge semiconductor, nice caps and lot of non-ferrous metals I found this tunable 1:1 transformer (it has worm core which you can move left and right) so I think I can make sepparation transforer out if of to measure primary of the transformer directly, whaddaya think? I can set it the way basically the whole core is on one side.
              Attached Files
              Last edited by Behemot; 08-10-2013, 07:39 PM.
              Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

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              Hardware Insights - power supply reviews and more!

              Comment

              • Behemot
                Badcaps Legend
                • Dec 2009
                • 4845
                • CZ

                #47
                Re: Another SAMSUNG 2493HM !

                Do you think it's worth a shot? I don't want to blast my new O-scope off…
                Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

                Exclusive caps, meters and more!
                Hardware Insights - power supply reviews and more!

                Comment

                • the_raver514
                  New Member
                  • Mar 2013
                  • 5
                  • canada

                  #48
                  Re: Another SAMSUNG 2493HM !

                  hi.

                  i had this exact model of monitor to repair for a Customer. you know what... the problem was exactly that same resistor... color code is red red silver gold wich is 0.22 ohm, did the replacement and yes it did revive the monitor! always keep faith even when youre desperate...

                  Comment

                  • the_raver514
                    New Member
                    • Mar 2013
                    • 5
                    • canada

                    #49
                    Re: Another SAMSUNG 2493HM !

                    lol sorry wrong thread

                    Comment

                    • Leonrsa
                      Member
                      • Mar 2014
                      • 13
                      • South Africa

                      #50
                      Re: Another SAMSUNG 2493HM !

                      Hi, I am new to the forum so forgive (or reprimand) me if I am out of line!
                      I have the same dark screen but an image is visible via the torch test. I will be replacing the 2 470uF caps on the inverter board and report back. The caps on the power supply board has been replaced 3 months ago, but the problem came back...

                      Comment

                      • Behemot
                        Badcaps Legend
                        • Dec 2009
                        • 4845
                        • CZ

                        #51
                        Re: Another SAMSUNG 2493HM !

                        Clean that bloody glue on the power board immediatelly otherwise over time you will only add to the number of people with blown power supply unable to fix it. After that replace all the bad-brand caps (not only the ones obviously bad) with quality ones.
                        Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

                        Exclusive caps, meters and more!
                        Hardware Insights - power supply reviews and more!

                        Comment

                        • Leonrsa
                          Member
                          • Mar 2014
                          • 13
                          • South Africa

                          #52
                          Re: Another SAMSUNG 2493HM !

                          I replaced the 2 caps and cleaned off the glue. The monitor now seems to be completely dead. No image using the torch test, and obviously no backlighting. Only the glowing blue light...

                          Comment

                          • Behemot
                            Badcaps Legend
                            • Dec 2009
                            • 4845
                            • CZ

                            #53
                            Re: Another SAMSUNG 2493HM !

                            Is the polarity OK?
                            Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

                            Exclusive caps, meters and more!
                            Hardware Insights - power supply reviews and more!

                            Comment

                            • budm
                              Badcaps Legend
                              • Feb 2010
                              • 40746
                              • USA

                              #54
                              Re: Another SAMSUNG 2493HM !

                              @leonrsa: post pictures of your boards please.
                              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

                              • Leonrsa
                                Member
                                • Mar 2014
                                • 13
                                • South Africa

                                #55
                                Re: Another SAMSUNG 2493HM !

                                I hope these are clear enough.
                                Attached Files

                                Comment

                                • Behemot
                                  Badcaps Legend
                                  • Dec 2009
                                  • 4845
                                  • CZ

                                  #56
                                  Re: Another SAMSUNG 2493HM !

                                  Looks to me like (s)Hitano caps.
                                  Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

                                  Exclusive caps, meters and more!
                                  Hardware Insights - power supply reviews and more!

                                  Comment

                                  • budm
                                    Badcaps Legend
                                    • Feb 2010
                                    • 40746
                                    • USA

                                    #57
                                    Re: Another SAMSUNG 2493HM !

                                    Check the capacitance of that rectangular blue cap (CM812). You still have quite a bit of glue on the components, especially the dark brown glue one (some of the glue did not turn dark brown yet).
                                    This will happen when glue gets worst:
                                    https://www.badcaps.net/forum/showthread.php?t=34692
                                    Last edited by budm; 03-28-2014, 04:26 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

                                    • Leonrsa
                                      Member
                                      • Mar 2014
                                      • 13
                                      • South Africa

                                      #58
                                      Re: Another SAMSUNG 2493HM !

                                      Originally posted by Behemot
                                      Looks to me like (s)Hitano caps.
                                      Yes they are Hitano. Are those bad caps?

                                      A search of the list of bad caps on this forum for Hitano came up blank...
                                      It did come up on the good caps list though.
                                      Last edited by Leonrsa; 03-28-2014, 10:56 PM.

                                      Comment

                                      • Leonrsa
                                        Member
                                        • Mar 2014
                                        • 13
                                        • South Africa

                                        #59
                                        Re: Another SAMSUNG 2493HM !

                                        Originally posted by budm
                                        Check the capacitance of that rectangular blue cap (CM812). You still have quite a bit of glue on the components, especially the dark brown glue one (some of the glue did not turn dark brown yet).
                                        This will happen when glue gets worst:
                                        https://www.badcaps.net/forum/showthread.php?t=34692
                                        Hi budm, quite difficult to scrape the glue off! Is there a way to soften or perhaps dissolve it?
                                        I have no way of measuring capacitance, should I replace the cap(CM812)?
                                        Incidently, the voltage on the big 450WV82uF cap is 292Volts. Is that within spec?

                                        Comment

                                        • budm
                                          Badcaps Legend
                                          • Feb 2010
                                          • 40746
                                          • USA

                                          #60
                                          Re: Another SAMSUNG 2493HM !

                                          I soften the glue with IP alcohol. 292V is on the low side, it should be close to 360~400VDC range, it sounds like the PFC Voltage booster circuit is not working. Your meter does not have capacitance measurement function? I would remove the cap then may take it to repair shop that may have cap meter to verify the value for you. If that cap is bad, you will not have 24V for running the inverter board, I assume that you do not have 24V at the inverter fuse?
                                          Last edited by budm; 03-28-2014, 11:09 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

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