Another SAMSUNG 2493HM !

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  • Leonrsa
    Member
    • Mar 2014
    • 13
    • South Africa

    #61
    Re: Another SAMSUNG 2493HM !

    Originally posted by budm
    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?
    Correct, I do not have 24V out. I will have the cap measured. And clean off all the glue.

    Comment

    • Leonrsa
      Member
      • Mar 2014
      • 13
      • South Africa

      #62
      Re: Another SAMSUNG 2493HM !

      The cap was measured and checked out to be correct.
      I am however worried as I am getting a reading of 294VDC across the big cap - the testing point there indicates that it should be 380V, with nothing but the AC cable connected. Am I correct in assuming the problem appears to be on the Hot side? Which components should I check out?
      Ok, I connected all but the inverter board and measured 380V on the big cap, but still no 24V...
      Where should I go from here?
      Last edited by Leonrsa; 03-29-2014, 03:50 AM.

      Comment

      • Behemot
        Badcaps Legend
        • Dec 2009
        • 4845
        • CZ

        #63
        Re: Another SAMSUNG 2493HM !

        Originally posted by Leonrsa
        Yes they are Hitano. Are those bad caps?
        Yep and it does not seem you even have low-ESR caps. What series are they?

        Originally posted by budm
        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.
        It is not with low output so if there is some preventing the main PSU turning on, the PFC boost is not active, rendering aprox. 315 V rectified. When the PSU turns on the boost turns on as well. Possibly low input voltage, in the range of 220 V AC?
        Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

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        • Leonrsa
          Member
          • Mar 2014
          • 13
          • South Africa

          #64
          Re: Another SAMSUNG 2493HM !

          I will try and obtain the correct low-ESR caps, and replace them all(again). Will report back whether the problem has been solved...

          Comment

          • Behemot
            Badcaps Legend
            • Dec 2009
            • 4845
            • CZ

            #65
            Re: Another SAMSUNG 2493HM !

            Have you also replaced the small capacitors? Usually you have to be very carefoul, sometimes changing low-ESR for GP and vice versa breaks the circuit operation. If you did, I can have a look at my board what caps are in each position.
            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

              #66
              Re: Another SAMSUNG 2493HM !

              Check the DC voltage on PS_ON pin on the power supply when you toggle the power switch, it should toggle between <1 and > 2V. hat is your AC line voltage feeding the unit? at 220VAC, the voltage on the main filter cap should be around 310VDC when monitor is OFF.
              BTW, you have to have the monitor connected to running PC, otherwise it will go into standby mode in a few seconds if it does not see the video signal.
              Last edited by budm; 03-29-2014, 07:43 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

                #67
                Re: Another SAMSUNG 2493HM !

                Originally posted by Behemot
                Have you also replaced the small capacitors? Usually you have to be very carefoul, sometimes changing low-ESR for GP and vice versa breaks the circuit operation. If you did, I can have a look at my board what caps are in each position.
                I did replace all the small caps about 3 moths ago, but it seems that the caps were GP Hitano. The salesman assured me that they were the correct type for the job...

                I was under the impression that all the electrolytics had to be low-ESR?
                This is the list I obtained of caps to be replaced:
                Qty (2) 1000uf 35v
                Qty (1) 2200uf 10v
                Qty (1) 470uf 35v
                Qty (1) 1000uf 10v
                Qty (2) 10uf 50v
                Qty (1) 2.2uf 50v
                Qty (3) 47uf 50v
                Qty (1) 22uf 50v
                I will try and find caps of the make as listed on this thread:
                https://www.badcaps.net/forum/showthread.php?t=2280
                thanks for the help so far

                Comment

                • budm
                  Badcaps Legend
                  • Feb 2010
                  • 40746
                  • USA

                  #68
                  Re: Another SAMSUNG 2493HM !

                  So what DC voltage do you have at PSON pin?
                  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

                    #69
                    Re: Another SAMSUNG 2493HM !

                    Hi budm, I am afraid I did not measure the voltage on PSON as I have put the monitor aside until new caps arrive. I was informed that the caps I used (Hitano) as replacements 3 months ago were bad and not ESR. I have ordered the best (in South Africa) low-ESR caps I could find, being Rubycon YXF series, and will report back on progress.

                    Comment

                    • Behemot
                      Badcaps Legend
                      • Dec 2009
                      • 4845
                      • CZ

                      #70
                      Re: Another SAMSUNG 2493HM !

                      I got first sucessfull pacient, this tiem only caps were bloated. Still got two with blown primary, unable to bring them back to life
                      Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

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                      Comment

                      • Leonrsa
                        Member
                        • Mar 2014
                        • 13
                        • South Africa

                        #71
                        Re: Another SAMSUNG 2493HM !

                        PSON, Off - 0.12V, On - 3,2V
                        Replaced caps, still no image. Blue light comes on. Can someone please suggest the way forward?

                        Comment

                        • budm
                          Badcaps Legend
                          • Feb 2010
                          • 40746
                          • USA

                          #72
                          Re: Another SAMSUNG 2493HM !

                          You have PS_ON bu the PFC Voltage booster is still not working, PFC circuit section will need to troubleshoot next.
                          Last edited by budm; 04-01-2014, 11:12 AM.
                          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

                            #73
                            Re: Another SAMSUNG 2493HM !

                            Budm you sure? The booster is off when only SB supply runs, with aprox. 315 V DC rectified.
                            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

                              #74
                              Re: Another SAMSUNG 2493HM !

                              In standby mode with 220VAC input, the VDC on the filter cap is about 220VAC X 1.414 = 311VDC. When PS_ON is applied, the PFC Voltage booster will kick in to boot the voltage to about 360~400VDC range. He indicated that he has 292VDC on the cap which lower than it should be unless his line voltage is <220VAC.
                              Last edited by budm; 04-01-2014, 11:53 AM.
                              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

                                #75
                                Re: Another SAMSUNG 2493HM !

                                What else than some undervoltage may that be? Where else would the power go when the boost is not active? It would have to be burned somewhere, he did not indicated somethig is heating in it…
                                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

                                  #76
                                  Re: Another SAMSUNG 2493HM !

                                  The only load it has is the standby power supply. He needs to find out first what is his AC voltage is, if it is 220VAC, then next place to check will be that main filter cap, check it capacitance and the AC ripple on 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

                                  Comment

                                  • Behemot
                                    Badcaps Legend
                                    • Dec 2009
                                    • 4845
                                    • CZ

                                    #77
                                    Re: Another SAMSUNG 2493HM !

                                    Oh yeah, good point with the capacitance, non-true RMS voltmeters won't read amplitude
                                    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

                                      #78
                                      Re: Another SAMSUNG 2493HM !

                                      I use FLUKE with T.R.M.S.
                                      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

                                        #79
                                        Re: Another SAMSUNG 2493HM !

                                        On the other hand it won't tell you capacitor may be bad if you don't have ESR meter…while El Cheapo meter would at least indicate.
                                        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

                                          #80
                                          Re: Another SAMSUNG 2493HM !

                                          Originally posted by budm
                                          In standby mode with 220VAC input, the VDC on the filter cap is about 220VAC X 1.414 = 311VDC. When PS_ON is applied, the PFC Voltage booster will kick in to boot the voltage to about 360~400VDC range. He indicated that he has 292VDC on the cap which lower than it should be unless his line voltage is <220VAC.
                                          I found the following...
                                          Line voltage - 205VAC
                                          450V Cap - Standby - 290VDC
                                          - On - 390VDC
                                          Seems to be OK

                                          Comment

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