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Samsung UE49KS7000SXXH - No standby light

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    #41
    Re: Samsung UE49KS7000SXXH - No standby light

    can you trace that diode back? the dark green is the trace, see what it leads to.

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      #42
      Re: Samsung UE49KS7000SXXH - No standby light

      maybe check those 2 transistors on that heatsink.

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        #43
        Re: Samsung UE49KS7000SXXH - No standby light

        I'm looking at a picture of a similar board but it isn't very clear to see, not focused.

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          #44
          Re: Samsung UE49KS7000SXXH - No standby light

          .
          Last edited by nomoresonys; 07-28-2022, 10:52 AM.

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            #45
            Re: Samsung UE49KS7000SXXH - No standby light

            Originally posted by nomoresonys View Post
            I'm looking at a picture of a similar board but it isn't very clear to see, not focused.
            Image of the board.. if something is causing diode to get shorted, do we need to look before diode or after?

            That diode and one next to it (second adn third diode) are connected to the transformer pin. I guess that in the middle is the transformer? Another two diodes are connected to the oppsoite transformer pin
            Attached Files
            Last edited by B0r1s; 07-28-2022, 11:00 AM.

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              #46
              Re: Samsung UE49KS7000SXXH - No standby light

              looks like it feeds to CM891, maybe check that cap.

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                #47
                Re: Samsung UE49KS7000SXXH - No standby light

                you were getting 390 at the big cap, I think that means the transformer is ok.

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                  #48
                  Re: Samsung UE49KS7000SXXH - No standby light

                  a diode that failed from reverse voltage in excess of the breakdown voltage of the diode will tend to fail to a short, while one that failed from excessive forward current leading to overheating will tend to fail open, but that is not guaranteed.

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                    #49
                    Re: Samsung UE49KS7000SXXH - No standby light

                    So short can happen if 60+ voltage (SB560 is 60v) come to the cathode (-) of the diode?
                    Last edited by B0r1s; 07-28-2022, 12:21 PM.

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                      #50
                      Re: Samsung UE49KS7000SXXH - No standby light

                      yes I believe so.

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                        #51
                        Re: Samsung UE49KS7000SXXH - No standby light

                        in many cases fluctuating voltages have to do with faulty caps, did you check that cap relating to that diode?

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                          #52
                          Re: Samsung UE49KS7000SXXH - No standby light

                          check sa803 and sa805 and dm801, dm803.
                          Last edited by nomoresonys; 07-28-2022, 12:56 PM.

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                            #53
                            Re: Samsung UE49KS7000SXXH - No standby light

                            All 4 caps are on the shorted diode path, plus sign of caps are on that line.
                            What to test on it? Voltage or? I need to solder diode back before testing it with power on?
                            Attached Files

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                              #54
                              Re: Samsung UE49KS7000SXXH - No standby light

                              hell I would just check all the resistors, there's a handy chart, just google resistor chart or sum such.

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                                #55
                                Re: Samsung UE49KS7000SXXH - No standby light

                                I think just start with resistance check, ohm mode, tv UNPLUGGED from power, check all 4.

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                                  #56
                                  Re: Samsung UE49KS7000SXXH - No standby light

                                  from what I understand, it isn't a good idea to power on a tv with any diodes out of place.

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                                    #57
                                    Re: Samsung UE49KS7000SXXH - No standby light

                                    some use a dim bulb tester, it helps to save parts from blowing up or shorting out, easy to make, lots of how tos on youtube.

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                                      #58
                                      Re: Samsung UE49KS7000SXXH - No standby light

                                      I'm facing a repair that has the same exact description, did you ever find out what was wrong?

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                                        #59
                                        Re: Samsung UE49KS7000SXXH - No standby light

                                        Yes, one of the connections from big transformator in the centre of the board was broken i guess. I removed solder from all these connections and added new solder at these spots, and it's working after that. There is a video on youtube, some guy fixed his samsung tv with reflowing these spots but cant find it now.

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                                          #60
                                          Re: Samsung UE49KS7000SXXH - No standby light

                                          So you couldn't be bothered to come back and type a sentence that you fixed it by reflowing the solder joints, you are no more important than the rest of us, right?

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