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Samsung UN65JS9500 / BN44-00818A - no LED backlight

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    #41
    Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

    Originally posted by Joseph MARTIN View Post
    What reference ICM852 and ICM952
    Hi, are you asking what the manufacturer part number is?
    does it have the same markings as CM901?

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      #42
      Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

      The cm 901 is a capacitor which is located in the backlight cicuit. It simply plays the role of filtering.
      My question was: what is the reference of the cicrcuit cms ICM951 which controls the two MOSFETs QM951 and QM952. I don't find the datasheet of this circuit on the net. On this component it is marked S7422.

      Comment


        #43
        Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

        Originally posted by Joseph MARTIN View Post
        The cm 901 is a capacitor which is located in the backlight cicuit. It simply plays the role of filtering.
        My question was: what is the reference of the cicrcuit cms ICM951 which controls the two MOSFETs QM951 and QM952. I don't find the datasheet of this circuit on the net. On this component it is marked S7422.

        I haven't been able to figure out what manufacturer part number that is yet. I searched a lot of synchronous rectifier controller ICs but none seem to have that pinout. I also have looked at a bunch of other samsung power supply schematics and they don't use this same circuit.

        Anyone have ideas on this part?

        Comment


          #44
          Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

          The only information I can find is "S7422 SEM7422 New LCD Power Chip IC"

          It's likely to have the following pins but in what order?
          Supply voltage, Ground, Enable Input, Led Driver output, Over Voltage Protection, PWM and Current Sense inputs
          Willing to help but I'm no expert.

          Comment


            #45
            Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

            Originally posted by dick_barton View Post
            The only information I can find is "S7422 SEM7422 New LCD Power Chip IC"

            It's likely to have the following pins but in what order?
            Supply voltage, Ground, Enable Input, Led Driver output, Over Voltage Protection, PWM and Current Sense inputs
            I haven't taken the time to figure out the whole pinnout but it looks like gate drive A goes to pin1 and gate drive B goes to pin4 .

            Comment


              #46
              Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

              FYI, to close this out. I replaced the primary controller chip and FETs as well as the secondary FETS and obviously the fuse. When it powered up it was squealing which I assumed was running in current limit. I unplugged the LED driver board and the squealing went away. I already had another LED driver board from when my brother was trying to fix this. I swapped the other driver board in and the squealing went away and has been running great. Unfortunately I am not sure which LED driver was the original so I am not sure what caused the original power supply failure.

              Comment


                #47
                Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

                Can you share which IC you ended up using?

                Comment


                  #48
                  Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

                  SEM3110A
                  https://www.ebay.com/itm/254409159810

                  Comment


                    #49
                    Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

                    Also, which FETs are you referring to as the secondary ones?

                    Comment


                      #50
                      Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

                      Originally posted by silentkav View Post
                      Also, which FETs are you referring to as the secondary ones?
                      QM951 and QM952

                      Comment


                        #51
                        Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

                        what is the reference of the cicrcuit cms ICM951 which controls the two MOSFETs QM951 and QM952. I don't find the datasheet of this circuit on the net. On this component it is marked S7422.

                        Comment


                          #52
                          Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

                          So what happened at the end .Did you fix the problem or no .I asking because I have the same problem with the same tv ...

                          Comment


                            #53
                            Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

                            He said yes, after putting in new primary controller and fets and swapping out the led driver board in post #46.

                            Comment


                              #54
                              Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

                              Ok Tnx .I have the same problem but I have no time to chase parts .I would like to buy power supply board and hope it will work .Hope is not backlight gone because to replace backlight on this Tv is not easy.
                              Does anyone know any good services who can change the backlight or where i can buy. power board? Thanks ...

                              Comment


                                #55
                                Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

                                Well I see repair services there for powerboards, about 90 bux and up, have not used any of them personally, if it's bad backlights it will cost more for sure because it involves tearing it all the way down, some repair shops won't do it because it's very easy to break the panel:

                                https://www.ebay.com/sch/i.html?_fro...acat=0&_sop=15
                                Last edited by nomoresonys; 03-11-2021, 05:21 PM.

                                Comment


                                  #56
                                  Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

                                  I will try to buy new power supply because I check some mosfets and if I check some pins on it and heat sink screw is showing short also it’s short drain to source .
                                  So hope it’s only power supply not back lights also .
                                  Pins that goes from power supply also I have 5.5 v on pin 1 and 13 on pin 3 but no voltage at all on vdrive pins ...

                                  Comment


                                    #57
                                    Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

                                    Being a samsung it's probably wise to verify the backlights are good before replacing powerboard because bad backlights can damage powerboard.

                                    Comment


                                      #58
                                      Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

                                      That’s good idea but I don’t know how to check backlights on this particular tv .I can bring external power supply from work but i don’t have a info what voltage and how I can supply voltage to backlight

                                      Comment


                                        #59
                                        Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

                                        Hi my mates tv has got the same problem no backlights. Fuse blown mosfets blown and ic blown
                                        on psu.

                                        He has removed the glue of the ic but theres no ic part number- two questions

                                        1. Is it a SEM3110A ?( cannot find a datasheet to compare)
                                        2. Can it replaced by a ucc25600 ic?

                                        Thanks in advance

                                        Comment


                                          #60
                                          Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight

                                          Has anyone encountered problems with this board related to the optoisolators? the "EL1018" chips? My brother is doing the analysis, he thinks one of these is bad on my TV: the symptom prior to the backlight going out entirely was occasionally when the TV was turned on the backlight would "strobe" quickly... he's getting the part and will be able to replace it but just wondering of others have had this particular part fail on the BN44-00818a board.
                                          Attached Files

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