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    Samsung UN46EH5000F no backlight

    Trying to figure out why the backlight went out. No visible bad caps or burning on power board. Shining light on panel I can see the menu.

    Read this post
    https://www.badcaps.net/forum/showthread.php?t=50471
    Everything looks the same but I will get pics if you want.

    Unplugged the cable from power board to main board.

    Voltage across main cap on power board - .115 V
    D1+ to chassis gnd = .001V - sometimes I see it jump to 1.7 and then back down.
    I can hear a light whining coming from the board.

    Where should I start?
    Last edited by m4a2t0t; 02-05-2016, 01:36 PM.

    #2
    Re: Samsung UN46EH5000F no backlight

    Check output voltage going to backlights.
    Please Do Not PM My Page Asking For Help Badcaps Is The Place For Advise, Page Linked For Business Reasons Only. Anyone Doing So Will Be Banned Instantly !

    https://www.facebook.com/Telford-Tel...7894576335359/

    Comment


      #3
      Re: Samsung UN46EH5000F no backlight

      All pins on CNL802 connector are below 1.0V, most are .3V to .6V

      Comment


        #4
        Re: Samsung UN46EH5000F no backlight

        Please upload pictures of YOUR boards, also what is the P/N of your POWER SUPPLY /LED driver board BN44-?????
        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


          #5
          Re: Samsung UN46EH5000F no backlight

          I'll upload some in a min.

          BN44-00667A
          Attached Files
          Last edited by m4a2t0t; 02-05-2016, 03:26 PM. Reason: upload pics

          Comment


            #6
            Re: Samsung UN46EH5000F no backlight

            any suggestions.

            Is there a way to test the backlight and make sure it didn't cause the problems with the power board.

            Comment


              #7
              Re: Samsung UN46EH5000F no backlight

              Turn the TV on and check the BLon pin on the PSU (bottom left corner).

              Comment


                #8
                Re: Samsung UN46EH5000F no backlight

                Comment


                  #9
                  Re: Samsung UN46EH5000F no backlight

                  I assumed the top left pin was pin 1.

                  1-12.8
                  2-1.04
                  3-12.8
                  4-12.8
                  5-12.8
                  6-4.8
                  7-12.8
                  8-10-GND
                  11-5.2
                  12-5.2
                  13-5.2
                  14-3.4

                  Comment


                    #10
                    Re: Samsung UN46EH5000F no backlight

                    Pin names for each 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


                      #11
                      Re: Samsung UN46EH5000F no backlight

                      CN803 IP SMPS to /fro MAIN BOARD
                      1-B13V
                      2-PWM_DIMM
                      3-B13V
                      4-B13V
                      5-Vamp 13V
                      6-BLU On/Off
                      7-Vamp 13V
                      8-GND
                      9-GND
                      10-GND
                      11-B5V
                      12-A5V
                      13-B5V
                      14-Power On/Off

                      Comment


                        #12
                        Re: Samsung UN46EH5000F no backlight

                        Well, I am just going to order a new power board. Hopefully that is it

                        Comment


                          #13
                          Re: Samsung UN46EH5000F no backlight

                          You have all the correct Voltages. I doubt it is the power supply board.
                          https://www.badcaps.net/forum/showth...ht=BN44-00667A
                          https://www.badcaps.net/forum/showth...ht=BN44-00667A
                          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


                            #14
                            Re: Samsung UN46EH5000F no backlight

                            Hi Bud,
                            I have the same TV and when I disconnect the main board the backlight turns on by itself.Does that mean the LED's are ok and the main boards the problem?
                            Ed

                            Comment


                              #15
                              Re: Samsung UN46EH5000F no backlight

                              If the backlights come on with the mainboard disconnect then it generally indicates a problem on the mainboard.
                              Can you list all the voltages as in post #11
                              Willing to help but I'm no expert.

                              Comment


                                #16
                                Re: Samsung UN46EH5000F no backlight

                                Thank you for the quick responce.I was following the procedure until I unpluged the main from the power board to check the voltage at the 450volt cap and it showed about 385v and i saw all the leds light up.So I'm hoping a 23$ board from eparts on ebay will do the trick.Most people with this TV are having LED backlight issues.But I can't imagine a bad LED would light up.
                                The other thing I failed to mention was when the main board is connected,I can turn the TV on it makes the samsung "jingle" the backlight is OFF but I can barely see the menu option.The other important thing I think is I cannot turn the tv off using the power switch.I have to pull the plug from the wall.
                                sounds like an unlikely defective main board doesnt it?
                                Ed

                                Comment


                                  #17
                                  Re: Samsung UN46EH5000F no backlight

                                  "The other important thing I think is I cannot turn the tv off using the power switch.I have to pull the plug from the wall.
                                  sounds like an unlikely defective main board doesnt it?"

                                  Yes.
                                  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


                                    #18
                                    Re: Samsung UN46EH5000F no backlight

                                    Thank you both for the quick responses I'll post when the board come in.
                                    Bud,
                                    I might have lucked out on this one.It might be interesting to note that unplugging the main from the power supply made the LED light up,is that normal?
                                    Ed

                                    Comment


                                      #19
                                      Re: Samsung UN46EH5000F no backlight

                                      Originally posted by ed123 View Post
                                      Thank you both for the quick responses I'll post when the board come in.
                                      Bud,
                                      I might have lucked out on this one.It might be interesting to note that unplugging the main from the power supply made the LED light up,is that normal?
                                      Ed
                                      Yes, that is normal, that is how you do the self test of the power supply and backlights.
                                      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


                                        #20
                                        Re: Samsung UN46EH5000F no backlight

                                        Well....I got the new main board in from electro parts and nothing.The TV turns on when it's plugged in and no backlight and I cannot turn it off by the remote or the power switch.I called e-parts back and will try the power supply.But still when the main is unplugged the backlights all turn on.

                                        Comment

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