Samsung LN46E550 no backlight

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  • Jtroutt19
    Senior Member
    • Aug 2011
    • 164
    #1

    Samsung LN46E550 no backlight

    Hey guys got this tv in front of my that has no backlights. I have no voltage at the back connector either. Bought a rebuild kit off eBay. Still no backlights and no voltage at connector. Thoughts.

    Replaced all parts in red
    Attached Files
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    • diif
      Badcaps Legend
      • Feb 2014
      • 6978
      • England
      #2
      Re: Samsung LN46E550 no backlight

      What testing/measuring did you do before fitting the kit ?
      What's the voltage across the main caps ?

        Comment

        • jetadm123
          Badcaps Legend
          • Feb 2010
          • 2169
          #3
          Re: Samsung LN46E550 no backlight

          Check fuse next to the large caps. Also, the main fuse if you get no voltage across main caps.
          Last edited by jetadm123; 04-18-2018, 02:59 PM.

            Comment

            • Jtroutt19
              Senior Member
              • Aug 2011
              • 164
              #4
              Re: Samsung LN46E550 no backlight

              Voltage across main caps is 394 volts. Fuse next to main caps is good.


              The only testing I did before fitting the kit was checking for voltage at connector for backlights,

                Comment

                • diif
                  Badcaps Legend
                  • Feb 2014
                  • 6978
                  • England
                  #5
                  Re: Samsung LN46E550 no backlight

                  Did you test at the LED connector correctly as you turned on the TV ?
                  Voltages at the other connector ?

                    Comment

                    • jetadm123
                      Badcaps Legend
                      • Feb 2010
                      • 2169
                      #6
                      Re: Samsung LN46E550 no backlight

                      A good focused shot of the other side of the power supply would be good as these power supplies were known to suffer from bad solder joints.

                        Comment

                        • Jtroutt19
                          Senior Member
                          • Aug 2011
                          • 164
                          #7
                          Re: Samsung LN46E550 no backlight

                          yes I tested for voltage as unit was powered up. I tested for voltage at the powersupply connector. I have went over this board with low power magnification looking for bad solder joints have not found any. I will look over it againl

                            Comment

                            • budm
                              Badcaps Legend
                              • Feb 2010
                              • 40746
                              • USA
                              #8
                              Re: Samsung LN46E550 no backlight

                              The output (primary drive for the inverter transformer) CNI801 of the power supply board go the inverter transformer board.
                              We need to know if you do have BLU_ON at pin 6 of the connector CN802 or not.
                              It is best to report all the dc Voltage of all the pin of CN802.
                              Notes: exposed pins on the top side of the boards are the ODD Number pins, the EVEN number pins you have to probe from the back side of the connector.
                              You must report the pi name and number and follow by the reading when TV is OFF and when the TV is turned ON.
                              For eaxmple:
                              TV off TV ON
                              PIN 1 (B13V) = XX XX
                              PIN 2 (P_DIM) = XX XX

                              BTW, if you look at the LCD panel in the dark room, do you see the backlights even flash on for seconds?
                              I suspect the DC Blocker CI818 (2W 474K, SIC 460S series) to be bad, it is commonly failed cap in the inverter circuit. Look real close to see if it bulging from the side, or remove it and test its capacitance.
                              Did the repair kit come with that cap? It should.


                              Samsung BN44-00441A (I46F1_BHS) Power Supply Unit
                              http://www.shopjimmy.com/samsung-bn4...upply-unit.htm
                              Last edited by budm; 04-19-2018, 07:30 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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