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samsung un55f6300af no power

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    samsung un55f6300af no power

    Got one of these with no power.Power led flashes repeatedly looks like 2 flashes.Unplugged main board and no lamps even though lamps tested fine as i had panel off and all good with lamp tester.Haven't seen a lot on this model only had one before and lamps were gone on that one.Narrowed down to power supply,as lams don't lighrt with cables off to other board. All caps good 391 v on main cap.Anyone else have this issue?
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    #2
    Re: samsung un55f6300af no power

    Check CNM803 pins, I suspect you have A5V (standby) but what are the voltages on PS_ON, BL_ON & P_DIM, do these voltages change if the power button is pressed?
    If you disconnect the plug from the main board to the power supply, do you get B5V or B13V, there is a pullup resistor for the PS_ON so the power supply should turn on, but the pullup resistors for BL_ON and P_DIM go to the B5V.
    Last edited by R_J; 06-24-2019, 08:03 PM.

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      #3
      Re: samsung un55f6300af no power

      The ps on is 3.3 when power led is solid but goes to .25vdc when power led flashing.No effect on any voltages while pressing power button.Only other voltage present 5.3vdc on pin 12.power led cycles solid for short time with 3.3 on ps on then flashes with .025vdc present.

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        #4
        Re: samsung un55f6300af no power

        It does seem like the PS_ON command is coming from the main board, thats good.
        There is a white capacitor (CM811S) near TM801s transformer, if you have a cap checker, check this cap, if not have a close look at it and see if it is bulged,it the sides should be nice and flat.
        I suspect the fault might be with ICM801CS
        Shojimmy has a repair kit that includes this ic
        Last edited by R_J; 06-24-2019, 08:55 PM.

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          #5
          Re: samsung un55f6300af no power

          What is the power supply board P/N? 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

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            #6
            Re: samsung un55f6300af no power

            Bn44-00612b

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              #7
              Re: samsung un55f6300af no power

              Have a look at the solder side of the power supply and check the solder connections on TM801CS transformer, they are likely ok but worth checking. the next voltage I would check is the VCC for ICM801CS. Using HOT ground (- of cp807s) check the voltage on JP812 or JP805. I suspect the voltage is there because the pfc circuit is working
              Last edited by R_J; 06-24-2019, 09:36 PM.

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                #8
                Re: samsung un55f6300af no power

                Wonder if it's a faulty/loose connection in backlight circuit?

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                  #9
                  Re: samsung un55f6300af no power

                  Don't think its faulty lamps as i tested with lamp tester each circuit from the cable on back and got very close readings.

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                    #10
                    Re: samsung un55f6300af no power

                    You can disconnect the led lamps completely, that will not cause the missing B13V & B5V
                    and without these voltages nothing else will work.

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                      #11
                      Re: samsung un55f6300af no power

                      RJ hit nail on head with this one it was ICM801CS.

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                        #12
                        Re: samsung un55f6300af no power

                        Originally posted by sputnikoff View Post
                        RJ hit nail on head with this one it was ICM801CS.
                        What did you do to fix the problem? Replace or resoldered loose connection?

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                          #13
                          Re: samsung un55f6300af no power

                          There were no loose connections i could see.I had board under microscope so joints looked good.I replaced that regulator ICM801cs and she powered up perfectly.

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