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Samsung LE26B450C4W Dead PSU

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    Samsung LE26B450C4W Dead PSU

    After some help with this TV. I got the set from an auction and it is dead with no signs of life. The set has the BN44-00259A PSU fitted. I have done the usual checks and found that the second main fuse FM802S was blown, a closer check of the board i found that UM801S (ICE3BR0665J) had damage to pins 3 & 4 (looked like shorted with a test probe by others).

    Replaced the IC and checked all diodes etc (only have access to standard DVM at moment) and all checked out. Replaced fuse and powered up set still dead but fuse now intact. Checked out voltages on large cap as another thread https://www.badcaps.net/forum/showthread.php?t=21816 on here and getting 600V also getting 230V at FM802S fuse. No voltages at any pins on output header.

    I used to work on some digital stuff in the past but not great on SMP's so any help would be great.

    No obvious damage to track side of board pic below of PSU
    Attached Files

    #2
    Re: Samsung LE26B450C4W Dead PSU -* Fixed *

    Set now working Appears zener diode ZM801 was spiked (and was shorting internally) when UM801s pins were shorted or had failed (and they killed ZM801fault finding).

    Comment


      #3
      Re: Samsung LE26B450C4W Dead PSU

      600V?!

      Has that filter capacitor blown up yet? It's only rated for 450v!

      Good job on the repair, you didn't need our help at all!
      Muh-soggy-knee

      Comment


        #4
        Re: Samsung LE26B450C4W Dead PSU

        Hi windy, I have the same defect on this PSU. I have ordered a replacement IC, but I cannot read the numbers on the ZM801 diode.

        The symbol states a zener-diode, and it starts with 1N and ends on 47A, but in between something like 4? (stil 10 combo's)

        Can you remember or look up the correct type for that diode?

        Comment


          #5
          Re: Samsung LE26B450C4W Dead PSU

          dpijl10: bn44-00259A diagram.
          1N4740A, check the OPTO PC801 also.
          Attached Files
          Last edited by budm; 10-24-2014, 01:42 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


            #6
            Re: Samsung LE26B450C4W Dead PSU

            Thanks very much budm - also for the schematics! This will help me fix this psu

            Comment


              #7
              Re: Samsung LE26B450C4W Dead PSU

              Just to let u know: The PSU is alive again - a new fuse, new controller (ICE3BR0665J) and new zener diode 1N4740A. PC801 is fine (no replacement done).
              Total cost: € 2,54

              Comment

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