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LG Flatron M237WD - After approx. 30 minutes the backlight goes off

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    LG Flatron M237WD - After approx. 30 minutes the backlight goes off

    Have a nice day.
    First of all I want to point out that English is not my language. Thank you for your understanding and apologize for my mistakes.
    As I wrote in the title - After approx. 30 minutes the backlight goes off.
    Television has already been repaired by somebody before me. Soldering was not its strong side.
    After the measurements are at both 5V and 15V sources.
    Exactly. 5.1V and 15.2V. I decided to measure some of the components.
    See marking numbers on the image.
    I measured the QS2015 tester (https://www.buyincoins.com/item/68729.html).
    It also measures ESR capacitors. For amateur measurement sufficient - I think.
    CCFL tubes I think are OK. If the light lasts 30 minutes

    1
    Component - IT2604L, Dimension -21x13mm
    primary 1Ohm - 0,19mH
    secondary 948 Ohmu - 660mH

    2
    primary 0,6Ohm - 0,19mH
    secondary 959 Ohmu - 648mH

    3
    primary 0,6Ohm - 0,19mH
    secondary 945 Ohmu - 607mH


    4
    primary 0,6Ohm - 0,05mH
    secondary 945 Ohmu - 604mH


    5,6,7,8
    Component - BN 471k 1KVL
    5,6,7,8 ESR 17Ohmu
    5 - 479pF
    6 - 473pF
    7 - 472pF
    8 - 460pF

    9,10
    Component - 680μF/35V
    9,10 ESR 0,14Ohmu, 0,13Ohmu
    9 - 617 μF
    10 - 623 μF

    11,12
    Component - BN 102k 1kVL
    11,12 ESR 17Ohmu
    11 - 952pF
    12 - 962pF

    13
    Component - BN 222k 1kVL
    13 ESR 17Ohmu
    13 - 2178pF

    14,15,16,17
    Component - 1000μF/25V
    14,15,16,17 ESR 0,14Ohmu, 0,13Ohmu, 0,13Ohmu, 0,12Ohmu
    14 - 949 μF
    15 - 933 μF
    16 - 960 μF
    17 - 960 μF

    18,19,20
    Component - 1000μF/10V
    18,19,20 ESR 0,21Ohmu, 0,19Ohmu, 0,20Ohmu
    18 - 1036 μF
    19 - 1019 μF
    20 - 988 μF

    21,22,23,24
    Component - BN 10k 6KVL
    21,22,23,24 - unknown or damaged can tester measure them?

    25,26,27,28
    Component - MOSFET 25,27 typ N -62T03GH
    MOSFET 26,28 typ P -9563GH
    25,26,27,28 - testet multimeter - OK

    I think they are faulty, components 1, 3, 4.
    1 primary 1Ohm
    3 secondary 607mH
    4 primary 0.05mH and secondary 604mH

    Is my diagnosis correct? Thank you with regards to Paul
    Attached Files

    #2
    Re: LG Flatron M237WD - After approx. 30 minutes the backlight goes off

    #14 cap looks suspicious on the photos. Is that electrolytic that is showing on the top? Also, how did you test the caps, in circuit or you took them out before?

    Comment


      #3
      Re: LG Flatron M237WD - After approx. 30 minutes the backlight goes off

      So, if you restart the tv immediatly backlight does it last less time? If you dim the brightness at minimum does it last longer?
      Last edited by Dumah Brazorf; 02-12-2018, 12:04 PM.

      Comment


        #4
        Re: LG Flatron M237WD - After approx. 30 minutes the backlight goes off

        Originally posted by Dumah Brazorf View Post
        So, if you restart the tv immediatly backlight does it last less time? If you dim the brightness at minimum does it last longer?
        I do not know. I try.

        Comment


          #5
          Re: LG Flatron M237WD - After approx. 30 minutes the backlight goes off

          I am thinking the problem is on those little HV transformers. See which one runns the hottest.
          Last edited by CapLeaker; 02-19-2018, 06:03 PM.

          Comment


            #6
            Re: LG Flatron M237WD - After approx. 30 minutes the backlight goes off

            Originally posted by CapLeaker View Post
            I am thinking the problem is on those little HV transformers. See which one runns the hottest.

            The hottest one is the number four. The only replacement I found here has the most similar parameters to others.http://www.ame.cz/Trafo-inverteru-CC...152_10699.aspx

            place: 0,19mH
            has: 0,16mH
            versus measured: 0,05mH

            I write after the exchange and the test. Paul

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