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  • retiredcaps
    replied
    Re: Samsung 731BF no light

    Originally posted by xifias View Post
    hello
    i have an lcd monitor,samsung 731bf that goes off from illuminocity almost imediately.
    If I understand you correctly, it sounds like you are describing 2 seconds to black. If yes,

    2 seconds to black can be

    a) bad caps
    b) bad ccfls
    c) bad ccfl wiring (especially the return wiring)
    d) bad secondary windings on the inverter transformer

    More details starting with post #19 at

    https://www.badcaps.net/forum/showthread.php?t=10419

    Also, see budm's Inverter tester using old CFL

    https://www.badcaps.net/forum/showthread.php?t=19987

    here are some info
    Post your pics and schematics following my instructions below exactly.

    i placed it on the upper end of the last resistor on the left and to the ground.typically the output is 650 volt there.the cap didnt even warmed up even its rated 100V.
    Indicate that in your picture. Right now, I have no idea what area you are talking about.

    Leave a comment:


  • xifias
    started a topic Samsung 731BF no light

    Samsung 731BF no light

    hello
    i have an lcd monitor,samsung 731bf that goes off from illuminocity almost imediately.i changed the bulged caps from the power supply board,yet the problem insists.i found accidentally that if the voltmeter is in paralel on the high voltage output,it manages to stay on and show picture normally.
    i tried a 47nF/100V capacitor that laid around instead of the voltmeter and it worked also.

    but i want a more confident solution.why is that happening?will it be dangerous or so?its not mine you see,its for a friend,and i wont be able to monitor it after i give it back.

    here are some info
    http://monitory-lcd.magazyn.pl/pic_m...sung-731bf.jpg

    http://www.gzskyhorse.com/images/FGH001.jpg

    and the schematics

    http://dc435.4shared.com/doc/NYMefbxe/preview001.png

    http://dc435.4shared.com/doc/NYMefbxe/preview002.png


    the model of the power supply board is IP-35155A

    many thanks in advance!!

    PS:the voltmeter is a typical multimeter,no high voltage.it reads no voltage,but the picture is on.i placed it on the upper end of the last resistor on the left and to the ground.typically the output is 650 volt there.the cap didnt even warmed up even its rated 100V.
    Last edited by xifias; 09-06-2012, 01:31 PM.
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