Benq ET-005-N No backlight

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  • b19_george
    New Member
    • Sep 2016
    • 9
    • Romania

    #1

    Benq ET-005-N No backlight

    Hello,

    I have an Benq ET-005-N with backlight problems, the CCFL lamps are not starting at all but i test them and are fine, I know the monitor works because I used another board to fire up the CCFL lamps and once the lamps are on you can see the image on the screen, the caps are replaced are not bulging and tested for capacitance, the transformers have the same resistence both of them (0.63K) so either are both damaged or is the right reading. Any advice will be more than helpfull!
    Thank you very much!
    Attached Files
  • boyebaran
    Badcaps Veteran
    • Sep 2015
    • 247
    • iran

    #2
    Re: Benq ET-005-N No backlight

    hi
    how about dc voltage on d803 d805?
    check F802
    if all voltage is ok so read SMD ic part number(ccfl controller under inverter board)and inform.
    tnx

    Comment

    • budm
      Badcaps Legend
      • Feb 2010
      • 40746
      • USA

      #3
      Re: Benq ET-005-N No backlight

      https://www.badcaps.net/forum/attach...8&d=1474979853
      What DCV do you have on pin 5 (ON/OFF = BL-ON) and pin 6 (Brightness = DIM) with ref. to the chassis GND?
      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

      • b19_george
        New Member
        • Sep 2016
        • 9
        • Romania

        #4
        Re: Benq ET-005-N No backlight

        Originally posted by boyebaran
        hi
        how about dc voltage on d803 d805?
        check F802
        if all voltage is ok so read SMD ic part number(ccfl controller under inverter board)and inform.
        tnx
        on d08 with red probe on the middle pin and black on the other 2 pins is 14.9 V
        on d805 same probe arrangement is 5.1

        part no: OZ9938GN

        Comment

        • b19_george
          New Member
          • Sep 2016
          • 9
          • Romania

          #5
          Re: Benq ET-005-N No backlight

          Originally posted by budm
          https://www.badcaps.net/forum/attach...8&d=1474979853
          What DCV do you have on pin 5 (ON/OFF = BL-ON) and pin 6 (Brightness = DIM) with ref. to the chassis GND?
          there are 6 pin notations and 8 wires so looking at the back of the board starting with the upper pin (blue wire) that is near the hole with the ground of the board the voltages are as follows:
          - 3.27
          - 0.03
          - 0.88
          - 3.3
          - 0
          - 0
          - 5.1
          - 5.1

          Thank you very much for your help. another thing that i should say that the monitor when stooped working i replaced the caps, they were bulged, i don't know if they are any good brand and they were not tested with an ESR meter.

          Comment

          • b19_george
            New Member
            • Sep 2016
            • 9
            • Romania

            #6
            Re: Benq ET-005-N No backlight

            Originally posted by budm
            https://www.badcaps.net/forum/attach...8&d=1474979853
            What DCV do you have on pin 5 (ON/OFF = BL-ON) and pin 6 (Brightness = DIM) with ref. to the chassis GND?
            thanks a lot for your help!

            Comment

            • boyebaran
              Badcaps Veteran
              • Sep 2015
              • 247
              • iran

              #7
              Re: Benq ET-005-N No backlight

              do you check F802?if yes so:

              As picture put 10k ohm resistance and inform me what happen after turning on the monitor.if did not work please jump this point together .
              Attached Files
              Last edited by boyebaran; 09-30-2016, 11:13 PM.

              Comment

              • boyebaran
                Badcaps Veteran
                • Sep 2015
                • 247
                • iran

                #8
                Re: Benq ET-005-N No backlight

                for more information .this inverter board like as LG :w 1934sI.

                Comment

                • b19_george
                  New Member
                  • Sep 2016
                  • 9
                  • Romania

                  #9
                  Re: Benq ET-005-N No backlight

                  Originally posted by boyebaran
                  for more information .this invertor board like as LG :w 1934sI.
                  hello, the fuse you mentioned is fine, if i will try that test with the 10k resistor and if is still not working there is nothing else to try?

                  i will try to put the resistor and see if i managed anything

                  Comment

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