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NEC lcd display is white

Discussion in 'Troubleshooting and Repair' started by canactech, May 31, 2010.

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  1. canactech

    canactech

    38
    2
    Jul 7, 2009
    I have received an LCD monitor, model Accusync LCD72VX who was hurted by a tunderstorm. Since then the display is completely white, even the OSD is appearing white. The ccfl are OK because of the white display but I hesitate between replace the power suply/inverter or the logic board.

    If any one has any idea about it, it will be very helpfull.

    Thank you.

    Canactech.
     
  2. Tesla

    Tesla

    165
    2
    May 10, 2010
    Is the OSD working, or is the VGA input working? Is there any indication that the logic board is working (processor running)?

    Logic board likely needs 3.3vdc and/or 5vdc coming from the PS board ... are you getting that?
     
  3. canactech

    canactech

    38
    2
    Jul 7, 2009
    Thank you Tesla for your post.
    No the OSD is not working. For the VGA input, I try a cable that I know to be good because the cable is not fixed on this monitor so I can tyr as many cable as I want. I've checked also the tesion that arrives from the PS board, I've found a 3 volts, a 5 volts and a 12 volts. It's hard to told you if the logic board is working because all I have to check the board is a multimeter, and the screen is white as the case so if anything is appearing on the display, I can't see nothing because of it. It looks like if the logic board is defective but without any certitude.
     
  4. davenn

    davenn Moderator

    13,813
    1,945
    Sep 5, 2009
    I'm wondering if the brilliance cct is running at full ?? just a thought..... have seen that b4 on a completely white read - bright) screen sometimes the brilliance level only has a small effect.

    Dave
     
  5. canactech

    canactech

    38
    2
    Jul 7, 2009
    I think the light is at it's maximum, but to give you a good idea of what I see is when you open a new document in Microsoft Word, you just have to stretch the page all over the screen and it will be exactly the same.
    I've checked the mosfet and the diodes on the PS/inverter board and everything is OK statically. I also verify the tension for the cct and it's 605V AC. It seems to be normal.

    Pierre
     
  6. canactech

    canactech

    38
    2
    Jul 7, 2009
    I've find on another site that this problem could be caused by a missconnected display cable. So I unplug the flat cable that goes from the logic bord to the LCD screen and take care that the connector on the screen side be very thight. The screen is working as normal.

    Thank you for your help.

    Pierre
     
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