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Sony GDM-FW900 Monitor Brightness Problem

Discussion in 'Electronic Repair' started by Bob Kos, Jan 23, 2006.

  1. Bob Kos

    Bob Kos Guest

    Hi All:

    I was recently given a Sony GDM-FW900 widescreen monitor. It was in horrible
    condition as received. I went to great pains to clean up spilled beer and
    other vile stuff that was inside this monitor. To my suprise and delight, it
    actually powers up. However - There is a problem with it that I need help
    with . The screen is WAY over bright. Also, there are retrace ( term?) lines
    running diagonally down the screen about every two inches. It will display a
    windows desktop properly although out of focus a little bit. The additional
    brightness and lines are included with the desktop image. I would like to
    get this monitor running 100%. I can do some basic repairs myself, but will
    yield this job to a good tech if the required repair is highly specialized
    ( SM IC, reprogram, etc ). Can anybody help get me working in the right
    direction? Thanks for any replies.
     
  2. Is the Screen voltage set correctly?

    Tom
     
  3. Bob Kos

    Bob Kos Guest

    I don't know if the screen voltage is set correctly. I'm not familiar with
    that term. I presume that you are referring to the 'Focus' adjustments on
    the flyback? I carefully marked those and moved each a little to see if the
    condition got better or worsened. It didn't change much for better or
    worse, so I set them back where they were.
     
  4. No, the screen is different, usually on the flyback, but I think on
    Sony monitors there is special software you need to use.

    Tom
     
  5. Guest

    Look here! Dani.

    http://www.hutzelman.com/home/hardware/mods/monitor/


    There is a modification used on some Sony monitors, I have done it
    three times, with no problems. If your screen is too dark, then maybe
    your G2 is too low. try the "R459 fix"!
    Not sure if your model is the same. It's a 4 - 10 meg I think on the
    CRT board. You have to play around with the value, as the level of
    overall brightness varies. solder a 1 Megohm resistor piggyback on top
    of the one there sometimes works.
     
  6. Bob Kos

    Bob Kos Guest

    Problem solved. I found a setting in the menu system called 'Image
    Restore'. This setting doesn't work until the monitor has been on &
    stabilized for a while. I selected this menu option and the monitor went to
    work. It corrected the overbright condition and retrace lines on its own!!
    The colors are very nice now! I'm happy!

    Thanks to all who replied with help.
     
  7. Andy Cuffe

    Andy Cuffe Guest

    I've fixed countless large Sony monitors with that.
    Andy Cuffe

     
  8. Bob Kos

    Bob Kos Guest

    Any idea what the actual purpose of this menu selection is? The fact that
    it fixed my monitor is great, but I can't imagine a menu setting designed to
    compensate for screwed up components or anything like that. The manual is
    quiet regarding the use of this option. Any thoughts?
     
  9. Andy Cuffe

    Andy Cuffe Guest

    I believe it measures the CRT cathode current for each gun and adjusts
    them to the correct preset levels. It's similar to the AKB used in
    TVs, only it doesn't operate continuously. My only question is why
    the CRTs in these monitors get so much brighter with age.

    The monitors made before they added the restore feature required
    either a DAS calibration, or a modification to reduce the G2 voltage.
    There are also a lot of 21" Sony monitors with a restore feature that
    doesn't work.
    Andy Cuffe

     
  10. Bob Kos

    Bob Kos Guest

    I'd like to try and find out more information as to how this feature should
    be PROPERLY used. If you know of any good sources of info, please send me
    in the right direction. I'll continue to Google on it.

    Thanks again.
     
  11. Andy Cuffe

    Andy Cuffe Guest

    Did you try the manual? I'm pretty sure all it's supposed to do is
    compensate for aging of the CRT and electronics. It allows the
    monitor to maintain accurate color reproduction over its entire life.
    Monitors without this feature gradually lose proper gray scale
    tracking and the guns age unevenly.

    Andy Cuffe

     
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