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Monitor fault, advice please

Discussion in 'Electronic Repair' started by John Fryatt, Jun 8, 2005.

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  1. John Fryatt

    John Fryatt Guest

    Hi,

    A while ago I got a used Eizo F56 monitor to use as a secondary screen
    on my Dell Dimension with a Matrox G450 dual-head video adapter. I was
    using an old Sony 15" but wanted the Eizo because a) it is 17" and b) it
    has dual inputs, which is useful for connecting to two PCs.
    Ok, so far, so good.

    Recently, it has started flicking off for a fraction of a second,
    accompanied by a little crackle noise. The screen starts to go dim and
    the image seems to expand a little off the edges, but then it comes back
    on again and returns to the correct size.
    Sometimes this may happen 4-5 times in quick succession, then not again
    for 30 minutes or so, then it might do it twice and again after only 2
    minutes. I.e. pretty random.

    It might be connected to heat or humidity, as when we had a couple of
    very hot days recently it was doing the flicking a lot more.
    I don't think it happens when I first power up the monitor, only after
    maybe 5-10 minutes, when it has warmed up a bit.

    I read somewhere about dust possibly casuing this problem, so I opened
    up the back of the monitor and blew out any dust with a compressed air
    can. There was some dust, but nothing much.
    I alos read about sluicing the HT bits on the back of the tube with
    alcohol, so I tried that as well. I used iso-propyl alcohol and left it
    24 hours to dry.
    I think these measures have improved the problem, although it still
    happens. It's an intermittent thing though so I could be wrong.

    Before anyone says, I know I should expect problems if I buy secondhand
    old crap, but I'm a bit low on the finances at the moment, and I'd like
    to get TFTs a bit later anyway, so this is a stop-gap

    Any thoughts? Anything I can do to fix it?

    John
     
  2. Cobalt

    Cobalt Guest

    | Recently, it has started flicking off for a fraction of a second,
    | accompanied by a little crackle noise. The screen starts to go dim and
    | the image seems to expand a little off the edges, but then it comes back
    | on again and returns to the correct size.
    | Sometimes this may happen 4-5 times in quick succession, then not again
    | for 30 minutes or so, then it might do it twice and again after only 2
    | minutes. I.e. pretty random.

    you can try a heat gun or cold spray on certain parts in the monitor, and
    look for sensitivity that activated that condition.
    the expanding image likely means insufficient high voltage from the flyback
    xfmr. you could have cold solder on the flyback pins, or just a flyback that
    is on
    its way out soon, and one day the monitor will probably have no image at all
    displayed. you can probably purchase the flyback online at a reasonable
    price if you knew its part number - usually as indicated with a white
    sticker stuck on the flyback.

    this site has a good research form for locating a flyback
    http://www.technotronic-dimensions.com/FBT_RESEARCH.html and also a lot of
    pages of monitor flyback listed on the site map.

    when you change a flyback, its a good idea to replace the horizontal output
    transistor at the same time too, for optimum performance, even if it still
    tests ok.
     
  3. John Fryatt

    John Fryatt Guest

    Okaaay. I was kind of hoping for something simple, and to me this is not
    simple. ;-) I'll have a look re. the solder thing, but after that I
    think the monitor is headed for the skip once it dies. I only paid £14
    (approx $26) for it so no big loss. It's more the hassle involved that
    is annoying. It'll teach me that you get what you pay for. :-(

    Thanks for the advice.

    John
     
  4. Jerry G.

    Jerry G. Guest

    In this model, it is very probable that the high voltage multiplier
    section is failing. In these monitors it should be part of the flyback
    transformer assembly.

    It is still possible to pick up new CRT type monitors very cheap, and
    they have a minimum of a 1 year warranty. The asking prices are very
    low until they run out of them.

    As for used CRT monitors, these come for very cheap these days.

    Jerry G.
     
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