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Thread: LCD monitor, repairable?

  1. #1
    Flashaholic*
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    Default LCD monitor, repairable?

    There's something weird going on with my LCD monitor. When I turn the computer on, it come out of sleep mode and back light come on for a sec but goes off, as if it receives no signal. Only after leave it in that state for some time (which is getting longer), and I turn it off and on it will recognize the signal and come on, as if it needs warm up.

    The computer is fine, I hooked up an old CRT monitor and it turn on instantly. And if I turn the power source off on the LCD monitor, turn on computer, wait some time and turn on the monitor, it still need the "warm up" time, so it need certain amount of the time connected to a computer sending video signal in order to work.

    Should I bother repair it or just chuck it and get a new one?

  2. #2
    Flashaholic* bshanahan14rulz's Avatar
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    Default Re: LCD monitor, repairable?

    You probably have some leaking or popped capacitors on the backlight inverter board. If you take a flashlight and shine it on the panel while it is supposedly on, can you see the liquid crystal panel displaying correctly, but without light?

  3. #3
    Flashaholic*
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    Default Re: LCD monitor, repairable?

    You are right, there's image, it's just the back light not coming on.

  4. #4
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    Default Re: LCD monitor, repairable?

    You might find you can buy a new inverter board of ebay or a monitor spares site.

  5. #5
    Flashaholic ejot's Avatar
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    Default Re: LCD monitor, repairable?

    My monitor did this for two years. Eventually the backlight would only blink the one time and never come on. I took it apart looking for something blown but nothing obvious. Just used it as an excuse to get a bigger monitor.
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  6. #6
    Flashaholic Muddquez's Avatar
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    Default Re: LCD monitor, repairable?

    you need a new CCFL lamp.

  7. #7
    Flashaholic Dr Jekell's Avatar
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    Default Re: LCD monitor, repairable?

    I had a problem with a one of the Toshiba Satellite laptop series that was a known issue but they just said to send it in for repair (and again when it reappeared later, then again.......)

    I did a bit of searching & found that if you disconnected the inverter board for the back light (with power & battery removed) for ~10 sec & reconnected it, the problem was fixed.

    You could try this solution.
    There are no foolish questions and no man becomes a fool until he has stopped asking questions

  8. #8
    Flashaholic Pöbel's Avatar
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    Default Re: LCD monitor, repairable?

    It can be fixed

    Open the Monitor

    You will see a lot of capacitors (the round tubes). One of them might be popped, but i found that you can rarely see such in monitors, it happens more often on mainboards. So the defective piece will not be visually detectable.

    It does not necessarily have to be on the inverter board !!!

    What you do is the following.

    Take a hair dryer. Turn it on and swipe the board, only short burst to any area, you do not want to melt it! At one point the backlight should turn on.

    Turn the screen off and wait.

    Now you take a piece of paper or flexible plastic and a hair dryer. You just detected the approx. aerea with the defective cap in the step before, now you isolate a single capacitor (with the paper so the hot air is only blown onto on cap) in that area and give it a short burst with the hair dryer. Continue until you find the defective unit. Let everything cool down and check that it was not a coincidence.

    Replace that cap.
    Enjoy.

  9. #9
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    Default Re: LCD monitor, repairable?

    Thanks. I'll see if I can do that but I've never worked on any monitors before. If not I'll just get a new bigger one.

    Maybe it's just me but I really don't like the disposable society today, if I take it to the shop it'll probably cost me more to repair than buy a new one.

  10. #10
    Flashaholic* bshanahan14rulz's Avatar
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    Default Re: LCD monitor, repairable?

    Right now, I'm kind of in the same boat. Perfectly good monitor, just went out of warranty. 4 of the 10 caps on the inverter board are blown. I'm hoping the mosfets haven't fried, as those can be harder to find replacements for, but these caps aren't easy to find either.

    Mine are 35V 100uf 105*C electrolytics, but I don't know if they are a special kind or not, besides high-temp.

  11. #11
    Flashaholic Pöbel's Avatar
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    Default Re: LCD monitor, repairable?

    You do not have to get the same specs. Voltage should of course not be lower and capacity should be at least as high as the original.

    I even used much bigger (in size) and just relocated them to empty space inside the monitor.

  12. #12
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    Default Re: LCD monitor, repairable?

    What model is it? I had an HP f1703 that has a manufacturing problem with the wave soldering of the components on the inverter board. There were cold solder joints on some of the components that were glued to the board. The backlight would go on for a few minutes then go off.

    I reheated some of the connections with a soldering iron and it worked fine.

    I made a blog post about it and have had 349 responses from people who have had a similar problem.

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