Can I replace the light source behind an LCD screen?
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  1. #1
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    Lightbulb Can I replace the light source behind an LCD screen?

    We have a Daewoo 4020, Fanuc 21i controller with an 11" color screen that seems to be getting darker as time passes. Does anyone know if it's possible to change just the light source behind the screen, you know, kinda like the little bulbs behind the dash on my old Ford pickup, or do I have to replace the whole display?

    Thanks, guys.

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    Not familiar with that particular unit but I'm guessing it's a miniature fluorescent tube. They are usually soldered in but are easy to replace once you get at it.

    If it's the driver circuit not so easy but most times the bulbs go first.

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    Hi aj,

    You can change the light source. I have a Hitachi Seiki TS15 and it has a monochrome LED which was illuminated with a small florescent tube as was common back then. New LCD monitors are illuminated with a row of very small LEDs. You can buy a replacement LED for $18 on Amazon that will work well for CNC monitors.
    Here is the link for the one I used.
    Amazon.com: 2x LCD Laptop Backlight Lamps Update to Dimable LED Kit Adjustable Light Board+ Strip 9-25v Input Support 7''-15.4'': Computers & Accessories

    Review a Youtube video on the procedure and you can have it replaced in under an hour. My monochrome LCD was so dark I had to use my bifocals to see what was going on, now it's probably righter than new.

    I hope that helps.

    Stuart

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    I did this on an older TC-S2A Brother...it's easy once you get in there. It will change your life. Enjoy!

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    What about an old crt? Mazak t-Plus control. There is a brightness dial on the front of the control but it is still very dim at the brightest setting.

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    Quote Originally Posted by EnderDRM View Post
    What about an old crt? Mazak t-Plus control. There is a brightness dial on the front of the control but it is still very dim at the brightest setting.
    I don't know anything about Mazak in particular, but if it is just getting dim from age, I would try increasing the screen voltage a bit to extend the useful life. The fly back transformer which produces the high voltage (probably 15-30kV) usually has two controls on it. One is focus and the other is the screen voltage. I think the screen or G2 is almost always the lower control closer to the circuit board. Increasing the screen voltage will start making the blacks kind of washed out but is likely to be an improvement. We have an old CRT with washed out green (it's green monochrome) and retrace lines readily visible. It's been running that way for years. Do note that there are very high voltages here so proceed with caution.


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