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Fix dead LCD monitor with LED's (Show idea)


giantjoebot
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I found an article that tells you how to fix a dead LCD using a cheap cold cathode case kit.  The method is a bit dangerous because of the stuff in the bulbs.  At the end of the article, he says that he has been email a bunch of times by people that told him ultra bright LED's, about ten work.  This has an advantage since it doesn't carry the danger of the other method, the LED's last forever, and I think possibly use less electricity.  The only problem is that I couldn't find anything, with a quick google search, on how to do the LED method.  They have done a few segments with LED's, and I think this would be a perfect segment for the show. 

Personally I would really like to learn how to do this, because there have been a couple of LCD that the bulb went out at my work.  They offered them to me, and I turned them down.  Now another one is going out, and if I can fix it, I'm sure I can find a use for it.

Here is the article that I mentioned   

http://www.inventgeek.com/Projects/shorts/overview.aspx

and here is a quote about using LED's

I have received several emails from people who have tried to tackle this very project with a different angle. There using ultra bright white LED's. the claim is that about 10 of them will not only perfectly fix the monitor, but they last for ever. Now I am not disputing the longevity of LED's. but I find it hard to believe that you wouldn't have light and dark streaks across the screen as the LED's have a build in lenses that would not evenly diffuse the light. But for what its worth it's a creative solution that can be done for just about the same price. I just recommend that you  dump the inverter if you try it.

It would be interesting if Hak5 did it so we can see if it get the streaks or not.

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A fairly easy way to do this would be to solder a couple of wires to the DC input socket where you plug in the monitor's power brick. This is usually somewhere around 12v which is a good start for LEDs. You can't use the existing power socket that the CCFL used because it's a much much higher voltage and it's AC, which isn't much use for your LEDs.

So now you have a power source you can make yourself a strip of LEDs. I'd imagine, though I'm no expert, that running them in parallel would be the best method for this task. Assuming the LEDs consume 20mA at 3v (which is quite possible/likely for ultra bright LEDs), according to http://led.linear1.org/led.wiz, the below diagram (which I've adapted slightly) is a viable option for a layout:

  12v                        0v/Ground

    +                                  |

    |----|>|----|>|---///----|

    |----|>|----|>|---///----|

    |----|>|----|>|---///----|

    |----|>|----|>|---///----|

    |----|>|----|>|---///----|

                LEDs    Resistors

The resistors in this case would be 330 ohms.

There's a ton of ways you can lay out the LEDs in the circuit and it's a really simple circuit to make.

Anyway, with the circuit made, you would place the LEDs in a line where the CCFL used to be, and you'd point them downwards for best light output.

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