Replacing LEDs

Discussion in 'General Mac Discussion' started by supergod, Mar 23, 2005.

  1. supergod macrumors 6502

    Joined:
    Jul 14, 2004
    Location:
    Toronto
    #1
    I love my computer setup but recently one thing has been bugging me about it: I got a widescreen LCD and have started watching movies in the dark and the differently colored LEDs that are in my setup are distracting and ugly.
    There is one green LED in my speakers and a few acting as backlights on the buttons of my monitor, a red and a blue LED in my preamp, orange backlight LEDs in my main keyboard and blues in my backup keyboard and MIDI connector (this one blinks too).
    I was wondering whether anyone has had any experience with replacing the LEDs in computer products: I wanted to find some white LEDs and put them in to match the one on the front of my powermac. Are there any issues as far as wiring are concerned: for instance, would there be a difference between the LEDs used in a backlit button and the one dirrectly exposed on my speaker.
    Thanks for any help: I hope this will be a cool little project.
    By the way, I can take pictures of my setup or the individual gizmos and post them if that helps.
     
  2. supergod thread starter macrumors 6502

    Joined:
    Jul 14, 2004
    Location:
    Toronto
  3. rainman::|:| macrumors 603

    rainman::|:|

    Joined:
    Feb 2, 2002
    Location:
    iowa
    #3
    I believe LED voltages vary, you'll have to get slightly different ones for each replacement. Get a voltage tester to see, hook it up to a couple of different LEDS and see if they measure the same.

    The biggest problem would probably be the fact that LEDs are usually held in place by the leads, if you chop them off and resolder, it may not be as strong. Do it 10 times and you're bound to make a mess of one of the devices, i would think. Depends on how good you are with hardware. I think Radioshack has a large supply of LEDs, probably a good place to start.

    Personally, I just ignore the lights. Tho they did force me to move all electronics out of my bedroom.
     
  4. jer446 macrumors 6502a

    Joined:
    Dec 28, 2004
    #4
    you would just need to check the resistance of the leds for each component.. all of the components already have the right resistors, just you would need to find the right voltage leds to run it..
     
  5. stevep macrumors 6502a

    stevep

    Joined:
    Oct 13, 2004
    Location:
    UK
    #5
    1. Get a catalogue from a good electronic supplier (RS components or Rapid Electrinics in the UK). This will give you an idea of the range of physical sizes available- usually 3, 5, 8, 10 or 20 mm dia, plus a range of rectangular ones.
    2. Try to identify the existing led's in your equipment - physical size and colour are the two obviously easy attributes.
    3. Now for the tricky bit - red and green leds are the most common, as they're cheap. Most 'standard' or common led's are not current-limiting devices, IOW if you connect them to a battery (even of the correct voltage) they will draw too much current and fail, often within a few seconds. You have to add a resistor in series with one of the legs to limit the current drawn. The easiest way to calculate this is to use a little Windows app called Electronics Assistant . If you don't have Windows, just use V = I x R, or try this web site http://linear1.org/ckts/led.php
    4. Some led's -often v.small or fancy coloured ones (eg white!) come with an internal resistor as part of the package.
    5. If you're still keen to go ahead, I would suggest getting a few spares to allow you to experiment. All led's are low voltage devices, and the only risk is that you connect them the wrong way round (solution- turn them round!) or with the wrong resistor. Use a multimeter to check polarity - led's have very low or zero resistance one way and very high or infinite resistance the other.
     

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