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Electronics Need Help w/LED Switch wiring

Discussion in 'Modding' started by Espie79, 20 Sep 2011.

  1. Espie79

    Espie79 What's a Dremel?

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    Hi All,
    I am working on my 1st case mod and bought some LED switches for the power and reset buttons. No instructions came with the switches so I need some help.

    I have attached a photo of the pin layout on the switches. I need to know how to wire the switches so the LED's come on when the power is on. At the moment, the power stays on when the computer is turned off.

    I wired the switches + and - to a molex connector but I think this is perhaps where I went wrong. Please help. I need to know how it should be wired.

    [​IMG]
     
  2. Archer

    Archer Talga Vassternich - Deserve Victory

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    First question - did you get momentary switches? You need these for power and reset, a latching switch wont work at all. Just double checking :)
    As for the LEDs - on your motherboard (usually bottom right) you have all those pins for HDD activity, power LED, power on/off etc. This is where you want to get power for the LED inside the switch, not a molex connector. You should see something like "-pwr LED+" this is the one you want. Make sure you get the polarity correct obviously.
    Now if you answered yes to the first question this isnt required, but just in case - to actually use it as a power switch you wire the C1 and NO1 contacts to the power on/off pins on the motherboard. Mine says "+PW-"
    Do the same with the reset button, and for the reset button LED most people wire it up to the HDD activity light on the motherboard.

    If there is anything else just shout :)
     
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  3. Espie79

    Espie79 What's a Dremel?

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    Thanks for your quick and informative response. I found the headers PLED on the motherboard which is what I was after. The only problem is, I don't get enough power to the switches and power LED as they don't come on. I isolated the circuit with 1 LED and it bareley lit up. Is there some way of getting more power as at the moment, there isn't enough.
    Thanks
     
  4. Archer

    Archer Talga Vassternich - Deserve Victory

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    Could you post a link to the switch you have? I wired mine up this weekend and it worked fine (Bulgin switches). There should be ±3V on the mobo pins when powered on, this is enough to light up an LED. If you have the same kind of switch as I do then no resistor is required, that would also cause the LED to be very dim.
     
  5. Espie79

    Espie79 What's a Dremel?

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  6. Archer

    Archer Talga Vassternich - Deserve Victory

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    Did you get the 12V LED switch? If so that would explain the dimness - the LEDs are rated for 12V, not the 3.3V from your motherboard. The Bulgin switches I got have LEDs rated at 3 - 12V which means they work perfectly with the 3.3V from the motherboard. The one you linked to looks like they need at least 12V, so 3.3V is way too little. That and you say they are latching switches :(

    The good news, your motherboard is most likely fine :)
     
  7. Nexxo

    Nexxo * Prefab Sprout – The King of Rock 'n' Roll

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    Not all switches are created equal. Some have a resistor built in for the LED. The specifications in the eBay link clearly state that the supply voltage for the LED is 12V.

    So my advice is to ditch the switches and buy some nice Bulgins, momentary switch, 3V supply to the LED.
     
  8. Espie79

    Espie79 What's a Dremel?

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    I have found a work around. I can still use the switches because they don't actually latch like they should. You have to press really hard for them to latch so they generally wrk like a momentary switch....thank God for cheap dodgey switches. I got around the LED power buy connecting the LED switches and power light to a fan header. Now it works fine, except for the HDD activity light which doesn't seem to be working at all no matter what I do....I'm pretty sure there is something wrong with the motherboard....I think that might be why it was in storage, I think I might have had problems with it in the past.
    I will check it out though later with my already working PC. Thanks for all the help though.
     
  9. PabloFunky

    PabloFunky What's a Dremel?

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    You will find that that is a deliberate feature, so you can push lightly for momentary or harder for latching.

    I could draw you a circuit to convert a momentary switch to a latching one, but not the other way around.(well i prob could, but cant think off hand)

    Do you have a meter, then its easy to work out a mom.switch operation

    Its a pretty basic thing to learn how a switch works, once you know how to do it, youl always remeber.
     

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