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Discussion Starter #1
Hi,

My LED's finally arrived this morning and I've got another question. I bought a pair of these (one red, the other green). There's no info regarding the max limits on voltage or amps.

What I've done so far is to simply get a 3v disc battery (CR2025 - which I found in my iStation remote) and directly connect the LED's to that, which worked perfectly fine.

From my motherboard manual, I have the following info about the front panel header pins:

Quote:
HD_LED
Pin: 1 - HD_PWR - Out - Hard Disk LED pull-up to +5V
Pin: 3 - HDA# - Out - Hard disk active LED

PWRLED
Pin: 2 - HDR_BLNK_GRN - Out - Front panel green light
Pin: 4 - HDR_BLNK_YEL - Out - Front panel yellow light
Keeping in mind that I actually have little to no understanding of volts and amps, would it be safe to simply get my wire and attach it to the LED's at one end and the motherboard at the other?

Also, which pin would connect to what? Because to get the LED to light up, both pins have to connect to something which completes the circuit, right? When I pinched a battery between the pins on the LED, it would only light up if the anode was touching the positive side of the battery and the cathode was touching the other side. So how is the circuit completed with the header pins?

Thanks.
 

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you dont need resistors. as stated, the headers can draw up to +5V. Typical LED's have a switch on voltage of 1.7V, ie, they use about 1.7V minimum.

Polarity of the diode does matter. (where positive and negative are connected to)/ You connect the legs of the LED to the wire that comes off the motherboard saying PLED or PWRLED or something similar. And similarly, HDDLED or HDLED for the other LED. You know when you connect up the lights normally to the motherboard? the stuck together cables that are usually the power switch button, reset sw, etc etc? Well just follow the Power and HDD cables to the LED's which they are attached.

Disconnect the original LED's and wire your new ones in place.

If the LED'a dont light up the first time (provided you connected the wires correctly), it means the LED is in reverse bias mode, where the led has infinitely high resistance, and no current flows through it..... a bit off topic, but i throw it in anyway.

Common sense tells you to reverse the orientation of the legs of the LED and it should work.

Sorry for the essay, lol.

Good luck
 

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if i can better explain...

headers pins from mobo --> LEDs and switches at front of case.

What you want to do is replace the existing LED's with your ones. Just cut them off, and solder in your new ones, and hey presto!
 

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Discussion Starter #5
Thanks for the replies. I'm going to try it out with the Power LED tonight or tomorrow and I'll post back.
 

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Discussion Starter #6
Done it. I used a 2-pin motherboard header and put the LED directly into that. I'm only testing it for now, when I do it properly I'll wire it and move it into its proper location, but for now it's just sitting on the motherboard. Works flawlessly.

film_go.png
 

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the motherboard power/HDD headers typically use a nominal 3.3V output, which is fine for most LEDs (even those rated at 1.8V and those for 5V) since the output is also current limited and will not burn out the LEDs.
 
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