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blueswitch
11-17-05, 04:41 PM
I bought some LED's from cooler guys
http://www.coolerguys.com/840556000235.html

Now im trying to figure out what the rules are for soldering these guys...what I really want to do right now is replace my HDD activity light since it broke...I was just going to take the chord from the old HDD activity light and solder this new one on. Is that ok to do?...also I was surprised to see these LED's have three prongs...I was only expecting two + - so..whats up with that?
SolidxSnake
11-17-05, 05:19 PM
OH. they are dual LEDs. if you hook it up one wya, it'll glow white, one way it'll be red.

from the looks of it, you put power to the middle lead, and then put negative to either of the outer leads. but if thats wrong, the LED will still work, just reverse them.

Get a power source, and try each combination.
blueswitch
11-17-05, 05:37 PM
ok your gonna laugh probably but just stuck the prongs over a 9v battery. short one is negative..the middle one is white the outside is blue. After doing it a couple times the thing burnt up. I saw on cooler guys site about using different resistors...so what do I have to run to radio shack so these things don't blow? Here is what cooler guys said:


# Voltage: norm 3.2v - max 3.5v (white)
# Voltage: norm 3.0v - max 3.5v (blue)

USAGE
White and Blue:
# 100 Ohm resistor for 5v supply
# 470 Ohm resistor for 12v supply

so can someone explain this to me real quick...I know on a molex yellow is 12v and red is 5v. What about HDD activity light?..just need a crash course answer so I know what to do with these.
bchur83
11-17-05, 05:47 PM
For the HD activity light, you dont need a resistor. They already have them on the board.
blueswitch
11-17-05, 05:49 PM
For the HD activity light, you dont need a resistor. They already have them on the board.

ok but if I were to come off of a PSU rail...then I would?..and it looks like Id run it off the 5v rail (red) correct?
SolidxSnake
11-17-05, 05:50 PM
ok but if I were to come off of a PSU rail...then I would?..and it looks like Id run it off the 5v rail (red) correct?


IF you plug it into the board, it won't run off the 5v rail.
blueswitch
11-17-05, 06:20 PM
IF you plug it into the board, it won't run off the 5v rail.

no I know that...this is for future reference.
SolidxSnake
11-17-05, 06:34 PM
no I know that...this is for future reference.


Oh, then you get a 100ohm resistor. RS has em, as does LSDiodes (which is where i reccommend buying anything LED related)

www.lsdiodes.com

VERY cheap prices.
blueswitch
11-17-05, 06:36 PM
Humm...so I soldered the new LED in to work as the HDD activity light....but it won;t go....I even soldered the old HDD LED inline with it and the old LED glows but not the new....is it possible the new LED's take more juice than what the MOBO puts through that activity monitor?
bchur83
11-17-05, 07:08 PM
Did you put it in correctly? LEDs have a polarity.
blueswitch
11-17-05, 07:10 PM
yup even switched it around just to make sure
subtotal
11-17-05, 07:22 PM
maybe the problem was with the wire or connection rather than the LED
SolidxSnake
11-17-05, 07:26 PM
try all different combinations of wires, cause its a 3-lead LED.
kayson
11-17-05, 07:49 PM
If you have a digital multimeter, test the voltage you're getting to your led. It's quite possible that if your LED is big enough its not getting enough juice, in which case you should bypass a resistor on the circuit.
Captain Slug
11-17-05, 08:00 PM
Nothing I can recommend for bypassing the motherboard LED activity lead would be within your level of expertise.
The HDD activity lead off of the motherboard generally supplies 2.5 volts so it may or not not be able to supply the LED you purchased. You may want to try another LED to make sure it's not your motherboard lead that's defective.
blueswitch
11-17-05, 08:48 PM
Nothing I can recommend for bypassing the motherboard LED activity lead would be within your level of expertise.
The HDD activity lead off of the motherboard generally supplies 2.5 volts so it may or not not be able to supply the LED you purchased. You may want to try another LED to make sure it's not your motherboard lead that's defective.

I think that it's not enough juice then...they are rated at 3v for blue and 3.2v for white....I have a red LED hooked up now that works so it's not the mobo...these must take more juice.
Avatar28
11-17-05, 11:47 PM
Yes, blue LEDs do generally take more voltage and aren't as efficient as red ones. You might be able to locate a suitably low voltage blue LED for what you're attempting if you search around enough. Otherwise you could probably built some sort of a circuit to bump up the voltage slightly to drive the blue LED but I probably wouldn't bother with that myself.
Navig
11-18-05, 12:09 AM
For future reference, take a look at various LED faq sites such as:

linear 1 (http://led.linear1.org/)

especially take note of the LED wiring/resistor wizard.

navig
Nebuchadnazzar
11-18-05, 01:10 AM
it's too bad they didn't give the current rating of those LEDs cause you could find the perfect resistence for max brightness. if you are going to hook it up to 5V then put a 100ohm resistor in series like others have mentioned.
Red leds can usually work at low voltage, so it should glow with 2.5v, it may not glow with a second led in series with it, because then the 2.5v is split even lower over the leds.