replacing k70 blue led

[climbalima]

My friend has a k70 that he is willing to sell to me for cheap because his leds are failing. I cant seem to find much online about switching the leds other than it may be difficult because of the voltage. Can anyone shed some light on this for me?

[merlin64]

shed some light? Pun intended? LOL

It's mainly brightness levels and colors. But I would check the resistors on the PCB just to make sure.

Use the LED calculator http://led.linear1.org/1led.wiz

Mini USB has voltage of 5V, you will have to see the specs on the LEDs you buy, plug them in and see if they are somewhat close to the resistor values already on the PCB.

[falkentyne]

Someone said that replacing the blue LED's will not do ANYTHING on the Corsair K70.
You need to check the Corsair forms for this, but basically the reason the blue LED's were dying was due to the STANDBY VOLTAGE--when the LEDs were *NOT* powered in, being twice as high as they were designed to take, so basically when rebooting the computer or turning the LED's *OFF*, they were slowly being cooked to death. 
Please don't take that as fact.  Either buy a multimeter and find the specification for the standby voltage and then measure it yourself or accept what was already said; the choice is yours.

if this is the case, then replacing them would just amount to another slow death of LEDs, and there is rumor that that was the entire reason the blue LED K70's were discontinued while the red LED K70s were not.

I'm going only from memory of what I read on the Corsair forums years ago, when all the complaints about mass dying of LED's started appearing.  it's up to you to do your own research to find out more.

[climbalima]

Someone said that replacing the blue LED's will not do ANYTHING on the Corsair K70.
You need to check the Corsair forms for this, but basically the reason the blue LED's were dying was due to the STANDBY VOLTAGE--when the LEDs were *NOT* powered in, being twice as high as they were designed to take, so basically when rebooting the computer or turning the LED's *OFF*, they were slowly being cooked to death. 
Please don't take that as fact.  Either buy a multimeter and find the specification for the standby voltage and then measure it yourself or accept what was already said; the choice is yours.

if this is the case, then replacing them would just amount to another slow death of LEDs, and there is rumor that that was the entire reason the blue LED K70's were discontinued while the red LED K70s were not.

I'm going only from memory of what I read on the Corsair forums years ago, when all the complaints about mass dying of LED's started appearing.  it's up to you to do your own research to find out more.

Thanks so I guess it's not worth trying to repair it and sell it

[tp4tissue]

couldn't you just put a resistor in there, and it'd be fine?

[falkentyne]

I really don't know.  I'm going off years old memory and evidence (after all, *I* had a dying gunmetal K70 vengeance MX red with blur LED's and I got a full refund for it via a Corsair issued check since I bought it from their shop so it's not like I'm anti-corsair).  But you need to find out what the correct standby voltage is for the LED's and then test your exact board to see what voltage it gives the LED's when they are off.

I know nothing about electronics except (nuclear explosion).

*edit*
Hope you thank me for doing this work for you.  I found the source.
Apparently posts around there were people suggesting the LED Off button was killing the LED's, as they didn't have LED's fail until pressing the LED off button.

http://forum.corsair.com/v3/showthread.php?t=121181&highlight=K70+dying+LEDs&page=7

ok so i think i know what is happening and why led burn mostly when they are turned off

the cheapest led i found that looking like the one in my k70 is KINGBRIGHT - L-7104QBC-G - LED, 3MM, BLUE, ULTRA BRIGHT http://www.farnell.com/datasheets/1519892.pdf now if you look at the data sheet it says rated voltage 3.3v and MAX reverse current 5v
while my keyboard is in use it's expose the led to up to 3.4 volt AC but while it's turn off the led are exposed to 1.7 volt AC and 4.547 reverse current DC while not outside the led spec it's terribly high and may cause early failure of the led as it's not design to have this kind of reverse current 24/7


EDIT: tested from the keyboard space bar led open lead with a FLUKE 115 meter

when i look at my keyboard the led that are dead are the one i don't turn on and there 5 or 6 that are about to go from what i can see

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Last edited by Krawm; 02-10-2014 at 03:53 PM.

[tp4tissue]

welll.. maybe install a power switch on the usb line so you guys can turn it off  ? hahaha