Disabling 120mm case fan LEDs; Can I just cut the traces?

alfa147x

Lifer
Jul 14, 2005
29,307
105
106
Quick question, I have 2x 120mm casse fans with BRIGHT Blue LEDs. One on the HSF and One zip-tied into the 5.25 drive area ;). The problem is I like my bedroom dark, I HATE how bright my room gets from the fans. I could just order some cheap fans from newegg but I don't want to if I don't have to. So my question is, can I just cut the traces that are connected to the LEDs on them?

I have something like this:
54336368.jpg


Thanks ATc&c,
Alfa147x
 

alfa147x

Lifer
Jul 14, 2005
29,307
105
106
Found this:
Ok I figured it out. There's a small wire that runs along the bracket of the fans, if I snip that wire the LED cannot turn on. That apparently is the only way to disable the blue LED lights on the Nine Hundred.


Figure I'd post that since I've seen a lot of posts by people saying they'd like the Nine Hundred case for the cooling, but do not like the look due to the LEDs.

If I don't get any "DONT DO IT!" type post by 1500 I'll do it and report back
 

Fallen Kell

Diamond Member
Oct 9, 1999
6,145
502
126
You "should" be able to, but it all really depends on how they wired them. If they are in series with the motor power, then cutting them will cause the circuit to "open" and thus, not power will flow through the motor and it will not spin the fan. If they are wired in parallel (and probably should be) to the fan motor, cutting them will be fine.
 

alfa147x

Lifer
Jul 14, 2005
29,307
105
106
Can I some how figure out how it's wired? I'm no loger doing this today, crazy sore after my PFT this morning ;)
 

Rubycon

Madame President
Aug 10, 2005
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I've done this many times. Cut ONE lead as close as you can to each LED. A GOOD pair of dikes is all you need. Nice thing is this is reversible just by bridging the small gap with a tiny drop of solder. :)
 

alfa147x

Lifer
Jul 14, 2005
29,307
105
106
I've done this many times. Cut ONE lead as close as you can to each LED. A GOOD pair of dikes is all you need. Nice thing is this is reversible just by bridging the small gap with a tiny drop of solder. :)

Ah so the motor and LEDs are in parallel but the LEDs themselves are in series?
 

Rubycon

Madame President
Aug 10, 2005
17,768
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Ah so the motor and LEDs are in parallel but the LEDs themselves are in series?

The LEDs are powered by the power supply. The motor is brushless and its circuitry is independent of the LEDs altogether. (one way to verify is turn the blades fast - if the LEDs glow then the motor is in parallel with the LEDs) Some LEDs may be in series while others may have dropping resistors and others still may be powered off a driver maintaining brightness regardless of voltage input. If you want to disable the LED you can be cutting one lead - does not matter if it's the anode or cathode. Some use a flexible pcb ribbon with the LED packages directly soldered. You can cut this through (making it permanent) or if you have decent (de) soldering skills removing the solder around the lead isolating it from the pad will also squelch the LED. (personally I find it easier to purchase non LED fans which are better quality. ;) )
 

alfa147x

Lifer
Jul 14, 2005
29,307
105
106
The LEDs are powered by the power supply. The motor is brushless and its circuitry is independent of the LEDs altogether. (one way to verify is turn the blades fast - if the LEDs glow then the motor is in parallel with the LEDs) Some LEDs may be in series while others may have dropping resistors and others still may be powered off a driver maintaining brightness regardless of voltage input. If you want to disable the LED you can be cutting one lead - does not matter if it's the anode or cathode. Some use a flexible pcb ribbon with the LED packages directly soldered. You can cut this through (making it permanent) or if you have decent (de) soldering skills removing the solder around the lead isolating it from the pad will also squelch the LED. (personally I find it easier to purchase non LED fans which are better quality. ;) )

Thanks for the info


Honestly I don't want to spend money on new fans ATM but I wouldn't mind so if I fuck these oh well. I them for free from a friend so meh ;)

Thanks again
Alfa147x
 

Rubycon

Madame President
Aug 10, 2005
17,768
485
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LED packages are quite tough. I've zapped them with a NdYAG pump laser (80W 808 nm). Liquid electrical tape (cover it up!) also works too. ;)
 

somethingsketchy

Golden Member
Nov 25, 2008
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LED packages are quite tough. I've zapped them with a NdYAG pump laser (80W 808 nm). Liquid electrical tape (cover it up!) also works too. ;)

I've heard black nail polish also works well on LEDs for fans. Haven't tried it out myself, but that's what I've heard. Also the above mentioned liquid electrical tape works well
 

Rubycon

Madame President
Aug 10, 2005
17,768
485
126
you can always just mash the soldering iron into the led ?

It can also cause them to short together which is not good.

I've heard black nail polish also works well on LEDs for fans. Haven't tried it out myself, but that's what I've heard. Also the above mentioned liquid electrical tape works well

Black nail polish will need a few coats though as it's surprisingly transparent.
 

TheStu

Moderator<br>Mobile Devices & Gadgets
Moderator
Sep 15, 2004
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I cut the wires on a 120mm fan with blue LEDs, it worked just fine.
 

daw123

Platinum Member
Aug 30, 2008
2,593
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I don't think they are as fragile as fluorescent lamps

LED packages are quite tough. I've zapped them with a NdYAG pump laser (80W 808 nm). Liquid electrical tape (cover it up!) also works too. ;)

I crushed an LED in my electronics class at school using a mechanics vice, like one of these:
REC25.jpg


It still worked afterward.

They're tough little bastards and difficult to destroy.
 

alfa147x

Lifer
Jul 14, 2005
29,307
105
106
Today I got around to trying to disable the LEDs. The problem is that the targeted case fan is zip tied into the 5.25 drive slots, I don't have zip ties here :(

So I can't really take the fan out of the computer to preform the surgery. I got to the fan and it had two wires going to one of the four leds. I was trying to cut both but they where too thin and I cut both :\ after testing this killed 2 of 4 LEDs.
X----X
|......|
|......|
X----X

The bolded LEDs are dead :D

My question is: if I cut two more wires going to a live LED will my fan still run?

Thanks guys!