Changing Fan LEDs

[Fuganater]

How hard is it to change Fan LEDs? I can't find new pink UV ones for my wife's computer so I figured I would just get white ones and put pink LEDs in them. Do I need to worry about a new resistor?

Help appreciated.

[TheMainMan]

Look carefully at the type of LED used in the fan before you buy. I've swapped LEDs in a few different styles and depending on how the LED is installed they can be really easy or really hard. Fans that are lit from the four corners usually have a 3mm LED or occasionally even a 5mm LED (like most Cooler Master fans. Some fans have SMD LEDs on a band that light around outer part of the round frame, though in my experience these are quite rare. On small fans, like the 60mm ones on most RAM coolers, the LEDs are mounted to a central circuit board and will be tiny SMDs.

I've never had an issue with resistors, though to be honest, I've only ever gone from blue to red LEDs. I'll gladly answer anything else I can, I've had some frustrations swapping LEDs on fans in the past.

[Fuganater]

I could have sworn I ordered some fans... but I can't figure out from where lol! Once I figure out which ones I got I'll let you know.

[Konrad]

Another way to change the colour is to use LED condoms.

I don't mean this kind:

I do mean this kind:

They are apparently quite popular with automotive and pinball-machine people, not sure why.

[AmEv]

Ohhhkayyyyyyyyyyy.....



I think the reason is so they can order 100,000 white LEDs at super-cheap and get the covers, also super-cheap.

[Fuganater]

So I got 4 of theses: http://www.frozencpu.com/products/13...tl=g36c331s518

How do I know what voltage the LED's are running at? Once I know that I can figure out what size resistor I need.

[Konrad]

I'm not familiar with that specific fan, but it seems very likely the LED draws about 20mA from 12V through a 470 Ohm resistor. Look here. Values are not critical, especially since the fan itself is probably dumb (ie: contains no integrated logic) and rated for anything between about 7V and 14V, although it'll work slower and dimmer at lower voltages; if you use a fan controller you might notice the LED brightness varies with rpm settings.

There's probably already a resistor before the LED, you can easily check its value with a meter without even pulling it out of circuit (although still wise to first disconnect the fan from your mobo or power source). It's unlikely the resistor is integrated with the LED semiconductor within the same package because of heat issues and because such a nonstandard part would cost a tiny bit more.

You can buy a pile of LEDs and resistors for a buck, then experiment and blow a few out without any great loss. You might be able to purchase dollar-store junk with matched LED/resistor components already integrated, or alternately salvage them from any random 12V automotive accessory. Almost all PC mobos contain regulators which won't allow dedicated devices (like fans) to draw excessive power and cause damage, although LEDs are pretty insignificant anyhow so no need to worry.

[Fuganater]

I'm going to bring home a fluke from work and I'll check them out. LEDs should be here soon.

[Konrad]

Take note to match polarity of the new LED with the one you removed; it's a diode device with anode/cathode. In simplest terms, just make sure the squared/flattened and the rounded pins on the new part match the placement of those on the old one. Plugging an LED backwards certainly won't work and is likely to damage it (although there are special LEDs which operate differently); the resistor and fan motor are not polarized thus won't be damaged by a backwards or nonfunctional LED, nor will the mobo.

[Fuganater]

I think the resistors are on the board because there isn't one inline. I'll take pictures tomorrow.