Led fan how to wire?

[gui dube987]

Hello, i bought a 140mm fan with blue led wich is in front of my case and i would like to plug it with my switch button in the back of my case wich is a on/off button for my 2x 200mm fan on top with blue led too.. but the problem is that my front fan is a 3 pin connector only and my stich button is a 2 pin..
is there a way i could plug them together?
here are some picture

140mm front fan






switch button plug on/off for led



Thx

 

[dtrunk]

custom job... i'd assume the 200mm fans have two leads, a lead to power the fan, and then a lead that plugs in to this 2-pin you show above. the two pin actually controls the LED power, not the fan. is this the case?

it's hard to know for sure, but i'd assume the three pin is a standard 3 pin (power,negative, rpms) and that you'd have to modify the 140mm fan to be able to switch on/off the led.

Most likely, the LED+ lines have a resistor inline on the circuit board. if this is the case, you can't simply re-route the power lines to the switch connector. it's hard to tell. do you have a volt meter? can you read the volts coming off of the circuit board LED+ solider point? maybe trace the LED wires to see if there is a bulge where the resistor is inline with the wire.

if the LED+ lead is 12v on all solider points, then this will be an easy mod.

 

[gui dube987]

Thanks for your quick answer, im not home right now so ill check it later when im back, ill give you some news about it, thanks for helping

 

[gui dube987]

So i tested the voltage like this, i dont know if this is right but thats how i tried it..


tried the red circle with all the yellow one and didn't seem to have 12v anywhere :S

there is how i put my volt meter


and this is what i see from the other side of the fan


but i dont see any resistor on the board..


so i dont know what i can do?

 

[Bobnova]

The fan needs to be plugged in to test the voltage. Plug it in and test the voltage between the two leads of one LED while the thing is running. If it's 12v you're in luck.
If not, there are still options, they're just more complicated.

 

[gui dube987]

the 2 lead u mean the grey and black wire of a led? if yes i tried this too when it was plugged in and it wasnt 12v..

 

[Bobnova]

What was it? Something in the 2v to 3.3v range?

 

[gui dube987]

yes exactly, 2.69v

 

[Bobnova]

In that case you're going to need to desolder (or cut) all of them and redo the wiring.
You can wire all four in series (black to grey) and through an 82 ohm 1/4w(or larger) resistor (on just one of the wires) then then to the controller plug.

 

[gui dube987]

so you mean i wire these together? i need 4 resistor and to wich wire i wire them to the switch? and for the green color, the grey wire is solder with an other black wire, what do i do with it?


Thank you very much for helping

 

[gui dube987]

well how i think, this doesnt work at all

 

[gui dube987]

how would you wire them in series?

 

[dtrunk]

so you need to CUT each LED set of leads as close as possible to where they're soldiered. RED slices in the picture, the bottom lead you'll have to lift the power in leads to get as close *** possible.
the thin pink lines represent wiring the fans in series, you essentially need to wire black from one to white of the next; but only on three leads.
this will leave you with one white and one black
the last white lead (or is that greay) is the power in and needs a resistor inline (you can use a LED calculator to figure out the size of the resistor OR someone here might be able to help you figure this out) brown and yellow blob in picutre
the other side of the resistor will be wired to run to the HOT lead of 2 pin you pictured
the leftover black wire can be jumped to the GROUND lead on the 2 pin

 

[gui dube987]

thank you very much, thats what i needed, ill try this and give you news about it

 

[dtrunk]

did you test the lead of the LED button? you should, and make sure it's 12v.

another option would be to wire them all in series and then directly to the 2 pin. at almost 2.7v x 4 LEDs = ~12v. the issue here is, WARNING, too much voltage burns out LED either immediately, or over time. so the resistor is to bring the voltage down to 2.7v x 4 = 10.8v (ish)

you can pick up an expensive pack of 10 to 50 misc resistors for $5 at radio shack; you'll only need the one in whatever watt size you determine. resistors generally cost about $ 0.001 - 0.005 each, yes, that cheap.

 

[gui dube987]

i did everything and the led dont turn on when i turn the switch on, they turn on when the switch is off :O Like my 2 top led fan turns on but not the front one and when i turn off the 2 top led fan the front one light up?

 

[Bobnova]

Measure the voltage between the two connectors on the switch lead with the switch on and the switch off. They may be doing something odd there.

 

[dtrunk]

you have the leads backwards?

that or the switch could be something special, like a on1 > on2 > on1+2

 

[nrbxbuev]

you can't simply re-route the power lines to the switch connector.

 

[gui dube987]

Do you know an other 140mm fan with blue led which would be easier to use with my switch? Cause im not really good with electricity..