Please!

[Lumba Ogir]

Hi everyone,
how to simulate a fan (to fool the computer) on a 3 pin system fan connector (ground-+12V-sensor)?
Thanks.

 

[MJL21193]

Measure the DC resistance on the gnd/12V leads from the fan and match it with a fixed resistance maybe? Worth a try.

 

[Gary P]

Are you trying to get the computer to not give you the "CPU fan fail" warning at boot?

Look in the bios settings for a setting about CPU fan check and disable if possible.

 

[dangus]

Bios settings, or use the speed signal from another fan in the system. Or use an oscillator to fake a signal.

 

[Lumba Ogir]

Hi guys,

Are you trying to get the computer to not give you the "CPU fan fail" warning at boot?

Exactly.

Look in the bios settings for a setting about CPU fan check and disable if possible

That´s not an option in this custom-made BIOS/MoBo.

I once solved the problem with a resistor between sensor and ground. It does not seem to work this time.

 

[stinius]

Hi

You will need a “Pseudo Fan” to fool the controller. The controller needs to see a square wave to “think” that the fan is running.

See July/August issue of Elektor page 17.

Link:

Cheers

 

[Lumba Ogir]

dangus and stinius,
interconnecting the sensors of system fan and processor fan (which is active) would be a simple enough solution.

 

[wwenze]

If you have an extra fan and your motherboard can use speedfan, just connect the extra fan and set speedfan to auto disable to fan after booting into Windows.

That's what I do anyway. My mainboard is also OEM with no option to disable CPU fan warning. And I have a Scythe Ninja to run fanless an undervolted A64 with.

 

[Lumba Ogir]

Hi,
no success yet, fan speed control is very problematic these days...
Fan Speed Control is Cool! - Maxim
http://pdfserv.maxim-ic.com/en/an/AN1784.pdf

 

[stinius]

Hi,
no success yet

Hi

What have you tried so far without success?

stinius

 

[Lumba Ogir]

stinius,
I have a 4-wire processor fan working nicely and a 3-pin system fan connector, however, I rather need a small 2 terminal fan for the video card. Interconnecting the speed sensor outputs did not help. A hardware solution would be preferable.

 

[stinius]

stinius,
I have a 4-wire processor fan working nicely and a 3-pin system fan connector, however, I rather need a small 2 terminal fan for the video card. Interconnecting the speed sensor outputs did not help. A hardware solution would be preferable.

Hi

As I told you here you will need to make a circuit that “simulates” a fan, on the control pin.

It’s as simple as a 555 with some extra components. I can email you the circuit if you drop me an email.
You can also try it by putting a square (digital) signal on the control pin, in the 35Hz to 150Hz range.

Cheers
Stinius

 

[Lumba Ogir]

stinius,
would you please send me the circuit scheme, if I emailed you?

 

[stinius]

stinius,
would you please send me the circuit scheme, if I emailed you?

Yes.

 

[Lumba Ogir]

stinius,
file successfully received and viewed, looks very promising. Very kind of you, thanks again. I`ll tell you the outcome.

 

[Lumba Ogir]

stinius,
the circuit and everything else is working superbly. Thanks to everyone, especially you!