Please!

Lumba Ogir · 5th November 2009, 11:33 PM

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

MJL21193 · 5th November 2009, 11:49 PM

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 · 6th November 2009, 04:02 AM

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 · 6th November 2009, 06:52 AM

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

Lumba Ogir · 6th November 2009, 08:55 AM

Hi guys,

Quote:

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

Exactly.

Quote:

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 · 6th November 2009, 10:09 AM

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 · 6th November 2009, 10:21 AM

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

wwenze · 6th November 2009, 12:45 PM

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 · 7th November 2009, 10:06 PM

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 · 7th November 2009, 10:42 PM

Quote:

Originally Posted by Lumba Ogir

Hi,
no success yet

Hi

What have you tried so far without success?

stinius

5th November 2009, 11:33 PM	#1
Lumba Ogir Banned Join Date: Apr 2005 Location: Stockholm	Please! Hi everyone, how to simulate a fan (to fool the computer) on a 3 pin system fan connector (ground-+12V-sensor)? Thanks.

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5th November 2009, 11:49 PM	#2
MJL21193 Account disabled at member's request Join Date: Mar 2007	Measure the DC resistance on the gnd/12V leads from the fan and match it with a fixed resistance maybe? Worth a try.

6th November 2009, 04:02 AM	#3
Gary P diyAudio Member Join Date: Apr 2002 Location: Portland OR	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.

6th November 2009, 06:52 AM	#4
dangus diyAudio Member Join Date: May 2004 Location: Vancouver Island	Bios settings, or use the speed signal from another fan in the system. Or use an oscillator to fake a signal.

6th November 2009, 10:09 AM	#6
stinius diyAudio Member Join Date: Oct 2008	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

6th November 2009, 10:21 AM	#7
Lumba Ogir Banned Join Date: Apr 2005 Location: Stockholm	dangus and stinius, interconnecting the sensors of system fan and processor fan (which is active) would be a simple enough solution.

6th November 2009, 12:45 PM	#8
wwenze diyAudio Member Join Date: Mar 2008	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.

7th November 2009, 10:06 PM	#9
Lumba Ogir Banned Join Date: Apr 2005 Location: Stockholm	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

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