Question z87 motherboard fans refuse to respond. Anyone have any ideas?

[SugarTech]

I have an older motherboard, sabertooth z87. Recently I had to replace my PSU, reinstall windows 10 and ever since my motherboard assist fans have gone whack.

The assistant fan 1 is going on full turbo all the time (8000rpm) and the noise of it is driving me crazy. I imagine it's not good for the longevity of the fan either. No amount of changing the profiles in bios does anything. Silent, standard, manual, or off. Nothing.

Assistant fan 2 RPM is not being read for some reason but definitely is spinning, but at a normal rate as far as I can tell.

I installed thermal radar 3, running in windows 8 compatibility mode, and it also does nothing. I'm fact all my other fans started acting strange, so that just made it worse.

I do have the latest bios version. The assist fans cannot be changed to pwm; they are only 3 pin.

I'm on windows 10. I went from a corsair 850 gold to an evga 600 bronze if that had anything to do with it. Also my motherboard and cpu temps are at 30-35 degrees.

I have no idea what to do at this point. Can anyone assist?

 

[Fix_that_Glitch]

What model are the fans?

 

[SugarTech]

What model are the fans?

Hi. I can't say for sure. These are the original fans that came with the board, 35mm. I looked everywhere for a model number but it's not stated anywhere.

The closest I came are these with the exact same sticker: Ebay link

 

[scout_03]

could you post a picture where those fans are on the system since they are 3 pins fans they will always run at max speed and your board have 4 pwm connector so could be a better option to get these kind of fans .

 

[SugarTech]

could you post a picture where those fans are on the system since they are 3 pins fans they will always run at max speed and your board have 4 pwm connector so could be a better option to get these kind of fans .

As per your request.

As we can see, they are just 3 pin connectors. It still begs the question why this behavior occurs now and why UEFI gives me any options to regulate speed. I do not recall having this issue before.

If my board is faulty somehow I would rather know! Would resetting my battery do anything?

 

[Eximo]

It is possible the voltage control coming from the motherboard has simply failed, or an associated temperature sensor.

PWM rapidly turns on and off 12V to control fan speed.
You can still control a 3-pin fan through voltage and/or PWM so most motherboards support both.

Try swapping the fans and see if if does anything.

I think your best option is to get replacement fans (since they are probably due) and then connect them to one of the other fan headers or get a USB fan controller and control them that way.

 

[SugarTech]

It is possible the voltage control coming from the motherboard has simply failed, or an associated temperature sensor.

PWM rapidly turns on and off 12V to control fan speed.
You can still control a 3-pin fan through voltage and/or PWM so most motherboards support both.

Try swapping the fans and see if if does anything.

I think your best option is to get replacement fans (since they are probably due) and then connect them to one of the other fan headers or get a USB fan controller and control them that way.

I do fear something has broken, but I'm getting conflicting messages that either 3 pin fans cannot be speed regulated, but you say they can be.

 

[Eximo]

Not sure where the idea that 3-pin fans can't be controlled comes from.

Resistive loading is the simple way, drop the voltage across a resistor and waste some power as heat. Many physical knob/slider fan controllers work this way. Or pulse the 12V you got and you can simulate an RMS of a lower voltage. Modern motherboards pretty much stick to the latter method since they are usually 4-pin PWM headers.

If I recall, my Z87 had an option to switch from PWM to Voltage control, though that board didn't have motherboard fans. So I suspect they have hard configured voltage control headers for the motherboard fans, if that circuit has failed, and the failure mode is "always on", which is hopefully how they would have hoped it would fail, then my suggestions before are your best bet.