Any Cheap Method for running DC fan from PWM Signal?

[Jay Deah]

Just got myself a LANCOOL II case that includes 3x DC Fans.

 

Then motherboard i'm using is a lenovo prebuilt and it has 3x PWM case fan headers. Unforunately 2 of them need to be plugged in for the system to POST. If i connect a DC fan it posts fine but the fans fun @ 100%

 

What i'm after is a cheap alternative to running out and buying PWM fans to replace the included DC fans, retaining the fan speed control

 

do i have any options?

[Zagna]

Phanteks PWM Fan Hub takes in a PWM signal and has 6 3-pin outputs.

[Streetguru]

45 minutes ago, Jay Deah said:

Just got myself a LANCOOL II case that includes 3x DC Fans.

 

Then motherboard i'm using is a lenovo prebuilt and it has 3x PWM case fan headers. Unforunately 2 of them need to be plugged in for the system to POST. If i connect a DC fan it posts fine but the fans fun @ 100%

 

What i'm after is a cheap alternative to running out and buying PWM fans to replace the included DC fans, retaining the fan speed control

 

do i have any options?

Just get a DC fan controller from ebay/aliexpress

[Jay Deah]

5 hours ago, Zagna said:

Phanteks PWM Fan Hub takes in a PWM signal and has 6 3-pin outputs.

for the price of 2 of those i may aswell just buy some PWM fans

[LogicalDrm]

12 hours ago, Jay Deah said:

for the price of 2 of those i may aswell just buy some PWM fans

You would only need one. CPU fan should have PWM already. Or if you are using AIO, both pump and fans are PWM.

[Jay Deah]

swapped the SYS_FAN to PWM and it now POSTS without AUX1_FAN connected which is good...

read the reviews of the case and people said the fans it comes with are average anyway.

 

slightly more concerning is that the fan rams up to high RPM as the OS loads. the mobo is from a Lenovo workstation (its running a Xeon 12755v6) so possible it's "supposed" to be 100% fan speed.

 

hopefully i can do something with software fan control..

[LogicalDrm]

23 hours ago, Jay Deah said:

swapped the SYS_FAN to PWM and it now POSTS without AUX1_FAN connected which is good...

read the reviews of the case and people said the fans it comes with are average anyway.

 

slightly more concerning is that the fan rams up to high RPM as the OS loads. the mobo is from a Lenovo workstation (its running a Xeon 12755v6) so possible it's "supposed" to be 100% fan speed.

 

hopefully i can do something with software fan control..

Ramping up on boot is normal for older mobos. Its part of normal POST procedure.

[Jay Deah]

if you read what i said, it doesnt RAMP on POST. it rams after POST. and it's not an older mobo. the 1275 v6 is Kaby Lake.

 

The BIOS has some Thermal settings in it with some presets so i'll tweak that.

[LogicalDrm]

3 hours ago, Jay Deah said:

if you read what i said, it doesnt RAMP on POST. it rams after POST. and it's not an older mobo. the 1275 v6 is Kaby Lake.

 

The BIOS has some Thermal settings in it with some presets so i'll tweak that.

You can also try this one:

 

[Jay Deah]

Turns out the reason the fans were running so fast was that the plug in case temperature sensor wasnt connected. I omitted this when I transferred the board to a new case.

 

Guess the system must have gone into some kind of fault mode with no signal from this sensor and ramped up the fans. Now with this connected the CPU, SYS and AUX1 fans all run at sensible speeds. Unfortunately AUX2 still runs loud so I'm just going to run a splitter off of AUX1 for my third fan.