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Problem with PWM mode on CHA_FAN4 connector - Maximus VII Hero

Rixcoast
Level 7
Hi. First time poster! Having a strange problem with my new Maximus VII Hero MB and my case fans.

I've got four Cooler Master Jetflo 120 red LED PWM fans around my case. They are all connected to the CHA_FAN 1 to 4 connectors on the MB. I've set the fans to PWM in the BIOS.

The fans connected to 1, 2 and 3 behave as I expect - the LEDs stay on continually and the fans turn on and speed up as needed.

However, the fan connected to CHA_FAN4 behaves like it is in DC mode - the fan LEDs get brighter and dimmer depending on the fan speed, and it's speed can not be set as slow as the others.

I have swapped the connectors around so I know I don't have a faulty fan. Have also tried resetting the CMOS and updating the BIOS.

I'm inclined to think there is a problem with the CHA_FAN4 PWM driver but just wondered if anyone had any suggestions?

Thanks.
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15 REPLIES 15

thumbfu
Level 7
I have this same problem. Noctua NF-F12 fans, in the PWM2 connector the fan works fan, in PWM4 the fan has issues running at low rpm.

n0xlf
Level 7
Add me to the list with this issue...

Tuxxy_Thang
Level 8
Rixcoast wrote:
Hi. First time poster! Having a strange problem with my new Maximus VII Hero MB and my case fans.

I've got four Cooler Master Jetflo 120 red LED PWM fans around my case. They are all connected to the CHA_FAN 1 to 4 connectors on the MB. I've set the fans to PWM in the BIOS.

The fans connected to 1, 2 and 3 behave as I expect - the LEDs stay on continually and the fans turn on and speed up as needed.

However, the fan connected to CHA_FAN4 behaves like it is in DC mode - the fan LEDs get brighter and dimmer depending on the fan speed, and it's speed can not be set as slow as the others.

I have swapped the connectors around so I know I don't have a faulty fan. Have also tried resetting the CMOS and updating the BIOS.

I'm inclined to think there is a problem with the CHA_FAN4 PWM driver but just wondered if anyone had any suggestions?

Thanks.


I do not think the fan problem you describe is just on the M7h, I have the same problem on M7F, which I was about to post when I found your post.

I have 2 fans connected separately to CHA_FAN1 and CHA_FAN2. The AI suite only recognizes the one on CHA_FAN2 as does hwmonitor and all other monito software. When I do the spin down function in the AI+ suite to identify which is which, both fans stop, which could be a case of the software is crap. The BIOS seems to see they are there as DC fans but any attempt to manually tune them over a temp range results in max power across all temps.

The only software that seems to see both the dc fans is the Corsair Link program but that too is problematic.

So I think it is a general Maximus 7 problem.
ROG CROSSHAIR VII HERO

csimon
Level 10
I have a similar issue with CHA_FAN4. I have NB-eLoop B12-P PWM fans on all headers. It is especially noticeable after I optimize fans through bios or Ai suite 3 that all fans will set min speed at around 800 rpm but fan4 header will always be around 1000prm min or better.

Then as temps drop and fans spin down fan4 stops completely while the others turn, even if I have the "stop fan" unchecked in software. I just thought that this was how the motherboard was programmed so I haven't worried much about it, and I've uninstalled the software since then.

Would be nice to get this resolved so I could reinstall software.
ROG Strix Z790-H (2503) | 13700K-57/55 (LLC6) | Heatkiller/Monsta | DDR5-6800 (2X32) | RTX 2080 | RM850x

Raja
Level 13
From HQ:

"So far we can’t replicate the Cooler Master Jetflo 120 red LED PWM fan issue, they’ve tried on Chassis Fan4 with M7H and set to PWM mode under the BIOS, the PWM mode works fine under the AI Suite, even the AIDA64 works fine as well, the version for BIOS is 1104 and APP is AI Suite 3 V1.00.70, the OS version is Win7-64"

41464

Hi all,

Someone managed to resolve this issue or all comes down on asus inability to replicate it and we should move on.

I also have bios version 1104 and all fans are jetflo and same symptoms as people above.

If Asus agree they can send me their perfectly working mb and I will send them mine so they can replicate issue all day long 🙂
and hopefully find a solution.

By the way Asus, I have exactly the same graph as you in previous post. Controlable range for my fan 4 also starts at 18%, wether all others
starts at 11%. And led brightness depends on rpm yes? Like in dc mode? Brightness on all other fans is max on all rpm.

Edit: Problem solved with updating BIOS. Everything is working perfect now..