Question Help resolving CPU Fan Error (Update: problem semi-fixed)

[Zenoth]

Hey guys.

I recently bought a Noctua NH-D15S chromax.black cooler, here is a direct link for reference (official website):

NH-D15S chromax.black

The NH-D15S chromax.black is an all-black version of Noctua’s award-winning NH-D15S premium-quality quiet CPU cooler. Thanks to the same asymmetrical dual-tower heatsink design and single NF-A15 PWM fan, it stays true to the NH-D15S’s successful formula of fusing dual-tower performance with...

noctua.at

It comes with one fan already placed in the center, out of the box. So I installed the cooler properly, for a start; so physically-speaking it's all done and nothing went wrong (for the AM5 platform, in my case). I also used Noctua's AM5-rated thermal paste, along with their NA-STPG1 thermal pad guard thing you put on the CPU to avoid getting paste getting squeezed off the edges. And, finally, also bought a separate 120mm Noctua fan for good measure.

The Problem

When I start up, I notice that the 'main' CPU Fan (the one that was already installed in the center of the cooler between the fin columns) does not spin, and (of course) the BIOS gives me a CPU_FAN Speed Reading Error.

BUT, the separate 2nd fan I bought, which is also installed and connected to the OPT_FAN header, does work and it spins properly.

Now yes, of course, I checked to see if the main fan is actually physically connected to the proper CPU_FAN header on the motherboard, and yes, it is. My previous cooler, the Noctua U9S chromax.black did NOT have this problem and also had 2 fans connected to the motherboard (same motherboard, too). Which is why this situation is confusing me. It's not like I tried different FAN headers for fun. I'm also currently not using any extensions. It's just the direct connection from Fan-to-Header for both Fans. But only the 2nd fan that is connected to the OPT_FAN header currently works.

Finally, I went back to the BIOS (met the same error of course) and then tried to use the Q-Fan Tuning feature. It worked, but of course only for the Opt Fan, and the Chassis fans.

I'm not sure what to do right now, any suggestions?

Thank you very much.

 

[Heartbreaker]

You may have a bad fan.

Switch the connectors (connect center fan to OPT_FAN and your new fan to the CPU_FAN.)

 

[Zenoth]

You may have a bad fan.

Switch the connectors (connect center fan to OPT_FAN and your new fan to the CPU_FAN.)

I thought so for a moment too but..small update to this situation:

1) I tried to use the OPT_FAN header for the 'main' fan, and unplugged the 2nd extra fan (just left it unplugged for the test).

Result: the main fan actually works on the OPT_FAN header.

2) Alright, so I thought... "wtf" ... I re-tried on the CPU_FAN header...

Result: if the main fan is the ONLY fan plugged on the CPU_FAN header (I.E. only that fan and no other next to it on the OPT_FAN header), then it does work properly, and is detected in the BIOS.

So... I'm at a loss here.

A) The 2nd extra fan is the only fan that actually spins and works if it is plugged WITH the main fan (main fan on CPU_FAN header + 2nd one on OPT_FAN header).
B) However, if both are plugged, the main fan doesn't work...
C) If the main fan is the ONLY one plugged on the CPU_FAN header... then it works well (while the 2nd fan of course is just left unplugged).

I don't get it.

My next attempt will be:

Plug the extra fan on a Chassis header (still have 2 of those free and unused), worst case scenario it doesn't work on those headers, best case scenario the fan works but maybe doesn't spin as fast it might on those headers? I'll try this last solution in a couple of hours (or maybe tomorrow at the latest, I do have other things to do after I type this). This is weird though. As I mentioned, my previous cooler did not have this problem (with also a 2nd extra fan).

 

[Heartbreaker]

You can just ditch the second fan. From the testing I have seen, it's really not a big help.

Also you might try a splitter and run both fans off the same connector.

 

[Paperdoc]

First, check that the little "Low Noise" adapter item is NOT installed in the fan's cable connection to the header. All that does is reduce the power supply to the fan which makes it run slower than the header intends.

Check the details of the configuration of the CPU_FAN header. Its PROFILE should be Normal or Standard so it uses the default automatic fan control algorithm. Do not set tor a fixed speed or a slow "Quiet" speed. Ensure the header MODE is set to PWM Mode, not to DC or Voltage, and not to Auto. IF there is an option for Fan Stop, ensure that is DISabled so the fan cannot stop.

For the "fan curve", some headers allow you to change that curve on a graph only if you choose to use the Manual Profile. On some other boards you can make such changes to the graph any time you wish. Making this change may help out. For the lowest couple of temperatures move the dot up to a higher minimum speed so that the header will not send to the fan a really slow signal that causes it to stall.

After you have made your changes, be sure to use the Exit Menu to SAVE and EXIT so that these settings are saved and the system reboots.

 

[aigomorla]

Result: if the main fan is the ONLY fan plugged on the CPU_FAN header (I.E. only that fan and no other next to it on the OPT_FAN header), then it does work properly, and is detected in the BIOS.

Here is my guess.

The CPU Fan header will usually default (PWM-Load Value) unless its a CPU/PUMP header, which means it will output 100% without a PWN signal all the time.

The OPT Headers are all controlled under your boards extra features.
You probably need to set them up manually in bios, otherwise they are controlled (PWM-Load or Temp values)
Which is why your not seeing them spin as they are probably volted way down to like 5V unless load is applied, or you set them manually in bios.

Can you go in bios and set the headers to Manual 100%, start tuning things to your liking in bios, or set certain fans on manual and leave the rest on auto.

The reason the OPT detects when no CPU is plugged in, is because the board again is assuming you probably have a waterblock, hence no cpu header, and the OPT is the rear fan, so its turning it on 100%, as its the only fan connected in that node.

 

[Zenoth]

Hey guys, got the notification of replies to this thread but I had completely forgotten about it. First, thanks all for taking some of your time to help and give some advice; it is appreciated.

Now, this issue was fixed, solution was rather simple: I bought another fan.

The fan I bought was the exact same as the one that was included with the packaging and already installed on the cooler when I took it out of the box.

New working, 2nd extra fan is: Noctua NF-A15 HS-PWM (which is also the default fan included with the cooler)
Previous fan, the one that didn't want to work along with the main one was: Noctua NF-A14 iPPC-3000 PWM

The new fan worked immediately along with the main one, both respectively connected to the CPU_FAN and OPT_FAN headers. All is working well.

I'm keeping the previous fan for future use in a new, bigger tower which I might be using as either a frontal or back Chassis fan.

On a side note, the NH-D15S cooler with a 2nd fan now that I have it is - and I confirm - absolutely amazing. My temps are excellent.

 

[Paperdoc]

Thanks for the update. Glad it is fixed.