Question Case fans stop spinning sometimes.

Jul 8, 2021
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Please Help. This has happened twice now with a month in between occurrences. I will be using my computer and I suddenly smell it cooking and see my case fans have stopped working. The RGB remains on but they are all on 0 RPM. I have had this computer for 7 months with no problems until now. There are 4 Corsair LL 120's and two asus fans for my AIO. This is a random occurrence so I can't recreate it. If you have any questions please ask, I just want to get this fixed.
 

hedwar2011

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Please Help. This has happened twice now with a month in between occurrences. I will be using my computer and I suddenly smell it cooking and see my case fans have stopped working. The RGB remains on but they are all on 0 RPM. I have had this computer for 7 months with no problems until now. There are 4 Corsair LL 120's and two asus fans for my AIO. This is a random occurrence so I can't recreate it. If you have any questions please ask, I just want to get this fixed.
Do you have the fans on a fan controller of any sort or are they directly plugged into the motherboard?
 
how are the fans connected;
directly to motherboard headers,
to a 3rd party fan hub,
to a case hub,
to cable splitters, etc?

your case fans stopping for a short time shouldn't cause any "burning" smell.
it may lead to your components warming up some but the CPU and\or any GPU's fans would continue to spin and prevent them from burning at all.
also your system would shutdown before the CPU would be getting hot enough to create a burn smell.
what is it that you imagine is burning?
 
Last edited:
Jul 8, 2021
5
0
10
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how are the fans connected;
directly to motherboard headers,
to a 3rd party fan hub,
to a case hub,
to cable splitters, etc?

your case fans stopping for a short time shouldn't cause any "burning" smell.
it may lead to your components warming up some but the CPU and\or any GPU's fans would continue to spin and prevent them from burning at all.
also your system would shutdown before the CPU would be getting hot enough to create a burn smell.
was is it that you imagine is burning?
The fans are connected to the motherboard headers.
 

Paperdoc

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It would help if you gave us specific information:
For MOBO - what maker and model?
For case FANS - what maker and model, and how many?

My first thought is that the headers feeding the fans all have "fan curves" - that is, a group of settings for how fast the fan should go depending on how high the temperature is at a sensor on the mobo. Unless you have changed it, the most common arrangement is to use a default fan curve set in the BIOS. It may well be that yours are set so that they allow the fans to stop if the tempertures are cool enough. In that case, then if the tempertures rise again the fans should re-start. BUT most mobos also have options on each fan header to use a custom-set "fan curve". Using that option you can re-define the lowest speed the fans are set for at the lowest temperatures, so they never stop.

There is also a possibility that the fan type (3-pin or 4-pin) or fan MODE setting (Voltage Control of PWM) of the headers is involved in allowing the fan signals to go too low. That's why we need toe hardware details to examine all the factors.
 
Reactions: hedwar2011
Jul 8, 2021
5
0
10
0
It would help if you gave us specific information:
For MOBO - what maker and model?
For case FANS - what maker and model, and how many?

My first thought is that the headers feeding the fans all have "fan curves" - that is, a group of settings for how fast the fan should go depending on how high the temperature is at a sensor on the mobo. Unless you have changed it, the most common arrangement is to use a default fan curve set in the BIOS. It may well be that yours are set so that they allow the fans to stop if the tempertures are cool enough. In that case, then if the tempertures rise again the fans should re-start. BUT most mobos also have options on each fan header to use a custom-set "fan curve". Using that option you can re-define the lowest speed the fans are set for at the lowest temperatures, so they never stop.

There is also a possibility that the fan type (3-pin or 4-pin) or fan MODE setting (Voltage Control of PWM) of the headers is involved in allowing the fan signals to go too low. That's why we need toe hardware details to examine all the factors.
For the MOBO I have an MSI Z490 Gaming Carbon. As listed above I have 4 Corsair LL 120 fans and 2 Asus 120 Fans for the radiator. The PSU is a NZXT C 850, CPU is I7 10700k, GPU is EVGA 3080 FTW Ultra, 2 16 stick of G skill trident Z's and ROG Ryuo 240 AIO.
 

Paperdoc

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Let's deal with the CPU cooling system first, even though you say the problem appears to be the CASE fans. There is a single cable to go from the PUMP unit of that AIO system to the CPU_FAN header, and it just sends the pump speed signal to that header. Then there's a cable to go from a socket on the side of the pump to a mobo USB2 header. This is how the Armoury Crate software utility communicates with the AIO system. IT is what controls the speed of the rad fans. Those two fans are to be plugged into outputs attached to the pump. And of course, the pump has a cable with a wide connector that plugs into a SATA power output from the PSU.

Your four Corsair LL120 fans are plugged into mobo headers I gather - probably one fan per header. There are six such SYS_FAN headers. See your mobo manual p. 47 for how to enter BIOS Setup. You will get either the EZ Mode display (p. 50) or the Advanced Mode (p. 53). Either way, clock on the Hardware Monitor block to get to its Menu on p. 62. Go to p. 63 to make adjustments. Each fan header is adjusted separately, although you want all four of your headers in use to be configured the same. Choose a header (say, SYS_FAN1) at the top. As a first set, click on All Set Default at bottom centre. Now look at that graph with 4 blue dots. point and hold down the mouse key to drag the bottom left dot to a higher speed. Do the same for the next dot over. You have just told it to use those as the lowest speeds for the coldest temperatures, and set them faster than the original defaults. Now, choose another SYS_FAN header and do exactly the same. Repeat until all the headers you have fans plugged into have been adjusted. Then press the F10 key to pop up an Exit Menu. You will need to SAVE and REBOOT your system. The new fan speed settings will take over and should prevent any case fan from being told to run so slow it stalls.
 
Reactions: hedwar2011
Jul 8, 2021
5
0
10
0
Let's deal with the CPU cooling system first, even though you say the problem appears to be the CASE fans. There is a single cable to go from the PUMP unit of that AIO system to the CPU_FAN header, and it just sends the pump speed signal to that header. Then there's a cable to go from a socket on the side of the pump to a mobo USB2 header. This is how the Armoury Crate software utility communicates with the AIO system. IT is what controls the speed of the rad fans. Those two fans are to be plugged into outputs attached to the pump. And of course, the pump has a cable with a wide connector that plugs into a SATA power output from the PSU.

Your four Corsair LL120 fans are plugged into mobo headers I gather - probably one fan per header. There are six such SYS_FAN headers. See your mobo manual p. 47 for how to enter BIOS Setup. You will get either the EZ Mode display (p. 50) or the Advanced Mode (p. 53). Either way, clock on the Hardware Monitor block to get to its Menu on p. 62. Go to p. 63 to make adjustments. Each fan header is adjusted separately, although you want all four of your headers in use to be configured the same. Choose a header (say, SYS_FAN1) at the top. As a first set, click on All Set Default at bottom centre. Now look at that graph with 4 blue dots. point and hold down the mouse key to drag the bottom left dot to a higher speed. Do the same for the next dot over. You have just told it to use those as the lowest speeds for the coldest temperatures, and set them faster than the original defaults. Now, choose another SYS_FAN header and do exactly the same. Repeat until all the headers you have fans plugged into have been adjusted. Then press the F10 key to pop up an Exit Menu. You will need to SAVE and REBOOT your system. The new fan speed settings will take over and should prevent any case fan from being told to run so slow it stalls.
Thanks I'll give it a shot.
 

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