Question PC case fans stopped working ?

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May 26, 2023
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Hello. Just like in title, the case fans stopped spinning. Here's the thing though, I had problem like this few days ago, but I updated BIOS and the fans started working again (though not immediately, so not sure if updating bios was the thing that helped).

Now problem has occured once again. I went to BIOS and checked out about fans and on every sys1-sys3 fans there was 0 RPM. Also, enabling sys1-3 warnings gives me loud beeping sounds. Any idea what could possibly cause this?
 

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Tell us you mobo maker and exact model. ALSO tell us what settings you have used to configure the SYS_FAN headers.

Some mobos allow you to set whether or not the fans are allowed to shut down completely when the system is very cool. Generally I do not like to use that option. Even if you do not have that option, it is possible that the fan "curve" of those headers is set to send to the fans at low temperatures a speed signal that is so low the fans stall, and come on only when the temps rise. If that is the situation, a small change of settings can fix that.
 
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May 26, 2023
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Tell us you mobo maker and exact model. ALSO tell us what settings you have used to configure the SYS_FAN headers.

Some mobos allow you to set whether or not the fans are allowed to shut down completely when the system is very cool. Generally I do not like to use that option. Even if you do not have that option, it is possible that the fan "curve" of those headers is set to send to the fans at low temperatures a speed signal that is so low the fans stall, and come on only when the temps rise. If that is the situation, a small change of settings can fix that.
I am using b660m gaming x ddr4, and eveything is set to default (didn't changed anything) but here is the screen with more info. also here is another one with N/A like fans aren't connected to mobo ( they are ).
 
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May 26, 2023
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One thing to try. Check settings for each header to match fan 3pin (DC/voltage control) or 4pin (PWM). Also set them to maximum RPM just to try.
i will do as you say. but just one thing. what does this mean for you? i checked fans through Fan Control, and it's seem mobo see all fans, they just doesn't spin, i am not sure though.
 
i will do as you say. but just one thing. what does this mean for you? i checked fans through Fan Control, and it's seem mobo see all fans, they just doesn't spin, i am not sure though.
It doesn't see all fans, only ones that have actual RPM displayed and those ones are CPU and GPU fans.
Top 2 rows are what it should be (settings) and bottom row actual sensors.
 
May 26, 2023
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It doesn't see all fans, only ones that have actual RPM displayed and those ones are CPU and GPU fans.
Top 2 rows are what it should be (settings) and bottom row actual sensors.
so what are fans-2-4? are they from systemfans?
 

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I presume all your concern is about the CASE ventilation fans, and NOT the fans on the CPU, graphics card or PSU.

FIRST, with the system shut down, open the case. For EACH of those fans, examine carefully its cable of wires.
1. Where does it plug in? Is each on its own separate mobo SYS_FAN header, or are they all going to one central Fan Hub? IF they all connect to one Hub, then that Hub should have one cable that goes to one SYS_FAN header. Which one, in that case?
2. For each fan, how many wires are there in that cable? Or, if you cannot see that, how many HOLES are in the connector on the end? Three or Four? This is important for my point #5 below.

Now to check SYS_FAN header settings in BIOS Setup. When you updated the BIOS it would have used a default group of options which may NOT be the same as you had before, so that could have made changes you did not notice. For each of these headers that actually IS used to plug in a fan, look at these items. Refer to the BIOS Setup Guide downloaded from here


on p. 6-7.

3. Fan Speed Control - should be "Normal" to use default automatic control.
4. Fan Control Use Temperature Input should be Motherboard, not CPU.
5. Fan / Pump Control Mode should be Voltage IF your fans have THREE wires/holes in the connection, OR set to PWM if the fans have FOUR wires / holes. Do not leave this on Auto.
6. Fan / Pump Stop. Do NOT ENable this! Using that feature allows the mobo to shut off the fan when the temperature is lower than a setting you can make here. DISable this feature so that it never stops the fans.
7. Fan / Pump Fail Warning - ENable this so you DO get a warning when the fan is NOT running. As you have seen, this works. When you get the fans to NOT stop, you will get no meaningless warnings.

After you have made all the changes you need for EACH fan header, use the Esc key to back out to the Main Menu (p. 4) then F10 to reach the Exit Menu (p.28). There choose Save and Exit Setup to save your settings and reboot.
 
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May 26, 2023
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I presume all your concern is about the CASE ventilation fans, and NOT the fans on the CPU, graphics card or PSU.

FIRST, with the system shut down, open the case. For EACH of those fans, examine carefully its cable of wires.
1. Where does it plug in? Is each on its own separate mobo SYS_FAN header, or are they all going to one central Fan Hub? IF they all connect to one Hub, then that Hub should have one cable that goes to one SYS_FAN header. Which one, in that case?
2. For each fan, how many wires are there in that cable? Or, if you cannot see that, how many HOLES are in the connector on the end? Three or Four? This is important for my point #5 below.

Now to check SYS_FAN header settings in BIOS Setup. When you updated the BIOS it would have used a default group of options which may NOT be the same as you had before, so that could have made changes you did not notice. For each of these headers that actually IS used to plug in a fan, look at these items. Refer to the BIOS Setup Guide downloaded from here


on p. 6-7.

3. Fan Speed Control - should be "Normal" to use default automatic control.
4. Fan Control Use Temperature Input should be Motherboard, not CPU.
5. Fan / Pump Control Mode should be Voltage IF your fans have THREE wires/holes in the connection, OR set to PWM if the fans have FOUR wires / holes. Do not leave this on Auto.
6. Fan / Pump Stop. Do NOT ENable this! Using that feature allows the mobo to shut off the fan when the temperature is lower than a setting you can make here. DISable this feature so that it never stops the fans.
7. Fan / Pump Fail Warning - ENable this so you DO get a warning when the fan is NOT running. As you have seen, this works. When you get the fans to NOT stop, you will get no meaningless warnings.

After you have made all the changes you need for EACH fan header, use the Esc key to back out to the Main Menu (p. 4) then F10 to reach the Exit Menu (p.28). There choose Save and Exit Setup to save your settings and reboot.
Yes it's about case
i have "controller" in that case for all fans - i pin fans to controller and then i pin controller to sysfan2. and pretty sure it's pmw (so 4).
3. Set
4. You mean system1 or system2? I have plenty of options but not Motherboard.
5. Set to PMW
As for 7. I enable this, and I have loud booozing sound, so I guess it's that warning. Still fans in pc case dosn't work :(
 

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OK, so you should have only ONE case fan speed showing, on the SYS_FAN2 header. Any mobo fan header can accept the sped signal from only ONE fan. So that fan Hub you are using will send to that header the speed of only ONE of the fans plugged into it. Now, WHERE those three fans are plugged into that Hub is IMPORTANT. Only ONE of the output ports on the Hub can send back a fan speed. It may be Port #1, or it may actually be marked some way. SOME such Hubs have a port labelled for CPU cooler fan use, and it is THAT port that MUST have a fan plugged into it. That fan should NOT be your CPU cooler fan; it should be one of your three case fans. So, if there is NO fan plugged into that Hub's identified port, that is why the SYS_FAN2 header is NOT receiving any case fan speed.

Note also, because of this factor, that you will "see" on the SYS_FAN2 header the speed of only that fan, and the speeds of the others on that Hub will never be seen anywhere. You are just supposed to assume their speeds are similar. HOWEVER, an important second function of any header is to monitor its fan's speed signal for FAILURE and warn you when that happens, as you have experienced. But when several fans are connected via a Hub to one header, the header can NOT monitor the speeds of ALL those fans for failure. So from time to time YOU should look and verify that all your case fans are working.

Item 4. Either of those - system1 or system2 - should be OK. Try System 1 for now.

You did not comment on my item 6 - ensure the Fan / Pump Stop option is DISABLED.
 
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May 26, 2023
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OK, so you should have only ONE case fan speed showing, on the SYS_FAN2 header. Any mobo fan header can accept the sped signal from only ONE fan. So that fan Hub you are using will send to that header the speed of only ONE of the fans plugged into it. Now, WHERE those three fans are plugged into that Hub is IMPORTANT. Only ONE of the output ports on the Hub can send back a fan speed. It may be Port #1, or it may actually be marked some way. SOME such Hubs have a port labelled for CPU cooler fan use, and it is THAT port that MUST have a fan plugged into it. That fan should NOT be your CPU cooler fan; it should be one of your three case fans. So, if there is NO fan plugged into that Hub's identified port, that is why the SYS_FAN2 header is NOT receiving any case fan speed.

Note also, because of this factor, that you will "see" on the SYS_FAN2 header the speed of only that fan, and the speeds of the others on that Hub will never be seen anywhere. You are just supposed to assume their speeds are similar. HOWEVER, an important second function of any header is to monitor its fan's speed signal for FAILURE and warn you when that happens, as you have experienced. But when several fans are connected via a Hub to one header, the header can NOT monitor the speeds of ALL those fans for failure. So from time to time YOU should look and verify that all your case fans are working.

Item 4. Either of those - system1 or system2 - should be OK. Try System 1 for now.

You did not comment on my item 6 - ensure the Fan / Pump Stop option is DISABLED.
I mean, i get it. As for CPU I have dedicated cooler that is pin to CPU Fan. Also, I think you would be right, but as I said - fans stopped working, then one day start working again, and now they stopped working once again, so I am not sure if this is were I should look for solution :( As for item 6 = Yes, It's disabled. Can you tell about that warning thing tho? Because whenever I enable this I have loud "beeping", like immiedtly. So does that mean that sysfan2 is N/A?
 

Paperdoc

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Well, that is a possibility. You could just switch the cable from the Hub to go to a different SYS_FAN header and see if that fixes it. But the real story appears to be that there is no fan speed signal getting from ONE of the case fans through the Hub to the host header. Why?

Maybe the Hub is faulty, so NONE of the case fans is running. Try disconnecting all three case fans from the Hub and plugging each one into its own mobo SYS_FAN headers. See if they work that way. You will want to be sure that all of those headers are configured exactly the same.

Another possibility. The Hub has a second connection required. This may be a second cable from it, or more likely an edge connector. This must be connected (typically) to a SATA power output connector direct from the PSU. That is how the fans plugged into the Hub get power. Without that those fans cannot run. s this connection made securely?
 
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May 26, 2023
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Well, that is a possibility. You could just switch the cable from the Hub to go to a different SYS_FAN header and see if that fixes it. But the real story appears to be that there is no fan speed signal getting from ONE of the case fans through the Hub to the host header. Why?

Maybe the Hub is faulty, so NONE of the case fans is running. Try disconnecting all three case fans from the Hub and plugging each one into its own mobo SYS_FAN headers. See if they work that way. You will want to be sure that all of those headers are configured exactly the same.

Another possibility. The Hub has a second connection required. This may be a second cable from it, or more likely an edge connector. This must be connected (typically) to a SATA power output connector direct from the PSU. That is how the fans plugged into the Hub get power. Without that those fans cannot run. s this connection made securely?
forget it. Yeah, fan hub is at fault.
 
May 26, 2023
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Do you mean that you got it to work when the Hub is NOT used? Good! Glad you have a solution.
i mean, the hub is working now. I did as you said, where i pinned one fan directly into header - it worked, then I checked out if maybe there is some load voltage, so I tried only with 3 fans pinned into hub, and then i pin it into header. It's worked, so I checked with 4th - it's also worked. So all fans connected to hub are working now. I am kinda troubled - previously I tried just unpin hub from sysfan2 and then pinned it again, but that didn't do a thing, so I am kinda afraid that problem will occur once again :(
 

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You may have had one bad or dirty connection that was fixed just because you disconnected things and then re-connected. That can happen with oxidized contacts or sometimes poor springiness in the contacts. So IF you have the problem again, try disconnecting and re-connecting. If it happens too often, consider replacing the Hub, but for now see if it just continues to work well.
 
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