[SOLVED] Fans not spinning

[DramaChimp]

The fans on the front of my case sometimes don’t spin when I turn the PC on. They twitch a little before giving up and stopping. Sometimes it’s all three of them, sometimes just one or two. The ways I fix it now is to either poke them or turn the PC power is off and on before turning the PC proper on. I’ve also tried changing the fan power to DC in the Bios but that didn’t seem to help. My case and fans are the Cooler Master MB520. Does anyone know how to solve this?

 

[Ralston18]

Update your post to include full system hardware specs and OS information.

Include PSU: make, model, wattage, age, condition?

Disk drives: make, model, capacity, how full?

My thought is a failing or faltering PSU but overall too early to really know.

Double check that all connectors, cards, RAM, and jumpers are fully and firmly in place.

 

[DramaChimp]

Update your post to include full system hardware specs and OS information.

Include PSU: make, model, wattage, age, condition?

Disk drives: make, model, capacity, how full?

My thought is a failing or faltering PSU but overall too early to really know.

Double check that all connectors, cards, RAM, and jumpers are fully and firmly in place.

My PSU is a corsair rm 750x that has been used for about a week (as has the rest of the pc)
My SSD is an NVMe 512GB MP33

Everything seems to be in place, the issue also only sometimes occurs and never after cycling the power.

 

[Ralston18]

After the next successful boot, look in Event Viewer and Reliability History for error codes, warnings, or even informational events that correspond with the times that the fans fail to spin and PC startups fail.

Access BIOS and set the POST output to be as verbose as possible. In other words have the system constantly display what is going on during boot up and what does or does not happen.

And more hardware information (specs) is needed:

Motherboard
CPU
RAM
GPU
Other drives.

Based on "about a week" does that mean the PSU/PC are new and is actually only a week old?

Will the PC boot into Safe Mode without any problems?

 

[Paperdoc]

Tell us what mobo maker and exact model number. Also, exactly what are the fans at the front? That case comes with only one pre-insalled fan at rear. AND, where are those fans plugged in? I suspect you have the mobo fan header for these fans set to some reduced fixed speed for reduced noise, and not to the default automatic control system. Please check in BIOS Setup for how you have configured the fan header(s) used to power those front fans.

 

[DramaChimp]

After the next successful boot, look in Event Viewer and Reliability History for error codes, warnings, or even informational events that correspond with the times that the fans fail to spin and PC startups fail.

Access BIOS and set the POST output to be as verbose as possible. In other words have the system constantly display what is going on during boot up and what does or does not happen.

And more hardware information (specs) is needed:

Motherboard
CPU
RAM
GPU
Other drives.

Based on "about a week" does that mean the PSU/PC are new and is actually only a week old?

Will the PC boot into Safe Mode without any problems?

Motherboard: Asrock B560 Pro4
CPU: Intel i5-11400F
RAM: PNY XLR8 2x8GB
GPU: GeForce RTX 3060ti Gaming 8G
Other Hard drive: Seagate Barracuda 2TB

By about a week I mean that I received the parts and built the pc on the 31st of October. I have no idea when the parts themselves were built.
The event viewer and Reliability history didn’t seem to have any info. Interestingly, when I exit bios all the fans start.

Tell us what mobo maker and exact model number. Also, exactly what are the fans at the front? That case comes with only one pre-insalled fan at rear. AND, where are those fans plugged in? I suspect you have the mobo fan header for these fans set to some reduced fixed speed for reduced noise, and not to the default automatic control system. Please check in BIOS Setup for how you have configured the fan header(s) used to power those front fans.

The fans are the default included with the case, not sure what name. Something worth noting is that today the back case fan didn’t start for the first time (usually the front ones). The only fiddling I’ve done with the fans in the Bios is to change the setting from ‘auto’ to ‘dc’, but that didn’t seem to change anything. The rear fan is plugged into CHA_FAN1/WP and the front 3 into CHA_FAN5/WP (they came on a splitter). Motherboard is Asrock B560 Pro4. Not sure if it’s related, but sometimes in the Bios the front fans’ (slot 5) RPM isn’t shown. This might happen whenever the fans aren’t spinning but I’m not able to check at the moment. If so, I’m not sure if it’s the problem or just a symptom. If you think it’s important to confirm I can do so.

 

[Paperdoc]

You say, "Interestingly, when I exit bios all the fans start." When you Exit BIOS Setup the system reboots. In almost all systems at the beginning of the reboot process, ALL fans are given a signal to start up at full speed to be sure they do that. After about 5 sec or so the automatic fan speed control system then slows them down to what is actually required for the measure temperatures. So that observation is normal.

I expect you are quite right about the times that CHA_FAN5 shows zero fan speed - that is because at that moment the speed of one of the three connected there IS zero.

What you describe - various fans apparently stalling and staying stopped - MAY indicate that the automatic fan speed control system is sending your fans signals to run at too low a speed so they stall. When that happens they will not re-start until something (like a higher measured temperature) sends a signal for much faster speed . That should not happen. SOME mobos offer an option in the configuration settings of all their fan headers to specify the minimum speed the system will request form the fans. I do NOT see such an option in the details of your mobo's manual, but look though them in case you have that choice available. That way you could prevent a signal for a too-low speed. There is another way such a low-speed limit can be done, but again I don't see this in your mobo manual for the CHA_FAN headers. Some mobos allow you to set a custom"fan curve" for each header, rather than using the pre-programmed one in the "normal automatic system. IF you find that option, you can set it so at the lowest temperatures the lowest speed called for is higher than what already exists.

 

[DramaChimp]

You say, "Interestingly, when I exit bios all the fans start." When you Exit BIOS Setup the system reboots. In almost all systems at the beginning of the reboot process, ALL fans are given a signal to start up at full speed to be sure they do that. After about 5 sec or so the automatic fan speed control system then slows them down to what is actually required for the measure temperatures. So that observation is normal.

I expect you are quite right about the times that CHA_FAN5 shows zero fan speed - that is because at that moment the speed of one of the three connected there IS zero.

What you describe - various fans apparently stalling and staying stopped - MAY indicate that the automatic fan speed control system is sending your fans signals to run at too low a speed so they stall. When that happens they will not re-start until something (like a higher measured temperature) sends a signal for much faster speed . That should not happen. SOME mobos offer an option in the configuration settings of all their fan headers to specify the minimum speed the system will request form the fans. I do NOT see such an option in the details of your mobo's manual, but look though them in case you have that choice available. That way you could prevent a signal for a too-low speed. There is another way such a low-speed limit can be done, but again I don't see this in your mobo manual for the CHA_FAN headers. Some mobos allow you to set a custom"fan curve" for each header, rather than using the pre-programmed one in the "normal automatic system. IF you find that option, you can set it so at the lowest temperatures the lowest speed called for is higher than what already exists.

I can change the power percentage of the fan depending on what temperature the motherboard or cpu is at, so I changed the minimum to 30%, but it didnt seem to help. Would you have a recommended percentage? Otherwise I will just keep increasing by 10%. (It was set on 20% by default.)

Also, I appreciate how you explained what was going on instead of a single sentence answer

 

[Paperdoc]

I forgot to mention another point. Look closely at the cables from your fans that plug into fan headers on the mobo. It they have FOUR wires in each cable and end in a connector with FOUR holes, then you have PWM-style 4-pin fans. For those you SHOULD set the fan headers to use PWM Mode, and not Voltage Control Mode (aka DC Mode). Use Voltage Control only for 3-pin fans.

From your last post I am not clear whether you are using automatic fan speed control that changes fan speeds for you according to temperature measurement, OR have set fixed fan speeds that YOU adjust manually as you monitor temperatures. Automatic control with an adjustment (if needed) for minimum speed is much better than fixed manually-set speeds. By using manual settings only you do run the risk that the START-UP setting is too low so the fans never start up. That will not happen if you let the default automatic speed control system operate.

 

[DramaChimp]

I forgot to mention another point. Look closely at the cables from your fans that plug into fan headers on the mobo. It they have FOUR wires in each cable and end in a connector with FOUR holes, then you have PWM-style 4-pin fans. For those you SHOULD set the fan headers to use PWM Mode, and not Voltage Control Mode (aka DC Mode). Use Voltage Control only for 3-pin fans.

From your last post I am not clear whether you are using automatic fan speed control that changes fan speeds for you according to temperature measurement, OR have set fixed fan speeds that YOU adjust manually as you monitor temperatures. Automatic control with an adjustment (if needed) for minimum speed is much better than fixed manually-set speeds. By using manual settings only you do run the risk that the START-UP setting is too low so the fans never start up. That will not happen if you let the default automatic speed control system operate.

All of the fans are 3-pin fans

The fan control seems to be a line graph with % on the side and temperature on the bottom and I can adjust the lines. The initial setting was 0-50° or so on 20% fan power, which I changed to 30%. I can't remember what the higher temps were but the fan scaled accordingly. It was already set to the 'standard' graph option (which had the 20%), and I switched it to 'custom' (exactly the same except starting at 30%). The other settings were something like 'silent' and 'performance'.

 

[Paperdoc]

What you did sounds right - that is how I would suggest you can address your problem. If the 30% setting is not good enough, try somewhat higher for the minimum. And yes, with THREE-pin fans, you SHOULD set the headers involved to use Voltage Control Mode (aka DC Mode).