Power Supply Fan Not Spinning & Your PC Runs Quiet? Here’s Why

Is your computer running super silent? That might sound good, but if the fan inside the power supply isn’t spinning at all, it could be a problem.

The PSU fan is super important and it keeps the internal components cool.

If it’s not spinning, it will overheat and cause serious issues like system crashes, hardware damage, and even fire hazards.

In this post, I’ll shed some light on why your power supply fan is not spinning and how to fix it.

Why Is My Power Supply Fan Not Spinning?

Here are the main reasons your PSU fan is not working:

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#1 Fan Behavior Under Load

While some modern PSUs have zero-RPM modes where the fan doesn’t spin at idle to reduce noise, it should definitely turn on when your computer is under heavy load.

Here’s how to see if the fan spins under load:

● Running demanding applications: Open applications that require a lot of processing power and graphics processing, like video editing software, 3D games, or running benchmarks. These push your CPU and GPU to work harder, which in turn increases heat generation.

If the PSU fan is functional, it should automatically kick in to cool the components within a reasonable timeframe (usually a minute or two under heavy load).

● Using Benchmarking Tools: Software benchmarks are specifically designed to push your hardware to its limits. Popular options include Prime95 for stressing your CPU, or FurMark for stressing your GPU.

Be aware, that these tools can generate a lot of heat, so only run them for short durations (5-10 minutes) and monitor your system temperatures with software like HWMonitor.

If the PSU fan remains inactive even after running benchmarks for a short time and your system temperatures are reaching concerning levels (above 80°C for CPU and 90°C for GPU), then there might be an issue with the PSU fan.

Important Note: Even if the fan spins under load, a constantly running fan at high RPMs could indicate failing internal components within the PSU itself, not necessarily a fan issue.

If this is the case, consult a professional for further diagnosis and potential replacement of the PSU.

#2 Loose Fan Cable

The power supply fan is linked to the main power supply unit using a small cable or connector.

Over time, this connection might loosen or even disconnect completely, which stops the fan from getting the power it needs to spin.

To fix this, find the power supply fan cable inside your computer case.

It’s usually a small 3-pin or 4-pin connector that plugs straight into the power supply.

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Gently unplug the connector, check for any damage, and then firmly plug it back in, making sure it’s securely attached.

Also, make sure the cable isn’t tangled with any other parts or blocked in any way.

If the connection seems solid but the fan still won’t spin, there might be a problem with the fan itself or a more serious issue with the power supply.

Warning: Power supplies contain high-voltage capacitors that can hold a dangerous electrical charge even when unplugged. Opening a power supply unit (PSU) is risky and should only be attempted by experienced technicians.

If you’re not comfortable troubleshooting electronic components, it’s best to consult a qualified computer repair professional for any repairs that require opening the PSU.

#3 Blocked Fan

Dust and debris can also stop a power supply fan from spinning.

As air gets sucked into the power supply, tiny particles can gather around the fan blades, and makes it harder for them to move freely.

So check out the power supply fan carefully.

Use a can of compressed air to blow out any dust or debris that might be blocking the fan.

But make sure to hold the fan blades steady with your finger while using the compressed air.

Otherwise, the sudden blast of air could make the fan spin fast and possibly cause damage.

#4 Faulty Capacitor

The next cause is a faulty capacitor.

Inside the power supply, there are several capacitors responsible for regulating the voltage and current going to your computer’s components.

If one of these capacitors stops working, it can stop the fan from getting the right voltage it needs to start spinning.

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If this is the case, the capacitor might bulge out or even leak a gooey substance.

So, if your PSU fan isn’t spinning and you see anything suspicious happening with the capacitors inside, that might be the culprit.

To fix this, you need to replace the capacitor. I wouldn’t recommend doing it yourself at all if you don’t know much about electronics. It’s best to take it to a technician.

#5 Dead Fan

Finally, it’s also possible that your fan has simply died or failed entirely. This is very possible if the fan was making grinding and rattling noises before.

How could this happen?

The small ball bearings that allow the fan to spin freely can wear out over time.

And the electrical components that power the fan, like the motor windings or control circuitry, can fail and prevent the fan from receiving the necessary voltage and current to operate.

It could also be a design or manufacturing flaw.

Nevertheless, if this is the case you can try replacing the fan, but depending on the PSU model, it might be more cost-effective to just replace the entire unit.

Advanced Troubleshooting (For Tech-Savvy Users)

Disclaimer: Modifying BIOS settings can be risky if done incorrectly. It’s important to understand the potential consequences before making any changes. If you’re not comfortable with these steps, it’s best to consult a qualified professional.

For tech-savvy users who want to delve deeper, here are some additional tips:

● Monitor PSU Temperatures and Fan Curves: Some motherboard manufacturers include utilities that allow you to monitor PSU temperatures and fan curves within the operating system.

Alternatively, you can use third-party monitoring software like HWMonitor or Open Hardware Monitor. These tools can provide valuable insights into PSU behavior under load.

● Check BIOS Settings (Advanced Users Only): Caution: Venturing into the BIOS can be risky. Make changes only if you understand the potential consequences. Consult your motherboard manual for specific instructions on navigating your BIOS.

Some advanced BIOS settings might offer options to adjust PSU fan curves. This could be helpful if the default settings are too conservative and the PSU fan isn’t kicking in early enough.

However, be cautious when modifying these settings. Setting unrealistic fan speeds could damage the PSU fan or reduce its lifespan.

Important Note: Even if you manage to adjust fan curves in the BIOS, a constantly running fan at high RPMs could indicate failing internal components within the PSU itself, not necessarily a fan issue.

If this is the case, consult a professional for further diagnosis and potential replacement of the PSU.

If you need any more assistance reach out to us for computer help.