Symptoms
- PSU fan stays still even while the computer is running normally
- Fan doesn't spin even during demanding tasks or gaming
- PSU feels warm to hot near the fan vent
- No unusual smell or shutdowns, just a silent fan
Likely causes
- CommonZero RPM fan mode, a normal efficiency feature on many modern PSUsThese PSUs only spin the fan once load or temperature crosses a threshold.
- PossibleDust buildup preventing the fan from spinning freelyYears of accumulated dust can add enough resistance to stall a fan.
- PossibleFan motor has failedThis becomes a real concern under heavier loads, since the PSU could overheat.
- PossiblePSU is old and its fan bearing is wearing outAging fans can eventually seize entirely.
What to do
- Check whether the fan spins under heavier load (like gaming or a stress test), since silence at idle is often intentional.
- Listen and feel for airflow from the PSU's exhaust vent during heavy use.
- If comfortable and the PSU is unplugged, gently check the fan blades for dust buildup through the vent, without inserting anything into the PSU itself.
- If the fan never spins even under sustained heavy load, and the PSU feels hot, this is a real problem, not the normal zero-RPM feature.
- Do not open the power supply casing yourself; internal capacitors can hold a dangerous charge.
- Replace the power supply if its fan doesn't work under load, rather than risk it overheating.
Tools and parts
Replacement power supplySearch: “ATX power supply matching wattage”
When to call a pro
If the PSU fan doesn't spin under real load, replace the unit rather than attempt any internal repair yourself.
Safety
Use caution
Never open a power supply's casing, even when unplugged; its internal capacitors can retain a dangerous electrical charge.