The power supply unit (PSU) is responsible for delivering stable power to every component in your computer.
When the PSU begins to fail or cannot provide enough power, the system may shut down, restart, or refuse to
turn on. This guide explains the symptoms of PSU problems and how to troubleshoot them safely.
Symptoms of Power Supply Problems
Power supply issues can appear in several ways, including:
- computer not turning on at all
- system shutting down randomly
- fans spinning for a moment, then stopping
- burning smell or unusual noises from the PSU
- system restarting during gaming or heavy load
- no display even though the PC seems to power on
Check the Power Connections
Before assuming the PSU is failing, confirm all power cables are connected properly:
- 24‑pin motherboard power connector
- 8‑pin (or 4‑pin) CPU power connector
- PCIe power connectors for the graphics card
- SATA or Molex power for drives
A loose connection can prevent the system from powering on or cause random shutdowns.
Check the Power Button and Outlet
Sometimes the issue is external rather than the PSU itself. Check the following:
- power outlet or power bar is working
- power switch on the back of the PSU is turned on
- power cable is firmly connected
- try a different outlet or power cable
If the system still shows no signs of power, the PSU may not be delivering electricity to the motherboard.
Signs the PSU Is Failing
These symptoms strongly indicate a failing or unstable power supply:
- system shuts down under load (gaming, video editing)
- PSU fan not spinning or making grinding noises
- burning smell or electrical popping sound
- system restarts without warning
- graphics card losing power during use
If you notice burning smells or electrical noises, stop using the computer immediately.
Check for Insufficient Wattage
If you recently upgraded your graphics card or added new components, your PSU may not have enough wattage to
support the system.
Common signs of insufficient wattage include:
- PC shutting down during gaming
- GPU fans stopping suddenly
- system rebooting when under load
Check your graphics card’s recommended PSU wattage and compare it to your current power supply.
Testing the Power Supply
You can test the PSU using the following methods:
1. Paperclip Test (Basic Power Check)
This test checks whether the PSU can turn on, but it does not confirm full stability. Only perform this if you
are comfortable working with PC hardware.
2. Test with Another PSU
If you have access to another power supply, connect it to your system.
If the computer works normally, your original PSU is likely faulty.
3. Use a PSU Tester
A PSU tester can check voltage levels and detect major faults. These devices are inexpensive and easy to use.
When to Replace the PSU
You should replace the power supply if you experience:
- burning smell or electrical noise
- system shutting down under load
- PSU fan not spinning
- frequent restarts or power loss
- PSU failing basic tests
A failing PSU can damage other components, so replacing it early is recommended.
Summary
Power supply issues can prevent your computer from turning on or cause random shutdowns and instability. By
checking connections, testing the PSU, and watching for warning signs, you can determine whether the power
supply is failing and needs to be replaced. A stable PSU is essential for reliable system performance.
