How to Test a Power Supply (PSU) If Your PC Won‘t Boot

If your PC suddenly won’t turn on, or it restarts and shuts down randomly while gaming, most people immediately suspect the motherboard or memory. But did you know? The power supply unit (PSU) is often the hidden culprit behind these problems!

In this guide, we’ll show you how to test if your PSU is failing, so you can avoid wasting money replacing the wrong parts.

Common Signs of a Failing PSU

If you notice any of the following, your PSU might be to blame:

• Pressing the power button does nothing

• Random shutdowns or restarts

• Blue screen errors (BSOD) or unexpected reboots

• BIOS shows abnormal voltage readings

How to Test if Your Power Supply Is Working

Follow these simple steps to check your PSU with a paperclip test:

1. Turn off the power supply and unplug it from the wall.

2. Disconnect all power cables from components, leaving only the 24-pin ATX motherboard connector.

3. On the 24-pin connector, locate pins 16 and 17.

   (Tip: With the latch facing up and the pins facing you, count from the left — pins 4 and 5 from the left are the ones you need.)

4. Use a paperclip or a piece of wire to short pins 16 and 17.

5. Turn the PSU back on and see if the fan spins and power comes on.

6. If the PSU doesn’t power up, it’s likely faulty.

What to Do If Your PSU Is Faulty

• Check if your PSU is still under warranty. Many PSUs come with warranties ranging from 5–10 years, depending on price and tier.

• If it’s a new unit or still within warranty, contact the manufacturer or your retailer for a repair or replacement.

• If it’s out of warranty, it might still work, but replacing it with a new, reliable PSU is highly recommended to keep your system stable.

Why the PSU Is So Important

The power supply delivers power to all your components. Stable, clean power is crucial not just for CPU and GPU performance, but also for the long-term health of your system.
Choosing a PSU with 80 PLUS certification, sufficient wattage, and a long warranty is your best defense against gradual damage to your components.

Protect Your System With the darkFlash PMT Series PSU

If you’re planning to upgrade to an RTX 50-series GPU or build a high-end system, don’t overlook the PSU.

The darkFlash PMT Series power supplies feature the latest ATX 3.1 and PCIe 5.1 standards, 80 PLUS Gold certification — perfect for gamers and creators alike who need reliable, long-term performance.