✓ E-E-A-T VerifiedUpdated: July 13, 2026

How to Test a PSU Safely

Troubleshooting PC boot failures requires validating if the power supply works. This guide provides step-by-step instructions for testing a PSU at home.

Visual Inspections

Before doing electrical tests, turn off the AC power switch and disconnect the wall cord. Check all internal modular cable pins for thermal damage, discoloration, or loose pinouts.

The Paperclip Test (Basic Jumpstart)

This test verifies if the PSU turns on its internal fan and supplies stand-by current:

  1. Unplug all modular connections from motherboard, GPU, and drives.
  2. Take a standard paperclip, shape it into a U, and locate the 24-pin ATX connector.
  3. Insert one end into Pin 16 (PS_ON, green wire) and the other into any adjacent COM pin (black wire, ground).
  4. Plug the AC wall cord in and turn on the PSU switch. The fan should spin up (unless in Zero-RPM silent mode).
⚠ Safety Rule: Never stick fingers or metal tools inside the PSU chassis holes. High-voltage capacitors retain dangerous electrical charges for hours after power-off.

Digital Tester Verification

For exact rail measurements (+12V, +5V, +3.3V), purchase a cheap 24-pin LCD digital PSU tester. It provides instantaneous voltage readings, flagging rail tolerances (should remain within ±5% specs).