The Power Supply Unit (PSU) is a critical component of your computer system, responsible for converting Alternating Current (AC) power from the wall outlet to Direct Current (DC) power for your computer's components. A malfunctioning or inadequate PSU can cause system instability, shutdowns, or even damage to your components. In this article, we'll walk you through the steps to check your PSU, ensuring it's functioning correctly and capable of meeting your system's power requirements.
PSU-DIAG-2024-01 Date: [Current Date] Subject: A systematic approach to verifying the operational health and output stability of a computer Power Supply Unit. how to check psu
A failing PSU can mimic the symptoms of other hardware failures, such as bad RAM or a failing motherboard. Therefore, systematic testing is crucial. PSUs contain high-voltage capacitors that can hold a charge even when unplugged. This guide focuses on external testing methods that do not require opening the PSU casing. The Power Supply Unit (PSU) is a critical
| Test Result | Interpretation | Recommended Action | |-------------|----------------|---------------------| | Paperclip test: No fan spin | Dead PSU (or blown fuse) | Replace PSU immediately | | Paperclip test: Fan spins, but multimeter shows 0V on +5VSB | Failed standby rail | Replace PSU (cannot wake from sleep) | | Software: Voltages within tolerance at idle but drop >8% under load | PSU aging or insufficient wattage | Replace with higher-wattage unit (e.g., 750W → 1000W) | | Multimeter: +12V rail reads 12.8V at idle | Overvoltage protection failure | Replace PSU immediately (risk to components) | | Dedicated tester: PG signal <100ms or >500ms | Timing circuit failure | Replace PSU (may cause boot loops) | | All voltages perfect but system randomly shuts off | Intermittent connection or overheating PSU | Check for bulging capacitors inside (do not open – replace) | PSUs contain high-voltage capacitors that can hold a