This article explains how to test the power supply unit (PSU) in your computer using a power supply tester. Instructions apply specifically to the Coolmax PS-228 ATX power supply tester, but should be sufficient for most other PSU testers with an LCD.

If you have some experience working on your computer and are comfortable following the instructions, this process should take about 30 minutes. However, it may not be suitable for people who are new to computer maintenance. Read the safety tips before proceeding. Once you have done that, you can begin the process.

Turn off the PC, remove the power cord, and disconnect all other connected components from the computer. Then open the case.

To make testing the power supply easier, move the disconnected and opened enclosure to a location where you can easily work with it, such as a table or other flat, non-static surface.