Is your Computer restarting all of a sudden, frequently crashes freezes or whatever you may call. Many may be wondering that their system is affected by virus or some hardware failure. One of the main cause that many of us fail to check is the Power Supply Unit(PSU).
Yes! A faulty power supply unit can cause all these problems. But we are not aware and will be cursing other hardware which is causing the problems. A faulty PSU fails to give the required voltage to the computer during the load which causes the system to crash or freeze.
If you have opened the computer case, you might have noticed that there are many colored wires coming to the PSU which connects the various parts of the computer. These colored wires carry different voltages which the colors signify.
There are two ways to test a PSU. A Paper Clip Test will help you to confirm that your PSU is working or not. But you need a multimeter to test voltages that pass through the wires.
Testing the Power Supply Unit with the Multimeter gives you more flexibility of testing the amount of voltage that passes through the each wire from the PSU.
Important: Please be aware of the Problems of Electrostatic Discharge (ESD) to the internal components of your computer and steps to prevent it.
1. A Multimeter
2. A Power Supply Unit
3. A Screw Driver( To remove the PSU from the Computer case)
Here’s how to do it:
1. Open your computer case. This involves turning off the computer and removing the side panel of the computer case. Take your computer to a free place where you have ample space to work with your computer.
Note: Do not unplug all the peripherals that have been connected from PSU. We show you how to test the PSU without removing all the connections. This will be also useful to check the voltage under the CPU load.
2. Check the voltage setting of your computer.
Note: In the US, the voltage should be set to 110V/115V. Check the Foreign Electricity Guide for voltage settings in other countries.
3. Turn ON your multimeter and set the dial to Volts setting. Keep turning the dial until you reach the range to 10.00V.
Note: The multimeter should be set properly so that it can display the correct voltage that is flowing through the wires.
4. Now we will test the 24 pin connector that supplies the current to the entire motherboard.
Connect the negative probe(Black) of the multimeter to any ground wired pin i.e. connect it to the point where the black color wire from the PSU connects and connect the red wire to the wire terminal which is tested as shown.
The black probe is inserted into the black wire terminal and the red wire is inserted into the wire terminal which has to be tested
5. Switch ON your computer. Now your multimeter will start to show some values. Take note of the values. The different color wire carries different voltages. Mostly 4% limit within the prescribed voltage is acceptable.
|Wire color||Normal voltage||Voltage under load|
|Orange||+3.3V||+3.17 to 3.43V|
|Red||+5V||+4.8 to 5.2V|
|Yellow||+12V||+11.52 to 12.48V|
Now run any program or game which will make the system run at full load. Now take down the readings. The readings should fall within the range that is specified in the table.
6. That’s it. Your testing is done. Based on the results you can either buy a new PSU or confirm that your PSU is doing good.
1. Is there any risk of getting the electric shock?
No! There is no risk of electric shock involved in this test.
2. My PSU is working fine, but my system is not switching ON!
There may be numerous other reasons for why a computer is not switching ON. Visit Troubleshooting DEAD PC for more on why the computer is not switching ON!
3. Are you facing problems testing your power supply or following the directions above?
If you still have problems testing your PSU, feel free to Contact Us and we’ll do our best to help out.