Testing System Power

Computer systems can sometimes experience fatal power failures that can result in one or more component malfunctioning or simply no longer work due to various reasons. This guide covers the troubleshooting of a common problem whereby system doesn’t turn on at all when you power it up.
Things to know

Keep in mind that this issue is not similar to that where system does indeed turn on but no display is shown. The no-display issue will be covered on our more extensive guide coming up next week, whereas this guide will only focus on the no-power issue.



Most common reasons for this behavior are:

1)      Recent power surge or power outage

2)      Overvoltage or overwattage of the components causing failure

3)      Excessive heat

4)      Failure of cooling components

5)      Random failures

If your system simply doesn’t turn on when you press the power button, there are couple little things you can check first that can save you a lot of time.

1)      Power cable

a.      Try different cable

b.      If plugged into UPS, try plugging directly into Wall outlet

c.       Try a wall outlet in a different room

d.      Check power switch on the back of the power supply near the power cable

2)      Switch

a.      Remove side panel and press ON switch on motherboard (if equipped)

b.      Remove switch from motherboard lead and attempt to short switch with a screwdriver (Dangerous method, consult motherboard manual for proper operation, do not attempt if you’re not familiar with basic electrical properties)

If none of these help, then the issue is either related to power supply component or the motherboard.

Testing power supply

You can begin testing power supply as this component is easier to test. PSU is a fairly simple device and can be tested easily by “jumping” it and see if it turns on. This can also be done with an off-the-shelf power supply tester, so if you have one of those you can plug in all your connectors.

If you do not have a power supply tester, there’s an easy, inexpensive way of turning on the power supply without the need of a tested.

First, you want to begin by shutting off your system, unplugging the power cable and removing the side panel.

Next, you want to disconnect both power cables that go to your motherboard. Usually, this is a large 24-pin power cable located typically on the right hand side along the boards’ edge. Also, you want to disconnect the 4-pin or 8pin connector from the other end of the board, typically located in the top right corner of the board. This will ensure that you’re not starting your motherboard when you jump the power supply.

The area of interest is going to be the 24-pin connector. You will need to locate the GREEN wire. When you have located the GREEN Wire, you will notice that it is the 4th wire from the corner. You will need to take a large paperclip, unfold it and stick one end into the GREEN wire socket, and the other end into the next black pin over, which can be 3rd or 5th wire.

Picture above shows proper jumping procedure.

When you have the paperclip firmly inserted in these sockets, it’s time to start the power supply. MAKE SURE THAT YOU DO NOT TOUCH THE PAPERCLIP OR THAT IT TOUCHES ANYTHING METAL while you try to turn the power supply on.

Connect the power cable and hit the switch on the power supply. If the power supply works, it should turn on and continue to run. If it turns on then off right away or if it simply doesn’t turn on at all, you have a defective PSU.

If the PSU is good

Should the PSU run normally, this indicates that it works fine and can start the system if needed

At this point, it’s safe to say that the motherboard is the problem and will need to be replaced.

Sometimes, you can also have a ground issue inside of the case that can cause the system not to start. If possible, you should remove the motherboard and try to power up the system while it’s outside of the case. Make sure that if you go this route that you place the board onto something soft and non-metal such as original motherboard box.

If the system still doesn’t start when the board is outside of the case, then the board is surely defective and will need to be replaced.

If the system does power up, then you should inspect all of your metal contacts in the case, starting with the motherboard stand-offs. It’s best to replace them all in situations like these, as well as inspect your backplate. It should be firmly inserted and flush around the edges. Once you replace these items, you should be able to start your system if the board is operational.

Avoid making any permanent modifications to either motherboard or power supply during this process. Doing so will void your manufacturer’s warranty, and should the unit need to be replaced it will be denied if any tampering is present. These procedures will not void your part warranty as long as you don’t damage anything in the process or you modify anything in a permanent manner.

Please note that some of these procedures do require basic electrical knowledge, therefore if you’re not familiar with basic electrical concepts you should not be attempting this kind of troubleshooting. It is best to contact your system builder for further instructions.

*Disclaimer: AVADirect and its Staff are not responsible for any damage to software/hardware, loss of data or personal injury by following our How-To guides. These guides are provided only as an aid to help you troubleshoot system problems. If you do not feel comfortable performing these steps its always best to send in your system to a local repair shop or contact an appropriate technical support line for additional assistance.