Testing A Desktop Power Supply

Many PC problems are power supply related. When the power supply of a computer goes bad, the system will stop functioning. In addition, other symptoms such as unexpected reboots, booting problems, and lockups can be due to a faulty power supply as well. To test for a faulty power supply one has to use a multimeter. A multimeter is a device that can be set to work as an ammeter to measure current, a voltmeter to measure voltage, and so on. The power supply converts the 115-volt AC from electrical outlets into direct current (DC) that the personal computer can use.

Follow the steps below to test a desktop power supply. These steps are designed for desktop computers; however, it can come in handy in resolving similar issues on laptop computers.

Test with a multimeter

1. First, test for a connection problem. Make sure you switch off the computer from the power source and check to see if the voltage selector is at the 115-volt mark (For USA). The next step is to check to see if the fan is spinning. If it is, then nothing is wrong with the fan or the power connector. The focus at this point should be on power source.
2. The next step is to try to resolve the problem by looking at the supply outlet. At this stage, the service of the electronic multimeter is employed. Set the device to AC voltage slightly above 115V to test the power outlet.
3. Now, the multimeter is set for continuity test. First, we connect the positive pole of the multimeter (ammeter in this case) to the red wire (positive terminals) from the connection outlet, and the negative pole of the multimeter is connected to the black wire or the connection outlet (negative terminal). For wall sockets, the negative terminals are usually located in the right-hand side.
4. If there is a deflection to the right of the multimeter then nothing is wrong with the power outlet. On the other hand, no deflection at all shows that the fan is faulty. Replace the fan before you use the computer again. 5. Next, it is time to test the motherboard to see if it is causing the problem. Motherboards usually have more than one wire that connect it to the power supply. Disconnect the system from the power outlet. AT power supplies usually have P8 and P9 connectors. Make sure you tag them so you won't make the mistake of placing them back in the reverse. This could damage your system, so be careful.
6. Conduct continuity test.

Test a new power supply

Nowadays, it may be easier to just test a new power supply. This makes sense if you do not have a multimeter or cannot find a multimeter. Power supplies can be relatively inexpensive depending on your PC specs. If your computer has stopped working due to a power outage, testing a new power supply could be a good thing to try before buying a new computer.

To test a new supply, purchase a new power supply with similar or better specs than your current power supply. Make sure the Watts is the same or higher than your original supply. Also, make sure the new power supply has the correct connections for your motherboard and processor. Most current PCs require a 20 or 24 pin connector for your motherboard and 4 pin connector for your CPU.

Changing out a power supply is relatively simple. First, make sure your computer is unplugged from the wall. Next, you need to disconnect all hardware from the original power supply. For example, your hard drive(s), motherboard, cd/dvd drive will all have a connector from the power supply that need to be disconnected. After this, unscrew the screws holding your power supply to the computer tower. These screws are usually on the outside back of the tower. Remove the old supply. Next, insert the new supply and screw it to the tower. Last, reconnect all hardware to make sure all of your hardware has power. Close up your case and power on the computer. If you computer powers on correctly, you know that your power supply was the problem.

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-By Dominic

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