When a computer crashes, you don't immediately think of an outage in the power supply. However, it is easy to test the diet and it could save you a lot of headaches looking for a problem where it isn't. A power failure manifests itself in different ways: you can have a blue screen, untimely crashes, hard drive errors. The computer may also simply not start. So learn how to do some tests that cost nothing or little, before you throw yourself into crazy expenses.
Part 1 of 2: Check if the computer starts
Step 1. Shut down your computer
Then, toggle the power button to the off position. Unplug the plug from the wall.
Step 2. Open your computer case (central unit)
Unplug all the power cables (connected to the different components) inside. Follow the cables to make sure everything has been unplugged.
Take care to locate, one way or another, the connections to be able to make the reinstallation later
Step 3. Do the paper clip test
In fact, you can test the power supply with a paper clip that you have first unfolded, then folded into a "U" shape.
The ends of the paper clip will act as pins and will be inserted into the power supply. So your computer will be powered without going through the motherboard
Step 4. Locate the 20/24 pin connector that supplies power to the motherboard
This is the widest of the power connectors, you can't go wrong!
Step 5. Find the green pin and the black pin (# 15 and 16)
Both ends of the paper clip should be pushed into these two pins (there is only one green cable and the black cable is the one right next to the green). Before proceeding with this operation, check once again that you have disconnected the power supply from the electrical outlet, that the computer switch is in the "Off" position and that the internal components have been separated from their power supplies. respective.
The green pin, if fitted correctly, is pin # 15
Step 6. Insert the paper clip into the two holes
Then place your beam where it won't get in your way. Then plug the general power cable back into the outlet and press the computer's start switch.
Step 7. See if the fans are spinning
Once connected, you should hear (or see) the fans spinning. This is a sign that the power has been restored. Otherwise, turn off and unplug everything. Then check your paperclip connection and try again. If nothing happens, you have a power problem.
This test will not tell you that your power supply is working perfectly, it will only tell you that it is working for certain operations. To find out more, you have to take the second test
Part 2 of 2: controlling the outputs
Step 1. Test your outings using dedicated software
If your computer is in working order and you can access your desktop, try running software that will test certain electrical parameters. Thus, SpeedFan is a freeware which establishes an electrical diagnosis and then establishes a report on the temperatures and voltages that it has measured. Then you will need to check that these numbers match those advertised in the manufacturer's manual.
If your computer is not working, skip the next step
Step 2. Shut down your computer
Unplug the plug from the wall. Toggle the power button on the back of the system unit to the off position. Open your computer case (central unit). Unplug all the power cables (connected to the different components) inside. Follow the cables to make sure everything has been unplugged.
Step 3. Check your power supply with a current tester
This type of device is available in stores that sell computers and on the Internet, it is not very expensive. Locate the 20/24 pin connector that supplies power to the motherboard. This is the widest of the power connectors, you can't go wrong!
- Connect your device to the 20/24 pin connector.
- Turn on the power to the box and turn on the computer. Your tester should turn on as well.
Some testers turn on automatically, others must be turned on by toggling or pressing a button
- Check the voltages. On this 20/24 pin connector, we have outputs at different voltages, on average 4:
- the outputs in +3, 3 volts
- the outputs in +5 volts
- the outputs in +12 volts
- the outputs in -12 volts
- You must check that the voltages read are within the norm. Overall, the 3, 3, 5 and + 12 volts accept variations of +/- 5%. The -12 volts test accepts variations within the limit of +/- 10%. If you exceed these standards, your power supply is defective and must therefore be replaced.
- Test the other connectors. Once the main connector (the one on the motherboard) has been verified, do the same with each of the other connectors. Do them one after the other. Between each test, remember to disconnect the power and turn off the box.
Step 4. Test your power supply with a multimeter
Unfold a paper clip, then bend it into a "U" shape. Find the green pin and the black pin (pins 15 and 16). Both ends of the paper clip should be pushed into these two pins (there is only one green cable and the black cable is the one right next to the green). This maneuver short-circuits (or shunts) the motherboard.
- Then plug the general power cable back into the outlet and press the computer's start switch.
- Obtain the factory-supplied power data. Thus, you will know what voltage must deliver each pin.
- Set your multimeter to voltmeter mode. If your multimeter does not adjust automatically, turn the calibration knob to 10 V.
- Connect the negative tip of your device to a pin of the connector (colored black) connected to earth.
- Connect the positive tip to the pin you want to test. Note the voltage displayed.
- Check that the voltages are within the limits prescribed by the manufacturer. If not, your power supply is faulty.
- Repeat this with all your connectors. Refer to the instructions given for each connector to find out which pins to test.
Step 5. Reassemble your central unit
Once all the tests are done, you can reassemble your central unit. Make all the necessary connections. Plug in the connectors well, especially those on the motherboard. Once everything is reassembled, you can restart your computer.