You’re getting ready to start a daily task with your computer, but after barely starting, it turns off.
It’s too stressful, especially when you think your computer is reaching the end of its life.
However, spending some time can help you pin down and solve the issue.
Computer Cycles On And Off (7 Causes, Fixes)
Cause 1: Power Button Issues
A sticky power button (in front of the case) may cause your computer to turn off after a while.
To test for a potentially sticky button, turn off the power switch in the back of your case and press the power button multiple times.
You can easily sense if the power button is sticky.
How To Fix
No matter why the power button got sticky, you can easily fix it.
You need to dampen a soft cloth with isopropyl alcohol and wipe the button and the area around it.
You could also use a damp cotton swab to run it around the edges and get better access.
If you can’t clean the power button (which is unlikely), you could replace the button.
That said, there are other ways to turn on your computer without the power button.
You can use the reset button to turn on your computer.
You just need to open the case and replace the reset cable with the power cable.
Now, by pressing the reset button, your computer turns on.
Cause 2: Power Supply Issues
The power supply voltage switch is located on the back of some desktop cases, and it defines the source voltage for the power supply unit (PSU).
As a result, the PSU can adapt to electric power.
However, modern cases adapt to the voltage automatically without a switch.
The switch voltage must correspond with that of the outlet.
If it’s lower, your computer may turn off after a few seconds and potentially damage the motherboard.
If it’s higher, your computer doesn’t turn on at all.
How To Fix
Since voltages in wall outlets vary in different countries, the Foreign Outlet Guide can help you set the voltage switch according to your country’s outlets.
For instance, if you live in Italy, you have to set it at 230 volts.
To change the voltage, after powering off the computer, switch the power button on the PSU and unplug the power cable.
The voltage switch is located below the power switch, which you need to toggle until you get to the right value.
Defective Power Supply Unit
A PSU modifies the electric current to be used by different components.
It’s composed of four main parts.
The transformer changes the voltage and the rectifier converts it to DC.
The vibrating DC power becomes smooth in the filter part, and finally, the regulator produces a steady DC.
An issue in any of these four PSU components may result in a faulty PSU and unsteady power cycles.
Therefore, you need to observe the other symptoms, including blue screens or extra noises from your case.
PSU malfunctions usually don’t involve fans.
You can also expect that the fan spins with an off PC while using a dead PSU.
If your case has experienced electrical interference or overheating, it’s likely to lose the PSU function.
How To Fix
To troubleshoot your PSU, you need to open it and look for the broken part.
However, since even an unplugged PSU has electricity in its components, it may shock you.
Therefore, we recommend that you have an experienced technician do that.
They’ll tell you whether you need to buy a new PSU or it can be repaired.
However, if you have the technical skills, you can test the PSU yourself.
How To Test Power Supply Unit
1. Paperclip Test
To test the PSU function, you need a paper clip and the power supply disconnected from the other PC components.
In this test, you trick the power supply and simulate the conditions that the PC is on to see how it works.
Follow the steps for the paperclip test:
- Turn off the power button in the back of the PSU and unplug the 24-pin connector.
- Reshape the paperclip into a U.
- Put one end in the green wire and the other in any black wires in the 24-pin connector.
- Turn on the power button.
- See if the internal fan works. If not, your PSU has an issue.
The paperclip test checks any electric shorts, defective components in the PSU, and the connections of the motherboard cable.
Passing this test just confirms the PSU’s functionality.
You need to be sure of voltage changes, possible PSU failure, and overheating, too.
2. Swap Test
The swap test is also used for checking the PSU function, but you need more equipment.
You need a spare PSU to connect it to the wall outlet and the motherboard and see if it works.
If your PC doesn’t turn off, your PSU is faulty.
3. Use A Multimeter
To check your PSU via a multimeter, you need to spend more time.
After flipping the power button off, unplug all the cables except the 24-pin and follow these steps:
- Make an electric short between pins 15 and 16 of the 24-pin cable (green and black).
- Set the multimeter on VDC.
- Flip the power button on.
- Connect the negative cable (black) to a ground pin, then connect the positive (red) one to each pin.
- Write down the numbers shown for each pin.
- Compare the number with the approved ones in power supply coverage tolerances. If any of them was out of the range, you need to replace your PSU.
For more certainty, consider voltage for other power connectors.
You have to remove the shortcut from the motherboard then turn the power button off.
Afterward, plug in the other internal devices.
Flip the power button on and turn your computer on, too.
Repeat steps 4 and 5 for floppy, SATA, and peripheral connectors.
Cause 3: Dirt And Dust
Dirt and dust don’t have any immediate effects on PC function, but they can damage the CPU over time.
Their primary effect is decreasing the airflow through the components.
The air inside the case gets warmer, and the fans become ineffective at sending it out.
When the CPU gets hotter than its allowed threshold, it’ll shut off the entire system.
How To Fix
First, bring your case to a well-ventilated room and unplug all cables for more safety.
Now, wear a mask and start opening the case, including the side and front panels.
Use a piece of microfiber cloth or compressed air to remove dust.
Finally, use a vacuum to remove the dust gathered on your case floor.
Remember to cover every little space and don’t exert too much pressure.
Otherwise, you’ll damage the delicate components.
Cause 4: Fan Failure
All PCs have at least two fans, each functioning differently.
One is responsible for sucking cool air into the case and the other is the exhaust fan which moves generated heat out.
The second one is near the PSU and has a vital role in keeping it cool.
Fan failure causes your CPU to get warmer and may result in your computer cycling on and off.
Detecting a faulty fan is easy because you can simply open the case, turn on the computer, and see if it works.
However, before making any hardware changes, it’s recommended to reset your BIOS settings to default to make sure the root cause isn’t software-related.
To flash BIOS, follow the below steps:
- Turn off your computer.
- Turn it on and quickly press F2.
- Select Load BIOS Default from the new window.
- Save the changes by pressing F10.
- Your computer restarts.
Depending on the fan problem, you could fix the fan or have to replace it.
For example, there may be wires tangled around the blades, preventing them from moving.
In this case, untangling the wires is simply the solution.
In other cases, lubricating the fan may be the solution if it’s stuck.
It removes dust gathered over time, which stops its shaft from spinning.
Follow these steps to lubricate your case fan:
- Pull out the fan connector.
- Rotate four pins 90 degrees installed in corners of the fan.
- Pull the pins up. Now, hold the fan sides and remove them from the motherboard.
- There’s a label on the center of the fan. Remove it.
- Remove the small plug above the label.
- Now, you can see the shaft. Drop some oil in the hollow space.
- Connect it to the motherboard and push the blade.
If this didn’t solve the problem, unplug the fan and connect it to a nine-volt battery.
If that doesn’t work, you may need to change the fan.
Otherwise, read the below section.
If your fan doesn’t get enough power to work, the motherboard might be the issue.
To check your motherboard, follow these steps:
- Connect the fan to the motherboard.
- Use a voltmeter to diagnose the fan. If you’re using a multimeter, set it on VDC.
- Each connector has a red and black cable. Put each multimeter cable on pins and check its reading.
- If the motherboard has an issue, the multimeter shows nothing special.
To fix the problem with your motherboard, you should get help from a technician.
However, if you don’t have a problem with the price, replacing the motherboard can be the last option to solve the problem.
Cause 5: Electrical Shorts
A stray screw can be one of the factors that cause electric shorts.
Without warning, it can get out of different components connected to the motherboard, making various signs of trouble.
The motherboard is attached to the case via a few screws.
A single loose screw can cause it to touch other components, making even more electric shorts.
How To Fix
First of all, unplug your case, then shake it to see if you hear any rattling noises.
Even if you don’t hear any extra sounds, you can’t be sure there are no loose screws as the screws may be stuck.
Open your case to look for the stray screws.
It’s a good idea to use a big magnet to make the screw move.
Damaged Wires And Cables
If the plastic cover of wires or cables is damaged, they may contact the other components and cause electrical shorts.
You need to open the case and inspect for naked wires.
Although a frayed wire doesn’t make electric shorts, it can cause problems in the long term.
How To Fix
In most cases, it’s better to replace it with another wire, especially when it’s decayed.
By doing that, you’ll permanently fix the issue.
Plus, it’s safer.
However, if that’s not possible, you can use electrical tape to cover it.
Note that you can only use this option if the wire cover is damaged, not the whole wire.
Plus, to provide the same protection as using a new wire, you need to wrap the wire many times.
Also, you can cut the damaged wire and tie the two ends together.
This makes the wire more resistant and safer than just using tape.
Cause 6: Defective RAM
As a component that stores short-term information, RAM plays an essential role in your computer speed and performance.
Defective RAM prevents the PC from booting normally and opening different apps together.
The memory modules help the CPU access faster to information.
However, if they’re seated improperly on the RAM slots, they cause problems.
Open your computer case and see if the modules are properly seated.
They’re usually in pairs with the same colors.
Remove the modules and reseat them to make sure they’re properly seated.
Cause 7: Faulty Surge Protector
A surge protector is an essential component because it keeps the voltage within an acceptable range.
If the electricity fluctuates to a higher level, the surge protector transfers the extra electricity to the ground wire.
However, an old and overused surge protector may reduce the electrical current too much.
As a result, it can’t provide enough electricity to the PC, and after a while, your computer turns off.
To make sure this is not the issue, remove the surge protector and plug your PC directly into the outlet.
If everything is okay, the surge protector is the culprit.
How Do I Open My Case?
There’s not a particular way of opening all the desktop cases.
Depending on your case model and its manufacturer, we can divide the computer cases into two types explaining their opening methods.
First of all, don’t forget to unplug all the cables before starting.
Make sure that no electricity flows in your case components, and open up your case.
1. Screw Or Thumbscrew Cases
Most cases have screws to secure case panels firmly together.
The screws are usually tiny and need special screwdrivers for working with them.
However, the thumbscrews (case screws) are large enough to be tightened or loosened by hand, so you usually need no tool to do that.
If your case has thumbscrews, open them first, then take a precise look at your case’s back edges to find the screws.
Afterward, put the case on the side and unscrew them using a screwdriver.
2. Screwless Computer Cases
Instead of screws, you find levers and buttons in these cases.
However, some of them have thumbscrews (case screws), too.
As mentioned, to open the case, start with thumbscrews if they exist.
Afterward, put it on its side and look for small levers and buttons on top and back.
Push the buttons and pull the levers to free the side panels.
Now, push the panels to the back of your case to remove them.