How to Test a Power Supply Unit

How to Test a Power Supply Unit

When it comes to the beating heart of your computer, the power supply unit (PSU) is the unsung hero. It is a critical component that provides stable power to the motherboard, CPU, drives, and other internal components. As the PSU ages, it can become less efficient and even fail, leading to crashes, data loss, or failure to boot. Testing a PSU thoroughly and regularly is important to ensure the health and stability of your system.

In this article, we will cover the basics of how to test a PSU to determine if it is still functioning properly or needs to be replaced. We will look at visual inspection, voltage testing with a multimeter, and stress testing under load. A step-by-step guide will show you how to safely test your PSU using commonly available tools. With the right information and tools, you can diagnose problems with your PSU before they lead to catastrophic failures. Read on to learn how to test your power supply unit.

What is PSU?

A Power Supply Unit (PSU) is a hardware component that provides electrical power to a computer or other electronic device. It converts AC power from the wall outlet into DC power that is suitable for the computer’s components to use. PSUs come in different wattage ratings and connector types to match the requirements of different computer systems. Some PSUs can also supply a standby voltage, allowing certain computer functions to remain powered even when the system is in hibernation or shutdown. Without a reliable PSU, your computer’s performance and stability could be compromised.

How to Know Your PSU Is Failing?

Your computer’s power supply unit (PSU) is a critical component that often goes unnoticed until problems arise. Understanding the signs of a failing PSU can help you address issues early, preventing potential hardware failures or data loss. Here are the key indicators to watch out for:

1.    Smoke or Burning Smells:

If you detect any smoke or notice a faint scent of burning plastic, it’s a red flag. These signs can indicate component failure or electrical arcing within the PSU. Address this promptly to prevent further damage.

2.    Electric Shocks:

Experiencing an electric shock when touching your computer case or peripherals is a clear sign of PSU trouble. The shielding and grounding in your system may have failed, posing a safety risk.

3.    Random Shutdowns or Blue Screens:

If your computer shuts down unexpectedly or displays blue screen errors without an apparent cause (such as software issues or new hardware), the PSU could be responsible. Voltage drops from a failing PSU can lead to system instability.

4.    Inconsistent Boot Stability:

If your computer behaves erratically during boot-up—such as frequent errors or crashes—it’s time to suspect the PSU. Inconsistent boot behavior often points to PSU issues.

5.    Unusual Noises:

Listen for abnormal sounds from the PSU. Fan grinding, high-pitched whining, or buzzing beyond the usual fan hum can indicate impending failure. Note that most PSU fans are not user-serviceable.

6.    Bloated Capacitors:

If you observe bloated or leaking capacitors on the power supply board when you open your computer or device, it’s a sign that the power supply is failing. Bloated capacitors can impede proper functioning of the power supply and may cause additional issues.

7.    Overheating

Overheating can lead to power supply failures. When a power supply overheats, it might not deliver sufficient power to all the components in your computer or device. Consequently, this can result in random system shutdowns, crashes, and potential damage to other hardware components.

NOTE: Don’t wait for a complete failure; test your PSU if you suspect power supply problems. It’s better to address issues early than risk hardware damage.

Tools Needed to Test a PSU

To test your Power Supply Unit (PSU), you’ll need a few tools and equipment. Here’s what you’ll require:

  1. Multimeter: A digital multimeter is essential for accurate voltage measurements. Make sure it’s set to DC voltage mode.
  2. Paperclip or Jumper Wire: For the basic paperclip test, you’ll need a straightened paperclip or a jumper wire.
  3. Load (Optional): If you want to perform a load test, connect a load (such as a case fan) to the PSU during testing.

How to Test your PSU

To test your Power supply unit (PSU), follow the steps below:

1.    Disconnect Everything:

  • Unplug your computer from the power source.
  • Disconnect all components (drives, GPU, RAM, etc.) from the motherboard.

2.    Paperclip Test (Basic Test):

  • Locate the 24-pin ATX connector that connects your PSU to the motherboard.
  • Straighten a paperclip and insert one end into the green wire (PS_ON) pin and the other end into any black wire (COM) pin on the same connector.
  • Plug the PSU back into the power source.
  • If the PSU fan spins up, it’s receiving power and likely functional. However, this test doesn’t guarantee its stability under load.

3.    Multimeter Test (Advanced Test):

  • Set your multimeter to DC voltage mode.
  • Connect the black probe to any black wire (COM) pin on the 24-pin ATX connector.
  • Connect the red probe to the yellow wire (12V) pin.
  • Turn on the PSU.
  • Read the voltage displayed on the multimeter:
  • +12V rail: Should be around 12V (within a small tolerance).
  • +5V rail: Should be around 5V.
  • +3.3V rail: Should be around 3.3V.
  • If the readings are significantly off, the PSU may be faulty.

4.    Load Test (Recommended):

  • Reconnect the PSU to the motherboard.
  • Connect a load (such as a case fan) to the PSU.
  • Turn on the computer.
  • Monitor stability during normal usage (e.g., gaming, running stress tests).
  • If the system remains stable, the PSU is likely fine. If it shuts down or exhibits issues, consider replacing it.

Safety Precautions:

  • Ensure you’re working in a safe environment.
  • Disconnect your computer from the power source before testing.
  • Handle the PSU carefully to avoid electrical shocks.

Remember, safety first! If you are not confident in carrying out the procedure yourself, consult a professional or use a dedicated PSU tester.


Testing a power supply unit is an important troubleshooting step to ensure your computer’s stability and longevity. As outlined in this article, there are visual inspections, multimeter voltage tests, and load testing under normal usage that can help you to determine if your PSU is still functioning properly or needs replacement. Remember to adhere to the safety precautions and guidelines when testing your PSU. With the right tools and step-by-step procedures, you can accurately test your computer’s PSU and catch issues before they lead to system failures. Feel free to reach out if you have any questions or concerns about the procedures.

How to Prevent PC Overheating

How to Prevent PC Overheating

Computers have become indispensable tools in our daily lives, serving us in various ways, from work to entertainment. However, when our PCs start to overheat, it can lead to performance issues, crashes, and even hardware damage. If you’ve noticed that your PC feels excessively hot to the touch or if your fans are running loudly and working overtime, these are clear signs that your computer might be grappling with overheating problems.

These issues tend to arise when your computer is pushed to its limits, especially during resource-intensive tasks like gaming or video editing. In this article, we’ll explore the common causes of PC overheating and provide you with effective strategies to prevent it from happening, ensuring your PC remains cool and performs optimally.

Common Reasons for PC Overheating

Here are some of the common reasons why your PC may be overheating:

  1. Excessive Processes and Applications: Running too many processes and applications simultaneously strains your PC’s resources, leading to increased heat generation.
  2. Unresponsive Applications: When apps become unresponsive or hang, they consume excessive CPU cycles, contributing to overheating.
  3. Multiple Browser Tabs Open: Each open browser tab consumes memory and processing power, straining your system.
  4. Defective Fans: Malfunctioning or damaged fans fail to dissipate heat effectively, causing temperature spikes.
  5. Blocked Air Vents: Dust accumulation in air vents restricts airflow, hindering proper cooling.
  6. Outdated Software: Using outdated operating systems or drivers may result in inefficient resource management and heat buildup.
  7. Malware and Viruses: Infected systems exhibit abnormal behavior, leading to increased CPU usage and heat.
  8. Overheated CPU or GPU: Intensive tasks or inadequate cooling can cause the central processing unit (CPU) or graphics processing unit (GPU) to overheat.
  9. Dust Buildup: Dust settling on fans and vents reduces their efficiency, impeding heat dissipation.

Effects of PC Overheating

PC overheating can have serious consequences for your computer. These effects include;

  1. The first consequence of PC overheating is being hot to touch. If your computer feels unusually hot, it’s a clear indicator of overheating.
  2. When your fans start running at full speed causing loud sounds, it’s often due to excessive heat.
  3. Unexpected shutdowns can occur when your PC reaches critical temperatures.
  4. Overheating can cause your screen to freeze or become unresponsive.
  5. Overheating can damage internal components, leading to potential data loss and irreparable harm.
  6. Excessive heat can cause blue screen errors, crashes, and other problems in both software and hardware.

How to Cool your Overheating PC

An overheating computer can cause performance issues, system crashes, and hardware damage. Thankfully, there are several ways to reduce your computer’s temperature.

1.    Clean your PC

Cleaning the inside of your computer regularly is an important way to keep it running fast and prevent overheating. Dust, pet hair, and other debris can build up inside the case and clog the fans and air vents that allow airflow to cool the components. It’s a good idea to open up your computer case and clean it out at least every 6 months, or more often if you have pets that shed hair. Use a can of compressed air to blow out dust from the fans, heatsinks, and other nooks and crannies inside the case.

2.    Improve airflow to PC

Proper airflow is crucial for keeping your computer from overheating. Laptops draw in cool air through vents on the bottom and expel warm air through side and rear vents. Using your laptop on soft surfaces like a bed or couch can block the bottom vents, restricting airflow and causing the inside to heat up. Instead, place your laptop on a hard, flat surface like a desk or lap desk to allow maximum airflow.

For desktop computers, airflow is also important. Avoid putting a desktop PC directly on thick carpet or enclosing it in a small, cramped space which doesn’t allow adequate air circulation. Instead, place it on a hard surface like a desk or table, with open space around and above it. Keep it away from walls and heat sources. Also make sure cables are neatly routed and not restricting fans or vents.

3.    Inspect the PC fans

Check that the fans in your computer are working right. Fans draw in cool air and blow out hot air to regulate the temperature inside your PC. If the computer is overheating but the fans are not spinning or are making loud rattling noises, there is likely an issue. The fans could be obstructed by dust, wires, or other debris causing them to stall. Or their bearings might be worn out causing extra noise and improper spinning. Try cleaning the computer to remove dust and improve airflow. Or you may need to replace damaged fans. Working fans help keep your computer cool.

4.    Re-apply thermal paste

Thermal paste is a specialized compound that enhances heat transfer between the CPU/GPU chips and their heatsinks inside a computer. It fills microscopic gaps in the surfaces to improve thermal conduction. Over time, thermal paste can dry out or become less effective, especially if the computer runs hot regularly.

Reapplying fresh thermal paste can improve cooling in older computers. However, it involves disassembling the computer to access the CPU and heatsinks. Unless you have specific experience doing this, it’s best to have an expert computer technician replace the thermal paste.

5.    Utilize external cooling systems

Laptops are designed to draw cool air in through vents on the bottom and expel warm air from the sides or rear. If your laptop frequently overheats, using an external cooling pad can help lower its temperature. These pads have fans that blow air upwards directly into the laptop’s air intake vents. This improves airflow and heat dissipation. Look for a sturdy, adjustable cooling pad that aligns properly with your laptop’s vents. Use it on a hard flat surface rather than on a bed or couch to allow maximum air intake through the bottom.

6.    Close Programs or Turn Off PC

One simple method to help cool down an overheated computer is to close any intensive programs that are taxing the CPU and GPU and generating excessive heat. Video editing, 3D rendering, and gaming software can drive components to 100% usage, creating substantial heat very quickly. Simply closing these programs can allow the computer to cool back down.

You can also try fully shutting down the computer for an extended period of time, such as a few hours. This allows the components like the CPU and GPU to cool completely to ambient room temperature. When powered back on, the computer will start much cooler rather than heating up again immediately.

How to Prevent in Computers

Overheating computers can lead to system crashes, laggy performance, and hardware damage. Luckily, there are several ways to keep your computer cool and prevent overheating issues.

1.    Monitor Resource-Intensive Applications

Applications that use a lot of system resources like CPU and RAM can cause overheating. Use Task Manager on Windows or Activity Monitor on Mac to see which apps are using the most resources. Close any unused resource-heavy applications to free up computing power and prevent overheating.

2.    Clean Out Background Apps and Temporary Files

Too many background apps and temporary files cluttering up your system can lead to overheating. Use a system optimizer like AVG TuneUp to automatically clear out junk files, bloatware, and unused apps running in the background. This frees up valuable system resources and storage space.

3.    Optimize GPU Settings

Graphically intense games and programs can overwork your GPU and cause overheating. Go into your system’s graphics settings and optimize the GPU performance for the app you’re using. Keep your GPU hardware clean and dust-free for maximum cooling.

4.    Improve Physical Usage Conditions

Direct sunlight, dust, pet hair, and poor ventilation can all contribute to an overheating computer. Keep your computer out of the sun in a dust-free space. Clean out vents and fans regularly to allow for proper airflow.

5.    Update Software

Outdated software tends to use more resources and run less efficiently. Keep your OS, drivers, browsers, and other software updated to the latest versions. Updates often include bug fixes and optimizations that allow software to run cooler.

6.    Scan for Malware

Viruses and malware can overwhelm your computer’s resources leading to overheating. Run antivirus scans regularly to detect and remove any malicious programs lurking in your system. Prevent future infections by using comprehensive antivirus software.


Preventing overheating is crucial for getting the most out of your computer. Monitor your PC temperature regularly and be proactive about maintaining your computer. With proper care and maintenance, your computer will run smoothly at safe temperatures for years to come. Implementing these overheating prevention tips will save you from instability issues, crashes, slowdowns, and expensive hardware repairs down the road. A cool computer is a happy computer.

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