Apple Logic Board Failure: How to Test and Repair a Logic Board

The main circuit board that controls the interaction of components on a computer, such as a laptop or desktop Apple device, is called the logic board. This ensures that the computer functions normally. A failure of the logic board can cause a loss in communication and ultimately a crash of the system. The CPU, which is the brain of the computer can’t transmit signals to the rest the system through the logic board.

This type of failure can lead to system failures which can be very difficult to detect. It is one of the most difficult things to repair and diagnose. This requires extensive testing and intricate parts to navigate. This guide will discuss the causes of logic board failure and what you can do to protect your Apple desktop Mac or laptop.

Comparison of motherboard and logic board
There is no difference in the function of logic boards and motherboards. Apple invented the term logic board to describe a motherboard. While Apple might have specific specifications that are compatible with certain Apple computers, logic boards don’t differ from motherboards because most motherboards are unique.

Failure of the logic board is caused by several factors
Liquid spill

This is a common mistake. It can be dangerous to spill liquids or drinks on your laptop. Your computer hardware may become damaged. The logic board is the first to be damaged if liquid gets inside a laptop’s computer. The liquid can cause the board to fail by causing the connecting points to stop working.

Do not panic if your laptop is damaged by liquid. First, disconnect the power supply from your laptop. You shouldn’t attempt to clean the laptop with a hair dryer. This type of unprofessional cleaning can lead to further damage to other parts of your computer.


Overheating can cause irreparable damage to the computer. For the entire computer’s smooth operation, it is important to cool all parts, including the logic board. The CPU and video cards draw a lot power and produce a lot heat. The heat is then distributed by the cooling system to maintain a comfortable internal temperature.

The heat will build up if it isn’t dispersed quickly. This can lead to the logic board crashing or causing connecting points and other parts to warp. Large dust accumulations or malfunctioning cooling fans can cause inefficient heat dispersion.

Wear and tear from natural wear
Many hardware components don’t last long, as we know. Although we can’t predict the likelihood of logic board failure due to natural wear and tear, it is one of many factors that can cause this.

A faulty logic board could look like
Sometimes, the damage to the logic board may not be visible enough for you to notice. This can have an impact on your computing experience.

If a logic board fails, the components of it lose their communication channels and are unable to interact with one another. This can have a major impact on the computer’s performance. This can lead to system crashes or complete system failures.

There are certain signs that a logic board is not working properly
You may notice certain signs that your logic board is not working properly. The “system management controller” is a part of the logic board that can be checked with Apple Diagnostics. If Apple Diagnostics reports an error with the system management controller it is a problem on the logic board.

You may also experience problems with the USB ports located next to the HDMI/MIDI ports. Video ports are directly connected with the logic board. Any failure in this area could cause connectivity issues for ports and components.

A very dim screen on Macbook Air or Macbook Pro could indicate a failure of the logic board. A dimmed screen is one that you cannot turn back on. You will need to use a torch to illuminate it. The logic board controls the brightness of the LED screen on Macbook Air and Macbook Pro laptops.

After “dying”, a logic board can “come alive” but it will most likely crash again. A faulty logic board does not provide early warning signs that could prevent crashes. Your system won’t function if it doesn’t have a functioning motherboard. To confirm the faults and then find a solution, it is important to test your system.

How to test your logic boards for issues
As a way to eliminate other problems, we have briefly discussed testing the logic board. If necessary, this includes testing RAM and video cards, as well as the hard drive.

Your computer’s ability to pass the Power-On Self Test (POST) will also affect this. The POST (Power-On Self Test) is performed when your computer starts. POST tests your computer’s CPU, memory and network interfaces. If your computer hardware passes the POST test successfully, you will see the Apple logo splash screen on a light gray background.

Hardware to test
If your Apple laptop/desktop Mac passes POST, then you will need to test the hard drive, RAM and GPU. If your Mac laptop or desktop passes POST, you will need to test your hard drive, RAM, and GPU.

Any issues with the built-in RAM and GPU embedded on the logic boards can be referred to as a failure of the logic board. These parts are part of the board and will need to replaced if they are damaged.

Testing hard drive

Disk Utility First Aid or Apple Diagnostics can help to diagnose any issues with your hard drive. Startup problems and other storage-related issues can be caused by hard drive failure. A hard drive problem can be indicated by a folder appearing in question marks at startup.

If your Mac boots successfully, Disk Utility can check your hard drive. First Aid can detect and repair damaged sectors and help prevent premature failure. Apple Diagnostics can be used to diagnose problems with your computer’s startup. To run Apple Diagnostics, press the “D” key on the Apple splash screen. This will allow you to identify hardware issues such as RAM, hard drive, or battery.

You can also use dedicated hard drive software such as WD Drive Utilities Mac for more detailed testing. The drive must be tested on a separate Mac computer using a USB-to-SATA enclosure box. This isolates the drive from any other factors that might affect its performance.

If your hard drive is working properly, you can test other components. If your hard drive does not work, you can follow this guide to repair or test it. If you have only a hard drive problem, it is better than the logic board.

RAM Testing

RAM can be either embedded on the logic board or detached chips. Most laptops have this option. This will affect how we test RAM for problems.

You can remove the RAM chip from Apple desktop Macs such as the iMac or Mac Mini for testing. For most Apple laptop Macs, this is not possible. The logic board houses the RAM. To make sure, you can open your laptop and check if the RAM is on the motherboard.

POST is when your computer passes
Apple Diagnostics allows you to test embedded and detachable RAM for problems, provided your Mac passes POST. MemTest86 RAM testing software could be useful if your Mac is not starting up correctly.

We have already spoken about embedded RAM being part the logic board. If your laptop’s RAM is not working properly, it could indicate that the logic board is defective. You can replace your RAM chip if you find out that it is defective. We can test the video card if it is not defective.

If your computer fails to pass POST
If your computer does not turn on and stays on black, it isn’t passing POST. To test your system, you will need to remove your RAM chip. This applies only to desktop Macs, as laptop RAM is not easily removed.

You can check to see if your problem persists with the spare RAM. This will help you determine if you have a problem with your logic board. If the spare RAM is not working, your RAM problem may be serious. If your computer does not work with this spare RAM, then you may have a failure of the logic board.

Test GPU

Apple Diagnostics can help you test your video cards if your Mac passes the POST. FurMark, a video card analysis program from Geeks3D, can provide more detailed results.

Your Mac will not post if it does not have a separate video card. You can only test the video card if it is independent from your motherboard. The majority of Apple Mac laptops include an embedded GPU, which you cannot take out to test on another Mac.

Either you can find the cause of the failure by eliminating all possibilities or by looking for a problem with an embedded component on your logic board. This will usually require that the logic board be repaired.

You might be interested in replacing your logic board yourself.
Complex parts and connections are found on Logic boards, which is the main circuit board of a Mac. Even for experts like us, replacing one can be a difficult task.

If you are skilled in DIY and tech, it would be very time-efficient to replace a logic board by yourself. A replacement is usually only 70-80% successful due to the complexity of the logic boards. Everything in the logic board will need to be removed and put back after it is replaced. You might not be able to do this yourself.

Are you confident in your DIY skillset? There are many online guides for replacing logic boards at fixit. There might be guides that are specific to your Mac model. First, however, you will need a new logic board.

Logic boards can be made to fit the specific model of computer. You might also need to adjust the size of your logic board depending on how much you have. To replace the logic board, you will need to purchase the exact same model. Find the model number of your logic board, and then look up the universal part numbers for Apple parts when you order it online or in-store.

Here are a few things you might want to know…
Anyone who uses an Apple desktop Mac or laptop can experience a logic board failure. There are still some things you can do to prevent a logic board failure.

Protecting your logic board
Some logic board failures can be avoided, but it is possible to prevent them from happening. You can do this by keeping your computer’s airflow clean and your cooling system in good shape.

Keep it clean
Your laptop’s cooling fan can pull dust into your computer. Heat dispersion can be hindered by excess dust in your computer. Overheating can cause your computer to work slower than normal if the heat is not distributed.

It’s possible to clean your computer’s interior once a year, which is not too difficult. This could be done with the help of cleaning products such as lint-free cloth or isopropyl alcohol.

Make sure your cooling system is in good shape
You should keep your cooling fan in good condition as it is the main barrier against heat buildup. A fan that makes unusual rattling noises while it’s running is an indication that it is failing. Apple Diagnostics can also be used to check the fan’s status.

Proper airflow can also be achieved by clearing out the vents. Using your laptop on a cloth surface can block ventilation and trap heat.

Professional repair
It’s not easy to fix macbook logic board repair. This is why it’s best to hire a professional. Once you have a good understanding of the process, you will be able to determine what is needed to get the computer working again.

If your device has a valid warranty, Apple Care or service contract, you can get free servicing at the Apple Store. You might also want to verify whether your Apple warranty or Apple care is valid. Apple may not be able provide support if it is not possible or your device is too old to service. This applies to Apple desktop Macs and laptops made before 2012.

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