The motherboard of any computer is the circuit board, which handles interactions between different components. On a Mac, it is called the logic board, and it ensures that all functions are working optimally.

Just like any other part of your Mac, your logic board can get damaged. If this happens, there will be a communication loss in your device.

A faulty logic board can eventually lead to a system crash, except you can determine the causes and identify the signs.

What Causes Logic Board Failure in Macs?

M1 iMac 24 internal layout
Image Credit: Apple

Like any other device or machine, your Mac's logic board is susceptible to wear and tear. After using your Mac for several years, the logic board may get faulty or damaged. However, other factors can cause a defective motherboard. The common culprit is dust and dirt, including hair follicles.

Some direct factors that can damage your logic board are physical impact, liquid spill, electrical surge, and heat. But how do you know that your Mac's logic board is faulty or damaged? Read on below.

7 Signs of a Faulty Logic Board in Your Mac

When troubleshooting a Mac, the logic board is one of the most challenging components to diagnose and repair. Here are seven signs that your Mac's logic board is faulty:

1. System Crashes

MacBook stuck on white screen

The logic board controls your Mac's components that help it function properly. So, an obvious sign of a faulty logic board is when your Mac starts to fail and crash.

Your Mac may boot properly but unexpectedly crash while you're using it. A sign of a crash might be your Mac shutting down on its own or occasional freezes as you use it. When this happens, you can restart or shut down your frozen Mac.

2. Your MacBook's Battery Is Not Charging

Another sign of a damaged logic board is when your battery doesn't charge even when connected to an electric source. The power input is connected to the logic board, whether your Mac has a dedicated charging port or uses a USB-C port. So, once the logic board gets damaged, it affects the charging ports.

If you are unsure why your Mac is not charging, check that the power source you're connected to is not weak, reduce the tasks running on your Mac, and check your battery health.

To check your battery health, follow these steps:

  1. Open System Settings from the Dock.
  2. Scroll down on the left pane and click on Battery.
  3. You'll see the Battery Health on the right. You can click on the Info (i) icon for more information.
  4. This will show your MacBook's battery capacity, similar to how you view your iPhone's battery health.

3. Your Mac Doesn't Turn On

When you have a defective logic board, your MacBook may not boot up when you press the power button. Although there are several reasons why your Mac won't boot or start, it is an obvious sign of a faulty logic board.

However, you'll need to ensure your battery is fully charged or plugged in when turning it on before you jump to conclusions.

4. USB Ports Stop Working

MacBook with external USB port device

All the ports on your Mac are connected to the logic board. It's also where external devices connect to your Mac, so a problem with the logic board will be evident through faulty and shaky USB ports.

The first sign of this problem is that your Mac will not recognize input devices plugged into the ports or doesn't support output devices.

5. Audio No Longer Works

MacBook on a table with a record player, speakers, and headphones

A defective logic board also means your Mac will no longer produce sounds. If the problem is related to the logic board's audio component, you won't get regular system sounds from your Mac.

Also, you will need help getting external audio devices like speakers and headphones to work. When you plug them into your audio jack, your Mac will be unable to recognize them as audio devices, or you will be unable to connect audio Bluetooth devices. You can try any of these fixes if your Mac's sounds aren't working, but if none works, then you likely have a damaged logic board on your hands.

6. Graphics and Display Problems

iMacs on table displaying designs on screen

For Macs with fans, you may hear your fan start to spin, but the backlight never comes up or only comes with a dim light. This issue may persist even when an external monitor like a projector is connected to your Mac. Although this can indicate a broken screen or display, it also points to a visual problem on the logic board.

In the case of a defective logic board, if the backlight eventually comes on, you will experience other hiccups like distorted graphics, gray scales, or colored lines across your screen.

The screen and graphics of your Mac are directly connected to the logic board, so a faulty or damaged board reflects on your Mac's display, affecting its brightness, among other things.

7. Failed System Diagnostics Test

You can also check if your logic board is faulty by using system diagnostics. To test for a defective logic board using hardware diagnostics, you will need to perform a series of tests on the various components of the computer, like the RAM, CPU, and GPU.

You can run these hardware tests using the built-in Apple Diagnostics in macOS or third-party diagnostic tools.

To use Apple Diagnostics on an Apple silicon Mac, you'll need to shut down the Mac, long-press the power button, release it when you see the Options screen, and then press Cmd + D. Intel Mac users need to press and hold the D key as their Mac boots. If you get an error code, refer to Apple's Support page for more information.

Get Your Mac's Logic Board Repaired

When checking for issues with your logic board, you might also notice that your Mac's Wi-Fi, Bluetooth, or integrated webcam is not working as it should be.

While all these signs may point to a faulty logic board, they may also be signs of other issues. Your Mac is not damaged beyond repair, even with a defective logic board. You can fix it yourself or take it to a professional to change and repair it.