Mac: Signs of a Bad Logic Board

By Avery Martin

The logic board provides the basis for all the other components in your Mac. The computer's processor, system memory, lighting, power functions, fans and other components all have a home on the logic board. The logic board generally doesn't lend itself well to upgrades, as many of its components are soldered directly to the board. Faulty manufacturing, heat, loosening solder and static can all cause a logic board to fail. Logic board issues can mask themselves as many other problems, so you may need to take your computer in for testing to know for certain if you have a bad logic board.

Common Symptoms

Commercially available programs can't usually diagnose a logic board problem. Repair technicians can test a logic board and discover the specific issue causing the board to fail. Users at home can look for symptoms of a failing logic board, such as stripes across the screen in a horizontal or vertical fashion. A blank, white or gray screen can also indicate an issue with the logic board. Of course, these issues could also have something to do with the monitor or inverter cable that leads to a monitor in a MacBook. One test involves trying a different monitor or connecting your MacBook to an external monitor to see if the problem remains.

Troubleshooting Hardware Issues

After updating your operating system and all of the software to the latest version, you should take additional steps to ensure you don't have a software-related issue. If you spilled anything on your computer and it leaked to the internal components, then you might have damaged the logic board. Remove all external devices, replace any non-factory installed memory modules and check to see if the problem remains. Losing Firewire, USB, Ethernet, audio or keyboard function could indicate a logic board issue.

Apple Diagnostics and Apple Hardware Test

Mid-2013 Macs come with the built-in Apple Diagnostics utility. Computers built before June 2013 and that haven't yet been updated to Mac OS X Mavericks 10.8.3 can use Apple Hardware Test in the same manner, but once you upgrade to 10.8.4 you must use the system software disk or the USB flash drive that came with your Mac to run the diagnostic software. This software provides a way to check your hardware -- including the logic board -- to see if you have any component issues.

Running Apple Testing Utilities

Restart your computer and hold down the "D" key while the computer boots. Wait until you see the Apple Diagnostics or Apple Hardware Test startup screen. If the computer boots, your computer doesn't support the built-in hardware test and you need to insert the system software disk or USB drive before booting the computer. Once the utility launches, select your language and follow the onscreen instructions to run the utility. When the tests complete, the utility shows you a list of any hardware issues discovered.