Mac Hardware issues - Problems and Diagnostics

The Macintosh computer's hardware includes items such as the keyboard, mouse, monitor, and actual computer (or CPU). If you are having trouble with your Mac's hardware and not the software, it's a good idea to try to isolate which piece of hardware might be causing the problem.

For example, if your mouse and keyboard are not working, then make sure that the keyboard cable is firmly plugged into the keyboard and the computer. If your printer is not working, be sure that all the printer cables are plugged in correctly. Unless you are using USB cables, turn off your Mac before unplugging and plugging in its cables.

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Modern Macs have a built-in diagnostic test that can be used to help troubleshoot a hardware problem. The technology has changed over the years, and the procedure is determined by how old your Mac is.

The first step is to determine the OS version and year your Mac was produced. The simple way to do this is to use Apple Menu > About This Mac. (If the production date for the unit isn't specified, you can use a great app called Mactracker to convert a model number to an introduction date.)

The recommended steps are:

• If your Mac is from 2013 or later, use Apple Diagnostics, which is built into your Mac.
  
• If your Mac is from 2012 or earlier and has OS X v10.8.4 or later, use Apple Hardware Test, which is built into your Mac.
  
• If your Mac is from 2012 or earlier and has OS X v10.8.4 or earlier, use the system software disc or USB flash drive that came with your Mac.
  

Apple Diagnostics for the Macs introduced June 2013 or later

The Apple Diagnostics has detailed steps on how to shut down your Mac, which peripherals to disconnect, and how to hold down the D key at boot. Note that there is no prefix key used here. Hold down just the D key right after you hear the startup chime.

Note that if you leave the Ethernet cable plugged in and boot with OPTION + D, you can do some extra things, such as access your support and service options and contact Apple support.

You should review this Apple Diagnostics page and even print it so you have a handy reference during the testing. Especially useful are the keyboard shortcuts that are available.

After booting, you will see a black screen with a progress bar when the Apple Diagnostics start.

The diagnostic test takes only a few minutes. When the test is completed, you will see a notice with error Reference codes that describe likely problems. Apple has an extensive page of error Reference codes that describe the problem(s) found.

If you get the code ADP000, "No issues found," you can look for the hardware trouble elsewhere. Otherwise, follow the steps listed on the Apple Reference codes page linked above.

Dead internal battery

A common hardware problem is having the internal battery of your Macintosh fail. One symptom of a dead or failing battery is if your Macintosh's clock is always off. If the time shown in the upper right hand corner of your screen is incorrect, then reset the time.
Mac OS 9.x
Go to the Apple menu and select Control Panels, then select Date & Time.
Change the time to the correct time and shutdown your computer.
Mac OS X
Go to the Apple menu and select System Preferences.
Click on Date & Time.
Change the time to the correct time and shutdown your computer.
If your Mac clock is wrong when you turn on your computer, the most likely is that the internal battery needs to be replaced. Other symptoms of a failing battery are failure to retain Chooser (printer) settings or difficulty in turning on the computer (the monitor doesn't come on).

Mac - Chimes of death

The “chimes of death” or a sad Mac can indicate a hardware problem. According to Apple, the "chimes of death" are a series of four to eight tones that are sometimes heard immediately after the normal start-up chime, after which you get a disk with a blinking question mark. On a PowerMac, the sound will be a 'car crashing'.
If you have just installed RAM into your computer and hear the "chimes of death" then double check that your RAM was installed properly, specifically that you have the right type of chip for your model, and that the chips are seated firmly.
Otherwise, try starting your Macintosh with extensions off (restart and hold down the shift key until you see "Extensions off" or "Extensions disabled") message. If your Macintosh will start, then one of your extensions is causing the problem. If it will not start, then try starting your Macintosh from a bootable diskette or CD. If your Macintosh now starts, you should perform a clean install of your system software.
For more information and troubleshooting, see this Apple article:
You hear "breaking glass" or musical beeps" (outside this site)when you startup your Mac.