Inside the Macintosh 512K

To avoid regular users from opening the Macintosh 512K, Apple used Torx TT15 screws, a very unusual type of screw to be used on computers (especially at the time), which require a special TT15 screwdriver at least 9 inches (230 mm) long. The same applies to the original Macintosh and to the successors to the 512K.

Inside of the computer, you would find the most commented on (and hidden) feature of the computer: the signatures of all members of the team that designed the Macintosh, including, of course, Steve Jobs. See Figure 9. These signatures were also present on the original Macintosh and kept on the successors of the Macintosh 512K, such as the Macintosh Plus and the Macintosh SE. Interestingly enough, the Macintosh Plus and the Macintosh SE were released after Steve Jobs left Apple, but for some reason Steve Job’s signature was kept inside the computer, even though he was not related to the development of these computers, in particular the Macintosh SE.

You will see several people selling old Macs on eBay saying “this Mac is so special that it has Steve Jobs’s signature” or “rare – signed by Steve Jobs.” Let’s make something clear. All early Macintoshes were signed by the whole team, and that is not a “special feature.” Since millions of these computers were sold, they are not rare.

Macintosh 512KFigure 9: The signatures of the Macintosh team

In Figure 10, you can see how the Macintosh 512K looked inside. It was comprised of two printed circuit boards: one containing the power supply and the electronics for the monitor; the other was the motherboard.

Macintosh 512KFigure 10: Inside the Macintosh 512K

In Figure 11, you can better see the power supply board, which was officially called “Sweep / Power Supply,” part number 630-0102. This is exactly the same board used on the original Macintosh.

Macintosh 512KFigure 11: Power supply/video monitor board


Gabriel Torres is a Brazilian best-selling ICT expert, with 24 books published. He started his online career in 1996, when he launched Clube do Hardware, which is one of the oldest and largest websites about technology in Brazil. He created Hardware Secrets in 1999 to expand his knowledge outside his home country.