Macintosh 512K


How to Generate Floppy Disks for Old Macintosh Computers
Service Source
Mac Startup Keys
Sad Mac Error Codes
Tutorial Cleaning, Lubricating And Fixing An Apple 800k 3.5′ Floppy Drive




Another motherboard of the same model, that has an interesting version of the MC68000 CPU.

Similarly to Macintosh Plus, the board uses a rare 4.5V PX-21 battery. The computer will perfectly boot and work without the battery, but the date and time settings will not be preserved.

Analog and Power Supply Board

USA version of the board marked 630-0102, supporting 120V only, can’t be easily modified to work with 230V mains.

International version of the board marked 630-0108, supporting both 120V and 230V. Can be switched by installing W12 jumper for 120V or removing it for 230V.

Three types of the flyback transformers installed on the board.

AC-058 ZHAT with a smaller footprint, goes into the narrower set of holes drilled in the board:

LIFON 157-0042C with wider distances of the pins:

An alternative version, MONITRON 157-0026-B:

List of capacitors for recapping the USA board:

Floppy Disk Drive

Sony OA-D34V floppy drive is a single side 3.5″ 400K drive. It produces a fantastic sound when working. In later versions of this Mac, called 512Ke an 800K drive was installed. OA-D34V was the oldest original drive installed in 512K and there were also upgraded versions called OA-D34V-22, which needed the Mac’s ROM to be in revision B.

The drive loading mechanism gets stuck with time due to the original lubricants getting thick. You can restore it using Isopropanol (IPA) in spray, ear buds and a little of gentle force.

With a working loading mechanism, the drive is also likely to not read disks well after a prolonged time of being not used. When drive can’t read the disks (or the disks are bad), Mac will report Sad Mac icon with 0F0064 code when trying to load the system.

One of the likely causes may be the head stepper motor – it won’t get stuck completely, but will become hard to move and loose calibration of the head position. Spraying the motor with IPA and carefully moving the head out of its original position and starting the Mac will force the motor to seek the zero track and eventually it can get into good shape, having repeated it several times. It worked well for the two drives that I have.

An upgraded version of the drive, to the 800K Sony MFD-51W:


Samsung 10ATY4N

An alternative Clinton Taiwan Corp. CRT:


Keyboard model number M0110

Keyboard model number M0110B

Numeric keypad M0120P


Apple Anti-Theft Lock


Some Older Pictures