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Macintosh 512K

Macintosh 512K

The "Fat Mac"
• Expanded memory with 512K
Introduced at $3,195 on September 10th
Macintosh 512K

Macintosh 512K on HD20
Do you want to add a fan, learn how to use a single floppy drive Mac, or get more historical information on the Macintosh 512K?

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Above is a Macintosh 512K on a HD 20. The HD20 works with any Macintosh from the Macintosh 512K and beyond.
You will need a special INIT to make it work on a Macintosh 512K. The Macintosh 512Ke and above support it in hardware.

Back of the Mac 512K
The back of a Macintosh 512K sitting on a HD 20.

The box the Macintosh 512K was shipped in.

Macintosh plastic box holding the diskettes, cassette tape and manual.

The Macintosh 512K is used today yet for word processing, spreadsheets, telecommunications and the like. 512K of memory is still useful and enough for many tasks if you play by the Mac 512K's rules. The make sure you have two disk drives, otherwise the disk swapping will drive you nuts.

The HD20 hard drive was a boon for the Macintosh line, it allows the Macs to store information and applications without the hassle of swapping disks. It is slower than the SCSI hard drives, but it is faster than dual floppy drives.

Third-party companies have created a SCSI add on board which will complete the transformation of the Macintosh 512K to a Macintosh Plus. The other way was to obtain an Apple upgrade kit which consisted of the Macintosh Plus logic board and new case (the back part only.)

Apple's recommended System Software version: System 3.2 / Finder 5.3 (System Software 1.1)

For AppleShare use: The Macintosh 512K cannot use the AppleShare 2.0 workstation software. You can still use the AppleShare workstation software version 1.1 with a file server that uses AppleShare File Server 2.0, although you will not be able to take advantage of the new features of AppleShare File Server 2.0. System 3.3 and Finder 5.5 are installed by the AppleShare 1.1 Work Station Installer disk.

Below the software chart shows that the Macintosh 512K has a n/a for the AppleTalk Version. The Macintosh 512K can in fact support the AppleTalk network.

For telecommunications use: Can use 9600 baud modem or lower, anything higher may cause problems. Stock Macintosh cannot be placed on the Internet, Internet needs 4MB of RAM, possible with a memory upgrade.

Hard Drive use: Can use the Apple's HD20 - plugs into the floppy port. Or use any third-party hard drive which plugs into the modem port. Stock Macintosh 512K cannot use any SCSI hard drive.

Quick answers to your questions here!

Apple official specs


  • Introduced: 9/10/84
  • Discontinued: 4/14/86
  • Floppy Size: 400K
  • Internal HD: none none
  • Upgrade From: none
  • Upgrade To: 512Ke, Plus
  • Form Factor: 128
  • Weight: 16.5 lbs.

Logic Board

  • Main Processor: 8 MHz 68000
  • PMMU: none
  • FPU: none
  • Data Path: 8 MHz 16-bit
  • Secondary Processor: none
  • Slots: none
  • MIPS Rating: .7


  • Memory on Logic Board: 0.5MB
  • RAM Range: 0.5MB to 0.5MB
  • RAM Slots: 0 n/a
  • RAM Type: ns n/a SIMMs in groups of n/a


  • Built-in Display: 9" monochrome CRT
  • VRAM Configuration: built-in CRT
  • VRAM Speed: n/a
  • VRAM Expansion: built in
  • Color Bit Depth by Screen Resolution:
  • 512x384: 1-bit
    (1-bit = Black & White, 2-bit = 4 colors, 4-bit = 16 colors, 8-bit = 256 colors, 16-bit = thousands, 24-bit = million)
  • The maximum color depth listed for 640x870 is 8-bit, reflecting the capabilities of the Apple 15 inch Portrait Display
  • Notes: Screen size is 512x342.


  • Sound In: none
  • Sound Out: mono, 8-bit
  • Microphone Port: none


  • ADB: none
  • Video: none
  • Floppy: DB-19 - Disk Drive Port: 500K baud
  • SCSI: none
  • GeoPorts:
  • Ethernet: none
  • Microphone Port Type: none
  • Ports: Printer Modem Speaker
  • Notes: The serial ports in this system do not support handshaking or synchronous modems.

Serial Port specs

  • AppleTalk: 230.4K baud
  • Asynchronous: 57.6K baud (maximum rate)
  • Synchronous: 920K baud (maximum rate with external clock)


  • Source: .5A 105-125V 50-60 Hz
  • Consumption: 60 W or 205.2 BTU
  • Battery Type: 4.5V alkaline, #523


  • Addressing Modes: 24-bit
  • Original System Software: 0.7
  • Original Enabler: none
  • ROM ID: $0000
  • ROM Version: n/a
  • ROM Size: 64K
  • AppleTalk Version: n/a
  • System Software Supported:
    • <1.0, 1.0, 1.1, 2.0, 2.0.1, 5.0, 5.1, 6.0, 6.0.1, 6.0.2, 6.0.3, 6.0.4, 6.0.5, 6.0.7, 6.0.8

All technical information from

[ System Showcase ] [AppleTalk-ing ] [ Mac Resources ] [ Help ]
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