Vintage Macs: Compact Macs

Macintosh 512K

code name: Fat Mac

Got a compact Mac? Join LEM's Vintage Macs Group.

Overview

Mac 512K Introduced to replace the 128K in September 1984, the 512K had four times the RAM of the original Mac. This made it possible to work with larger files, more powerful software, and have more files open (running more than one application was still in the future, awaiting MultiFinder).

Ports on the rear of the Mac 512K

You can convert a non-working compact Mac into a Macquarium. (Please, don't even think of converting a working one - you can always find someone interested on the Classic Macs or Vintage Macs lists.)

The Upgrade Box

4.5V Panasonic PX-21 alkaline clock battery for the earliest Macs, $12.99 shipped.

Details

introduced 1984.09.10 at $3,300; discontinued 1986.04.14
model no.: M0001W
Gestalt ID: 1
upgrade path: 512Ke, Plus

Mac OS

works with System 1.1 through 4.1 (System 4.1 and Finder 5.5)
addressing: 24-bit only

Core System

CPU: 8 MHz 68000
ROM: 64 KB
RAM: 512 KB, expandable to 4 MB with third-party upgrades

Performance

performance: 0.8 (relative to SE); 0.7 MIPS

Graphics

9" b&w screen, 512 x 342 pixels

Drives

floppy drive: 400 KB single-sided
floppy connector on back of computer

Expansion

keyboard attached via coiled telephone-like cable
mouse attached via DB-9 connector
serial ports: DB-9 modem and printer ports
SCSI ports: none

Physical

size (HxWxD): 13.6" x 9.6" x 10.9"
weight: 16.5 lb.
PRAM battery: 4.5V PX 21 (a.k.a. Eveready 523, ANSI 1306AP, IEC 5LR50)
power supply: 60W

Upgrades

Mac Plus motherboard, 800KB floppy drive
One of the coolest ideas ever, Computer Care's Mac Rescue adds a SCSI port and allows a 128K or 512K owner to install Mac Plus ROMs and up to 4 MB of system memory - plus a 2 MB RAM disk. Long gone, but you might get lucky and find one.

Online Resources

Golden Apples: The 25 best Macs to date, Michelle Klein-Häss, Geek Speak, 2009.01.27. The best Macs from 1984 through 2009, including a couple that aren't technically Macs.
Tales of old Mac data retrieval, Adam Rosen, Adam's Apple, 2008.06.13. Getting apps and documents off 400K floppies, old disk images, and a Mac running System 5.
Antique Macs are still useful computers, Charles Moore, From the MacCave, 2008.09.09. Charles Moore's first online article looks at the utility of compact Macs - and foreshadows his longterm affection for PowerBooks.
Unreliable Macs, future Apple CPUs, replacing a Mac Plus mouse, and more, Dan Knight, Low End Mac Mailbag, 2008.08.12. Also Windows Media Player content that doesn't work on Macs, Leopard on a 700 MHz iMac G4, Apple's $99 Pro Care service, and CPU options.
The compressed air keyboard repair, Charles Moore, Miscellaneous Ramblings, 2008.07.24. If your keyboard isn't working as well as it once did, blasting under the keys with compressed air may be the cure.
Linux still not friendly enough, widescreen and pivoting monitors, Mac 512K restoration, and more, Dan Knight, Low End Mac Mailbag, 2008.06.23. Also the utility of Apple's old Studio Displays, questions about ViewPowr video card for PowerBook 1400, and 9-year-old predictions that came true.
Getting inside vintage Macs and swapping out bad parts, Adam Rosen, Adam's Apple, 2007.12.14. When an old Mac dies, the best source of parts is usually another dead Mac with different failed parts.
Solving Mac startup problems, Adam Rosen, Adam's Apple, 2007.12.12. When your old Mac won't boot, the most likely culprits are a dead PRAM battery or a failed (or failing) hard drive.
A (Mac) classic spookfest, Tommy Thomas, Welcome to Macintosh, 2007.10.31. How to set up those old compact Macs with screen savers to enhance your Halloween experience.
4 steps for resurrecting old Macs, Sonic Purity, Mac Daniel, 2007.07.18. Hardware problems may be solved with a thorough cleaning, deoxidizing electrical contacts, replacing failed capacitors, and/or repairing broken solder joints.
Leopard compatibility list, bad capacitors kill Macs, 1 GHz G3 upgrade resurrected, and more, Dan Knight, Low End Mac Mailbag, 2007.06.26. Also tips for troublesome OS X installs, 'About This Mac' sometimes lies, PowerBook advice, and aluminum PowerBook design.
The truth about CRTs and shock danger, Tom Lee, Online Tech Journal, 2007.05.22. You've been warned that CRT voltage can injure and even kill. The truth is that this danger is overstated - and takes attention away from a greater danger.
Bringing my Apple Lisa back to life, Ted Hodges, Vintage Mac Living, 2007.03.26. The 400 KB floppy drive wasn't working the keyboard was rough. Some homebrew fixes got everything working again.
MacWrite 1.0: Defining word processing for a graphical user interface, Andrew Conachey, Classic Mac Nostalgia, 2006.11.15. The Mac's first word processor introduced a lot of features and norms that show up in today's word processing software.
Floppy drive observations: A compleat guide to Mac floppy drives and disk formats, Scott Baret, Online Tech Journal, 2006.06.29. A history of the Mac floppy from the 400K drive in the Mac 128K through the manual-inject 1.4M SuperDrives used in the late 1990s.
Life after the 400K click of death, A. Daniel King, Online Tech Journal, 2006.05.18. What to do when your 400K floppy drive will no longer read and write disks.
Software bundles: What came with the Mac 128K, 512K, and Plus, Andrew Conachey, Classic Mac Nostalgia, 2006.01.03. A look at the software and system versions that Apple shipped with the original Macintosh, the 512K Fat Mac, the Mac Plus, and the Mac 512ke.
Which system software is best for my vintage Mac?, Tyler Sable, Classic Restorations, 2005.11.22. Which system software works best depends to a great extent on just which Mac you have and how much RAM is installed.
Innovative Macintosh System 1.0, Andrew Conachey, Classic Mac Nostalgia, 2005.12.08. The first Mac OS brought a graphical user interface to the masses, and a lot of it looks familiar to long-time Mac users.
To err is human, to correct divine, Manuel Mejia Jr, Triassic Mac, 2002.11.21. More information on why the Mac Plus degrades over time - and how to fix it. Much of this applies to the Fat Mac as well.
Care for a Mac Plus, Manuel Mejia Jr, Triassic Mac, 2002.11.05. "Of all of the Triassic Macs, the Mac Plus has the most sentimental value among the Low End Mac community." Much applies to Fat Mac as well.
Replacements for High Failure Probability Parts on Mac 128K/512K/Plus Analog Board, the pickle's Low-end Mac FAQ
The compact Macs, Matthew Glidden, Profiles in Networking, ATPM, 2002.06. LocalTalk and ethernet networking for compact Macs.
Vintage Mac 400K Floppy Drive Repeating Click of Death, A. Daniel King. How to fix a 400K floppy drive gone bad.
The original Macintosh, Dan Knight, Online Tech Journal, 2001.05.29. An in-depth look at the original Macintosh and how it shaped future Macs.
Michael Crichton's first Mac was a 512K, Apple Masters, Apple Computer. "I have written on Macs ever since."
Making a video adjustment tool, Chris Lawson, Mac Daniel, 3/24. Would you believe you can craft one from an old toothbrush?
Email lists: Classic Macs Digest, Vintage Macs
Mac 512k User Group
Q&A for the Macintosh (128K) through the Macintosh 512Ke, The Mac 512K User Group
Obsolete Computer Museum
Software Compatible with 68000 CPU
512K Mac: Packing the missing punch; Apple introduces the Fat Mac, John J. Anderson, Creative Computing, February 1985. "Features that would have to be lopped off to make a program run in the 128K can be salvaged - even improved upon - in a 512K environment."
Get your compact Mac on the web with tips from JAG's House.
Macintosh 512K: Technical Specifications, Apple Knowledge Base Archive

Cautions

Never connect an Apple II 5.25" floppy drive to the Mac's floppy port. Doing so can ruin the floppy controller, meaning you can't even use the internal drive any longer.
You can use DiskDup+ on a newer Mac to create 400k floppies using standard double density floppies. The only physical difference between 400k or 800k disks is whether data is written on one side or both sides of the floppy. Do not use high density disks. If you want to copy a disk, open DiskDup+ and insert the "master" disk. It will be read and ejected. You will be asked for a copy disk. Insert the disk you are copying to. If necessary, DiskDup+ will format the disk. If the newly created disk is unreadable on the old Mac, try making a copy on another machine (this can be cause by a misaligned hard drive). DiskDup+ will work on old machines with 1 megabyte of RAM; it will require two passes to duplicate the disk, however.
DiskDup+ will also make copies from disk image files. You can download early system software as disk images by following links from The Mac 512K User Group. If you are using System 7.1 or later, drag the disk image to the DiskDup+ icon. The rest of the process is the same as when copying a physical disk. If you don't have drag and drop, DiskDup+ has the ability to read the disk image directly. Open DiskDup and click on the button that says "Open Disk Image."
The 512K and 512Ke can only access AppleShare volumes on a network with AppleShare 1.1 Work Station, not with AppleShare 2.0 Work Station. More details in Apple TIL 5356.
The 128K and 512K are not able to read 400k disks in an attached 800k MFD-51W-10 drive.
That monitor packs a lot of voltage. Read Compact Mac CRT Energy before working inside.
Reliably supports serial port speeds to 19.2 kbps, although default is 9600 bps.
Serial port does not support hardware handshaking required for 9600 bps or faster modems.
Apple discontinued support and parts orders for the 512K on 1998.08.31. You may be able to find dealers with parts inventory either locally or on our parts and service list.

Go to Vintage Macs Index or the Compact Macs Index.

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