Macintosh Plus

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Macintosh Plus
CPU: 8 MHz Motorola MC68000
RAM Type:30-pin SIMM
Maximum RAM: 4 MiB
Supported OS: System 3.2 - System 7.5.5
Introduced:January 16 1986
Discontinued:October 15 1990
Full Specifications

It had been two years since the original Macintosh had been launched and, although the Mac 512k had replaced it 8 months later, it would be nearly another 18 months before the third version of the Macintosh was launched: the Macintosh Plus. Unlike the Mac 512k, the Mac Plus brought a lot more than just a memory upgrade to the mix.


With the exception of the serial ports sported by the two previous Macintoshes, when it came to expansion, the Mac was a totally closed box. Users couldn't even upgrade memory without having to resort to grabbing a soldering iron and physically de-soldering chips from the motherboard. By 1986, the limits of the original Macintosh design were starting to become apparent. Users wanted more, they wanted to add things, to expand, to take their machines into new arenas. Users wanted the Mac Plus.

Launched in 1986, the Mac Plus was available to purchase for more than 4 years, making it the all-in-one (AIO) Mac with the longest shelf life by a country mile. A lot of this came down to what the Plus brought to the Macintosh line and what it allowed users to do.

Although the Plus used the same 8MHz 68000 CPU as its predecessors, the same 9" B&W (black & white) screen, serial mouse and bespoke keyboard connector, and was in many ways sticking with 'tradition', it did two things that gave the machine its longevity: expansion inside and outside of the box.

Shipping with an almost unheard of (for a desktop machine) 1 MiB of RAM, the Plus actually used four 30 pin SIMM slots that allowed users to easily replace memory sticks and take the machine all the way up to 4 MiB (N.B. The Plus allows four 1 MiB SIMMs to be inserted but will only access 2 MiB of this unless some surgery is performed on its motherboard and the R8 resistor removed). In addition to this easy expansion inside the machine, the Plus also sported a 25-pin Small Computer Standard Interface (SCSI) connector. Unlike the somewhat limited (and bespoke) serial ports seen on the Macintosh 128k and 512k, the SCSI port was not only high speed but was industry standard so a whole swathe of drives and devices were waiting to be hooked up — the most popular for Plus users being an external hard drive.

Full Specifications

  • General
    • CPU: 8 MHz Motorola MC68000
    • ROM: 128 KiB
    • Bus Speed: 8 MHz
    • Data Path: 24-bit
    • RAM Type: 30-pin SIMM (150 ns)
    • Standard RAM: 1 MiB
    • RAM Slots: 4
    • Maximum RAM: 4 MiB
  • I/O & Expansion
    • Serial: 2
    • SCSI: 1
    • Floppy Connector: 1
    • Audio Out: 8-bit 22 KHz mono (mini-jack)
    • Built-in Speaker: Mono
  • Storage
    • Floppy Drive: One 800 KiB 3.5"
  • Video
    • Built-in Display: Internal B&W 9" CRT
    • Max Resolution: 512×342 (1-bit)
  • Miscellaneous
    • Apple Model Number: M0001A
    • Codename: Mr T, Turbo Mac
    • Gestalt ID: 4
    • Power: 60W
    • PRAM Battery: 4.5V PX 21
    • Case Style: Macintosh
    • Dimensions: 9.6" x 10.9" x 13.6" (W x D x H)
    • Weight: 16.5 lbs.
    • Mac OS Support: System 3.2 - System 7.5.5
    • Introduced: January 16 1986
    • Introduced: October 15 1990
    • MSRP: $2599(US)

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