Atari 520 STM

The 520ST was an all-in-one unit, similar to earlier home computers like the Commodore 64. By the time the 520ST reached the market, however, consumers demanded a keyboard with cursor keys and a numeric keypad. For this reason, the 520ST was a fairly large and awkward computer console.

Adding to this problem was the number of large cables needed to connect this original model to the peripherals, a power supply cable was needed, and another for an external disk drive, This problem was addressed to some degree in the follow-on models, such as the far more common Atari STFM, which included a built-in floppy disk drive and power supply, though this addition resulted in the awkward placement of the mouse and joystick ports to a cramped niche underneath the keyboard, whereas on this model they are located conveniently on the side.

Early 520ST owners became accustomed to the "Atari Twist" and the "Atari Drop" service procedures. "Atari Twist" seemed to help discharge built-up static electricity (Atari soldered-down the metal shielding to fix the problem) while the "Atari Drop" appeared to help re-seat chips which may have become partially unseated over time.

The case design was created by Ira Valenski - Atari's chief Industrial Designer. The ST was basically wedge shaped, with a series of grilles cut into the rear for airflow. The majority of the machines had keyboards with soft tactile feedback resulting in a "cheap" feel, with rhomboid function keys across the top edge. The original 520ST design used an external floppy drive; the 1040ST-style case featured a built-in floppy drive. The power supply for the early 520ST was a large external brick while the 1040ST's was inside the machine.
Specification of the 520st:
CPU: Motorola 68000 @ 8 MHz. 16-bit data/24-bit address bus. RAM: 512 KB or 1 Megabyte, Display modes (60 Hz NTSC, 50 Hz PAL, 71.2 Hz monochrome):

Low resolution - 320200 (16 color), palette of 512 colors , Medium resolution - 640200 (4 color), palette of 512 colors, High resolution - 640400 (mono), monochrome

Sound: Yamaha YM2149 3-voice squarewave plus 1-voice white noise mono Programmable Sound Generator

Drive: Single-sided 3" floppy disk drive, 360 KB capacity when formatted to standard 9 sector, 80 track layout.

Ports: TV out (on ST-M and ST-FM models, NTSC or PAL standard RF modulated), MIDI in/out (with 'out-thru'), RS-232 serial, Centronics parallel (printer), monitor (RGB or Composite Video colour and mono, 13-pin DIN), extra disk drive port (15-pin DIN), DMA port (ACSI port, Atari Computer System Interface) for hard disks and Atari Laser Printer (sharing RAM with computer system), joystick and mouse ports (9-pin MSX standard)

Operating System TOS v1.00 (The Operating System) with the Graphical Environment Manager (GEM) WiMP (Windows, Mouse, Pointer) GUI.

Manufacturer: Atari
Date: 1st January 1985

Magazines RELATED to Atari 520 STM in our Library

Item Manufacturer Date
Monitor - The UK Atari Computer Owners Club - Issue 10 0000
Antic - The Atari Resource May 1983 May 1983
Antic - The Atari Resource June 1983 June 1983
Antic - The Atari Resource August 1983 August 1983
Antic - The Atari Resource September 1983 September 1983
Antic - The Atari Resource November 1983 November 1983
Antic - The Atari Resource January 1984 January 1984
Antic - The Atari Resource February 1984 February 1984
Antic - The Atari Resource April 1984 April 1984
Antic - The Atari Resource June 1984 June 1984
Antic - The Atari Resource October 1984 October 1984
Atari User - May 1985 May 1985
Practical Computing - June1985 June 1985
Atari User - June 1985 June 1985
Antic - The Atari Resource June 1985 June 1985
Personal Computer World - June 1985 01-06-1985
Atari User - August 1985 August 1985
Atari User - September 1985 September 1985
Atari User - October 1985 October 1985
Atari User - November 1985 November 1985
Atari User - February 1986 February 1986
Atari User - March 1986 March 1986
Personal Computer World Special: Business Computing The 1986 Survival Guide April 1986
Atari User - April 1986 April 1986
Antic - The Atari Resource April 1986 April 1986
Atari User - May 1986 May 1986
Practical Computing - August 1986 August 1986
Atari User - January 1987 January 1987
Atari User - February 1987 February 1987
Personal Computer World - February 1987 01-02-1987
Atari User - April 1987 April 1987
Atari User - May 1987 May 1987
Atari User - June 1987 June 1987
The Micro User - July 1987 - Vol 5 No 5 Database Publications Ltd July 1987
Atari User - July 1987 July 1987
Atari User - August 1987 August 1987
Atari User - September 1987 September 1987
Atari User - November 1987 November 1987
Atari User - March 1988 March 1988
Atari User - July 1988 July 1988
Atari User - August 1988 August 1988
The Micro User - April 1989 - Vol 7 No 2 Database Publications Ltd April 1989
Byte January 1986 16-09-2009
Byte June 1986 16-09-2009

Other Systems Related To Atari 520 STM:

Item Manufacturer Date
Atari 400 with Aftermarket Keyboard Atari November 1979
Atari 800 Atari November 1979
Atari 400 Atari November 1979
Atari 1200XL Atari 1982
Atari 800XL Atari 1983
Atari 600XL Atari June 1983
Atari 520 STFM Atari 1985
Atari 65XE Atari 1985
Atari 520ST (boxed) + External hard drive + software Atari 1985
Atari 1040 STE Atari 1986
Atari 520 STM Atari 12th September 1986
Atari Mega ST 2 Atari 1987
Atari ST Mega 1040 Tower Power Atari 1988
Atari 520 STE Atari 1989
Atari 1040STF Atari 1989
Atari Portfolio Atari 1989
Atari Stacy 2 Atari 9th December 1989
Atari TT030 Atari 1990
Atari Falcon Atari 1990
Atari Mega/STE Atari 1991

This exhibit has a reference ID of CH587. Please quote this reference ID in any communication with the Centre for Computing History.


Atari 520 STM

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