Atari ST520 with color monitor


  • Released: June 1985
  • Type: Personal computer
  • Introductory price: US$799.99 (monochrome monitor), US$999.99 (color monitor)
  • Manufacturer: Atari
  • CPU: Motorola 68000 @ 8 MHz
  • Memory: 512 KB
  • OS: Atari TOS/GEM (Digital Research)
  • ROM: 192 KB
  • Built in media: 3.5″ 360 KB floppy drive (external)
  • Predecessor: Atari 8-bit family
  • Successor: 1040ST
  • Graphic: 320 x 200 / 640 x 200 / 640 x 400
  • Colors: 16 of 512 (320 x 200) / 4 of 512 (640 x 200) / monochrome (640 x 400 – special monitor)
  • Sound: 3 voices, 8 octaves
  • I/O ports: RGB, Cardridge, MIDI, Centronics, RS232c, Hard Disk, Floppy drive, Joystick, Mouse

Released 1985: The Atari ST is a line of home computers from Atari Corporation and the successor to the Atari 8-bit family. The initial ST model, the 520ST, saw limited release in April-June 1985 and was widely available in July. The Atari ST is the first personal computer to come with a bitmapped color GUI, using a version of Digital Research’s GEM released in February 1985.

The Atari ST is part of a mid-1980s generation of home computers that have 16 or 32-bit processors, 256 KB or more of RAM, and mouse-controlled graphical user interfaces. It includes the Macintosh, Commodore Amiga, Apple IIGS, and, in certain markets, the Acorn Archimedes. “ST” officially stands for “Sixteen/Thirty-two”, which refers to the Motorola 68000’s 16-bit external bus and 32-bit internals.

My Atari ST520: I got it together with a lot of Commodore 64’s, it was complete with mouse, external floppy drive and a power supply. However, it was really dirty and didn’t worked when power on. I took the ST apart, including all the key caps and gave them a good clean. Inside, it had a 3rd part memory expansion that was “piggy back” type and some clamps for currents. It all had loosened. Once I fitted it correctly, the computer worked.

My Atari 520ST with some games
My Atari 520ST with some games.

Repair floppy drive
Next, the floppy drive was just spinning and refused to load any floppies. Once opened, I spotted the drive belt had melted/snapped. I found a rubber band as an replacement to temporary test if that was it. I succeeded loading the game “OutRun”. I then found a proper belt replacement on Internet.

Testing the floppy drive.
Atari 520ST

Remi Jakobsen

I'm collecting classic computers and video games, stretching from the 70's into the 90's. Restoration, history, usage ...

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