Atari 520STM

The Atari 520STM adapted the original 520ST for easier use with domestic televisions by adding an RF modulator and composite video output. It kept the short keyboard case, 512KB of RAM, external power supply and external floppy drive.

With TOS supplied in ROM, the 520STM avoided the operating-system boot disk required by the earliest 520STs. The model offered a practical lower-cost route into the ST range for buyers who did not initially purchase a dedicated Atari monitor.

Notable Features

• Added an RF modulator and composite output for use with a television.
• Kept the external power supply and external 3.5-inch floppy drive.
• Shipped with TOS in ROM.

Historical Significance

• Extended the original short-case ST design into markets where a household television was the most affordable display.
• The M suffix identifies the built-in television modulator.

Collector’s Notes

• The model badge may show a superscript M rather than the letters appearing on one line.
• A working television output and the external power supply/floppy combination are useful completeness checks.

Specifications

Technical Information
Name	Atari 520STM
Manufacturer	Atari
Launched	Tuesday, July 1, 1986
Discontinued	April 1989
Country	United States
CPU	Motorola MC68000 at 8 MHz
Units Sold
Operating System	Atari TOS with GEM desktop
I/O	MIDI In/Out, RS-232 serial, Centronics parallel, ACSI hard-disk, cartridge, floppy, monitor and two joystick/mouse ports
Keyboard	Integrated 95-key keyboard with numeric keypad and function keys
Storage	External 3.5-inch floppy drive; ACSI hard-disk support
Sound	Yamaha YM2149 three-channel programmable sound generator
Colour Palette	512 colours
Display	320x200 in 16 colours, 640x200 in 4 colours, or 640x400 monochrome
ROM	192KB TOS ROM
RAM	512KB
CPU Speed	8 MHz