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Atari 400

Atari 400 · 1979–1983 · desktop

Specifications

Cpu: MOS Technology 6502B, 1.79 MHz
Ram: max: 16 KB, soldered directly to the board (no memory module bays like the 800) · base: 8 KB (16 KB on later production runs)
Ports: 1x cartridge slot · 4x controller (joystick/paddle) ports · Serial I/O (SIO) bus for disk, cassette, and printer · Monitor and RF video out
Display: ANTIC/GTIA chipset: palette of 256 hues/luminances, 40x24 text, graphics modes up to 320x192
Storage: base: Atari 410 cassette recorder (no internal storage) · options: Atari 810 5.25" floppy disk drive over the SIO bus
Os Support: latest: Atari DOS 2.5 · shipped: Atari BASIC / OS ROM cartridge
Release Price: $549.95 (8 KB configuration)

Variants

Models

400 (CTIA)1979-1981, original CTIA graphics chip, membrane keyboard

400 (GTIA)1981-1983, upgraded GTIA chip, extra graphics modes

Storage

16KB1979-1982, soldered non-expandable RAM

48KB1983, revised board with 48KB RAM

Upgrade paths

RAM

16 KB by third-party solder-in RAM chip swaps · RAM is soldered to the board, not socketed in modules like the 800, so upgrading means desoldering and hand-wiring new chips rather than plugging in a module.

~$40 for chips

HARD

keyboard

Mechanical keyboard swap via third-party or hobbyist kits · Stock unit shipped a sealed membrane keyboard aimed at durability for a home/game market; hobbyists later fitted mechanical keyboards salvaged from other Atari 8-bit units.

~$30-$60

HARD

storage

Atari 810 (or later 1050) 5.25 inch floppy drive over the SIO bus · SIO daisy-chain made adding a floppy drive plug-and-play compared to the cassette-only base config, though the single cartridge slot and lack of internal memory bays kept the 400 the more limited sibling of the 800.

~$400-$600 at launch for drive and cabling

EASY