Atari 1040STFM

Atari 1040STFM
	Atari 1040STFM
Specifications
Manufacturer	Atari Corporation
Type	Home computer / personal computer
Released	January 1, 1987
Discontinued	1990
Intro price	UK £399 (1987 launch); approximately US$699–US$799 (varied by market and bundle)
CPU	Motorola MC68000 @ 8 MHz
Memory	1 MB RAM
Storage	Internal 3.5-inch DS/DD 720 KB floppy drive; external floppy via 14-pin DIN; external ACSI hard disks
Display	320×200 (16 colours), 640×200 (4 colours), 640×400 (mono); RF output for television
Sound	Yamaha YM2149F (3 voices + noise)
Dimensions	78 mm × 470 mm × 330 mm (3.1 × 18.5 × 13 in) approximately
Weight	≈5.5 kg (12 lb)
OS / Firmware	Atari TOS 1.02 / 1.04 (192 KB ROM)
Predecessor	Atari 1040STF
Successor	Atari 1040STE

The Atari 1040STFM is a model in the Atari ST family that combines 1 MB of RAM, an internal floppy disk drive, and a built-in RF modulator in a single "long case" unit with an internal power supply. The designation stands for 1040 (1 MB RAM), ST (Sixteen/Thirty-two), F (internal Floppy drive), and M (RF Modulator).

The 1040STFM was the most complete and versatile of the "standard" ST models, offering everything needed for both professional use (dedicated monitor via RGB) and home use (television via RF) in one box. It shares the C070789-001 motherboard with the Atari 520STFM, differing only in having all RAM positions populated to provide 1 MB.

History

The 1040STFM was introduced in 1987 as Atari refined its ST product line. While the 1040STF (1986) had been targeted at professional users who already owned a monitor, the 1040STFM added the RF modulator to serve the broader home computing market.

In the UK, the 1040STFM was particularly successful, selling alongside and eventually replacing the Atari 520STFM as the standard Atari home computer. The 1 MB RAM gave it an advantage over the 512 KB 520STFM, as more demanding software and larger applications became the norm.

The BYTE magazine cover from March 1986 famously showed a system labelled "1040STFM" while the article simply called it "the 1040ST", illustrating how the F and FM suffixes were often dropped in casual usage despite indicating important hardware differences.

The 1040STFM was eventually superseded by the 1040STE in 1989, which retained the 1 MB/floppy/modulator configuration but added significant hardware enhancements including DMA stereo audio, hardware fine scrolling, an enhanced colour palette (4096 colours vs. 512), and a BLiTTER chip as standard.

Architecture

CPU: Motorola MC68000 @ 8 MHz
Architecture: 16/32-bit (32-bit internal, 16-bit external data bus, 24-bit address bus)
RAM: 1 MB (all positions populated on the C070789-001 board)
ROM: 192 KB TOS 1.02 ("Mega TOS") or TOS 1.04 ("Rainbow TOS") in 2× 128 KB ROMs
Custom ICs: Shifter (C025914), GLUE (C025915), MMU (C025912 or C100109), DMA (C025913)
BLiTTER: Not standard; some C070789 boards have an unpopulated footprint for the optional BLiTTER chip

Major ICs

Function	Part Number	Notes
CPU	MC68000P8 / MC68000FN8	8 MHz, DIP-64 or PLCC-68
Video Shifter	C025914-38A	Pixel serialiser; some later boards use GST Shifter
GLUE	C025915-38A	Bus timing, video timing; some boards use combined GLUE
MMU	C025912-38 / C100109	DRAM controller
DMA Controller	C025913-38	ACSI/floppy DMA
FDC	WD1772-02-02	Floppy disk controller
MFP	MC68901	Timers, interrupts, UART
ACIA (×2)	MC6850	Keyboard/IKBD (7812.5 baud) and MIDI (31.25 kbaud)
Sound/PIO	YM2149F	3-voice PSG + parallel I/O
RS-232 drivers	MC1488 / MC1489	Serial port level conversion
RF Modulator	Internal shielded module	PAL or NTSC RF carrier output

Connectors

Rear panel:

Power: IEC C14 mains inlet (internal SMPS)
Floppy (external): 14-pin DIN
ACSI (Hard Disk): DB-19 female
Serial (Modem): DB-25 male, RS-232C
Parallel (Printer): DB-25 female
Video/Monitor: 13-pin DIN (analog RGB, mono, sync, audio)
RF Output: Phono (RCA) or coaxial connector for television

Left side:

MIDI In: 5-pin DIN
MIDI Out: 5-pin DIN
Cartridge: 40-pin edge connector
Reset button

Under keyboard:

Port 0: DE-9 male (mouse/joystick)
Port 1: DE-9 male (joystick)

Display

Low resolution: 320×200, 16 colours from 512-colour palette, ~50/60 Hz
Medium resolution: 640×200, 4 colours, ~50/60 Hz
High resolution (mono): 640×400, monochrome, ~71.2 Hz (SM124/SM125 only — not via RF)

The RF modulator provides colour modes via television. The monochrome mode requires a dedicated SM124/SM125 monitor.

Sound

PSG: Yamaha YM2149F — 3 square-wave channels + noise, 5-bit envelope generator
MIDI: Built-in MIDI In/Out at 31.25 kbaud
Audio: Mono line-level on monitor DIN connector; also mixed into RF output

Internal Floppy Drive

Type: 3.5-inch DS/DD (double-sided, double-density)
Capacity: 720 KB formatted (80 tracks × 2 sides × 9 sectors × 512 bytes)
Controller: WD1772 at 8 MHz, 250 kbit/s data rate
Common models: Epson SMD-340/360, Citizen OSDA, Alps DFxx

Internal Power Supply

Rail	Voltage	Typical Current	Purpose
+5V	5.0V ±5%	~3.0A	Logic, RAM, all ICs
+12V	12.0V ±10%	~0.5A	Floppy drive motor, RS-232
−12V	−12.0V ±10%	~0.05A	RS-232 negative rail

WARNING: The internal PSU contains mains-voltage components. Capacitors may retain dangerous charge even after the machine is unplugged. Always disconnect from mains and wait at least 5 minutes before opening the case.

Motherboard

The 1040STFM uses the C070789-001 motherboard, shared with the Atari 520STFM. The only difference is that the 1040STFM has all RAM positions populated for 1 MB, whereas the 520STFM typically has half populated for 512 KB.

Later production runs may use revised board numbers (e.g., C103175 Rev. D) with minor component changes, but the basic design and layout remain the same.

BLiTTER Upgrade

Some C070789 boards include an unpopulated PLCC-68 footprint for the Atari BLiTTER chip (C101675). When installed, the BLiTTER accelerates block transfer operations used by GEM and some applications. Requirements:

Atari C101675 BLiTTER IC (PLCC-68)
TOS 1.02 or later
Soldering skills (socket or direct soldering to the pads)

Comparison with Related Models

Feature	520STFM	1040STF	1040STFM	1040STE
RAM	512 KB	1 MB	1 MB	1 MB
Internal Floppy	Yes	Yes	Yes	Yes
RF Modulator	Yes	No	Yes	Yes
Internal PSU	Yes	Yes	Yes	Yes
BLiTTER	Optional	Optional	Optional	Standard
DMA Audio	No	No	No	Yes (stereo)
Hardware Scrolling	No	No	No	Yes
Colour Palette	512	512	512	4096
TOS Version	1.02/1.04	1.00–1.04	1.02/1.04	1.06/2.06

Known Issues

PSU capacitor failure: The most common failure — aged electrolytics in the SMPS cause instability, failure to start, or random crashes. Preventive recapping is strongly recommended.
Floppy drive failure: Internal drives wear over time; heads may need cleaning, and belts or the entire mechanism may need replacement.
Keyboard membrane: Degrades over time, causing sticky or unresponsive keys.
RF modulator degradation: Produces increasingly poor TV picture quality over time. Can be bypassed for composite output or replaced entirely.
DRAM failure: Ageing RAM chips can cause garbled display, crashes, or boot failure.

Service and Repair

Software Compatibility

With 1 MB RAM, the 1040STFM ran virtually all ST software:

Music: Steinberg Pro-24/Cubase, C-Lab Creator/Notator, Dr. T's KCS
DTP: Calamus, PageStream, Publishing Partner
Productivity: 1st Word Plus, WordPerfect
Programming: GFA BASIC, Lattice C, Pure C, Devpac
Games: Dungeon Master, Carrier Command, Populous, Captive, Stunt Car Racer

References