From Sega Retro

SC-3000 logo.svg
SC-3000.jpgSC-3000H AU 1.jpg
Manufacturer: Sega
Variants: SC-3000H
Add-ons: Super Control Station SF-7000, SP-400, Data Recorder SR-1000
Release Date RRP Code
1295 mk1295

The SC-3000 (Sega Computer 3000) is the first computer to be designed and manufactured by Sega. It was first released in July of 1983 in Japan, and serves as the home computer equivalent of the SG-1000 cartridge-based video game console. The SC-3000, often known simply as the "Sega Computer" or even just the "Sega", is an 8-bit home computer almost identical in nature to the SG-1000, but with a built-in keyboard and support for more hardware expansions.

Unlike later Sega systems, the SC-3000 did not receive a worldwide release, but in markets where it did compete, including Japan, Australia, New Zealand, France, Italy and Finland, the computer fared well as a low price, entry-level machine for the home. By 1985, the SC-3000 had been displaced by more popular computer standards, but is nevertheless said to have fared better than the SG-1000 console on the global stage, and has a strong group of followers to this day.

The SC-3000 was Sega's first and most popular home computer to be released to the general public. Other endeavours such as the rare Sega AI Computer saw only a small fraction of the success the SC-3000 received, and were built with very different aims. The company would partner with Amstrad and IBM for the Amstrad Mega PC and TeraDrive respectively in later years.


As a home computer, the SC-3000 was designed to be an affordable machine for use in a home environment, primarily for business and educational use. However, as with most home computers of the era, the device became a method of playing video games.

The SC-3000 comes with a 64-key keyboard mounted on the top of the unit, a cartridge port on the right hand side and two DE-9 joystick ports on the left. On the back, the system has a power switch and power supply, cassette, printer, monitor and television ports typical of the era. It is a relatively light and compact machine which is most commonly found in black, though white and red variants were also available in Japan.

The SC-3000 is fully compatible with almost all software and accessories designed for the SG-1000 or SG-1000 II, save for some BASIC cartridge variants and peripherals such as the SK-1100. In many situations the reverse is also true - the SK-1100 allowing the SG-1000 to interface with some SC-3000 software and accessories.

There are two major models of the SC-3000 - the standard SC-3000 model with rubberised keys, and an upgraded SC-3000H variant from later in the year, with a full-travel keyboard. Contrary to popular belief, both systems are otherwise identical aside from keyboard technologies, although the improved keyboard led to the SC-3000H being more expensive at launch. A third model, known as the SC-5000 is also known to exist, but very little is known about this unit.

By default, the SC-3000 has 2kB of work RAM and 16kB of VRAM. The system's main RAM is dictated by the cartridge inserted into the machine, and the system will not function if the cartridge port is empty, as it has no built-in ROM. RAM only becomes an issue when dealing with software not distributed on cartridge, and so, even though the systems are extremely similar, differing RAM requirements from software is not an issue that can affect the SG-1000.

For the most part, the SC-3000 was designed to be used in conjunction with a BASIC cartridge. BASIC Level II A offers no extra RAM, meaning only the standard 2kB is available, BASIC Level III A offers 16kB and BASIC Level III B offers 32kB. The values were often combined with the VRAM figure to create confusingly titled "16K", "32K" and "48K" varieties of the SC-3000 (neither of which are strictly accurate descriptions). Software intended for the "32K" SC-3000 will be incompatible with the "16K" variant, though those with 48K SC-3000s could run just about anything. The BASIC cartridges also double up as a programming language, allowing users to create their own software.

The SC-3000 hardware is comparable to the original MSX computer standard and the ColecoVision games console. Though in most regions the SC-3000 retailed at a cheaper price than many of its competitors, it was comparable from a technical perspective to more expensive home computers from the likes of Commodore.

On its own, the SC-3000 offers very few features over the SG-1000, but with the addition of a Data Recorder SR-1000, it is possible to load and save software to compact cassette. Perhaps more notably, 3-inch floppy disk support could be given to the computer via the Super Control Station SF-7000 add-on (which ups the RAM even further by adding 64kB, among other features). Documents can also be printed through the SP-400 printer.


Main article: SC-3000 computers.



Technical specifications

See SG-1000 specifications for further specifications

The SC-3000's technical specifications are largely the same as the SG-1000, with the following memory differences:

BASIC Level II B (1983) includes the following memory upgrade:[2]

  • RAM: 20 KB (4 KB main RAM, 16 KB VRAM)

BASIC Level III A (1983) includes the following memory upgrade:[2]

  • RAM: 34 KB (18 KB main RAM, 16 KB VRAM)

BASIC Level III B (1983) includes the following memory upgrade:

  • RAM: 48 KB (32 KB main RAM, 16 KB VRAM)


See SG-1000 technical specifications for SG-1000 specifications

The SC-3000 was roughly on par with the original MSX standard, which was largely identical in hardware. A key difference was that the original MSX standard had a higher amount of program RAM. However, both relied on the VRAM for graphics data, giving them largely identical graphical capabilities.

The SG-1000 and SC-3000 were technically comparable to the Commodore 64 (C64). The SC-3000's Z80 CPU and SRAM/ROM bus are clocked at 3.579545 MHz (NTSC) or 3.546893 MHz (PAL), while the C64's 6502 CPU and DRAM/ROM bus are clocked at 1.022727 MHz (NTSC) or 0.985248 MHz (PAL).[3] The SC-3000's Z80 processes instructions at 0.519034 MIPS (NTSC) or 0.514299 MIPS (PAL), while the C64's 6502 processes 0.439772 MIPS (NTSC) or 0.423656 MIPS (PAL).[4] The SC-3000's SRAM/ROM bus has an access time of 279 ns (NTSC) or 281 ns (PAL),[5] while the C64's DRAM/ROM bus has an access time of 978 ns (NTSC) or 1015 ns (PAL).

The SC-3000's VRAM write bandwidth during active display is 174.794 KB/s (NTSC) or 181.112 KB/s (PAL), while the C64's DRAM write bandwidth is 50 KB/s.[3] This gives the SC-3000 a write fillrate of 1.398352 MPixels/s (NTSC) or 1.448896 MPixels/s (PAL) during active display, while the C64's write fillrate is 400,000 pixels/s (1-color) or 200,000 pixels/s (3-color). The SC-3000's higher bandwidth and write fillrate allow it to transfer more sprite/tile graphics at a faster rate than the C64. The SC-3000's TMS9918 graphics chip supports 32 hardware sprites on screen, while the C64's VIC-II graphics chip supports 8 hardware sprites.

In terms of 3-color sprites, the TMS9918 supports 10 sprites (combining 30 sprites) and the VIC-II supports 8 sprites. The TMS9918 displays 4 sprites (or 9 flickering sprites) per scanline and 20 sprites per 21 scanlines, while the VIC-II displays up to 8 sprites per scanline and 8 sprites per 21 scanlines.[6] The TMS9918 lacks hardware scrolling, but the Z80 can program smooth per-pixel software scrolling, while the VIC-II supports 7-pixel coarse scrolling but not smooth per-pixel scrolling, which the 6502 could also program in software.




The SC-3000 was launched in Japan in July 1983 for the asking price of ¥29,800, being marketed as an entry-level computer. It was released at the same time as the SG-1000, as it was not entirely certain which sort of system would remain dominant – the cheaper, dedicated video game console, or the more expensive home computer. Possibly due to fears that one type of system would displace the other, Sega went with both.

Over time it was proved that Japanese consumers preferred the SC-3000 over the SG-1000 for its extra features, but neither device could compete with rival products. The more powerful Nintendo Famicom, released very close to the SG-1000/SC-3000 would go on to dominate the Japanese video game market for the rest of the decade, while the home computing market was already saturated, with numerous similar machines vying for public attention.

From day one Sega also found themselves under pressure from more established computers from technology giants NEC, Fujitsu and Sharp, the so called "big three" in the Japanese computing market. Each had entered the sector in the late 1970s, offering multiple tiers of hardware and attracting significant amounts of third-party software; Sega were much smaller players with a background in arcade machines and could not effectively compete. The low screen resolution and comparatively slow processing power of the SC-3000 made it unsuitable for business, while third-parties already had well established relationships with other players in the market.

Another issue was that of the MSX standard, divised by Microsoft's Japanese arm to unify what had become a fractious market between 1978 and 1982. While Sega were trying to market their bespoke computing standard, companies which had already tried and failed with this strategy had switched their alliegence to MSX machines, the first wave of converts including Canon, Fujitsu, Hitachi, JVC, Mitsubishi, National, Sanyo, Sony, Toshiba and Yamaha. A typical MSX machine is not too dissimilar from an SC-3000 in terms of hardware, but this vast amount of support is thought to have been the biggest factor in the SC-3000's failure to take off.

The SC-3000H, which originally sold for ¥33,800, does not appear to have fared much better.

Sega's advertising saw comic duo Tunnels (とんねるず) advertise the computer.

It is thought that support for the SC-3000 largely dried up in the first few months of 1985 as Sega began to concentrate on the Sega Mark III.


Unlike Sega's later endeavours, the SC-3000 was only distributed in select European countries, and often struggling due to the oversaturated market.

The SC-3000 was distributed in France by ITMC (under the Yeno brand), achieving mild success in 1983/1984 as it competed with computers from Atari, Commodore, Oric, Sinclair and the home-grown Thomson M05 and T07, among others. Despite gaining some traction, by the middle of 1984 ITMC were advertising an MSX machine as the SC-3000's "bigger sister"; the DPC-64 (adapted from the South Korean DPC-200 machine by Daewoo). With more memory, an AZERTY keyboard and wider software compatibility, the DPC-64 became the firm's main computer going into 1985, with the SC-3000 presumably being retired.

In Italy, the SC-3000 was distributed by Melchioni.

The computer was also seen in Finland, where it was distributed by Digital Systems.

Australia and New Zealand

The SC-3000 was a big success for Sega in Oceania. It was distributed in Australia by John Sands and in New Zealand by Grandstand. Both regions had comparatively less competition than in Japan, and so the SC-3000 (and SC-3000H) performed reasonably well as low-entry computers during the mid-1980s, fighting primarily against the Commodore VIC-20.

The SC-3000 outsold the SG-1000 in the market, and managed to make an impact on the educational and advertising markets too. Both John Sands and Grandstand strongly supported the system, releasing cassette-based software and building up third-party relations with local developers. At least 15,000 SC-3000s had been sold in Australia by 1986.

A Speech Synthesis unit and a light pen were supposedly manufactured by third party companies in New Zealand. New Zealand also had its own Sega Computer magazine.

Distribution in both countries stopped in 1986 for different reasons. It is said that Grandstand wanted to focus efforts on distributing Amstrad products instead (namely the Amstrad CPC).


The computer was released in Egypt by Cactus International. Also rumoured is a South African release of the console.


The SC-3000 was distributed in Singapore by Ocean Radio. In Taiwan, it was sold under the Aaronix brand.


By the end of 1983, the SC-3000 had sold 120,000 units worldwide[7].

Production credits

Developer mentions[8]

Magazine articles

Main article: SC-3000/Magazine articles.

Promotional material

Print advertisements

Print advert in Amusement Life (JP) #8: "No.8, 9" (1983-08-20)
also published in:
Print advert in I/O (JP) #1983-07 (1983-xx-xx)
Print advert in I/O (JP) #1983-08 (1983-xx-xx)
Print advert in I/O (JP) #1983-09 (1983-xx-xx)
Print advert in Computer Input (NZ) #1983-11: "November 1983" (1983-xx-xx)
also published in:
Print advert in Votre Ordinateur (FR) #4: "Mars 1984" (1984-03-xx)
also published in:
Print advert in Votre Ordinateur (FR) #7: "Septembre 1984" (1984-09-xx)
also published in:
Print advert in Votre Ordinateur (FR) #9: "Novembre 1984" (1984-11-xx)
also published in:
Print advert in Tilt (FR) #17: "Novembre/Décembre 1984" (1984-xx-xx)
also published in:
Print advert in I/O (JP) #1984-12 (198x-xx-xx)

Television advertisements

External links


Sega SG-1000 Hardware
 SG-1000 Variations   SG-1000 | SG-1000 II | SC-3000 | SC-5000 | Othello Multivision | Pasocom Gakushuudzukue | SD-G5 | Arcade
Add-ons   Super Control Station SF-7000 | 4 Color Plotter Printer | Data Recorder SR-1000 | Sega Keyboard
Game Controllers   Joystick (SJ-200) | Joystick (SJ-300) | Joypad (SJ-150) | SJ-151 | Handle Controller | Bike Handle | Sega Graphic Board
Misc. Hardware   Card Catcher | Extension Cable Kit (JC-100) | SD-80 | Sega Compact Floppy Disk
Unlicensed Clones   Dina 2 in one | Fullwis Video Game FR-II‎
Sega Home Video Game Systems
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Master System Master System II
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