Sanyo MBC-550 series
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The MBC-550 series, also known as the MBC-550/555,[1][2] is a series of personal computers sold by Sanyo. It was unveiled at the COMDEX/Spring '83 in April 1983 and first released to market in March 1984.[3][4]: 12 All models in the MBC-550 series featured pizza-box-style cases and Intel 8088 microprocessors and run versions of MS-DOS. On its release in 1984, the MBC-550 was the least expensive IBM PC compatible released to date, at a price of US$995 (equivalent to $3,080 in 2025).[5][6] The MBC-550 series followed Sanyo's MBC-1000 line of CP/M computers.[7]
 Sanyo MBC-555 on display at the Living Computer Museum | |
| Developer | Sanyo Electric |
|---|---|
| Type | Personal computer |
| Released | March 1984 |
| Lifespan | 1984–1988 |
| Introductory price | <$1000 |
| Discontinued | 1988 |
| Units sold | 10,000+ |
| Operating system | MS-DOS 2.11 (optional: CP/M 86, Concurrent CP/M-86) |
| CPU | Intel 8088 at 3.58 MHz |
| Memory | 128 KB |
| Removable storage | floppy disks |
| Display | RGB Color Monitor CRT-70; Monochrome Monitor CRT-36; 40×25 or 80×25 text modes; 144×200, 576×200 or 640×200 graphic modes with 8 colors |
| Graphics | HD46505 CRTC, RGB graphics adapter |
| Sound | Buzzer (single buzztone sound, fixed duration) |
| Input | Keyboard |
| Controller input | Apple compatible Joystick |
| Connectivity | 1 parallel port |
| Power | 120 V AC (North American model) |
| Dimensions | 380 × 112 × 360 mm |
| Predecessor | MBC-1000 |
Specifications
The MBC-550 has much better video display possibilities than the CGA card (based on the HD46505 CRTC, providing a 3-bit RGB palette of 8 colors at 640 × 200 resolution, vs CGA's 4 colors at 320 × 200 or 2 colors at 640 × 200). Other resolutions, like 144 × 200 and 576 × 200 were possible.[8] This display was not completely compatible with the IBM PC.[8]
The computer lacks a standard BIOS, having only a minimal bootloader in ROM that accesses hardware directly to load a RAM-based BIOS.[9] The diskette format (FM rather than MFM) used is not completely compatible with the IBM PC, but special software on an original PC or PC/XT (but not PC/AT) can read and write the diskettes, and software expecting a standard 18.2 Hz clock interrupt has to be rewritten.
The MBC-550 was also the computer for NRI training. Starting by building the computer, the NRI promised you would be "qualified to service and repair virtually every major brand of computer".[10] NRI was advertised in Popular Mechanics and Popular Science throughout 1985.[11]
The MBC-550 is less PC compatible than the IBM PCjr. Its inability to use much PC software was a significant disadvantage; [6] InfoWorld reported in August 1985 that Sanyo "has initiated a campaign to sell off" MBC-550 inventory. The company's newer computers were, an executive claimed, 99% PC compatible.[12]
Early MBC-500 machines used true Intel 8088 microprocessors. In late March 1984, Sanyo reached an agreement with Intel to manufacture the 8088 in Japan as a second source, prompted by a widespread chip shortage at the time.[13][14] As part of the agreement with Intel, Sanyo was not to sell their 8088 chips except as part of their Sanyo MBC-550 series computers.[14]
Software
There are 6 known commercial games for Sanyo MBC-550[15]
| Title | Year | Publisher |
| Cashman | 1984 | Michtron |
| DC-10 | 198? | Molimerx, Ltd. |
| Demon Seed | 1984 | Michtron |
| Emperor | 198? | Molimerx, Ltd. |
| King Arthur | 198? | Molimerx, Ltd. |
| Time Bandit | 1984 | Michtron |
Dedicated magazine
Soft Sector was a magazine for people who owned Sanyo MBC-550 and 555 DOS computers. (But much of the content equally applied to most IBM clones at the time.) A typical issue includes news, reviews, how-to's, technical advice and education, tips and tricks, as well as BASIC language programs that one could type in and adapt to suit one's needs.[8]
