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High-Performance 16-Bit Personal Computer with Color Graphics and Expandable RAM up to 256 kB with MS-DOS 2.11 & WordStar 3.30

The MBC555-2 is a highly efficient personal computer with tremendous potential for expansion. It features a high-performance design with a built-in 16-bit CPU, and two floppy disk drives. The powerful operating system can handle not only the popular BASIC language, but also other higher level languages as well. And when you're ready for it, the MBC 555-2 can be expanded into an even more powerful, advanced computer system to suit any application from home and hobby use business.


CPU 8088 (3.6 MHz) All RAM no wait
RAM 128 kB (standard)-256 kB (max) includes 16 kB V-RAM
V-RAM 48 kB (includes 16 kB of main RAM)
Display RGB color monitor mode
(Color monitor CRT 70)
  • 8 colors (included black & white)
  • 640 x 200 8-color standard
  • BASIC color assignment
  • 8 x 8 character box
  • 6 x 7 character font
  • 80 character x 25 lines
  • 15.75 kHz (Horizontal)
Monochrome monitor mode
(Monochrome monitor CRT 30)
  • 640 x 200 dot graphics
  • 8 x 8 character box
  • 6 x 7 character font
  • 80 character x 25 lines
  • 15.75 kHz (Horizontal)
Floppy disk drive MBC-555-2 360 kB x 2 (standard)
Printer Interface Centronics parallel

SANYO BASIC Supplied on a system diskette
Applications WordStar, SpellStar, InfoStar, EasyWriter
Operating System MS-DOS 2.11

RS-232C serial 1 port, 150-1200 bps ASYNC
Expansion RAM 128 kB installed on main PCB, 4164 x 8 pcs -> 64 kB step

Power supply U.S.A. 120 V
Frequency 50/60 Hz
Power consumption 90W (approx.)

Main unit 380(W)x112(H)x360(D) mm
Keyboard 442(W)x45(H)x174(D) mm

Sanyo and I

You haven't seen prices like this since

I bought my first working computer, a Sanyo MBC-550 in 1983. It came with one single-sided 5.25" disk drive, holding 160 kB of information. The operating system (MS-DOS 1.25) and WordStar 3.30 took up most of that.

The Sanyo MBC-550 was the first of the legitimate "clones" of the IBM Personal Computer. While others (notably the Taiwanese) were duplicating the circuitry and Read-Only Memories (ROMs) of the IBM PC, Sanyo Business Systems designed their own circuitry and wrote their own Basic Input/Output System (BIOS), part of which was in ROM and part was on disk. The character set was also in ROM. In Japan, this computer was the MBC-55. It came with a kanji character set and the CP/M-86 operating system. Sanyo had Microsoft write a special version of their disk operating system (MS-DOS) and command interpreter (COMMAND.COM). They had MicroPro write special versions of WordStar, CalcStar, and EasyWriter which they bundled with the MBC-550, making it a very attractive package, not only for their intended market, business; but also for the computer hobbyist.

A Sanyo Computer Users Group

From 1984 to 2000 I edited (and wrote most of) The Sanyo PC Hackers Newsletter. I also was custodian of a disk library of over 500 5.25" disks of software that would run on some version or other of the Sanyo MBC-550 series computer. I have a rather complete collection of pre-1985 Sanyo Business Systems computers.

During the heyday of the MBC-550, third-party developers of both hardware and of software flourished. CP/M-86, though transported to the MBC-550, never did take off; however, we thumbed our noses at MS-DOS's 640K limit. We could buy expansion memory boards for 768K and beyond. Some included clock chips. Even video boards that duplicated IBM's Color Graphics Adaptor (along with all its faults) were sold. Some users attached as many as four floppy drives to their computers. We found ways to read and write 1.2 MB 5.25" disks and 720 kB 3.5" disks.

It was the best of times for those willing to dig into their computers.

Can Your Computer Do This?

My Sanyo MBC-555 boots in 25 seconds. Verifying date and time take another 10-15 seconds. WordStar comes up in another 20 seconds. That's about one minute from pushing the power-on-button to selecting a file in a word processor.

That particular computer is in my ham shack. Due to its relatively slow clock speed (3.58 MHz) and good shielding, I notice no Radio Frequency Interference (RFI). I suppose that if I looked hard at 3.58 MHz and three times that frequency, I could find the main clock oscillator, but this machine gives me no trouble.

Not only is the Sanyo MBC-555 quiet radio-wise, it is also quiet sound-wise. Since its power consumption is low, only a small whisper fan is needed for cooling.


Well, the reason that Sanyo didn't take over the US computer market in 1984-5, is that the MBC-550 series is not 100% IBM compatible. Unless all the software you want to use is that which has been bundled with the computer, you are limited to that which you can obtain from Sanyo User Group disk libraries or you can write yourself.

That means, no windows, no Internet, no CD-ROM, and only limited hard disk support (20 MB).

Still, there are applications that don't need 1 GHz processor speeds. (How fast can you type; or read, for that matter.) This computer is a machine for the serious hacker, and by that I mean the person who wants to learn the "innards" of a computer rather than the person who wants to break into other people's computers as the term has now been reduced to.

sanyo.html 5/19/01 Victor Frank