Nikko PC-70100
This page was last modified 17:34, 3 April 2023 by Takamichi. Based on work by Mars2000you and Gdx.



The Nikko PC-70100 is a hidden MSX1 that is remained a prototype. It has never been released and the aimed utility of this machine is unknown. The Japanese word 見本市 ("trade fair") written on its EPROM hints the surviving unit was for exhibition.

There is no any MSX logo, but the EPROM with the BIOS/BASIC has the indication "MSX". It does not display the MSX logo but only "PC-70100" upon startup.

The BASIC start screen does not refer to MSX, but displays


apparently with misspelled COMPUTER.

It has only 16kB RAM, 1 cartridge slot and 1 general port for joystick, mouse, etc. The 32kB RAM mentioned on the computer actually includes the 16kB VRAM.

The blank key below the Return key works as another Return key, while four arrow keys are at the right of the spacebar. Katakana or hiragana are not printed on the keys but their mapping is same as the standard JIS. There is no kana or code key which is irregular for an MSX keyboard but as the workaround, pushing CAPS and some keys such as > and / keys at the same time toggles between kana and latin character input modes.

A reset button is not provided.

It is encased by the blue plastic upper and lower casing. The upper casing has a distinct profile with its narrow slot opening located so high that a cartridge with protrusion eg Philips NMS 1205 is trapped there and cannot reach the slot socket. The lower casing is apparently that of Panasonic FS-A1 reworked to accommodate the PC-70100 components.

Size (W/D/H): 360x213*x70 mm * 220 including printer bracket
Weight: 1.5 kg

Brand Nikko
Model PC-70100
Year unreleased, the prototype was built ≥1988
Region Probably Japan
Launch price
RAM 16kB (in slot 0)
Media MSX cartridges
Video Toshiba T6950, Texas Instruments TMS9918/TMS9929 compatible (Integrated in MSX-Engine T7937A)
Audio PSG-sound chip General Instrument AY-3-8910 compatible (Integrated in MSX-Engine T7937A)
Chipset Toshiba T7937A
Keyboard layout QWERTY/Japanese JIS (special layout)
Emulation ROM dumped and emulated



Note: More pictures can be found here.

Nikko PC-70100
Nikko PC-70100 underside
PC-70100 keyboard inside
Nikko PC-70100 PCB
Nikko PC-70100 PCB (back)
Nikko PC-70100 - Toshiba T7937A
Nikko PC-70100 back
Nikko PC-70100 cartridge slot
Nikko PC-70100 right side
PC-70100 text on underside
Nikko PC-70100 label

Character set

The character set is standard Japanese except the graphic characters 41-4FH and 5E-5FH are blank and 5DH has lost lower 6 rows of pixels leaving only upper 2 rows. All these character were originally kanjis.

PC-70100 character set with graphic characters at the left

Color Palette

The border color is different from other MSX machines, although it is recognized as color 7 in BASIC. There are other color differences, such as the white intensity. See the color palette below - from left to right: color 0 (transparent) to color 15 (white).

Nikko PC-70100 color palette
Nikko PC-70100 color palette converted to HDMI by Framemeister

Boot Sequence

These screenshots have been made on emulator with standard colors:

PC-70100 boot screen
PC-70100 MSX-BASIC start screen


The Nikko PC-70100 is a MSX1 prototype. The Z80A, the VDP and the PSG are integrated in MSX-Engine T7937A.

The integrated VDP is the Toshiba T6950, which does not support some undocumented features of the Texas Instruments TMS9918, TMS9928 and TMS9929 VDP's.

Slot Map

Slot 0 Slot 1 Slot 2 Slot 3
Page C000h~FFFFh RAM Cartridge
Page 8000h~BFFFh
Page 4000h~7FFFh Main-ROM
Page 0000h~3FFFh


  • Analog sound & Composite video (NTSC. Black outputs video and red outputs sound.)
  • Data Recorder connector
  • Centronics compatible Parallel port for a printer
  • 1 general connector (Joysticks, Mouse, Paddle controllers, etc)
  • 1 cartridge slot (apparently without -/+ 12V because only a regulator AN7805 is used to make 5V from the external AC-DC adapter)
  • 1 barrel jack for the 2.5 mm inner diameter center positive DC power supply input (DC 7.5 ~ 10V, 1 ~ 1.2A according the AN7805 datasheet and devices that use it). There is neither overvoltage nor reverse polarity protection.