Toshiba HX-51
This page was last modified 09:08, 14 July 2022 by Mars2000you. Based on work by Rderooy and Gdx and others.



The HX-51 computer, also known as the HX-51I, has been designed as a very simple MSX1 computer, in a white case.

This model was aimed at the Italian and Spanish markets, but the keyboard is "international". This computer seems to be the 'remake' of the HX-30, with an obvious difference : the original case is black, while the HX-51 case is white.

Brand Toshiba
Model HX-51
Year 1985
Region Italy and Spain
Launch price
RAM 64kB split between slots 0 and 3
Media Cartridges
Video Toshiba T6950 Texas Instruments TMS9918 compatible (Integrated in MSX-Engine T7937)
Audio PSG-sound chip General Instrument AY-3-8910 compatible (Integrated in MSX-Engine T7937)
Chipset Toshiba T7937
Keyboard layout QWERTY with accents key
Emulation ROM dumped and emulated (as the HX-51I)


Toshiba HX-51 manuals
Toshiba HX-51 box
Toshiba HX-51
Toshiba HX-51 label
Toshiba HX-51 PCB
Toshiba HX-51 left side
Toshiba HX-51 right side
Toshiba HX-51 back


The HX-51 is a MSX1 computer with 2 cartridge slots (one at the top, one at the back). All the main components (Z80A, VDP, PSG) are integrated in a MSX-Engine, the Toshiba T7937. It's actually the first time that such integration happens on MSX.

The 2 joystick ports are located on the right side of the computer, as well as the data recorder connector.

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

The 64kB RAM is split between slots 0 and 3, a configuration that can cause poorly written software to crash. Also, with this layout, the POKE-1,(15-PEEK(-1)\16)*17 trick to workaround buggy software that does not handle subslots properly will not work on this machine.

Slot Map

Slot 0 Slot 1 Slot 2 Slot 3
Page C000h~FFFFh Upper
32kB RAM
Slot 1
Slot 2
Page 8000h~BFFFh
Page 4000h~7FFFh Main-ROM Lower
32kB RAM
Page 0000h~3FFFh