Toshiba HX-33
This page was last modified 11:51, 20 March 2022 by Gdx. Based on work by Mars2000you and Zeilemaker54 and others.




The HX-33 is the first MSX2 computer in the third series with the "Pasopia IQ" label. It contains a Kanji-ROM level 1, that is the same as the one included in the HX-M200 cartridge.

As for many machines with this label, the PSG sound output is stereo, with a mono/stereo switch at the back.

The keyboard includes an extra key, marked COPY: when combined with CTRL or CTRL + SHIFT, it allows to make a screencopy and send it to a connected MSX printer. A 2kB SRAM is used as temporary buffer in the procedure.

This computer was aimed at the Japanese market, with as option a RS-232C interface with switch.

Brand Toshiba
Model HX-33
Year 1985
Region Japan
Launch price ¥99,800
RAM 64kB in slot 3-0, 2kB SRAM
VRAM 128kB
Media MSX cartridges
Video Yamaha V9938
Audio PSG (YM2149F)
Chipset Toshiba TCX-2001 and TCX-2002
Keyboard layout QWERTY/JIS
Extras firmware (Japanese Word Processor - Kanji-Kun v.3.0 + English Word Processor), Kanji-ROM level 1, Printer BASIC, stereo PSG sound, RS-232C BASIC, (optional) Toshiba HX-R702 RS-232C interface + switch
Emulation ROM dumped and emulated, except the COPY feature


The built-in firmware is a Word Processor in 2 versions: Japanese and English. From BASIC, the Japanese version can be launched with CALL JWP or _JWP and the English version with CALL EWP or _EWP. It includes the additional BASIC instructions for RS-232C and printer.

The Japanese Word Processor is actually version 3.0 of the same software available in versions 2.0 and 2.5 on the Toshiba HX-2x series. This version has disk support (and was also released separately on disk for ¥19,800).

The main menu includes 6 options (the 5th option is different from the other versions):

  • Japanese Word Processor - if you press twice on ESC, you can access many WP features
  • Conversion Tools
  • Load and Save
  • Printer Settings and Print 1
  • Printer Settings and Print 2
  • Tools for Idioms and Short Sentences

CTRL+STOP can be used to go back to the previous menu or the main menu, except if you are in the first option. You need to reboot to quit the Japanese Word Processor.

The English Word Processor is the same as on the International versions of the HX-20 and HX-22 machines, but the option to leave the program has been removed. As it was already the case with the Japanese Word Processor, you need to reboot the computer. Returning to the menu from the RS-232C sub-menu is also impossible in this version.



Toshiba HX-33
Toshiba HX-33 back
Toshiba HX-33 main PCB
Toshiba HX-33 box


Japanese Word Processor

Toshiba JWP 3.0 - Intro screen
Toshiba JWP 3.0 - Menu
Toshiba Japanese Word Processor
Toshiba JWP - Screen after ESC key
Toshiba JWP - Conversion Tools
Toshiba JWP - Load and Save
Toshiba JWP - Printer settings 1 (A)
Toshiba JWP - Printer settings 1 (B)
Toshiba JWP - Printer settings 2
Toshiba JWP - Idioms + Short Sentences

English Word Processor

Toshiba EWP - Menu on HX-33/34
Toshiba English Word Processor
Toshiba EWP - Variables Sub-Menu
Toshiba EWP - Screen Variables
Toshiba EWP - Printing Variables
Toshiba RS-232C Transfer Rate
Toshiba RS-232C Sub-Menu
Toshiba RS-232C Communication


The HX-33 is a MSX2 with 2 cartridge slots (one at the top, one at the back), a Z80A from Sharp (LH-0080A) and 2 unusual MSX-Engines, the Toshiba TCX-2001 and TCX-2002. The 2 joystick ports are located on the right side of the computer, as well as the data recorder connector.

This memory can be upgraded to 128kB by adding two same RAM (41464) at IC5 & IC6 and two ceramic capacitors (100nF) at C5 & C6 in much the same way as for the Toshiba HX-34. 128kB memory is enabled by moving the resistor R12 to GND instead of +5V. R12 location is close to TCX-2020 chip. I think you have to move R12 to the empty location right next to it. (See more information here)

Slot Map

Slot 0 Slot 1 Slot 2 Slot 3-0 Slot 3-1 Slot 3-2 Slot 3-3
Page C000h~FFFFh Cartridge
Slot 1
Slot 2
Page 8000h~BFFFh
Page 4000h~7FFFh Main-ROM
Page 0000h~3FFFh Sub-ROM
  • The firmware ROM is actually a 80kB ROM:
    • first 16kB = RS-232C BASIC + Printer BASIC + the extra instructions to launch the WPs
    • next 32kB = Japanese Word Processor
    • last 32kB = English Word Processor
  • 7FFFh in slot 3-3 is a control register:
    • bit 7: COPY button status (0 is pressed)
    • bits 5-6: switch ROM/SRAM in page 8000h-BFFFh
    • bits 0-1: ROM segment select in page 8000h-BFFFh (4 16kB pages - the remaining 16kB in page 4000h-7FFFh is the RS-232C ROM)