Yamaha YIS-604/128
This page was last modified 02:27, 27 December 2021 by Mars2000you. Based on work by Rderooy and Gdx and others.



The Yamaha computers were specifically targeted at music and sound production, and as such were regarded by many as non-standard MSX machines. However, they are in fact standard MSX computers and can be used as such.

The YIS-604/128 is the same computer as the CX7M/128, but was always sold without any SFG module. However, the mini-slot contains a mini-cartridge "Beginner's Lesson".

It was aimed at the Japanese market.

The YIS-604/128 has been localised

Brand Yamaha
Model YIS-604/128
Year 1985
Region Japan
Launch price ¥99,800
RAM 128kB (in slot 3-2)
VRAM 128kB
Media MSX cartridges, side slot modules
Video Yamaha V9938
Audio PSG (YM2149 integrated in MSX-Engine S3527)
Chipset Yamaha S3527
Keyboard layout QWERTY/JP50on
Extras Reset button, 60 pin module port, mini cartridge port, Beginner's Lesson mini-cartridge
Emulation ROMs dumped and emulated with exception of the Beginner's Lesson mini-cartridge


Yamaha YIS-604/128 with box
Yamaha YIS-604/128
Yamaha YIS-604/128 back
Yamaha YIS-604/128 left side
Yamaha YIS-604/128 underside
Yamaha Beginner's Lesson
Yamaha YIS-604/128 label
Yamaha YIS-604/128 manuals


The YIS-604/128 is a MSX2 with a Z80A from Sharp (LH0080A) and an MSX-Engine S3527 from Yamaha.

This model can be easily upgraded internally because RAM and VRAM are on separate boards with a connector, you just need to change the corresponding board.

Some machines don't have a separate VRAM board but you can change the VRAM on the mainboard.

The mini slot allows to add software.

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
  • By default the Mini-Cartridge slot contains the Beginner's Lesson cartridge