Sanyo PHC-23J
This page was last modified 17:19, 3 November 2021 by Mars2000you. Based on work by Sd snatcher and Sdsnatcher73 and others.



The Sanyo PHC-23J, a.k.a Wavy23 is a MSX2 computer released by Sanyo, and aimed at the Japanese market. It is the sequel to the PHC-23. The difference seems to be that the PHC-23J has a JIS compliant keyboard, unlike the PHC-23.

Three revisions of the Wavy23 were produced. In the last revision, Sanyo released a blue variant besides the original grey color. In all revisions, the GR reference is displayed on the box, but not on the label.

Note: At this time Sanyo was changing its logo. Some products have both the old logo and the new logo when you compare the computer, the box, the label and the manuals.

Revision Product Released Keyboard Color MSX-Engine Battery
1 Sanyo PHC-23 1986 JP50on Grey Yamaha S3527 Internal re-chargable
2 Sanyo PHC-23J 1987 JIS Grey Yamaha S3527 Internal re-chargable
3 Sanyo PHC-23J(B) 1987 JIS Blue Yamaha S1985 two AA batteries
3 Sanyo PHC-23J(GR) 1987 JIS Grey Yamaha S1985 two AA batteries

The PHC-23J has been localised for the Russian market with more RAM (see MPC-2300).

Brand Sanyo
Model PHC-23J / PHC-23J(B) / PHC-23(GR)
Year 1987
Region Japan
Launch price ¥32,800
RAM 64kB (in slot 3-2)
VRAM 128kB
Media MSX cartridges
Video Yamaha V9938
Audio PSG (YM2149 integrated in MSX-Engine S1985 or S3527)
Chipset Yamaha S1985 or Yamaha S3527
Keyboard layout QWERTY/JIS + numeric keypad
Emulation ROMs dumped and emulated.


Sanyo PHC-23J(GR)
Sanyo PHC-23J(B) PCB
Sanyo PHC-23J(B)
Sanyo PHC-23J back
Sanyo PHC-23J right side
PHC-23J(GR) manuals
Sanyo PHC-23J(B) with manuals
Sanyo PHC-23J(B) manual
Sanyo PHC-23J(B) box
Sanyo PHC-23J(B) underside
Sanyo PHC-23J(B) label
Sanyo PHC-23(GR) box
Sanyo PHC-23J(GR) underside
Sanyo PHC-23J(GR) label


The PHC-23J is a MSX2 with a Z80A from NEC (D780C-1) and an MSX-Engine S1985 or S3527 from Yamaha.

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