Panasonic FS-A1mkII
This page was last modified 02:29, 4 January 2023 by Mars2000you. Based on work by Gdx and Sd snatcher and others.




The Panasonic FS-A1mkII is identical to the FS-A1 but with an additional keypad.

It was aimed at the Japanese market and available only in dark gray.

The computer includes a pause button that allows users to pause the system at will.

It was provided with the external power adapter FS-AA51.

Brand Panasonic
Model FS-A1mkII
Year 1987
Region Japan
Launch price ¥29.800
RAM 64kB in slot 3-0
VRAM 128kB
Media MSX cartridges
Video Yamaha V9938
Audio PSG (integrated in MSX-Engine S1985)
Chipset Yamaha S1985
Keyboard layout QWERTY/JIS + numeric keypad
Extras pause button, DESKPAC firmware, Panasonic FS-JS221 joypad
Emulation ROMs dumped and emulated.


The firmware is launched automatically when you boot the machine. Bypassing this software on startup requires the user to press the DEL key during boot until a Beep sound. If you press GRAPH key the SRAM of the RTC will be initialized.

It can be also bypassed by software. For example, if you make a cartridge that requires disks, just write 023h in RAM at address 0C3D2h to avoid the Deskpac execution.

The built-in firmware is the second version of the well-known Panasonic DESKPAC software. It presents 8 options:

  • 1 - Clock
  • 2 - Calendar
  • 3 - Calculator
  • 4 - Game 1 - Roulette
  • 5 - Game 2 - Memory
  • 6 - Game 3 - Shooting
  • 7 - MSX-BASIC
  • 8 - Screen Colors

Besides, icons give access to Clock Settings and Screen Adjust. The icons of options 4 to 6 can be replaced by the Japanese name of the corresponding game when you click on the left bottom rectangle (it acts like a toggle).



Panasonic FS-A1mkII
FS-A1mkII battery location
Panasonic FS-A1mkII inside
Panasonic FS-A1mkII left side
Panasonic FS-A1mkII back
Panasonic FS-A1mkII right side
FS-A1mkII box and content
Panasonic FS-A1mkII label
Panasonic FS-A1mkII manual
FS-A1mkII & HB-F1 adapter
Panasonic FS-A1mkII box


DESKPAC Clock Settings
DESKPAC Screen Adjust
DESKPAC Calendar
DESKPAC Calculator
DESKPAC Game 1 - Roulette
DESKPAC Game 2 - Memory
DESKPAC Game 3 - Shooting
Options with Japanese names


The Panasonic FS-A1mKII is a MSX2 with 2 cartridge slots (one at the top, one at the back), a Z80A from ROHM (BU18400A-PS) and an MSX-Engine S1985 from Yamaha.

The FS-AA51 power adapter specifications are the same as the Sony AC-HB3 adapter for the Sony HB-F1 and HB-F1II.

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 Deskpac 1 Deskpac 3
Page 4000h~7FFFh Main-ROM Deskpac 2
Page 0000h~3FFFh Sub-ROM


Maintenance / Repair / Upgrades

Recommended batteries: Lithium batteries or Eneloop (white or cyan).
Batteries advised against: Alkaline batteries because they leak one day or another.