Jump to content

Panasonic FS-A1MK2

From RetroTechCollection
Panasonic FS-A1MK2
Panasonic FS-A1MK2
Panasonic FS-A1MK2 (FS-A1mkII), with the numeric keypad at the right. Photograph from the MSX Resource Center wiki; no freely licensed photograph has been found.
Specifications
ManufacturerMatsushita Electric Industrial (Panasonic)
TypeMSX2 home computer
Released1987 (Japan)
Intro price¥29,800
CPUZ80A
Memory64 KB RAM, 128 KB video RAM
StorageMSX cartridges, cassette
DisplayYamaha V9938
SoundPSG in the Yamaha S1985 MSX-Engine
PowerExternal adapter FS-AA51: DC 9 V 1.2 A and AC 18 V 170 mA
OS / Firmware—
PredecessorPanasonic FS-A1
Model no.FS-A1MK II

The Panasonic FS-A1MK2 (written FS-A1mkII by the MSX community and "FS-A1MK II" on its rating label) is an MSX2 computer made by Matsushita Electric Industrial and sold in Japan from 1987 at ¥29,800. It replaced the Panasonic FS-A1, adding a numeric keypad, and came only in dark grey, with a pause key, Panasonic's DESKPAC software in ROM and an FS-JS221 joypad in the box.[1][2]

The MSX Resource Center describes the machine as an FS-A1 with a keypad, but its own FS-A1 page and niga2, who has worked on both, say the main board is different. The FS-A1MK2 board has tracks on both sides, where the FS-A1's is single-sided, and adds kana, CAPS and PAUSE lamps.[3][4]

Hardware

[edit | edit source]

The board carries the Z80, the V9938 VDP, its video RAM, the system ROM, 64 KB of main RAM and the HIC-1 video board on the component side, and the Yamaha S1985 and the Mitsubishi M60002A-0108F gate array (the same gate array as the FS-A1) on the solder side.[4] The MSX Resource Center gives the CPU as a ROHM BU18400A-PS; niga2's machine has a Zilog Z80, so the maker varies.[1][4] The system ROM is a 1 Mbit mask ROM (DA1024D0364R).[4] A photograph of the inside shows a board printed "© Matsushita 1987" with an aluminium heatsink over the power supply and the HIC-1.[5]

The HIC-1 board (Mitsumi EMC-NX0039) holds the video encoder, the cassette interface and the sound amplifier, and runs from +5 V alone.[6][7] Its three surface-mount electrolytic capacitors leak with age; see the Panasonic FS-A1MK2 Capacitor Replacement Guide.[1]

Power

[edit | edit source]

Like the FS-A1, the FS-A1MK2 runs from the FS-AA51 adapter, rated DC 9 V 1.2 A and AC 18 V 170 mA.[2][8] The +5 V rail is regulated down from the 9 V, with a large heatsink inside to carry the heat. The 18 V AC is rectified and regulated to ±12 V by a 78L12 and a 79L12, and on the FS-A1MK2 those rails go only to the cartridge slots.[9]

The clock and settings are kept by two AA cells in a compartment in the base. The label inside it gives the type as R6P (SUM-3), two cells.[10]

Documentation

[edit | edit source]

No Panasonic service manual for the FS-A1MK2 has been found. The HIC-1 Hybrid Board Schematic covers its video board, and the Panasonic FS-A1 Schematic covers the earlier FS-A1's main board, which is a different design.

Repair guides

[edit | edit source]
[edit | edit source]
  • Inside, with the power supply at the upper left and the HIC-1 under the heatsink
    Inside, with the power supply at the upper left and the HIC-1 under the heatsink
  • The HIC-1 board
    The HIC-1 board
  • Rating label
    Rating label
[edit | edit source]

References

[edit | edit source]
  1. ↑ 1.0 1.1 1.2 Panasonic FS-A1mkII, MSX Resource Center wiki, 7 March 2026—link(accessed 2026-10-21) Community page: 1987, Japan, ¥29,800; described as identical to the FS-A1 with an extra keypad; dark grey only; pause button; FS-AA51 adapter (same specification as the Sony AC-HB3); 64 KB RAM in slot 3-0, 128 KB VRAM, V9938, PSG in the S1985, Z80A given as ROHM BU18400A-PS; QWERTY/JIS keyboard with numeric keypad; DESKPAC second version, bypassed with DEL at start-up; holding GRAPH at start-up initialises the clock's SRAM; FS-JS221 joypad supplied; the system board carries a daughterboard called HIC-1 with three SMD electrolytic capacitors that leak in time and badly damage the board round them; links to 512 KB memory upgrades and to a circuit diagram of the video board; lithium or Eneloop backup cells recommended, alkaline advised against.
  2. ↑ 2.0 2.1 Rating label on the underside of an FS-A1MK2: "MODEL NO. FS-A1MK II, 電源入力 DC9V 1.2A AC18V 170mA", Matsushita Electric Industrial, Made in Japan. File:Panasonic FS-A1MK2 rating label.jpg, from the MSX Resource Center wiki (uploaded by Mars2000you, 15 September 2020).
  3. ↑ Panasonic FS-A1, MSX Resource Center wiki, 7 March 2026—link(accessed 2026-10-21) "The main board is different from the board of the FS-A1mkII."
  4. ↑ 4.0 4.1 4.2 4.3 FS-A1Mk2のメモリ512kB増設– niga2—link(accessed 2026-10-21) In Japanese. Differences from the FS-A1: numeric keypad and kana, CAPS and PAUSE lamps, a greyer case and a redesigned board; the FS-A1 board is single-sided with many jumper wires, while the mk2 board has tracks on the component side too, joined to the other side by pressed-in conductors rather than plated holes, which makes rework awkward; component side: video RAM, VDP, CPU, ROM, RAM, the video HIC and logic; solder side: the S1985 MSX-SYSTEM II and the M60002A-0108F gate array (the same as in the FS-A1); a Zilog Z80 on the author's machine (his FS-A1 has a ROHM part); system ROM a 1 Mbit mask ROM DA1024D0364R at IC11 with IC13 unfitted; 64 KB of non-mapped RAM; the video HIC uses a Sony CXA1145 and surface-mount electrolytic capacitors that are worth replacing; a thick aluminium heatsink makes access awkward.
  5. ↑ File:Panasonic FS-A1MK2 inside.jpg, photograph uploaded to the MSX Resource Center wiki by Gdx on 12 August 2018: the board printed "© Matsushita 1987", the power supply capacitors and choke at the upper left, the green HIC-1 board under the heatsink, the cartridge connector at the top right.
  6. ↑ BABAX, Mitsumi Hybrid IC EMC-NX0039 (Panasonic parts no. DAMCNX0039XT), revision 02. File:Mitsumi EMC-NX0039 HIC-1 schematic (BABAX, Rev 02).pdf; see HIC-1 Hybrid Board Schematic. RGB-NTSC encoder (Sony CXA1145M), cassette interface, sound amplifier, pause and power muting; +5 V supply.
  7. ↑ FS-A1Fの改造 前編– niga2—link(accessed 2026-10-21) In Japanese. The HIC (Mitsumi DAMCNX0039XT) runs from +5 V alone, so the FS-A1mk2, which uses it, works without ±12 V.
  8. ↑ Panasonic FS-AA51, MSX Resource Center wiki, 17 September 2025—link(accessed 2026-10-21) Input AC 100 V 50/60 Hz 23 VA; output DC 9 V 1.2 A and AC 18 V 170 mA; same as the Sony AC-HB3; not the same as the Sony AC-HB1 series or AC-HB2P.
  9. ↑ FS-A1mk2の単一電源化改造– niga2—link(accessed 2026-10-21) In Japanese. On the FS-A1mk2 main board, +5 V is stepped down from the DC 9 V, and the large internal heatsink handles the heat; ±12 V is made from the AC 18 V with 78L12 and 79L12 regulators and, on the mk2, is used only for the slots (on the original FS-A1 it also feeds the hybrid IC); with a 9 V adapter alone the machine ran ROM games and PSG sound, but an FM-PAC needs ±12 V; adapters with the same connector but a different polarity or voltage will damage the computer.
  10. ↑ Photograph of the FS-A1MK2's battery compartment on the MSX Resource Center wiki (File:Fsa1mk2d.jpg, uploaded by Mars2000you, 15 September 2020): the label "バックアップ電池について" gives the cell type as R6P (SUM-3), 2 個, and tells the owner to replace the cells about once a year.



Retrieved from "https://retrotechwiki.com/index.php?title=Panasonic_FS-A1MK2&oldid=28133"