Sharp MZ-40K

The Sharp MZ-40K was a compact four-bit microcomputer kit released in Japan in 1978. Built around a Fujitsu MB8843 single-chip processor, it used a hexadecimal keypad and LED display for simple programming, timing, music and game activities.

Marketed as “Dr. Microcomputer,” the MZ-40K was intended as an approachable electronics and computing trainer. Although architecturally unrelated to later Z80 machines, its name and educational purpose made it the ancestor of Sharp’s better-known MZ computer family.

Notable Features

• Four-bit single-board computer supplied as a construction kit.
• Hexadecimal keypad and LED display supported monitor-style programming.
• Built-in clock, timer, music, organ and simple game functions.

Historical Significance

• Provided the name and educational starting point for Sharp’s later MZ computer family.
• Represents the brief late-1970s period when consumer microcomputers were often sold as learning kits.

Collector's Notes

• Unassembled kits are exceptionally rare and assembly affects collector value.
• The unusual AC adaptor is part of the clock circuit and must not be replaced with a normal DC supply.

Specifications

Technical Information
Name	Sharp MZ-40K
Manufacturer	Sharp
Launched	Thursday, January 5, 1978
Launch Price	Approximately ¥24,800
Country	Japan
CPU	Fujitsu MB8843 4-bit microcontroller
Units Sold
Related Models	SM-B-80T and remote-keyboard SM-B-80TC variants
Power	External 5V, 2A supply
I/O	Z80 PIO interface connector
Expansion	100-pin expansion connector
Storage	Cassette interface at approximately 1,200 baud
Keyboard	25-key hexadecimal and function keypad
Display	Eight-digit seven-segment LED display
ROM	2KB monitor ROM, expandable to 8KB
RAM	2KB static RAM, expandable to 4KB
CPU Speed	2.4576 MHz