Yamaha MK100

The Yamaha MK100 Multi-Programmable Personal Keyboard is the first keyboard of the Portasound series to feature the "DX-green" colour scheme seen a few months earlier on the DX7 and DX9, while trying to mimic some of their FM sounds. It's also remarkable for its user-programmability, achieved through what Yamaha calls the "Multi-Menu" — a set of controls that change function based on the position of the menu "prism", which can be controlled by a knob on the right (a very clever design solution, taken from the Electone line).

The shell was later reused for the Yamaha PSS450, another keyboard of the Portasound series, albeit with a lot less features. Along with the usual rhythm and auto bass chord sections, it's also possible to load and save sequences via cassette through a tape interface. The sounds are supposedly not stereo, with the ability to layer them as chorus or tremolo, or to stack them with the duet / trio function.

Features

• Synthesized Multi-Menu System - 1376 sound possibilities
• 12 Orchestral Voices
• Stereo Symphonic
• 2-track recording section with taping facility
• Transposer
• Rhythm section
• Auto Bass Chord
• Battery and mains power
• Melody Plus – duet and trio
• Can connect to stereo hi-fi system
• Sustain 1 and 2