Casio - Casiotone MT-540 - - Keyboard - Japan - 1988 (No reserve price)

Casio Casiotone MT-540 vintage keyboard
Good condition
These were Casio's first fully digital MIDI keyboards marketed as 'Tone Bank.' The sound engine was advertised as 'CD sound source' (obviously alluding to Compact Disc), and the sample-based high-resolution PCM timbres contain much reverb and stereo effects that gave them a distinct airy, ethereal appeal that was typical for the late 1980s.

This digital MIDI keyboard from 1988 (service manual date) has 20 preset sounds and rhythms. Its special feature is the 'sound effect' section, which plays 8 atmospheric background sounds based on complex algorithmic patterns. These are not accompaniments but include environmental noises like 'forest' or 'ocean' and movie-related sounds like 'wild western' and 'space wars'.

Specs:
49 midsize keys (well responding)
Two built-in 11cm speakers (of reasonable quality, stereo)
Main voice polyphony up to 10 notes (only 4 with accompaniment, 5 with dual voice sounds, 2 with dual voice + accompaniment).
20 semi-OBS preset sounds {piano, harpsichord, vibraphone, jazz organ, pipe organ, brass ensemble, flute, bells, percussion, sound effect 1 | electric piano, funky clavinet, jazz guitar, organ, accordion, strings, chorus, synth-ensemble, bass, sound effect 2} (selected through 10 OBS buttons + bank switch button)
10 additional hidden preset sounds {metallic sound, honkytonk piano, marimba, oboe, synth-reed, harp, synth-celesta, synth-clavi, fantasy, miracle} (accessible through MIDI or circuit bending).
20 semi-OBS preset rhythms {rock 1, 8 beat 1, 16 beat 1, disco 1, pops 1, slow rock 1, swing, samba, bossa nova, waltz | rock 2, 8 beat 2, 16 beat 2, disco 2, pops 2, slow rock 2, reggae, tango, beguine, march} (selected through 10 OBS buttons + bank switch button)
8 OBS sound effect pad rubber buttons {forest, ocean, street, space wars, rainy day, evening, concert hall, wild western} (with additional hold and 'fade in/ fade out' pads, apparently also used to set MIDI channels in MIDI mode)
Master volume slider
Separate accompaniment (with rhythm) and sound effect volume slide switches (each 5 steps).
'210 tone bank' button (to layer any 2 preset sounds for dual voice mode)
Single finger and two-finger accompaniments (only standard chords, manual chord with rhythm off).
Fill-in & intro/ ending buttons
tempo +/- buttons (43 steps?)
Wavetable sound generator with sounds based on two mixed medium-resolution loop samples, featuring independent, partly complex algorithmic volume and pitch envelopes, and FM tricks. Apparently, there is a built-in oversampling feature, because low notes do not become rough, grainy, or hissy, but only duller. The ROM samples are 16-bit at approximately 22,050 kHz.
multi-chip hardware
CPU= "NEC D938GD 005, 8843XK204, Japan" (120 pin SMD)
Main ROM= "NEC D23C2000AC-1 501, 8845KD001, Japan" (40 pin DIL, pinout 27C400, 256KB)
Effect ROM= "HN62404P G93, 9A1, Japan" (40 pin DIL, pinout 27C400 with OE inverted, 512KB)
SRAM = "NEC D4364C-15LL, 6808BU003, Japan" (28-pin DIL, 8KB)
DAC = "Sanyo LC7880, 85Y38" (20 pin DIL)
Simple sequencer (record and playback of all sounds and changes, no editing)
Demo melody 'Night Birds' by Shakatak (Latin/fusion music with effect sounds)
auto power-off
Jacks for AC adapter, sound output, MIDI in + out.
Including AC Adapter
Dimensions:
66.4cm x 23.4cm x 8.3cm
3.1 kg
Owner manual PDF link
The URL provided links to a manual for Casio MT-540 and CT-460, but no specific text was included for translation. Please provide the text you'd like translated.