Casio Casiotone MT-540 vintage keyboard Buen estado. 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 effect that gave them a distinct airy ethereal appeal that was typical for late 1980th. This digital MIDI keyboard from 1988 (service manual date) has each 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 no accompaniments but include environmental noises like "forest" or "ocean" and movie stuff like "wild western" and "space wars". Specs: 49 midsize keys (well responding) 2 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 ens, flute, bells, percussion, sound effect 1 | elec piano, funky clavi, jazz guitar, organ, accordion, strings, chorus, synth-ens, 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 & 2 fingered accompaniments (only standard chords, manual chord with rhythm off) fill-in & intro/ ending buttons tempo +/- buttons (43 steps?) wavetable sound generator with sounds based 2 mixed medium resolution loop samples with independent, partly complex algorithmic volume and pitch envelopes and FM tricks. Apparently there is an oversampling feature built-in, because low notes do not turn rough, grainy or hissy but only duller. The rom samples are 16 bit at about 22050kHz. 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 & playback of all sounds and changes, no edit) 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 3,1kg Owner manual link pdf: https://static.wikitide.net/circuitbendingwiki/e/ed/Casio_MT-540_%26_CT-460_Owners_Manual.pdf