Casio PT-100 Retro Keyboard from 1987!
38#casio
main features:
32 midsize keys (15 of them used for chord section)
built-in speaker
8 note main voice polyphony (only 6 with rhythm, 4 with accompaniment)
4 note polyphonic chords or accompaniment
8 preset sounds {piano, harpsichord, vibraphone, pipe organ, jazz organ, flute, strings, synth sound} (selected by slide switch with a small delay)
8 preset rhythms {rock, disco, swing, samba, bossa nova, tango, slow rock, waltz}
volume slide switch (5 steps)
tempo +/- buttons (26 steps)
CPU "HD61702A02, 8D 43" (100 pin SMD) with timbres based on 2 layered multipulse squarewave(?) waveforms with different digital envelopes, those are differently low pass filtered through capacitors.
single finger chord with fixed timbre (rough squarewave organ)
percussion {base, snare, cymbal, hihat, high & low woodblock} has unique electronic style, based on digital low- res waveforms with audible zipper noise.
demo melody (very nice classical tune that cycles through all sounds)
auto power off
power supply jack