Seiko DS-202 / DS-310 / DS-320 Synthesizer Sequencer 1983 Black

My father originally bought this for my mother back in the 80s shortly after I was born when she said she'd like to learn piano- but she didn't have the time, and gave up. They had it in storage in the attic since then, and I found it a few months back while helping them clean. They were going to toss it, but I grabbed it- and now it's available to all of you!
What you're seeing for sale here is a vintage, near-mint condition Seiko DS 202 additive synthesizer with bot the DS 310 and DS 320 attachments!
SEIKO's system was built around a 16 harmonic additive synthesis engine. The user can set any of 16 levels for creating the waveforms / sounds that could be played on the keyboard. The synth also features two envelopes and and LFO for shaping and modulation of the sounds.
Basic sounds (namely PIANO ORGAN HARPSICHORD FLUTE STRINGS ELECTRIC PIANO JAZZ ORGAN VIBRAPHONE CLARINET BRASS) are crystal-clear. They can be edited using the LPF filter, Envelope Selectors 1-4, 4 sounds that can be saved and two chorus effects. The delay (off, short or long) and sustain attack and release can be set using the ‘Time” sliders which happen to be very precise (values include 0, 0.01, 0.02 , 1, 2, 3, 5 or 10 seconds). Every parameter can be set using the LCD screen, the 4 envelopes available can be visualized as well as the spectrum settings (over 16 harmonics).
The youtube video shows the instrument, but know that this is not me, nor the specific keyboard you'd be buying: 

Of the two speakers, one is a little wonky and doesn't work all the time and there is a lot of static/dirt noise when you adjust the volume, but other than that all works as it is supposed to.
Everything included in the purchase:
Seiko Digital DS 202 Keyboard Seiko Digital Synthesizer DS-310 Seiko Digital Sequencer DS-320 Power supply cable <-- extremely hard to find! Sustain/foot pedal Original Hard Case (no key) Instruction booklets for all three parts Original bill of sale (interesting collectors item!) Keyboard stand (brand new)