via this auction
"Vintage 4-Voice Polyphonic Analog Synthesizer - with upgrades
Serial number dating it from January 1979, likely an early revision.
In great clean cosmetic condition inside and out, only a couple reasonable bumps and small chips to the wood sides, and what looks like an ancient sticker mark on top opposite the logo, nothing too eye catching overall, everything shown in the pictures.
Has the following upgrades :
- MIDI in to receive notes on channel 12
- Memory expansion accessible from an added rotary knob, 8 banks of 8 slots for a total of 64 user presets
- A Detune knob mainly useful to spread oscillators/voices further in unison mode.
220V model, fitted cable with standard European plug."