via this auction. Details below.

"Rar, fancy: vintage EML Synkey vintage analog punch-card programmable synthesizer in recently adjusted; absolute top condition. It's the top rar: OVATION - version. Fully works and sounds incredible: The low-pass filter goes to high-pass filter and the band-pass in between and this is extremely effective. It has ringmodulator and some arpeggioator-like LFO-waveform varies due to the speed. It's unique and you can make some unpredictable polyphonic arpeggiations. Dealing with punch-card makes this machine very exotic! So maybe you bid on technically one of the best Synkey of the world! Pitty, it runs on American standard current 110 V , so there's a 220 V -adapter in need or comit me to do the modification for some extra (ca. 35-50EU depending on trafo)!"
"... these came out as early as in 1976, not 1978/79 as stated on most synth-sites out there. At least, this is what I was told by one of the founders/owners of the EML company - States Mikael. Thank you for the info! "
Update via the comments: "The Synkey service manual I have dates the individual drawings from about April 1974 to March 1975. 1976 therefore seems about right."