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"Up for sale is a very rare Hammond 102100. It is a single oscillator analog monophonic synth made in the mid 70's (1974?) by Hammond Japan. It was originally meant to be a preset synth that would sit atop your Hammond organ. Supposedly there were only 200 ever produced, and there are probably less than 50 in working condition. So I would say it is extrememly rare to find one in this condition. It is much like the other early mono preset synths from the same era: Arp Pro Soloist, Moog Minitmoog, Moog Satellite, Roland SH-1000, Korg Micropreset & Minikorg. All great synths, but this may be the hardest to find.
It is100% functional. All keys work perfectly, no messed up key contacts, sliders move easily, no broken buttons. Very very clean/good physical condition. There is a chip to the wood paneling pictured below. Other than that there is barely a scratch on it.

How it works: There are six factory presets. French Horn, Tuba, Violin, Sax, Clarinet, Solar Echo. These are selectable via the buttons on the right. To the left you have a programming matrix, with buttons for all the functions. The matrix has sections for the following functions: Waveform, octave (3 octave keyboard with 6 octave selectable range), Filter (7 filter envelope positions), Cutoff, 3 Filter Modulations, Envelope, Attack Speed, VCA envelope release, pitch modulation, and vibrato contact delay.

Each button is numbered, so actually remembering a preset is quite easy. You just write down the 7 digit number of all the buttons that were depressed.
Final, but important, note: The power supply is European. It reads 230v 50-60khz 20va. I tested the synth with a basic step up transformer and it worked great."