via this auction
See this post for a demo and overview of one by Mark Jenkins, and this post for some additional info on the EX1 vs. EX42 which was the stage model of of GX1, precurssor to the CS80.
Update: It's not clear how much the EX1 is related to the GX1 and CS80. According to Colin f in the comments of this post, the oscillators are digital. The EX1 was released in 1977, the same year the Synclavier was released, as well the same year Bell Labs Digital Synthesizer was developed. You can find some history on digital synthesis on Wikipedia here. The EX1 is not mentioned. According to Mark Jenkins in the comments of this post, the EX1 is is a preset version of the GX1.
"Comes complete with:
One TX-III matching tone cabinet.
Stool.
Pedal board.
Music stand.
Original Yamaha voltage converter.
The good bits:
In good overall condition with minor marks.
All keys/pedals work.
Tone cabinet works and sounds great.
All the controls apart from the ones listed work perfectly.
The bad bits:
One note on the lower orchestra (synthesizer) section occasionally sticks, not sure what the fault is.
Tremolo function doesn't work - it's probably the belt or motor inside the tone cabinet, I use it connected to an amplifier through its separate out so don't use this function.
Sine wave LFO waveshape on the solo synth not working (other waveshapes work fine).
This is an amazing sounding instrument which can layer different types of analog/digital synthesier and organ tones all at once.
Very hard to find and in very nice cosmetic shape.
Cost £27,000 back in 1977!"
