A simple 1 vco monophonic synth with very basic controls (A-D envelope, VCF LF and HP cutoff dual sliders they call 'traveller', triangle, square, saw and two chorus effected waveforms, LFO and repeat rate controls and some useful toggles for a preset attack bend, lfo delay, sustain (release preset) and Exapand (applies the VCA EG to the VCF) and "Bright" which added some resonance. Great sounding little units.
Typical cleaning issues. Haven't heard of any specific typical failure otherwise. The service manual was hard to read, hoefully a better one will arise.
I believe you'll draw mostly blank looks from Korg on these units. I have some parts that are the same so feel free to ask what the current stock is on a given thing. Some of the less common parts are getting quite hard to find though. THings pop up on ebay now and then.. Contact