Easy, that is a Solina String Machine or any string machine of the time i.e. Roland Vp-330
http://www.hollowsun.com/HS2/products/vp330/index.htmEffect is easily achieved in Logic with the ES-E synth and Ensemble plug in effect.
If you don't have Logic then dial up a square wave on a synth until you get it to sound similar and the key to the sound is the ensemble chorus effect
The Micro Korg can make this sound, I don't have one but I have seen plenty of people achieve it with a Micro Korg