Today on my bench is a Korg MS20 vintage analog synthesizer from Robert Babicz. When he says, his Korg has a tuning problem then the synth has a tuning problem! Which again is very common. The issue here are the dirty rotary switches. The plastic sides are cracked in some places. I will fix that with some glue. Some screw heads are damaged. I took off all knobs and disconnected all pcbs to get them out. Now I have access to the rotary switches and potentiometers. I am going to desolder them all, open them up and clean them properly. On the pictures you can easily see how dirty and corroded these switches are. While I am in here I will change the electrolytics since they measure a bit leaky. All tantals have to go. I clean all jacks and refresh the nuts. Finally I do a full calibration on this unit. Roberts Korg MS20 is now in perfect technical and good cosmectic condition and waiting to create some phat techno waves. Like always I share my repair pictures with you.