I had this problem too. I took out the 3 outer screws on the back of the lens, one seemed loose, peeked in and decided there was no way I was going to fix this thing. Screwed it back on and the camera worked again. I suspect the screws were loose. Give that a try and see if it works.
I know I was about to throw my NX-mini out when I took the chance of unscrewing it. I wouldn't try to remove the back. Just try tightening the outer screws.
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=== Update (10/27/2017) ===
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Update: It stopped working again.
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I had a technician at work take a look at it and he found that a ribbon cable in the lens sheared. He removed the cable and it works, kind of, in manual mode. I will be sending the lens to International Camera in Chicago to have it repaired.
I had this problem too. I took out the 3 outer screws on the back of the lens, one seemed loose, peeked in and decided there was no way I was going to fix this thing. Screwed it back on and the camera worked again. I suspect the screws were loose. Give that a try and see if it works.
I know I was about to throw my NX-mini out when I took the chance of unscrewing it. I wouldn't try to remove the back. Just try tightening the outer screws.