I have a recurring problem with my mini kryptonite that sounds similar. It is hard to explain, but there are 2 parts inside the lock that can rotate. If the key slot isn't lined up between the 2 parts, you can insert the key into the lock, rotate it, but nothing happens. The first part is rotating, but not the lower part. The first time it happened, I thought the lock shot. I've since learned that when it happens I put the key in, turning and jiggling the key until the two parts line up. The key slips in another 3-5mm and then the lock functions correctly.