My issue was easy thumb press with right handed manipulation and he-man /hulk strength needed to press with the left thumb. I fixed it with a nail file (one of my wife's disposable ones). Real easy fix, just have some canned air available to blow the dust out. Here's a youtube on what I did (not my video, just one that I followed the steps for). My memory tells me there was another video with better camera work, but I can't find it right now, I'll update this post if I run across it.