The press down function not working well. So I open up the trackball and clean it. However, I found that the copper pad under the ball is rusty so I use alcohol to clean it also. Not only clean the copper pad , I also clean the surrounding. After that, the press down button improved a bit but still have to press hard to works. But now my problem is the "left right up down" doesn't work any more. It used to have no problem to move "left Right Up Down". Oh man, I improve the press down problem but damaged the scrolling function. Please help me.