I had the same problem when I replaced the glass on my Beomaster 3500, some wouldn't work. When you put the glass with the plastic frame back on the sensor board it slides to one side. The sensors then bend and don't stand up straight. This is fine, they are supposed to do this. If you take something and straighten them they don't work. You can also check where the sensor end is touching the glass, that is, it must touch the right part of the glass where you would touch it with your finger. This is what I have experienced.