Ya know, I drove myself nuts one time with the same problem. Turns out that I wasn't getting the crystal in the holes right. It felt like I was, and it stayed in, but I wasn't lined up right, and it wasn't even going in the sockets. The way the RX case was designed, the socket holes are 1/2 inch or so inside the case. It's kind of hard to hold the crystal with adult fingers, and get it to slip in just right.