You really can't tighten them unless the mounting screws are loose. The 4 screws are located inside the back cover and they're T8 I think. There are also screws deep inside the screen, but one or more of them would have to completely fall out for it to get loose inside of there. Pismos have terrible hinges, they may actually be cracked and ready to let go completely. I've gone through several pair and currently have a broken hinge once again that I care not to fix anymore.