My big screen in slightly out of focus and will blur now and then. there is also a cracking sound when the tv is turned on

Do you have a setting in the MENU where you can adjust the "Sharpness". If you have this setting, go up a few notches toward the "+" side and see if that helps. Also, there might also be a section in the MENU called "CONVERGENCE" and in this menu, select the "AUTOCONVERGENCE" option and it will reset the screen. You may or may not have this option in your menu, but if not, you should have something where you can adjust the focus. My TV is an RCA projection and I have the setting that I mentioned above, so your should be somewhat similar. As far as the cracking sound goes, some TV sets will do this with age when they are first turned on and are going through the whole "warm-up" process and that should not be a big concern. Hope this helps...