After 5 years of trouble-free use, my 797c SI has acquired the dreaded foggy screen. Essentially, the center of the screen is "foggy" with only the periphery of the screen visible. In about 45-60 minutes, the fog gradually disappears and the screen is normal. Apparently this is not an uncommon problem because I found several reports on the internet. The solutions appear to be to remove the back and let it dry out or send it in to Humminbird for "service" (which might be the same operation!). Anyone had this problem and, if so, were you able to fix it and how did you do it? Thanks!