Below black vinyl covering on nonmetered prism there are 3 screws. One is just up from the viewfinder and other two are on the opposite side from viewfinder - when you look at the front of the viewfinder on the bottom left and right side of the vinyl covering. Vinyl covering is padded with plastic where screws reside so you will not 'feel' them if you try to find them with screwdriver. You can just strip off those corners to reach screws. No need to remove complete vinyl covering.