IBM BladeCenter HT 8740 Problem Determination And Service Manual page 57

3. Lay the new filter on a clean flat surface and orient it so that the cutouts for the
light path extension assemblies are to the right and the large cutout at the
bottom of the filter is closest to you.
4. Orient the filter frame to the filter and place the filter frame on top of the filter;
then, pick up the filter assembly and install it into the bezel.
Chapter 4. Removing and replacing BladeCenter HT components
39