If prisms are adjustable, this will be by external grub screws (set screws) that are accessible under the rubber or leatherette covering of the binocular body, usually close to the edge of the prism housing where they can be accessed by minimal shifting and stretching of the rubber. If the binocular is covered with leatherette, there are usually little tabs in the leatherette that can be lifted to permit access to collimation screws. Alternatively, the collimation screws may only be accessible by removing the cover plate. They are the slotted-head screws (Figures 5.10 & 5.12).
Remove the eyepieces and bridge, then remove the cover plate and replace the eyepieces and bridge. The collimating screws are slotted grub screws that are immediately adjacent to the cross-headed screws that secure the prism cluster to the binocular body. The screws adjust in "push-pull" pairs. The procedure is to slacken the securing screw, adjust the collimating screw, then retighten the securing screw. Adjust one pair of screws at a time and turn the collimating screw no more than an eighth of a turn and examine its effect on the image. Adjust in small increments until the images are satisfactorily aligned.
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