Check that all screws are present.
Check that mounting surface (1) is clean and
free of nicks and burrs.
Check that M139 elbow telescope (2) is free of
dirt and foreign matter, that all parts are present,
and that paint is not chipped.
Look through eyepiece assembly (3) and check
that there is no dirt or moisture on lenses (4) and
reticle assembly (5).
Look through optical instrument cell assembly
(6) and check that no dirt or moisture is present
on lens (7) or optical instrument prism (8).
EYEPIECE ASSEMBLY FOCUS INSPECTION AND ADJUSTMENT
Position M139 elbow telescope on flat surface.
Focus dioptometer eyepiece (1) until reticle is
Set dioptometer range scale (2) at minus 0.75 to