88. Vertical Circle Images Have Moved in Relation
89. Micrometer Circle Has Unequal Light or No
to the Line Dividing the Two Images and to the
Light
Reference Mark
Probable cause
Possible remedy
Micrometer circle prism
Clean or replace prism
Probable cause
Possible remedy
dirty or defective.
Vertical circle prism im
Reinstall or replace prism
Defect in illumination
Refer to paragraph 83.
properly installed or
system.
defective.
Section V. ILLUMINATION MIRRORS
90. General
Clean the mirror with an approved
Two identical illumination mirrors are supplied with
cleaning solvent and polish it with lens
the theodolite. The vertical circle illumination mirror
tissue or a lens cloth.
mounts on the vertical circle collar and the horizontal
(2) Inspect the mirror for cracks, breaks, and
circle illumination mirror mounts on the socket on the
loose backing.
horizontal base. The mirrors illuminate the vertical,
(3) Inspect the sleeve and mount for bends,
horizontal, and micrometer circles.
cracks, and burs. Inspect the pins for
91. Illumination Mirrors
burs, bends, and wear.
a. Removal. Refer to paragraph 56 and remove
(4) Remove minor burs and straighten all
the illumination mirrors.
slightly bent parts. Replace a damaged
b. Disassembly.
Refer to figure 37 and
mirror. Cement the mirror firmly in place
disassemble the. illumination mirrors.
and let it dry thoroughly. Remove all
c. Cleaning, Inspection, and Repair.
excess adhesive.
(1) Clean all metal parts with an approved
d. Reassembly. Refer to figure 37 and reassemble
cleaning solvent and dry thoroughly.
the illumination mirrors.
e. Installation. Refer to paragraph 56 and install
the illumination mirrors.
Figure 37. Illumination mirrors, disassembly and reassembly.
56
AGO 5078A
