C1, TM 9-1240-318-35
d. Test and Adjustment of Parallax.
thoroughly cleaned before assembling and sealing.
(1) With the fixture setup as outlined in
(2) Assemble items 5 through 2. Install and
secure retainer (1) using tubular spanner wrench.
mount and secure in place with locking lever.
(2) View through eyepiece and move head from
f. Sealing. Using sealing compound gun 4931-
side to side and observe if there is any apparent
508-5428, inject sealing compound, MIL-S-11031, into
movement between the projector collimator reticle and
the sealing ports of cell. Lock retainer (1) in place by
the telescope reticle lines at the center of the field.
placing a small amount of sealing compound around its
Parallax must not exceed 0.1 mil (thickness of reticle
outer edge.
line).
(3) If parallax exceeds 0.1 mil of the center of
5-10. Replacement of Cell Assembly 1240-891-1288
the field, rotate objective cell assembly in or out until
(M120 only) or Cell Assembly 1240-483-1171
parallax does not exceed 0.1 mil.
(XM134 only)
(4) Place a small amount of sealing compound,
MIL-S-11031, on the threads of screws (1) and secure
Note. Item numbe rs shown below refer to figure
cell assembly (2).
5-9.
Disassembly of Cell Assembly 1240-891-1287
a. Removal.
(1) Remove diaphragm (1) using tubular
Note. Item numbers shown below refer to figure
spanner wrench.
(2) Remove the two set screws (2) securing cell
assembly (3). Remove cell assembly from tube using
a. Removal
tubular spanner wrench.
(1) Using tubular spanner wrench, unscrew
retainer (1).
b. Inspection.
(2) Remove items 2 through 5, from cell (6).
(1) Inspect diaphragm for damaged threads.
(2) Inspect the cell for dents or damaged
Note. Use care in removing retainer (1) and lens
threads.
(2) since they are sealed with sealing compound,
(3) Check exterior optics for loss of coating,
MIL-S-11031.
scratches, or digs.
b. Inspection.
c. Installation.
(1) Inspect retainer for damaged threads.
(1) Clean exterior optics and install cell
(2) Check lens for chips, digs, or scratches.
assembly in telescope tube. Cell assembly will be
(3) Check fluoride coati ng for excessive
secured after test and adjustment below has been
completed.
(4) Inspect the cell for dents and damaged
(2) Install diaphragm and secure in place by
threads.
placing a small amount of sealing compound, MIL-S-
11031, around the outer edge to lock in position.
c. Repair. Remove small chips or
fractures from
lenses that will interfere with performance by using a fine
d. Test and Adjustment of Reticle Plumb.
abrasive stone.
(1) With the fixture setup as outlined in
d. Cleaning.
assembled, place the telescope in the dovetail of the
(1) Clean all lenses thoroug hly using the
mount and secure in place.
materials specified in TM 9-254.
(2) Sight through the telescope and observe if
(2) Remove all traces of sealing compound from
the telescope reticle pattern (800 meter range line) is
cell, spacer, and retainer with cleaning solvent, 6850-
parallel to the fixture collimator reticle pattern within the
336-8170.
thickness of a reticle line; if not, remove two screws and
insert a pointed tool through one of the screw holes (for
e. Assembly.
cell assembly) and while viewing through the
(1) Since the presence of a film of grease
reduces adhesion the cell and its components must be
5-3