TM 11-2323
C4
(3) To reinstall the knobs and pivots, perform the procedures
above in reverse order.
Paragraph 56, heading. After "Assembly" add : (PH-637/PFP,
PH-637A/PFP, and PH-637B/PFP).
Page 61, paragraph 56. Add paragraph 56.1 after paragraph 56.
56.1. Projection-Head Assembly (PH-637C/PFP)
(fig. 2.2)
a . W i n d o w . Remove the two window frame mounting screws that
secure the left side of the window frame to the mirror housing. H o l d
the window frame in place and remove the two window frame mount-
ing screws on the right side of the mirror housing. Carefully lift the
window and window frame off the mirror housing. To reinstall the
window and window frame, carefully place the window in the window
frame, set the assembled window frame bark on the mirror housing,
and install the four window frame mounting screws.
b. Front Surface Mirror and Mirror Support.
(1) Remove the window (aabove).
Caution: Handle the front surface mirror carefully.
The reflecting surface of the mirror is coated, and the
coating is not protected. Clean the front surface mir-
ror only when absolutely necessary. Whenever handling
the front surface mirror, hold a chamois or a clean,
lint-free cloth between the hand and the mirror so that
the front surface mirror will not be spotted.
(2) Turn the elevation knob on the back of the projection head
counterclockwise until it comes off. Support the front surface
mirror with one hand.
(3) Remove the two screws on the back of the projection head.
The front surface mirror and the mirror support will drop
free; carefully lift them out of the projection head and place
them on a flat surface.
(4) Remove the two screws from the retaining clip that supports
the bottom of the front surface mirror.
(5) Remove the retaining clip and slide the mirror out.
(6) To reassemble the front surface mirror and mirror support,
perform the procedures in (1) through (5) above in reverse
order.
Note. When installing the elevation knob, be sure that it is threaded
far enough into the back of the mirror support so that the projected
image will be approximately centered.
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