US Army C3 Service Manual
Model C3 Army Camera
Instructions For Adjusting Range Finder
are only two adjustments to be made in correcting the rangefinder, when
easured distance from the front plate of the camera to target or
subject matter does not agree with the reading on the rangefinder dial
scale. Both of these adjustments must be made without removing
range-finder assembly or lenses from camera.
White cardboard target about 2 ft. x 2 ft. with black vertical and
horizontal lines about ¼ inch wide and several inches apart for use at
25 ft distance.
(2) Infinity target to be a vertical object (post, tree, ect.) at about
200 feet or more from camera.
(3) Wrench for removing rangefinder cap.
(4) Small screw driver.
(5) Tripod or any firm object on which camera can be firmly placed.
Procedure: (Vertical adjustment)
First make certain that the idler gear or coupler between focus
barrel and rangefinder dial wheel is properly set. Information on this
in the camera instruction book. Rotate range-finder
dial wheel to position marked infinitly on dial scale. Remove (with
special wrench) the rangefinder cap which covers the adjustment screws
"A1" and "A2" in diagram. Sight infinity target through rangefinder
window. If vertical line appears broken, place tip of screw-driver
edge of screw head "A2" and carefully slide forward or backward in
slot, at same time noting how the upper half of vertical line is moved.
Moving screw toward front of camera, moves image (or vertical line) to
the left. In the opposite direction, the vertical line is moved to the
right. Adjustment on infinity setting is complete when vertical line
appears as one line (unbroken).
camera on tripod. Set rangefinder dial at 25 feet, and place target
with horizontal line at 25 feet from front of camera. Sight target
through rangefinder window. If a horizontal line appears as two lines,
the adjustment is easily made by tightening one or the other of the two
screws marked "A1" and "A2" in diagram.
"A1" raises image on target. Tightening "A2" lowers the image. When a
horizontal line appears as one line, the adjustment is complete.
To Remove Camera Front Plate
(1) Loosen set screw in cocking lever (1), then unscrew cocking lever
(2) Set shutter speed button (2) to 1/300 to re-lieve tension on cam
(3) Raise covering over front plate screws (3) at four corners, and cut
covering where other two screws are located.
Remove the six-inch screws. Carefully lift front plate about ¼ inch
from bakelite case and then slide front plate in direction of top of
camera. This will prevent bending pin in cam follower.
To replace Shutter
replace shutter, remove the three mounting screws (4) from shutter
plate and install new shutter in same position. It may be necessary to
loosen screws (4) just enough to slightly shift the position of the
shutter assembly toward or away from the shuttle cock catch (12), see
figure "D". If shutter blade arm is too close to shuttle cock, the
blades will open too far and sometimes stick in shutter blade housing.
If shutter blade arm is too far from shuttle cock, the shutter will not
open fully. Tighten screws when shutter
To Replace Shuttle Cock Assembly
(1) Remove shutter as described in figure "C".
(2) Unhook springs (5 & 6) from post (7).
(3) Take out screw (8) and remove shuttle cock assembly.
Transfer shutter release cam (9), switch release arm (10) and two
screws (11) from old assembly to approximately the same position on the
(5) Set shutter release to "I" position on dial (13)
(6) Install shutter cocking lever (1) Figure "B" to check movement of
shuttle cock and shutter before installing front
plate. Cock shutter by depressing cocking lever. While holding cocking
lever down, press shutter release (13) and gradually
release pressure on cocking lever. Watch shutter blades open slowly.
Shutter must open fully but not so far that the blades
will bind in housing.
To Replace Shutter Escapement And
Shutter Release Assembly
Procedure: Shutter Escapement
(1) Before attempting to remove shutter escape-ment, mark bakelike case
around shutter escapement base (14). This will
simplify installing new shutter escapement in identical position of the
original one. Then remove Two screws (15) that hold
escapement assembly to camera case.
(2) Unhook wire link (16) from control arm of the escapement
Procedure: Shutter Release Assembly
front plate (see inst. on front plate figure "B"). Remove screw (17).
Remove screw (18) and spring beneath screw which presses against small
ball bearing. Carefully pull release assembly (19) from case.
Watch for ball bearing which may drop out when release
Installing Front Plate
shutter speed dial (2) to 1/300 (see figure "B"). Turn front plate over
and insert cam follower (20) in bracket (21) with pin pointing away
from front plate. Carefully turn front plate over so as not to disturb
position of cam follower. By holding plate at corners with thumb and
forefinger of each hand, lower plate to about ¼ inch above case. Note
position of pin in cam follower and hole in triangle lever (22) Fig.
"E" into which pin should be inserted. This allows enough space between
camera and front plate so that the pin (23) can be directed to engage
the hole of the triangle lever (22) as front plate is lowered to
correct position for inserting screws (3) see Fig. "B".
To Replace Gear Block Assembly
Remove counter dial screw (24), dial (25), cupped friction
and post (27). (Insert screw-driver between back gear and
prevent parts from turning while removing dial screw.)
(2) Remove screw (28) and unscrew button (29).
(3) Gear block assembly (30) can then be withdrawn from case