use a screwdriver with a blade
slightly wider than the slotted ends of
the take-up rollers central shafts.
Insert the screwdriver into the slotted
end of one central shaft and push
down — that depresses the locking
collar and frees the central shaft. You
can now turn the screwdriver to add
or let off tension.
Another departure from tradition is
the elimination of the interlocking-
stud arrangement common to the
drum-type focal-plane shutters. In the
shutter-cocked position, a slot in the
curtain wind gear clears the drum
gear at the bottom of the curtain
drum. Then, the opening curtain
latch, Fig. 6, drops into engagement
with the opening curtain cam
underneath the drum gear.
Depressing the release button
pushes the end of the flat release
spring against the opening curtain
latch. So the opening curtain latch,
pushed out of engagement with the
opening curtain cam, frees the
opening curtain. Simultaneously, the
flat release spring allows the closing
curtain latch, Fig. 7, to drop down and
engage the closing curtain cam.
meeting these specifications is the
setscrew on the flat release spring,
Fig. 6.
The " X " - s y n c adjustment is
another conveniently located
adjustment point visible in Fig. 6. The
collar with the Multispan notches
controls an eccentrically positioned
stud at the other side of the bottom
plate. And the stud, in turn, controls
the position of the fixed " X " contact.
Turning the collar corrects the "X"-
sync delay by setting the proper space
gap between the two contacts.
A second eccentric controls the
tension of the closing curtain brake
spring, Fig. 6. The brake spring,
which we'll see after removing the
body shell, engages a cam operated
by the closing curtain drum. And by
turning the eccentric from the bottom
of the camera, you can control the
amount of braking action.
Check the proper tension for the
closing curtain brake by first setting
the shutter to "bulb." Then, cock and
release the shutter. The closing
curtain should be stopped by the
brake spring before reaching the
extreme limit of its travel. So try
pulling the closing curtain in the
direction of its release movement —
you should be able to pull the curtain
an additional 0.1mm—0.5mm.
In some cameras, there's also an
eccentric adjustment for the opening
curtain brake; the opening curtain
brake eccentric is shown from a Leica
M3 in Fig. 8. Check the adjustment of
the opening curtain brake by holding
the shutter open at the "bulb" setting.
Now, looking from the front of the
focal-plane aperture, examine the
position of the opening curtain bar at
the right-hand side of the camera. If
the opening curtain brake is properly
adjusted, the edge of the opening
curtain bar should be 1.5mm —
2.5mm beyond the edge of the focal-
plane aperture.
Before moving too far away from
Fig. 6, we should point out the bayonet
cap in the focal-plane light shield. You
can remove the bayonet cap after
rotating it a partial turn. As you will
see a little later, removing the
bayonet cap uncovers an access hole
in the focal-plane light shield — a hole
which makes it easier to reach one of
the rangefinder retaining screws.
RELEASE BUTTON
LEICA M3 OPENING CURTAIN BRAKE ADJUSTMENT
CLOSING CURTAIN
LATCH
DRUM GEAR
FLAT
RELEASE
SPRING
Figure 7 '
OPENING CURTAIN
LATCH
RELEASE CYCLE
Leica's specifications here are that
the opening curtain should release
when you depress the release button
approximately 1.5mm. Once you let
up on the release button, the flat
release spring raises the closing
curtain latch above the closing curtain
cam. Checking the operation at
"bulb," the release button should
have an additional 0.2mm upward
travel after the closing curtain has
released. The adjustment point for
Figure 8
BODY SHELL
SCREWS
Figure 9 •
RANGEFINDER CONTROL ARM
RELEASE
ROD
REWIND
LEVER
SCREW
