Check the diaphragm-control circuit by
holding open the shutter on bulb. Then
push the armature away from the core of
M1, Fig. 20, to open S7 Now short the base
o f T13 (the violet or purple wire, Fig. 201 to
the camera body. You should see the ar
mature of M2 jump away from the core.
If shorting the violet wire to ground
causes M2 to repel its armature, all of the
diaphragm-control circuit on the bottom
of the camera must be working. W hat if
M2 doesn't repel its armature in normal
operation? Apparently the comparator in
side IC1 isn’t switching low to provide the
emitter bias for T13.
Similarly, you should be able to make
the mirror-release magnet M 1 repel its ar
mature by shorting the yellow wire to
ground (the yellow wire that connects to
the base of T6, Fig. 20). Shorting the
yellow wire to ground should turn on T6.
If M1 repels its armature and releases the
Figure 21 Early style board
mirror, the mirror-release components
must be good.
If you find that there's a problem on the
lower circuit board, however, you may
run into a parts snag — there are tw o d if
ferent versions of the board, and the tw o
types w o n 't always interchange. Fig. 21
shows the early version of the board; Fig.
22 shows the modified version.
W hether or not you can install the later
version in an earlier camera depends on
the flex circuit. You must then identify
the flex circuit. Alternately, you may have
to replace the complete flex circuit and
the lower circuit board as a unit. You'll be
able to identify the flex circuit after you
remove the top cover.
REMOVING THE TOP COVER
Unscrew the w ind-lever retaining
screw. Then disconnect the end of the
wind-lever return spring, Fig. 23, as you
lift o ff the wind lever. Also unscrew the
top-cover retaining ring around the wind
shaft. Fig. 24.
Next unscrew the retaining ring that
holds the speed knob. Fig. 24. Although
we used the bulb setting as a reference in
Fig. 24, the actual shutter-speed and film-
speed settings aren't im portant for
disassembly. Remove the speed knob and
note the loose release pin. The release pin
closes the switches for the metering and
release functions.
You can completely remove the camera
back by depressing the hinge pin. Then
unscrew the rewind knob. Remove the
film-speed dial by unscrewing its retaining
ring and take out the parts indicated in
Fig. 25 — the detent plate, the black
plastic decorator ring, the brass bushing,
and the exposure-compensation lever.
Finally, remove the top-cover screws.
Two of the top-cover screws also hold the
diaphragm-window plate, Fig. 26. If you
wish, you can remove the front decorator
plate. Fig. 26, after you take off the
diaphragm-window plate. However, unless
you know you're going to remove the front-
plate/mirror-cage assembly, you can leave
the front decorator plate installed.
Before lifting off the top cover, push
down the eyepiece-blind lever, Fig. 27.
The eyepiece blind then covers the
eyelens. This precaution prevents the
other end of the eyepiece-blind lever from
catching the flex circuit as you lift off the
top cover.
REPLACING THE TOP COVER
W hen you replace the top cover, the
mode selector, Fig. 24, must key to the
mode switch, Fig. 28. Fig. 28 shows the
mode switch set for manual shutter
speeds — the " M " position. To set
automatic shutter speeds, move the
mode switch to the center position; move
the mode switch all the way in a
c o u n te rc lo c k w is e d ire c tio n to set
automatic diaphragm openings.
Normally, you'll find that the mode
selector keys most easily at the " S " set
ting. Set the mode selector in the top
cover to " S . " Then turn the mode switch.
Fig. 28, all the way in a counterclockwise
direction. A fter seating the top cover,
check to see that the viewfinder scale
switches from the diaphragm calibrations
to the shutter-speed calibrations when
you move the mode selector to " A . ”
Also, w ith the top cover removed, the
film-advance indicator, Fig. 28, tends to
sneak under the counter dial. Tightening
the retaining ring around the wind shaft.
Fig. 24, then binds both the counter dial
and the film-advance indicator.
The film-advance indicator only moves
when there's film in the camera. As the
B L A C K
PURPLE OR VIO LET
Figure 22 M odified board
