Minolta XD - Page 20

17
9. Description of Circuit
9-1.
Operation
of
circuit
(Refer
to
Circuit
block
diagram
on
Page.
22)
1)
When
winding
is
completed,
Si
(exposure
prevention
SW.
and
release
switch
when
auto
winder
is
used)
is
ON.
When
camera
is
loaded
with
battery,
condenser
Ce
for
magnetic
release
magnet
(Mi)
and
condenser
C;
for
diaphragm
stop
magnet
(M2)
are
charged.
2)
When
Ss
(main
SW.)
is
turned
on
by
pushing
shutter
button,
T;
is
turned
on.
Then
indication
circuit,
metering
film
speed
operational
circuit,
aperture
control
circuit,
speed
control
circuit
and
magnetic
release
block
circuit
are
operated,
and
exposure
information
is
indicated
in
the
finder.
.
The
operation
of
indication
control
circuit
is
explained
in
the
following.
[1] Operation in S mode:
(Indication mode switch S13 is at S)
©®
Information
of
operational
circuit
of
scene
brightness
(BV)
which
SPC
receives
and
film
speed
(SV):
a,
information
of
aperture
setvalue
by
MC
ring:
b,
information
of
minimum
aperture
value
by
MD
coupler:
d,
information
of
shutter
speed
setting
(via
LED
flicker
prevention
circuit
against
fluorescent
light)
:
e.
These
are
sent
to
indication
circuit
and
the
appropriate
aperture
is
indicated
by
LED.
@
Over-range
warning
is
given
by
information
b
and
e.
When
standard
lens
(F
1.4/50
mm)
is
mounted,
over-range
warning
(A)
is
lighted
over
£16,
indicating
that
shutter
is
released
at
higher
shutter
speed
than
the
set
speed.
@
Under-range
warning
is
given
by
information
d
and
e.
Under-range
warning
(VY)
is
lighted
below
f1.4,
indicating
that
shutter
is
released
at
lower
shutter
speed
than
the
set speed.
@
The
exposures
in
@
and
@
are
appropriate
if
the
brightness
of
the
scene
is
within
the
control range of the camera.
©
When
the
aperture
is
not
set
at
minimum
with
MD
lens
mounted,
or
when
MC
lens
or
old
type
lens
is
used,
information
d
is
not
obtained
(MD
coupler
does
not
operate),
and
therefore,
LED
for
appropriate
aperture
value
indication
is
not
lighted,
and
only
over-
range
(A)
and
under-range
warning
(Y)
for
set
shutter
speed
are
indicated.
©
When
shutter
speed
dial
is
set
at
X,
B,
O,
information
e
becomes
nearly
earthed.
At
that
time,
information
a
and
b
become
nearly
power
source
voltage
by
the
function
of
circuit
not
shown.
Therefore,
over-range
warning
(A)
is
lighted.
@
When
exclusive
strobo
is
mounted,
on
completion
of
its
charge,
information
e
is
nearly
earthed
by
signal
p
via
Tio,
while
information
a
and
b
become
nearly
power
source
voltage,
therefore
over-range
warning
(A)
is
light
and
at
the
same
time,
the
indication
is
turned
on
and
off
by
signal
q.
(2) Operation in A and M modes:
(Indication mode switch Sj3 is at M, A.)
@®
Information
of
aperture
set-value
by
MC
ring
containing
information
BV
and
SV
in
indication
circuit:
b,
and
information
e
that
shutter
speed
is
kept
at
1/1000
sec.
by
Sj;
irrespective
of
the
shutter
speed
dial
position
(1~1/1000)
is
given,
and
appropriate
shutter
speed
for
the
set
aperture
value
is
indicated
by
LED.
@
When
shutter
speed
dial
is
set
at
X,
B,
O,
and
when
exclusive
strobo
is
used,
the
indication
is
the
same
as
in
S
mode.
3) When S3 (magnetic release switch) is turned ON by pushing shutter button, magnetic
release lock circuit input (f) is earthed, and condenser C. for magnetic release magnet
is discharged through T,, then power is supplied to magnet (M,) and release lever held
by permanent magnet is released and then body side preset starts operating and S; is
turned OFF.