on the
moin drive
col umn is
opproximotely
centered
on the
sync
pollet,
Fig.38.
NOTE:
Removing
the mqin drive
column
requires
re-
tensioning
the moinspring
on reossembly. The
correct
omount
of initiol
tension musl be
opplied
to the moin-
spring to bring
the
lrl300
second shutter
speed into time.
Since
your next lesson
describes
the methods
of testing
shutter speeds,
we'll
iust
go
through
the disossembly
ond
tensioning
procedures in this
text.
To remove
the moin drive
column,
you should first let
off the
moinspring
initiol tension. The
irick in
letting
off the initiol
tension is to
releose the
shufter
without cocking
(ond
thereby
tensioning) the moinspring.
Since you oren't
odding iension
lo
the moinspring by
cocking
the
shutter,
eoch
revolution of the
moin drive
column
lets off one
turn
of initiol tension.
Using
your screwdriver blode,
push up
on the releosed-
position lotch
--
thereby disengoging
the moin drive
column.
The moin
drive
column now
moves
from its releosed
position to
its
"reody"
position, held
by
ihe inner
releose
lever.
Next,
releose
the shutter by depressing
the
releose plunger. The morn
drive
column then runs
through its
releose cycle ond lets
off one
turn of initiol
tension.
Repeot this
procedure
untiI
lhe moinspring
connot turn the mqin
drive column
through its cycle
--thot
is, until
there isn't enough
tension left to turn
the moin drive
column.
Then,
use
your finger
to turn the moin drivecolumn in ihe
releose
direction
ond let off
ony
remoining tension. You
should now
know how mony turns of
initiol
tension
were originolly
on the
spring.
To
remove the moin drive
column, you must loosen
the two
threoded
pivots.
The
upper
pivot, on top of the mechonism,
moy
be
reoched through
theoccess
hole
in
the rongefinder bose
plote,
Fig. 48. But we'll
remove the rongef inder
ossembly
so
you
con
more
eosily
see the upper
pivot ond the
other odiustments. The
rongefinder
ossembly is
one complete
unit held
to the shutter
mechonism by
two screws.
NOTE: The
holes in the
rongefinder bose
plote
(for
the
two screws)
ore elongoted,
permitting o sliding odiustment
for the rongefinder. lf
you remove the
rongefinder, you
moy hove
to
moke
the
sliding odiustment
on reossembly
:
i
I
I
I
37
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