17
3.2.5 Adjusting the tension adjustment
collar
（
Fig.20
）
★
The tension of the coarse focus knob had
already adjusted before leaving factory. If it
is too loose(the mechanical stage slides
down because of its own weight), please
turn the tension adjustment collar
①
until
the tightness is appropriate. When the collar
is turned in the direction of the arrow,
tension of the coarse adjustment knob
increases. Turning the collar in the opposite
direction decreases the tension.
If the stage descends on its own or if the
specimen gets out of focus quickly even
when it is brought into focus using the fine
adjustment knob, it means the tension of the
coarse adjustment knob is too low. Turn the
collar in the direction of the arrow to
increase the tension
3.2.6
Aperture
Iris
Diaphragm
Adjustment
（
Fig.21
）
Turn the aperture iris diaphragm collar
②
to
adjust the aperture iris diaphragm. Turn the
scale mark of aperture iris diaphragm collar
to the same number as the objective
magnification.
★
The aperture iris diaphragm is designed
for the adjustment of the numerical
aperture,
not
for
the
brightness.
Generally, setting the aperture iris
diaphragm to 70- 80% of the N.A. of the
objective in use will provide an image
with good contrast. If you want to
observe the image of the aperture iris
diaphragm, remove one eyepiece and
look through the tube. You will see a dark
circle encroaching on the bottom of the
tube.
Fig.20
Fig.21
②
①
