Mechanical Maintenance - National 106 Instructions Manual

Elementary compound microscopes
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into proper position under the hole in center of stage. If aperture is not properly positioned, you will observe shadows in
the field of view when looking through the microscope.
M. Changing magnification
1.
Note that each of the three objectives have a different color ring. This permits the teacher to instruct the class to
switch magnifications by referring to the color of the ring.
2.
Total magnification obtained with each objective lens is determined by multiplying the magnification of the eyepiece
times the magnification of the objective. Keep in mind that as magnification is increased, field of view (area of the
specimen seen when looking through the microscope) decreases.
magnifications at most times. Always use the lowest magnification (4x objective) when first focusing on a new
specimen slide, as this low magnification provides the biggest field of view, there by making it easier to find and
position the specimen within the field of view.
10x eyepiece x 4x objective = 40 times mag. (biggest field of view), red color code ring
10x eyepiece x 10x objective = 100 times mag. (smaller field of view), yellow color code ring
10x eyepiece x 40x objective = 400 times mag. (smallest field of view), blue color code ring
3.
To change magnification:
a.
Rotate revolving nosepiece to position 10x objective into optical path. Some slight adjustment of focusing knob
may be required.
b.
Rotate revolving nosepiece to position 40x objective into optical path. Some slight adjustment of focusing knob
may be required.
4.
Note: Take care when rotating 40x objective into place. This is the longest lens and has a spring retractable
mechanism, which retracts slightly into its housing if the front of the lens comes in contact with the specimen slide
while focusing the microscope. This prevents damage to the lens or slide.
MAINTENANCE
WARNING: For your own safety, when servicing models with electric and LED illuminators, turn switch to OFF
position and remove plug from power source before maintaining microscope. If the power cord is worn, cut or
damaged in anyway, have it replaced at once to avoid shock or fire hazard.
OPTICAL MAINTENANCE
A.
Do not attempt to disassemble any lens components. Consult an expert technical service company when repairs not
covered by these instructions are needed.
B.
Prior to cleaning any lens surface, brush dirt and lint off lens surface with camel hair brush or compressed air. Use of air
in a can, available at most computer stores, is good source of clean air.
C. Do not remove eyepiece lens or objective lenses from microscope. Clean only the outer lens surface by breathing on
lens to dampen surface, then wipe with lens paper or cotton swab. Avoid wiping lens surface while dry, as lenses are
scratched very easily.

MECHANICAL MAINTENANCE

A.
Rack stop adjustment: Rack stop has been pre-adjusted at the factory, and should not require readjustment.
B.
Coarse focus tension adjustment: This adjustment prevents the body tube from drifting down on its own weight and
causing the image to move out to focus during viewing.
1.
Tension adjustment collar is located between arm and coarse focus knob on left side of microscope.
2.
With a small jeweler's screwdriver, loosen the set screw located in one of the four holes located on tension
adjustment collar.
You will find that you use the lower
5

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