5
g. Do not let the front lens element come into contact with a wet slide surface, as prolonged contact with any
moisture could damage the lens. If lens is exposed to moisture, promptly wipe with soft tissue to remove
moisture.
11. Diopter adjustment for models 132 and 132-CLED dual head.
These dual head models have a 30
°
inclined eyepiece to provide comfortable viewing for the primary viewer. They
also have a vertical eyepiece so that a second viewer can observe the image simultaneously. The primary viewer will
have focused the microscope using the coarse and fine focus knobs. To compensate for differences in vision
between primary and second viewer, second viewer may have to adjust image in vertical eyepiece by turning the
knurled diopter adjustment.
MAINTENANCE
WARNING: For your own safety, turn switch off and remove plug from power source before maintaining your
microscope. If the power cord is worn, cut or damaged in any way, have it replaced immediately to avoid
shock or fire hazard.
1. OPTICAL MAINTENANCE
Do not attempt to disassemble any lens components. Consult a microscope service technician when any repairs not
covered by instructions are needed.
Prior to cleaning any lens surface, brush dust or dirt off lens surfaces using a camel hair brush. Or use air to blow
dust and lint off surfaces. Use of compressed air in a can, available at any computer supply store, is a good source
of clean air.
Do not remove eyepieces or objective lenses to clean. Clean only the outer lens surface. Breath on lens to dampen
surface, then wipe with lens paper or tissue or use a cotton swab moistened with distilled water. Wipe lenses with a
circular motion, applying as little pressure as possible. Avoid wiping dry lens surface as lenses are scratched easily.
If excessive dirt or grease gets on lens surfaces, a small amount of Windex or distilled water can be used on a cotton
swab or lens tissue. To clean objective lenses, do not remove objectives from microscope. Clean front lens element
only, following same procedure.
NOTE: Fingerprints or other matter on the front lens element of the objective lens is the single most common reason
that you will have difficulty in focusing the microscope. Before having costly servicing done, or before returning to
National for “warranty repair”, make certain to examine the front lens element with a magnifying glass or eye loupe for
the presence of such contaminants. If a microscope is returned to National for warranty repair, and it is determined
that such contaminants are the problem, this is not covered under warranty and National will submit a cost estimate
for cleaning.
2. MECHANICAL MAINTENANCE
a. The rack stop screw has been pre-adjusted at the factory and should not require re-adjustment. However, if you
do attempt re-adjustment, note the following procedure.
Loosen round knurled locking nut by turning counter-clockwise. Then loosen stop screw. With fine focus
adjustment at mid-range, focus on standard slide until sharp image is obtained. Rotate rack stop screw in
clockwise direction until tight. Lock into position with the locking nut. A needle nose pliers might be needed to
loosen the round locking nut.
b. Coarse focus tension adjustment prevents the stage from drifting down from its own weight and causing the
image to move out of focus. This has been adjusted at the factory, but over the course of time it may loosen and
cause the stage of the microscope to slip downward on the focusing block.
The tension adjustment collar is located between arm and coarse focus knob on left side of microscope. With a
small jewelers screwdriver (models 131/132-CLED use supplied 0.90 “L” hex wrench), loosen the set screw
located in only one of the four holes on tension adjustment collar. Turn collar clockwise to tighten tension,
counter-clockwise to loosen tension. Use of a wide rubberband will provide a better grip on the tension adjustment
collar. After adjusting, tighten the set screw to lock collar in place.
