6
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
A. Do not attempt to disassemble any lens components. Consult a microscope service technician when any
repairs not covered by instructions are needed.
B. Prior to cleaning any lens surface, brush dust or lint off lens surface using a camel hair brush. You can also
use an ear syringe or canned compressed air, such as that sold by most computer stores.
C. 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
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.
Using a 2mm “L” type hex key wrench, loosen rack stop socket set screw. With fine focus adjustment at
mid-range, focus on standard slide until sharp image is obtained. Rotate rack stop set screw in clockwise
direction until tight.
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 right side of microscope.
Using a 0.9mm “L” type hex key wrench, loosen the set screw located in the hole 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.
NOTE: It is recommended that you leave the tension as loose as possible for ease of focusing, yet not so
loose that it permits the stage of microscope to drift downward from its own weight and cause the
microscope to “drift” out of focus.
C. Metal parts: Use a clean, damp cloth to remove dust or dirt from metal parts, followed by a dry cloth.
