Maintenance - National 130 Instructions Manual

c. Also note that each objective has a color ring, which permits you to instruct changes in magnification by referring
to an easily observed color rather than to a number.
d. The microscope has been parfocalled at the factory, which allows easy change from one magnification to
another, requiring little or no adjustment of the fine focus knobs.
e. As magnification is increased, the field of view (area of specimen seen through the microscope) will decrease.
That is why it is easier to find the specific area of interest on the specimen by starting with the lowest 4x objective
lens, before increasing magnification with the 10x or 40x objective lens.
f. NOTE: Care must be taken when rotating the 40x objective into place. This lens has a spring retractable
mechanism which retracts slightly into its housing if the front of the lens strikes the specimen slide. With fine
focus adjustment at mid-range, the rack stop has been adjusted at the factory to assure the 40x lens will clear the
thickness of a normal specimen slide and cover slip. However, if the rack stop has been improperly adjusted, or if
using a thicker than normal slide or cover slip, moving the 40x lens too quickly or carelessly could cause damage
to the front lens element or to the slide.
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 139 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.
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.
12. Camera adaptation for models 132 and 139.
Specific instructions for adapting a video camera to your microscope are not included in this manual, as the electronic
equipment used will vary. Please consult the dealer from whom you purchased the microscope.
A video camera can be mounted on the vertical eyepiece tube, using a simple adaptor available through your dealer.
Note that when using a video camera with the microscope, focusing of the image is accomplished by turning the
microscope focusing knobs while observing the image on the TV monitor screen. Under these circumstances, the
image observed through the inclined eyepiece will not be in focus.
Generally, there are two types of adaptors used to fit the microscope to a camera. One requires removal of the
eyepiece from the vertical eyepiece tube so that the adaptor can be inserted into the tube in place of the eyepiece.
The inside diameter of the eyepiece tube is 23.18mm. To remove eyepiece, observe that between the lower edge of
the eyepiece and the knurled diopter ring there is one small screw that prevents the eyepiece from being removed.
Using a very small screwdriver, loosen this screw just enough to permit removal of eyepiece from tube. Do not
remove the three small setscrews on the knurled diopter ring.
The second type of adaptor sometimes used is one that fits over the eyepiece. This type does not require removal of
the eyepiece. The outside diameter of the eyepiece is 27.95mm.

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.
5
The primary viewer