but not touch, the slide. Repeat
this with the 100x objective, if your microscope has one. the
100x objective must all but touch the slide. To adjust the
stop, first loosen the lock nut. Then move the thumbscrew in
to increase the distance between the slide and the objective lens
and out to decrease the distance between the slide and the
objective. Adjust the stop as needed and tighten the lock nut
to
hold it in place. Check the
position by focusing on the slide. Make sure you can bring the
slide into focus on the highest power objective, and then move just
past the focal point so you know you can accommodate the thinner slides than the one you're testing. If you're checking
many microscopes, you will to tell just by looking at the very small
space between the slide and the objective when the stop is set
correctly.
Following are some common problems encountered
in microscopy and some ways to correct them. If you use
the following techniques and still experience the problem,
please call our Customer Service Department at 800-828-7777.
Coarse focus knob won't change focus
1. Check and adjust tension (#2 in the Annual
Preparation section).
2. Push gently on stage or body tube to loosen
grease.
Fine focus knob won't change focus
Move fine focus both ways through its range.
If it will move the stage or objective up but not down, the
problem may be that the grease has stiffened. Move the
fine focus mechanism until it is all the way down, then gently
push the stage or body tube down. Repeat about three
times.
Focus moves, but one or more objectives will
not come into focus
1. Check and adjust stop (#3 in the Annual
Preparation section).
2. Check to make sure objectives are all the
way in (#1 in the Annual Preparation section).
3. Check to make sure the retraction device is
working on 40x and 100x objectives. You should be able to
push the metal housing at the top of the objective and have the
tip move up about 2 mm. When you let go, the tip should
return to its original position. If it does not, the
objective must be repaired or replaced.
4. If either the 40x or the 100x objectives
produce a fuzzy image, they may be dirty. Try removing the
objective from the nosepiece and
inspecting the small lens. You may want
to use a hand lens (or remove the eyepiece and use it as a hand
lens, look through it from the bottom and hold it and the
objective close to your eye) to check. If water or oil has
been allowed to contact the 40x objective, there may be dirt
between the lenses. The lens will have to be disassembled
to be cleaned.
Image "drifts" out of focus during viewing
Adjust tension (see #2 in the Annual
Preparation section).
There is dirt in the field of view, but you
can't locate it
1. Move the slide to make sure the dirt isn't
on the specimen slide.
2. Spin the eyepiece. If the dirt moves
it is on the eyepiece.
3. You may only see the dirt through one
objective. To check if the objective is the source,
carefully loosen the objective, and just begin to unscrew it to
see if the dirt moves. You may see dirt on one objective
because the magnification is high enough or the field of view is
large enough to show it, but the dirt may not be on the
objective.
4. If you have a focusable Abbe condenser, move
it.
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