Troubleshooting
Please use this table below for solving problems. If this table does not
offer a solution contact Valley Microscope:
Trouble
Cause
Solution
Switch on but no
light.
Plug is unreliable
Check cables
Bulb is broken
Replace bulb
Fuse is broken
Replace fuse
Bulb is flickering.
Bulb is broken
Replace bulb
Brightness of view
field is poor or
uneven.
Bulb brightness is low.
Rotate potentiometer to
increase brightness.
Objective isn’t in correct optical
path.
Rotate the objective in
correct position.
The size of aperture
diaphragm is too small.
Adjust the size of
aperture diaphragm.
Lens (objective,eyepiece,
condenser, illuminator
collector) has dust.
Clean lens
Position of condenser is too
low .
Rotate condenser up.
Image isn’t clear
(contrast or
resolution is poor).
Cover glass thickness is off-
standard.
Use required thickness
cover glass (0.17mm).
Cover glass of specimen isn’t
in up direction.
Place specimen
correctly.
Surface of objective lens is
dirty.
Clean it
Immersion oil isn’t used for
100
×
objective (oil).
Use immersion oil
There is a bubble in the
immersion oil.
Clear the bubble away
Size of aperture
diaphragm
isn’t correct.
Adjust the size of
aperture diaphragm .
Position of condenser is too
low.
Rotate condenser up.
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