Kowa D5300, Service Manual, Page: 36 / 44

nonmyd 8 GG-15010 Edition 1.1
35
Problem Cause Remedy
The image is
too dark.
The pupil diameter is small.
Turn Exposure compensation knob to +1 or +2 position.
If the patient’s pupil diameter equal to or smaller than that
shown by the working dots, press SP mode button and
photograph in SP mode.
The image is
out of focus
or blurred. The patient has developed a
cataract.
Avoiding the area of white turbidity during alignment may
allow you to obtain a good image.
The corneal surface is dry. Ask the patient to blink before imaging.
The lower
area become
whitened.
The eyelid or eyelashes intrude the
imaging area.
Ask the patient to open their eyes wide so that the eyelid
or eyelashes do not intrude the area of the pupil or you or
your assistant help the patient keep the eye wide open.
Flare appears on the
peripheral area.
The instrument is positioned too
close to the patient’s eye.
The instrument is positioned too far
from the patient’s eye.
Locate the camera to the position where working dots
become smallest. When flares still persist, pull or push
the camera a little.
(Working dots may be faded a little.)
Small pupil photography
（
SP mode
）
.
This is not a malfunction. Photography in small pupil
mode will cause a picture to have flare in its periphery at
a picture angle of 45°.
Patient's eye with contact lens on.
This is not a malfunction. Guide a patient to take off his
or her contact lenses from the eyes beforehand for
photographing over again.
Patient eye whose internal shape
tends to produce flare.
A picture photographed may tend to have flare
depending
on whose eye was examined. If the fundus
camera should be slightly moved backward and forward
from the position where the fundus working dots are
properly positioned, flare may disappear.
Internal diaphragm for photography
dislocated.
Please contact Kowa or your Kowa dealer.
A dark shadow appears in
the center of fundus.
Insufficient dilation.
Photograph in the small pupil mode. (Effective pupil
diameter for photography is 3.3 mm or more.)
If the pupil diameter is too small to photograph even in
the
small pupil mode, expedite a patient's pupil dilation
by making the room much darker or making longer the
dark-adaptation time in darkness.
Black spots appear of the
picture photographed.
Lowpass-filter of digital camera
contaminated with dust and dirt. Clean the lowpass-filter of a digital camera. (Refer to
"How to clean up the low-pass filter for Nikon D5300".)
White spots appear in the
center
of picture
photographed.
Lens contaminated with dust and
dirt. Clean the objective lens or the lens underneath the hole
mirror.
Focus mirror malfunctioning..
(Faulty solenoid )
Please contact Kowa or your Kowa dealer.After replacing
the focus mirror solenoid, mirror adjustment will be
needed.
White spots appear at
places off the center of the
picture photographed.
Lens contaminated with dirt.
Clean the objective lens.( Refer to " Cleaning the
objective lens ".)
Lens with scars on its surface. Replace the objective lens.
Dark shadow or bright
reflection appears at the
top or bottom of the
image.
The instrument is positioned too high
to the patient’s eye.
Perform all alignment steps to obtain a clear fundus
image with consistent brightness.
Depending on the patient’s eye fixation condition,
you may obtain a good image by locating working dots
away from the line.
The instrument is positioned too low
to the patient’s eye.
Dark shadow or bright
reflection
appears at the
left or right of the image.
The instrument is positioned too right
or left to the patient’s eye.
Perform all alignment steps to obtain a clear fundus
image with consistent brightness.
Depending on the patient’s eye fixation condition,
you
may obtain a good image by locating working dots away
from the line.
Diopter correction knob is left in a
middle position when switching. Check that Diopter correction knob is in the correct
position by slowly moving the knob to see if it cricks.