11
Trouble
Causation
Remedy
Switch on but bulb dark
Plug is unreliable
Plug in again
Bulb is broken
Change bulb
Fuse is broken
Change fuse
Bulb is flickering or
brightness is unsteady
Bulb is unstable
Insert it again
Bulb is broken
Replacing bulb
Brightness of view field
isn’t enough or is
uneven
Bulb specification doesn’t
meet the requirement
Replacing bulb
Brightness isn’t adjusted
correctly
Adjust rotation
potentiometer
Objective isn’t in correct
position
Make the objective in
correct position
The size of iris aperture is too
small
Adjust the size of iris
aperture
Lens (objective, eyepiece,
condenser, light collector) has
dust
Clean it
Position of condenser is too
low
Higher condenser
Image isn’t clear
Cover glass of specimen
doesn’t meet the requirement
Use required thickness
cover glass (0.17mm)
Cover glass of specimen isn’t
in up direction
Place specimen correctly
