21
Eye strain or fatigue
Check Interpupillary distance
Check Diopter adjustment
Field of view of left and right eyepiece differ
Inadequate illumination
2. Electrical
Lamp does not light
Power supply not plugged in
Lamp not installed
Lamp burnt out
Inadequate brightness
Specified lamp not being used
Bulb blows out immediately
Specified lamp not being used
Light flickers
Connectors are not securely connected
Lamp near end of service life
Lamp not securely plugged into socket