User Guide
120
Series
T
roubleshooting
20
Common Issues (Continued) 
Symptom  Cause  Remedy 
OPTICAL ISSUES
The color of the image is
not accurate 
The brightness adjustment knob is not in the right position  Adjust the brightness knob to a higher or lower setting for color
clarity 
No filter is used or filter is in use  Remove color filter if natural light is desired, or insert desired
filter 
(Trinocular Only) 
I cannot see anything in the
camera / Image is black 
The trinocular port shutter of the microscope is not open  Slide the silver metal pin out on the head of the microscope
to allow light to reach the trinocular port 
MECHANICAL ISSUES
The objective touches the
cover slip 
The cover slip is not standard sized  Replace the cover slip with the appropriate 0.17mm thickness slip 
The limit-stop is set too high or not engaged  Be careful to avoid contact between objective and the slide when
the limit stop is up (unless using the 100x objective with oil). To
reengage, focus the sample, then lock the limit stop into place at
the stage height to set max height at a safe but usable distance. 
Unable to move the slide
smoothly 
The slide is not secured correctly  Adjust the slide to use the stage clips and secure the sample 
The mechanical stage is not properly secured  Tighten the mechanical stage screws to better secure the stage 
Focus knob does not turn 
The tension knob is too tight  Loosen  it  by adjusting the  tension  ring  inside  the coarse  focus
knob counterclockwise (close  to  the arm of  the microscope on
the left of the microscope) 
Stage declines by itself 
The tension knob is too lose  Tighten it by adjusting the tension  ring  inside the coarse  focus
knob clockwise  (close to the arm of the microscope on the left
of the microscope) 
The coarse focusing knob
won’t raise the stage 
Limit-stop is engaged  Disengage the limit stop (move up) on the read of the stage of the
microscope inside the coarse focusing knob 
The fine focusing knob
won’t raise the stage 
Limit-stop is engaged  Disengage the limit stop (move up) on the read of the stage of the
microscope inside the coarse focusing knob 
ELECTRICAL ISSUES
The bulb/light source
flickers 
The bulb is close to burning out  The  unit’s  LED  bulb  should  not  burn  out.  The  bulb  is not  the
issue. Please contact customer service for  warranty repair infor-
mation. 
The microscope does not
light up 
The microscope is unplugged  Insert the plug into the wall socket to achieve electrical illumina-
tion 
The bulb burned out
  The  unit’s  LED  bulb  should  not  burn  out.  The  bulb  is not  the
issue. Please contact customer service for  warranty repair infor-
mation. 
The fuse burned out  Replace with fuse on the bottom of the microscope 
The fuse burns out fre-
quently 
The voltage is too high  Use the correct  power  supply  (110v if 110v unit, 220v if 220v
unit), or get a voltage adapter to convert to the proper electrical
system 
The bulb burns out fre-
quently 
The voltage is too high  Use the correct  power  supply  (110v if 110v unit, 220v if 220v
unit), or get a voltage adapter to convert to the proper electrical
system 










