Brother HL-820 Service Manual page 78

I-8 Black vertical streaks (in a gray background)
Possible cause Step
Translucent 1
stain on the
scanner window
I-9 White vertical streaks
Possible cause Step
Scanner window 1
dirty
Transfer failure 2
I-10 Faulty registration
Possible cause Step
Excessive paper 1
load
Print paper 2
Ditto 3
Paper resist 4
sensor position
incorrect
Check
Are there any stains on the
scanner window?
Check
Is the scanner window dirty?
Is the transfer roller scratched?
Check
Is the paper loaded in the
paper feeder more than 22mm
deep?
Is the specified weight of the
recommended paper being
used?
Is the first printing position
within ±1mm of the tolerance
specification?
Is the position of the paper
resist sensor normal?
IV-11
Result Remedy
Yes Clean the scanner window.
If it is not effective, replace the
scanner unit.
Result Remedy
Yes Clean the scanner window with
a dry tissue.
Yes Replace the drum unit.
Result Remedy
Yes Instruct the user to keep paper
loads below 22mm in depth.
No Instruct the user to use the
recommended types of paper.
Yes Adjust the Y offset by using the
utility software supplied.
No Reposition the sensor to the
correct position.