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1st August, 1994
Symptom: Dirty background all over the copy
Check
1. Make a printer test (see
section 4-1-13). Is it OK?
2. Try the following steps (a to f) to solve the problem. If they fail, go to step 3.
a) Clean the quenching lamp and cleaning blade.
b) Tighten the toner metering blade securing screws (see section 5-6-2).
c) If the toner contains dust or paper particles, change the CTM.
d) Clean the area around the bias terminal of the development unit.
e) If the pattern is constant down the page, clean the laser optics with a blower brush, or
clean or replace the corona wires.
3. Is the master grounded
properly?
4. Is the varistor shorted?
5. Does the development
bias terminal give a
constant correct voltage
(about -530 Vdc)?
6. Does the FCU output
constant power and bias
trigger signals to the
power pack?
7. Does the problem go
away if you change the
power pack?
8. Are the charge corona
unit and wire correctly
installed?
9. Does the FCU output
constant power and
corona trigger signals to
the power pack?
10. Does the problem go
away if you change the
power pack?
11. Does the quenching lamp
operate correctly?
12. Does the FCU send
constant power and drive
signals to the lamp?
13. Try replacing the master unit.
14. Clean the scanner optics, exposure glass, and white plate.
Check the SBU white waveform for peaks, dropouts, or noise in the signal. Change the
SBU or FCU if such wave patterns are present.
Adjust the RAM addresses containing contrast threshold levels.
COPY QUALITY TROUBLESHOOTING
Action if Yes
There may be a scanner
problem; go to step 13.
Go to step 4.
Change the varistor.
Go to step 8.
Clean the area around the
bias terminal. Go to step 7.
Finished.
Check the connections
between the corona wire
and the FCU. Go to step 9.
Clean the charge corona
unit. Go to step 10.
Finished.
Go to step 13.
Replace the quenching
lamp.
6-4
TROUBLESHOOTING
Action if No
Go to step 2.
Check the grounding wire,
terminals and plates. Clean
or replace if necessary.
Go to step 5.
Go to step 6. Do not adjust
the variable resistors on the
power pack.
Change the FCU.
Go to step 8.
Correct the problem.
Change the FCU.
Go to step 11.
Check the connections
between the FCU and lamp.
Go to step 12.
Replace the FCU.
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Troubleshooting
