Whole Uneven Density - Minolta CF910 Service Manual

(11) Whole Uneven Density

<Troubleshooting Procedure>
Cause Step
Defective IR 1
2
Defective PH 3
Defective 4
Developing
Unit
5
Defective PC 6
Drum
Defective PC 7
Drum Charge
Corona
Defective 8
Cleaning Unit
Defective 9
Image Trans-
fer Corona
10
11
Defective 12
Paper Sepa-
rator/ Charge
13
Neutralizing
Unit
Defective 14
Brush Section
Defective 15
Paper Take-
Up/Transport
Unit
Check Item
Are the connectors on PWB-A,
-B, and -C connected properly?
Is the source voltage being
supplied?
Is the window of the PH Lower
Unit dirty?
Is the Developing bias being
output properly?
If the problem persists even after these steps from 1 through 4, the
PH Unit is probably contaminated. Change the PH Upper and Lower
Assy.
("IR Area," "PRT Area," and "Gradation Adjust")
Is the PC Drum grounded
properly?
Are the Corona Wire and
Meshes dirty or deteriorated?
Is the Toner Antispill Seal
warped or deteriorated?
Is the Image Transfer Corona
dirty or deteriorated?
Is the Image Transfer Charge
being output properly?
Is the backup adjustment value
proper?
Is the Charge Neutralizing
Corona dirty or deteriorated?
Is the HV2 output proper?
Is the Retrieving Roller dirty?
Is the Paper in the Drawer
damp?
T-71
Result Action
NO Reconnect the connectors.
NO Change PU4.
YES Clean the window.
("Gradation Adjust")
NO Check the wiring between
PWB-I and HV4. If it is
intact, replace HV4.
NO Ground the PC Drum prop-
erly.
YES Clean or change the
Corona Wire and Meshes.
YES Change the Toner Antispill
Seal.
YES Clean or change the Image
Transfer Corona.
NO Referring to
DIS/REASSEMBLY,
ADJUSTMENT, readjust the
Charge Output.
NO Referring to
DIS/REASSEMBLY,
ADJUSTMENT, reaffix.
YES Clean or change the
corona.
NO Check the connection of the
connector on the board,
and if it is proper, change
HV2.
YES Clean the Roller.
YES A. Check if the Dehumidi-
fying Heater is malfunc-
tioning.
B. Check if the Paper
Dehumidifying switch is
on.