Minolta CF910 Service Manual page 437

<Troubleshooting Procedure>
Cause Step
Defective 8
Developing
Unit
9
10
11
Defective 12
Developing
Unit
Defective PC 13
Drum
Defective 14
Image Trans-
fer Corona
15
Defective 16
Paper Sepa-
rator/ Charge
Neutralizing
Unit
Check Item
Is the inside of the Developing
Unit plugged with foreign mat-
ter or toner?
Is the Toner Replenishing
Shutter clogged with foreign
matter?
Is the developing bias being
output properly?
Does each color Toner Replen-
ishing Motor turn?
Is the Magnet Roller position of
the Carrier Retrieving Assy
correct?
Or, Does the Carrier stick on
the Magnet Roller?
Is the surface of the PC Drum
dirty or scratched?
Is the Image Transfer Corona
dirty or deteriorated?
Is the Image Transfer Corona
output proper?
Is the HV2 output proper?
T-70
Result Action
YES Remove the foreign mat-
ter. If the problem recurs,
change the developer.
("Developer" and "Grada-
tion Adjust")
YES Remove the foreign matter.
NO Check the wiring between
PWB-I and HV4 and, if it is
intact, change HV4.
NO C. Check the wiring
between PWB-I and
Motor.
D. Check the motor drive
for possible overload,
change Motor.
YES • Readjust the Carrier
Retrieving Magnet Roller
Position by Jig.
• Clean the surface of the
Carrier Retrieving Mag-
net Roller with sand
paper.
• Clean the inside of the
Carrier Retrieving Assy.
YES Change the PC Drum.
Change the Cleaning Blade
as a set if necessary.
("AIDC Mode/AIDC Offset"
and "Gradation Adjust")
YES Clean or change the Image
Transfer Corona.
NO Referring to
DIS/REASSEMBLY,
ADJUSTMENT, readjust
the Image Transfer Corona
output.
NO Check the connection of
the connector on the board,
and if it is proper, change
HV2.