Xerox 7300B - Phaser Color Laser Printer Service Manual page 78

[Yellow] [Magenta] [Cyan] [Black] Imaging Unit
Failure
U26: Yellow U27:
Troubleshooting Procedure Table
Steps Actions and Questions
1 Is the Imaging Unit installed and seated
properly?
2 Visually inspect the Imaging Unit Drum
Contact Assembly and springs.
Are the contacts damaged or dirty?
3 Use service diagnostics to test the CMYK
IU Sensor.
Does the sensor function correctly?
4 Verify continuity between the IU Sensor
Board and the Engine Controller Board at
the JODEN connector.
Y pin 9 to pin 12
M pin 1 to pin 3
C pin 5 to pin 6
K pin 10 to pin 13
5 Check the wiring harness.
Is the wiring harness defective?
6 Use service diagnostics to check the IU
Up/Down motor.
Is the Transfer Unit functioning properly
by lifting the Imaging Unit?
7 Visually inspect the Transfer Unit gears
and lifting arm.
See "Transfer Unit Arm and Gear
Up/Down Movement of the Imaging Units"
on page 8-232.
The gears should lift the arm when
rotated in one direction and stop rotating.
Does the gear stop rotating when the arm
is in the raised position?
8 Check the appropriate fuse on the Engine
Controller Board to see if it is blown.
Cyan = F5
Magenta = F2
Yellow = F3
Black = F4
2-62
Magenta U28: Cyan U29: Black
Yes
Go to step [2].
Replace the IU
Drum Contact
Assembly.
Go to step [6}
Replace the
Engine Controller
Board.
Replace the wiring
harness
Go to step [11].
Go to step [8].
Go to step [10].
Phaser 7300 Color Printer Service Manual
No
Reseat the
imaging unit.
Go to step [3].
Go to step [4].
Go to step [5].
Replace the Back
Plate Assembly.
Go to step [7].
Replace the
Transfer Unit.
Go to step [9].