Xerox Phaser 7400

Print-Quality Troubleshooting 5-9
3
Perform the Light and Darkness Color
Balance Procedure.
Did this correct the problem?
Complete. Go to Step 4.
4
Remove the Imaging Units and
Transfer Unit and check for toner
contamination on the high voltage
contacts.
Clean the contacts. Go to Step 5.
5
Are the LED Heads dirty?
Clean the heads with a clean, lint-free
cloth.
Did this correct the problem?
Complete. Go to Step 6.
6
Are the harnesses on the LED Heads
undamaged, properly routed and
seated?
Go to Step 7. Replace or reseat the
wiring harness.
7
Is +5 V supplied to each LED Head? Go to Step 9. Go to Step 8.
8
Is +5 V supplied to the POWER
connector on the Imaging Unit Sensor
Board?
Replace the
Imaging Unit Sensor
Board (
page 8-142).
Replace the LVPS
(
page 8-121).
9
Is +24 V supplied to the POWER
connector on the Engine Control
Board?
Go to Step 10. Replace the LVPS or
wiring harness.
10
Is +24 V supplied to the HVOLT
connector on the Engine Control
Board.
Go to Step 11. Replace the Engine
Control Board
(
page 8-112).
11
Inspect the high-voltage wiring
harness.
Replace defective
wiring harness.
Replace the Transfer
Unit. If the error
persists, replace the
HVPS (
page 8-119).
Troubleshooting Procedure Table (Continued)
Step Actions and Questions Yes No