Test Prints; Control Panel Troubleshooting; No Control Panel Display After Power Is Turned On - Xerox Phaser 7400 Service Manual

Test Prints

Test Prints can isolate printing problems to the Engine Control or Image Processor
Board by eliminating image data transfer between the two. Test Prints does not
exercise any Image Processor Board circuitry. Test Prints gets its image data from
ROM. This allows the examination of Engine Control Board function in isolation.
Some other key features of Test Prints:
Is the only diagnostic utility to exercise the entire print cycle.
Isolated from the operating system (PostScript). Runs from firmware.
Isolates the Image Processor Board from Engine Control Board.
Helps to isolate events that cause print artifacts or prevents printing.

Control Panel Troubleshooting

No Control Panel Display after Power Is Turned On

Initial Actions:
Remove and reseat the Image Processor Board (page 8-113).
Print an engine test print.
Replace the Image Processor Board (page 8-113) (if Step 2 passes).
See "DC Power Supply Troubleshooting" on (page 4-17).
Troubleshooting Procedure Table
Step Action and Questions
1
Check for +5 V at the OPEPWR connector of
the Engine Control Board.
Is there +5 V at OPEPWR-5 <=> ground?
2 Check the Control Panel connection.
Is the Control Panel harness connected?
4-10
Yes
Go to Step 2.
Replace the
Control Panel
harness. If the
error persists,
replace the
Control Panel
(page 8-111).
Phaser 7400 Color Printer Service Manual
No
Replace the
Engine Control
Board
(page 112).
Connect the
harness.