Service Checks; Controller Card Service Check - Lexmark E450DN - E 450dn B/W Laser Printer Service Manual

Service checks

Service checks which involve measuring voltages on the LVPS/HVPS (low voltage power supply/
high voltage power supply board) should be performed with the printer positioned on its back side.
Note: When making voltage readings, always use frame ground unless another ground is
specified. See the wiring diagram in the back of the book for more information.

Controller card service check

Controller card service check
FRU
Controller card
assembly
Warning: Do not
replace the operator
panel and controller
card at the same time.
Each card contains the
printer settings. When
either of these cards is
new, it obtains some of
the settings from the
other card. Settings
are lost when both are
new and replaced at
the same time.
Action
POST (Power-On Self Test)
Note: The printer should complete POST in approximately 30 seconds.
If the printer fails to display lights or activate the drive motor, fuser or fan, check the
following order:
1. Power to the LVPS/HVPS
2. Power from the LVPS/HVPS to the controller card
3. Cables are plugged in correctly, especially for the operator panel. The printer will not
power-up without a functioning operator panel.
4. The controller card assembly.
5. The operator panel. See
Verify +24 V dc input from the LVPS/HVPS.
1. Turn the printer off.
2. Disconnect the LVPS/HVPS cable from the controller card at J19.
3. Turn the printer on.
4. Verify +24 V dc on positions 8 and 9 of the cable connector.
5. If voltage is correct, check the continuity in the other conductors of the cable. If the cable
is good, check the connectors to the controller board.
6. Verify that pins 7 and 12 on both the cable and the card connector are grounded.
7. If grounds are not correct on the cable, but the cable posses continuity otherwise, check
the LVPS/HVPS.
8. If the grounds are not correct on the controller card, replace the controller card. (Check
with one probe on the connector pin and the other on the card's ground plane found at
each screw head.)
Controller card voltage outputs
Turn the printer off, and plug the LVPS/HVPS cable into J19 of the controller card. See the
wiring diagram at the end of the book which identifies the voltages and grounds for a good
controller card.
Turn the printer off before plugging or unplugging any connectors.
"Operator panel service check" on page
4512-630
2-21.
2-17
Diagnostics information