Lexmark E 450 Dn Service Manual

							Diagnostics information2-25
4512-630
Black page
Note:  Incorrect laser exposure or incorrect charging of the photoconductor causes an all black page. Always 
verify the same results from a different print cartridge assembly and developer before proceeding.
Heavy background
Poor development or poorly charged toner particles cause excessive background. This is more noticeable as the 
toner cartridge nears end-of-life. FRU Action
Toner electrodes (not a 
FRU)Check the three rearward electrodes below the print cartridge assembly for contamination 
or damage. Correct as necessary. 
Check continuity between the cable (DEV, TAR, and doctor blade) connection PCN3 and on 
the contact tips below the print cartridge assembly.
• If continuity fails, call the next level of service.
LVPS/HVPS board
Controller card
Miscellaneous cablesWith the printer off, disconnect the LVPS/HVPS cable from J19 on the controller card. 
Turn the printer on, and verify +24 V dc on pins 8 and 9 of the cable. 
Verify ground on pins 7, 12, and 14. 
• If the voltage is incorrect, replace LVPS/HVPS board.
• If grounds are incorrect, check ground paths.
• Check confinuity in the cable. Replace the cable if necessary.
• If voltage is correct and the toner electrodes are good, replace the controller card. 
• See the “LVPS/HVPS service check” on page 2-20 and the “Controller card service 
check” on page 2-17, if necessary.
FRU Action
Toner cartridge (not a 
FRU)
PC Kit (not a FRU)Check the toner darkness setting in the driver. Try a lower setting.
Make sure the toner cartridge and PC Kit are correctly installed and the high voltage 
contacts are clean. 
If the toner cartridge and PC Kit are installed correctly, try a new PC Kit first and then toner 
cartridge.
LVPS/HVPS 
Controller cardCheck the contacts for correct installation and contamination where contact is made 
between the print cartridge assembly and spring contacts which connect to the LVPS/HVPS 
board at PCN3. Clean as necessary. 
If this does not correct the problem, replace the following FRUs one at a time in the order 
shown:
• LVPS/HVPS board (See “Black page” on page 2-25 for pin values.)
• Controller card  
						

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Partial blank image/white spots (no repeating pattern) 
Variation in image density horizontally across page 
Poor fusing of image 
FRU Action
Toner cartridge (not a 
FRU) Remove the toner cartridge assembly, and gently shake the assembly to evenly distribute 
the toner. 
Check to make sure that the laser light path is not blocked.
If toner cartridge is low, try a new one.
Paper (not a FRU) Make sure recommended media is being used.
Check the media settings in the printer driver. A heavier media may require higher heat to 
properly fuse.
FRU Action
PC Kit (not a FRU) The charge roll may have an unbalanced force against the PC (photoconductor) drum. 
Try a new PC Kit.
Transfer roll Note: Do not touch the transfer roll except at its ends. Place a sheet of paper over the roll to 
prevent damage from finger oils or hand lotion.
Check the springs in the left and right transfer roll bearings. The bearing assemblies should 
support the transfer roll, applying evenly distributed forces to the PC drum. 
Replace the transfer roll assembly if the springs or bearings show signs of damage or 
fatigue. 
Inspect the transfer roll for signs of wear, damage or contamination. 
Replace as necessary.
FRU Action
Fuser  The fuser may not be operating at the proper temperature to fuse the toner to the media. 
See“LVPS/HVPS service check” on page 2-20 for more information. Try changing the 
setting to heavier media or even card stock.
Media (not a FRU) Make sure recommended media is being used.
Check the media settings in the printer driver. 
						

							Diagnostics information2-27
4512-630
Light print 
White or black lines or bands 
Toner on back of page 
FRU Action
Toner cartridge (not a 
FRU)Make sure the toner cartridge and PC Kit are installed correctly and that the toner cartridge 
is not low on toner. 
If the problem continues, install a new toner cartridge.
Recheck condition before replacing PC Kit, if necessary. 
Transfer roll 
LVPS/HVPS card Check the transfer roll for signs of toner buildup and contamination.
Inspect the HVPS contact (transfer roll) for contamination. 
Verify the high voltage cable is plugged into the LVPS/HVPS.
If all components appear free of contamination, replace the following FRUs one at a time in 
the order shown: 
• Transfer roll
• LVPS/HVPS card
FRU Action
Print cartridge 
assembly (not a FRU)
Developer drive 
coupling assembly
Main gear driveBanding appears as light or dark horizontal lines on a uniformly gray page or on a page with 
a large area of graphics. Banding is primarily due to a variation in the speed of the media as 
it feeds through the printer, especially in the developer and transfer process. It may also be 
a result of overly dry or moist environments.
With the printer off, check to make sure that the laser beam is not blocked.
Inspect the toner cartridge and paper feed components, especially the drive coupler and 
drive gears for debris, binds, or damage.
FRU Action
PC Kit (not a FRU) Print a menu page found under Utilities, and check settings for media type.
Inspect the overall paper path for signs of spilled toner. 
Gently clean the contaminated areas with a soft cloth.
Fuser Inspect the fuser for signs of contamination. 
Replace the fuser as necessary.
Transfer roll A transfer roll contaminated with toner can cause toner to transfer to the back of pages. 
Inspect the transfer roll for contamination, and replace as necessary. 
						

							2-28Service Manual 4512-630
Solving print quality problems
Note:  Refer to the print defects guide at the end of the manual for repeating defects.
Print quality problems
Problem Cause / action
Light or blurred 
characters. Light print
See “Light print” on page 2-27.
The toner cartridge may be getting low on toner: 
• Remove the toner cartridge and print cartridge assembly. 
• Shake it from side to side to redistribute the toner. 
• Reinstall it and recheck for condition.
• Make sure to use the recommended print media (see media types and sizes in the 
User’s Reference).
• Use MarkVision
TM to define the custom type setting for media type, media texture, or 
media weight.
• The toner cartridge or PC Kit may be defective. Replace the PC Kit first and recheck.
Blurred characters 
Blurred images, including characters, are usually caused by a defective printhead.
Vertical white lines
See “Vertical streaks below.
Vertical white lines may be caused by the laser beam, which may be partially blocked. With 
the printer off, clear the path or clean the lens. The toner cartridge or fuser may be 
defective. Try a different toner cartridge. Inspect the fuser at its entry for debris. 
Toner smudges appear 
on the front or back of 
the page.• Make sure the media is straight and unwrinkled.
• Replace the PC Kit and recheck before replacing the toner cartridge. See “Toner on 
back of page” on page 2-27 for more information. 
Vertical or horizontal 
streaks appear on the 
page.Vertical streaks
Something could be caught between the PC kit and the fuser. Check the paper path around 
the fuser entry. Try a different toner cartridge.
Vertical white lines may be caused by the laser beam which may be partially blocked. With 
the printer off, clear the path or clean the lens. The toner cartridge or fuser may be 
defective. Try a different toner cartridge. Inspect the fuser at its entry for debris. 
Horizontal streaks
The toner cartridge or the fuser may be the cause due to excessive page count or defect. 
Replace as needed.
If the lines are parallel and match the two intended ghost images, the Form Type may be 
incorrectly set. Check those settings.
The PC cleaner sump may be full. Replace the PC kit. 
						

							Diagnostics information2-29
4512-630
Toner smears or rubs 
off the page. • Toner is not being fused to the media. Replace the fuser.
• Change the media texture setting in the driver. If special media is being used, such as 
card stock or labels, be sure to select the correct media type.
• Try a different kind of media. Media designed for copiers gives the best quality fusing. 
The print is getting 
light, but the printer 
has not indicated it is 
low on toner. • Toner is becoming low in the cartridge.
• The Toner Low message does not display if the 1,500 page toner cartridge is installed.
• Remove the toner cartridge, and gently shake it from side to side to redistribute the 
toner.
• Replace the toner cartridge.
The Toner Low 
message displays.• Remove the toner cartridge, and gently shake it from side to side to redistribute the 
toner. 
• Replace the toner cartridge.
Solid black areas on 
transparencies• There is a mismatch in the transparency and what the software is expecting.
• Choose a different fill pattern in the software program.
• Remove the toner cartridge, and gently shake it from side to side to redistribute the 
toner.
• Try a different type of transparency.
• Replace the toner cartridge.
Faint images or 
repetitive spots appear 
on the page.• Select a different media type or form type setting from the printer driver.
• Try a different type of media. Media designed for copiers gives the best quality.
• Replace the toner cartridge.
Pages are blank.  • The print cartridge may be out of toner or defective. Replace the cartridge.
• There may be a software error. Re-initialize the printer by turning it off and back on.
• With the printer off, check the printhead beam path. If clear, check for a printhead error 
on POR. See “Printhead service check” on page 2-31. Print quality problems (Continued)
Problem Cause / action 
						

							2-30Service Manual 4512-630
The printer is on and 
indicates ready, but 
nothing prints. • Make sure the parallel or USB cable is not damaged and is firmly plugged into the 
connector on the back of the printer.
• Make sure the toner cartridge assembly is installed properly.
• Print the menu page found under Utilities.
- If a menu settings page cannot be printed, contact the next level of support.
- If a menu settings page can be printed, the problem is one of the following:
•Computer 
•Software program 
•Cable
•(USB only) A failed controller card. Replace card.
Note: Test by unplugging USB and plugging it with the printer on. If the computer indicates 
“unknown device,” replace the controller card.
Toner Low light is on 
and printing stops. If a 3.5K or more page toner cartridge is being used and the Toner Low alarm is set to on, 
the printer stops printing until the toner cartridge is replaced.
The Error light alone is 
on.Make sure the printer front cover is closed. 
The Toner Low light is 
blinking, and the Error 
light is on.• Make sure the toner cartridge is installed correctly. 
• Install a new toner cartridge.
The media skews or 
buckles.• Tray is overfilled or media is too loose.
• Don’t overfill Tray 1 or the optional Tray 2 (see media capacities in the media types and 
sizes table in the User’s Guide).
• Make sure the paper guides are flush against the edges of the media.
The media sticks 
together, resulting in 
the printer feeding 
multiple sheets. • The friction between sheets is too high.
• Remove the media from Tray 1 or Tray 2, and fan it.
• Don’t overfill Tray 1 or the optional Tray 2 (see media capacities in the media types and 
sizes chart in the User’s Reference).
The media fails to feed 
from Tray 1.• Frictional force between tires and media is less than resisting force.
• Remove the media from Tray 1, and fan it.
• Make sure Tray 1 is selected from the printer driver. Do not overfill the tray.
• Check the condition of the rubber on the paper feed rolls. Replace if worn or 
contaminated.
• Verify that the ACM clutch is functioning correctly. 
The media fails to feed 
from the optional 
Tray 2. • Incorrect tray selection or inadequate picking force by tires.
• Make sure the correct tray and media type are selected from the driver.
• Make sure the tray is pushed all the way in.
• Remove the media from the optional Tray 2, fan it, and reload.
• Check the rubber on the paper feed tires for dirt or any other debris. Replace as 
necessary.
• Check the paper path in the tray for burrs or debris that may hinder media movement. 
• Make sure the media does not exceed the stack height indicator.
The Load Paper 
message displays 
even though there is 
media loaded in the 
optional Tray 2. • The input sensor does not sense media after picking.
• Make sure the tray is pushed all the way in. 
• Press .
• Check the feed tires. (See two preceding actions.)
The printer does not 
print after a paper jam 
has been cleared. • The printer is waiting on the next command.
• Clear all jams.
• Press and release   , or open and close the printer cover to restart the printer.
• Make sure the print cartridge assembly is installed properly. Print quality problems (Continued)
Problem Cause / action 
						

							Diagnostics information2-31
4512-630
Printhead service check
Transfer roll service check 
Unexpected characters 
print or characters are 
missing.• Ensure correct printer driver is being used.
• Select hex trace mode to determine what the problem is.
• Restore factory defaults. 
• Make sure the parallel cable or USB cable is firmly plugged in at the back of the printer.
Jobs are not printing, 
and the error light is on 
solid. • The printer is waiting for an appropriate command.
• Make sure the print cartridge assembly is installed properly.
• Make sure the printer front cover is closed.
While in PostScript 3 
emulation, the printer 
is flushing data 
(Ready/Data and Error 
lights are blinking).• Ensure the correct PostScript driver is being used.
• The printer doesn’t have enough memory to print the job. Install more memory.
FRU Action
Printhead
Note: New printhead 
must be aligned. See 
“Printhead assembly 
electronic 
adjustment” on 
page 3-6.Turn the printer off. 
Disconnect the printhead cables from J8 and J15 on the controller card. 
Turn the printer on with the front door closed. 
On the controller card, verify +5 V dc on pin 10 at J8 and +5 V dc on pins 1 and 2 at J15. 
Verify grounds on pins 2, 4, and 7 at J8 and on pin 4 at J15. 
• If voltages or grounds are incorrect, check the controller card. See “Controller card 
service check” on page 2-17 for more information. 
• If voltages are correct, replace the printhead (comes with cables). 
FRU Action
Transfer rollNote: Do not touch the transfer roll except at its ends. Place a sheet of paper over the roll to 
prevent damage from finger oils or hand lotion.
Check the springs in the left and right transfer roll bearings. The bearing assemblies should 
support the transfer roll, applying evenly distributed forces to the PC drum.
Note: Do not try to move the left spring.
Replace the transfer roll assembly if the springs or bearings show signs of damage or 
fatigue. 
Inspect the transfer roll for signs of wear, damage or contamination. 
Replace as necessary. Print quality problems (Continued)
Problem Cause / action 
						

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							Diagnostic aids3-1
  4512-630
3.  Diagnostic aids
This chapter explains the tests and procedures to identify printer failures and verify repairs have corrected the 
problem.
Accessing service menus
There are different test menus that can be accessed during POR to identify problems with the printer.
To run the printer diagnostic tests described in this chapter, you must put the printer in Diagnostic Mode.Diagnostics Mode 1. Turn off the printer.
2. Press and hold   and  .
3. Turn on the printer.
4. Release the buttons when 
Performing Self Test 
displays.The Diagnostics Mode group contains the settings 
and operations used while manufacturing and 
servicing the printer. 
See “Diagnostics mode” on page 3-2 for more 
information. 
Configuration Menu 1. Turn off the printer.
2. Press and hold  and  .
3. Turn on the printer.
4. Release the buttons when 
Performing Self Test 
displays.The Configuration Menu group contains a set of 
menus, settings, and operations which are 
infrequently required by a user. Generally, the 
options made available in this menu group are 
used to configure a printer for operation. 
See “This selection exits Diagnostics mode, 
and Resetting the Printer displays. The 
printer performs a POR, and the printer returns 
to normal mode.” on page 3-25 for more 
information. 
Flash system code 
mode1. Turn off the printer.
2. Press and hold  ,  , 
and .
3. Turn on the printer.
4. Release the buttons when 
Performing Self Test 
displays. 
						

							3-2Service Manual 4512-630  
Diagnostics mode
Entering Diagnostics mode
1.Press and hold   and  .
2.Turn on the printer.
3.Release the buttons when Performing Self Test displays.
Available tests
The tests display on the operator panel in the order shown:
Diagnostics mode tests
REGISTRATIONSee “REGISTRATION” on page 3-4
Bottom Margin
To p  M a r g i n
Left Margin
Right Margin
Printhead See “Printhead assembly electronic adjustment” on page 3-6
Quick Test See “Quick Test” on page 3-12
PRINT TESTS
Tray 1 See “Input source tests” on page 3-13
Prt Quality Pgs See “Print quality pages (Prt Quality Pgs)” on page 3-13
HARDWARE TESTS
Panel Test See “Panel Test” on page 3-14
Button Test See “Button Test” on page 3-14
DRAM Test See “DRAM Test” on page 3-14
CACHE Test
Parallel Wrap See “Parallel Wrap tests” on page 3-15
Parallel 1 Wrap (if installed)