Lexmark C 746 Service Manual

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Tray 1 missing service check
Step Questions / actions Yes No
11. Check if the tray assembly can close 
properly.
2. Make sure the paper path is cleared of 
jams. 
3. Check for any damage.
Does the tray assembly close properly?Go to step 3. Go to step 2.
21. Clear the tray path of any obstruction. 
2. Check for damage on the tray.
Is the tray free of damage?Go to step 3. Replace the tray.
31. Remove the tray and inspect the narrow 
media flag on the paper pick assembly for 
any damage.
2. Reseat the connector Jtray1 and JFDPCK 
on the system board, then check for any 
damage on the connectors. 
Are the flag and cable connectors free of 
damage?Go to step 4. Replace the paper pick 
assembly. See “Paper pick 
mechanism assembly 
removal” on page 4-137.
41. Disconnect the cable in JTRAY1, and 
connect the cable from the new paper pick 
mechanism.
2. Bring the printer up in the Diagnostics 
menu (turn off the printer, press and hold 
buttons 3 and 6, turn on the printer).
3. Navigate to Sensor Tests > Dynamic 
Sensors > Narrow Media.
4. Activate the narrow media sensor
Did the narrow media sensor status change on 
the touchscreen?Replace the paper pick 
assembly. See “Paper pick 
mechanism assembly 
removal” on page 4-137.Replace the system board. 
See “System board 
removal” on page 4-155. 
						

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Tray linking service check
Tray linking is useful for large print jobs or multiple copies. When one linked tray is empty, paper feeds from the 
next linked tray. When the Paper size and Paper Type settings are the same for any trays, the trays are 
automatically linked.
Step Questions / actions Yes No
1Load the same size and type of paper in each 
tray. Move the paper guides to the correct 
positions for the paper size loaded in each 
tray.
Does tray linking work properly?Problem resolved. Go to step 2.
2Print a menu settings page from the Admin 
Menu, and compare the settings for each tray.
Are the settings for each tray to be linked the 
same for paper type and paper size?Problem resolved. In the Admin menus, set the 
same settings for paper size 
and paper type in each tray. 
						

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3.  Diagnostic aids
This chapter explains the tests and procedures to identify printer failures and verify repairs have corrected the 
problem.
Accessing test and diagnostic procedure 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 Diagnostics mode.Diagnostics menu 1. Turn off the printer.
2. Press and hold buttons 3 and 
6.
3. Turn on the printer.
4. Release the buttons when the 
clock graphic displays.The Diagnostics menu group contains the settings 
and operations used while manufacturing and 
servicing the printer. 
See “Diagnostics menu” on page 3-2 for more 
information. 
Configuration menu 1. Turn off the printer.
2. Press and hold buttons 2 and 
6.
3. Turn on the printer.
4. Release the buttons when the 
progress bar 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 “Configuration menu (CONFIG MENU)” on 
page 3-27 for more information. 
Network SE Menu 1. While in Network/Ports Menu 
(Menus—Network/Ports—
Standard Network—STD 
NET SETUP), press and hold 
buttons 6, 7, and 9.The Network SE menu contains advanced network 
menu tools. This key press only accesses the 
Network SE Menu when the panel displays the 
top-most settings inside the Standard Network 
menu.
SE Menu From browser, add “/se” to 
device’s IP address (e.g. http://
158.183.3.2/se) 
						

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Diagnostics menu
Note:  Tray 2 refers to the 550-sheet tray located in the 550-sheet option assembly.
Diagnostics menu structure
When the Diagnostics mode is entered, each Diagnostics main menu item displays on the operator panel. When 
a diagnostic test is selected from the main menu, a sub menu displays and each individual test displays in the 
order shown. Any options that are referred to in the menus are displayed when the option is installed.
Available tests
The tests display on the operator panel in the order shown:
REGISTRATION
Top Margin See “Registration” on page 3-5.
Bottom Margin
Left Margin
Right Margin
Skew See “Skew” on page 3-5.
Quick Test See “Quick Test” on page 3-8.
ALIGNMENT MENU
Cyan See “Alignment” on page 3-8.
Magenta
Yellow
Factory Scanner A summary page for all the color alignment settings. Can be used in 
place of alignment pages for each individual color.
Factory Manual
MOTOR TESTS (order differs depending upon model)
Align Motor TestNote: Many of these tests require special conditions in order to 
successfully test the motors. See “General motor tests procedures” 
on page 3-10.  Cart 1
Cart 2
Cart 3
CAM
COD
DUPLEX
Fuser
MPF
Transfer Belt
Option Motors
Tray 1 
						

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PRINT TESTS
Tray 1 See “Input source tests” on page 3-12.
Tray 2 (if installed)
Tray 3 (if installed)
Tray 4 (if installed)
Tray 5 (if installed)
Multi-Purpose Feeder
Print Quality Pages See “Print quality test pages (Print Quality Pages)” 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.
Serial 1 Wrap (if a serial port is 
available in the PCI slot 1)See “Serial 1 Wrap” on page 3-14.
USB HS Test Mode See “USB HS Test Mode” on page 3-16.
DUPLEX TESTS (if installed)
Quick Test See “Quick Test (duplex)” on page 3-16.
Print Test See “Print Test (duplex)” on page 3-17.
Top Margin See “Top Margin (duplex)” on page 3-18.
Left Margin See “Left Margin (duplex)” on page 3-18.
Skew See “Skew (duplex)” on page 3-18.
SENSOR TESTS
Static Sensors See “Sensor Test” on page 3-19.
Waste Toner 
Belt Waste
Fuser Temp
Fuser BUR Temp
Power
Dynamic Sensors
Fuser Exit
Input
Front Door
Narrow Media
K Toner
M Toner
C Toner
Y Toner
TPS
Bubble
Dynamic MPF
Other Sensors
Bin Full Test
PRINTHEAD TESTS
Mirror Motor Test See “Mirror Motor Test” on page 3-20. 
						

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Servo Laser Test See “Servo Laser Test” on page 3-20.
DEVICE TESTS (if hard disk or flash is installed)
Quick Disk Test See “Quick Disk Test” on page 3-21.
Disk Test/Clean See “Disk Test/Clean” on page 3-22.
Flash Test See “Flash Test” on page 3-22.
PRINTER SETUP
Defaults See “Defaults” on page 3-22.
Prt Color Pg Count See “Page Counts” on page 3-23.
Prt Mono Pg Count
Perm Page Count
Serial Number See “Serial Number” on page 3-23.
Model Name See “Model Name” on page 3-23.
Engine Setting 1 through 4 See “Engine Setting 1 through 4” on page 3-23.
Configuration ID See “Configuration ID” on page 3-23.
Reset Color Cal See “Reset color calibration (Reset Color Cal)” on page 3-24.
Par 1 Strobe Adj See “Parallel 1 strobe adjustment (Par 1 Strobe Adj)” on 
page 3-24.
Motor Calibration See “Motor Calibration” on page 3-24.
EP SETUP
EP Defaults See “EP Defaults” on page 3-24.
Fuser Temp See “Fuser temperature (Fuser Temp)” on page 3-24.
DC Charge Adjust See “DC Charge Adjust, Dev Bias Adj, Transfer Adjust” on 
page 3-25.
Dev Bias Adj
Transfer Adjust
REPORTS
Menu Settings Page See “Menu Settings Page” on page 3-25.
EVENT LOG
Display Log See “Display Log” on page 3-25.
Print Log See “Print Log” on page 3-26.
Clear Log See “Clear Log” on page 3-26.
EXIT DIAGNOSTICSThis selection exits Diagnostics mode, and Resetting the Printer 
displays. The printer performs a POR, and returns to normal mode. 
						

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Registration
Note:  If you need to perform alignment or registration, see “Printhead alignment” on page 4-8. 
The following information is meant to explain the uses for the menu items.
Print registration makes sure the black printing is properly aligned on the page. This is one of the steps in 
aligning a new printhead. It is also the first step in aligning the duplex registration. See “Quick Test (duplex)” 
on page 3-16. 
The settings available are Top Margin, Bottom Margin, Left Margin, Right Margin, Skew, and Quick Test.
Skew
One printhead houses the four color planes. The black plane is aligned to the printer, and the color planes are 
internally aligned to black. Adjust the skew mechanically by moving the printhead with a printhead adjustment 
screw. See “Printhead mechanical alignment (C746)” on page 4-8 for instructions on setting printhead 
alignment. Electronic alignment fine tunes the alignment of the color planes to the black plane once the 
printhead is installed. Skew adjustment must be performed before color alignment is attempted. The following 
illustration shows proper alignment versus skewed alignment. 
Proper alignment Skewed alignment 
						

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Print registration
Print registration (C746x)
To set print registration:
1.Select REGISTRATION from the Diagnostics Menu.
2.Select Quick Test.
The message Quick Test Printing… appears on the display.
Note:  Retain this page to determine the changes you need to make to the margin settings.
3.Use   or   to select the margin setting you need to change, and press  .
4.Use   to decrease or   to increase the offset values, and press   to confirm the value.
5.The message Submitting selection displays and the original REGISTRATION screen appears.
The print registration range is:
6.Continue changing the settings by repeating steps 2 through 4.
7.Print another copy of the Quick Test to verify your changes.
To exit without changing the value, press  . 
Print registration (C748x)
To set print registration:
1.Select REGISTRATION from the Diagnostics Menu.
2.Select Quick Test.
The message Quick Test Printing… appears on the display.
Note:  Retain this page to determine the changes you need to make to the margin settings.
3.Select the margin setting you need to change.
4.Touch   to decrease or   to increase the offset values,.
5.The message Submitting changes displays and the original REGISTRATION screen appears. Description Value Direction of change
Skew -50 to +50 Each increment 
corresponds to 1/1200 of an inch.Skew settings should be between -5 
and +5. If not, readjust the skew 
with the printhead mechanical 
setting. See “Printhead 
alignment” on page 4-8.
Top margin -25 to +25 Each increment 
corresponds to 8 scans at a 600 dpi 
scan rate (0.0133 inches or 
0.339 mm)
. A positive change moves the image 
down the page and increases the 
top margin. A negative change 
moves the image up and decreases 
the top margin.
Note: Make sure media selection 
size matches the media size in tray 
1.
Bottom margin -25 to +25 Each increment causes 
approximately 0.55 mm shift in the 
bottom margin.A positive offset moves text up the 
page and widens the bottom 
margin. A negative offset moves 
text down the page and narrows the 
bottom margin.
Left margin -50 to +50 Each increment 
corresponds to 4 pels at 600 dpi 
(0.00666 in. or 0.1693 mm).A positive change moves the image 
to the right. A negative change 
moves the image to the left. 
Right margin -50 to +50 Each increment 
corresponds to an approximate shift 
of 4 pels at 600 dpi.A positive change moves the image 
to the left. A negative change 
moves the image to the right. 
						

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The print registration range is:
6.Continue changing the settings by repeating steps 2 through 4.
7.Print another copy of the Quick Test to verify your changes.
To exit without changing the value, touch Back. Description Value Direction of change
Skew -50 to +50 Each increment 
corresponds to 1/1200 of an inch.Skew settings should be between -5 
and +5. If not, readjust the skew 
with the printhead mechanical 
setting. See “Printhead 
alignment” on page 4-8.
Top margin -25 to +25 Each increment 
corresponds to 8 scans at a 600 dpi 
scan rate (0.0133 inches or 
0.339 mm)
. A positive change moves the image 
down the page and increases the 
top margin. A negative change 
moves the image up and decreases 
the top margin.
Note: Make sure media selection 
size matches the media size in tray 
1.
Bottom margin -25 to +25 Each increment causes 
approximately 0.55 mm shift in the 
bottom margin.A positive offset moves text up the 
page and widens the bottom 
margin. A negative offset moves 
text down the page and narrows the 
bottom margin.
Left margin -50 to +50 Each increment 
corresponds to 4 pels at 600 dpi 
(0.00666 in. or 0.1693 mm).A positive change moves the image 
to the right. A negative change 
moves the image to the left. 
Right margin -50 to +50 Each increment 
corresponds to an approximate shift 
of 4 pels at 600 dpi.A positive change moves the image 
to the left. A negative change 
moves the image to the right. 
						

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Quick Test
The Quick Test contains the following information:
•Print registration settings
•Alignment diamonds at the left, right, top and bottom
•Horizontal lines to check for skew
•General printer information, including current page count, installed memory, serial number, and code level.
Note:  Print the Quick Test Page on letter or A4 paper.
1.Select REGISTRATION from the Diagnostics Menu.
2.Select Quick Test.
The message Quick Test Printing… appears on the display.
Once the Quick Test Page completes printing, the Registration screen displays again.
Alignment
Note:  If you need to perform alignment or registration, see “Printhead alignment” on page 4-8. 
The following information is meant to explain the uses for the menu items.
Alignment is part of the process of adjusting the printhead and the color planes to the black plane and to each 
other. Before you start, perform the black alignment (Registration). See “Printhead alignment” on page 4-8. If 
you are replacing a new printhead, see “Printhead removal, installation, and adjustment” on page 4-145. 
Alignment (C746x)
To perform alignment:
1.Select ALIGNMENT MENU from the Diagnostics Menu. Scroll until you reach the color that you desire to 
align. Go to each submenu, press   and use the right and left arrow keys to zero out all settings. Press 
 after you zero out each setting.
Note:  It is important to zero out all settings to make the adjustment easier.
2.Scroll to Quick Test in the same color menu. Press  ; two pages print.
3.On the pages, make sure all the Current Values are set to zero. If not, go back two steps and repeat.