Lexmark C736 Service Manual

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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 3-14. 
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” 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
To set print registration:
1.Select REGISTRATION from the DIAGNOSTICS menu.
2.Select Quick Test, and press Select ().
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 Select ().
4.Use   to decrease or   to increase the offset values, and press Select ( ) to confirm the value.
5.The message Submitting selection displays, and the original REGISTRATION screen appears with 
the  beside the previously selected margin setting.
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 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 right. A negative change 
moves the image to the left. 
						

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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.
To print the Quick Test page:
Note:  Print the Quick Test Page on letter or A4 paper.
1.Select REGISTRATION from DIAGNOSTICS, and press Select ().
2.Select Quick Test, and press Select ().
The message Quick Test Printing… appears on the display.
Once the Quick Test Page completes printing, the Registration screen displays again. 
						

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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 4-135. 
To perform alignment:
1.Select ALIGNMENT MENU from DIAGNOSTICS. Scroll until you reach the color that you desire to align. 
Go to each submenu, press Select ( ) and use the right and left arrow keys to zero out all settings. 
Press Select ( ) 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 Select ( ); 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.
4.Look at the coarse and fine adjustments on the top left of the page, and enter the best number for the top 
adjustment in the T space. Transfer this number over to the computation area for Z.
5.On the operator panel, use   and   to locate Top Margin. Press Select ( ), and then use   or  to 
enter the setting computed for T. Press Select ( ) to save.
6.Repeat this process for skew (Z). Add the T value and the current Z value to obtain the new skew (Z) 
value.
7.Reprint the Quick Test page, and observe the results. Make additional adjustments if necessary before 
proceeding on to Quick Test step two page.
8.Obtain left (L), right (R), and Bow (P) value using the same method as obtaining T from Quick Test Step 1. 
Reprint the Quick Test to ensure the settings are correct. Make additional adjustments as required.
9.Press Back ( ) to return to ALIGNMENT MENU. 
See “Printhead mechanical alignment” on page 4-8 for printout samples and additional information. 
						

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Motor tests
The motor tests are run primarily to locate noises in the printer. 
General motor tests procedures
In some instances, when you enter a particular test, you will be given the choice to run the motor in forward or 
reverse. Other times, there will only be the option to run the motor in forward direction.
In general, the test should work as follows:
1.Select MOTOR TESTS from DIAGNOSTICS, and press Select ().
2.Select the motor that you need to test, and press Select ().
3.Check the table below for setup requirements, if any.
4.Select the direction if a choice is offered (Forward or Reverse) or other setting for that test, and press 
Select (). 
Press Back () or Stop ( ) to stop the motor and end the test.
The following tests have special setup before running the test:
Motor testSetup requirements
Values in 
menuNotes
Top cover 
positionLower door 
position
Align Motor Test N/A Closed* Forward,
Reverse* If this test is run with the lower door 
open:
• Remove the right cover (see 
“Right cover removal” on 
page 4-37),
• Manually activate the 5 V interlock 
switch and the 24 V interlock 
switch must be pushed in. Fuser Closed Closed* Forward, 
Reverse
Cart 1 N/A Open Forward Remove the right cover to observe the 
motor moving. See “Right cover 
removal” on page 4-37 Cart 2 N/A Open Forward
Cart 3 N/A Open Forward
Transfer Belt Closed Closed Press 
Select()
Option Motors—
Tray 1 PickupN/A N/A Single, 
ContinuousRemove all paper from the input source 
tray to avoid paper jams while 
performing this test. 
MPF N/A Closed* Reverse Remove any paper in the multifunction 
feeder in order to run this test.
* If this test is run with the lower door 
open:
• Remove the right cover (see 
“Right cover removal” on 
page 4-37),
• Manually activate the 5 V interlock 
switch and the 24 V interlock 
switch must be pushed in. 
						

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Print Tests
Input source tests
The purpose of the diagnostic Print Tests is to verify that the printer can print on media from each of the installed 
input options. The contents of the Print Test Page varies depending on the media installed in the selected input 
source.
Check each Test Page from each source to assist in print quality and paper feed problems.
To run the Print Test Page:
1.Select PRINT TESTS from the DIAGNOSTICS, and press Select ().
2.Select the media source, and press Select ().
Tray 1
Tray 2 (if installed)
Tray 3 (if installed) CAM N/A Closed Forward, 
ReverseIf the cam or COD are at the farthest 
extent forward or backward, selecting 
this value does not show a result. If this 
happens, select the other value. For 
example, if you select Forward, and 
nothing happens, select Reverse. This 
time you should get results.
COD stands for Color on Demand. COD N/A Closed Forward, 
Reverse
DUPLEX N/A Closed Forward Remove all paper from the input source 
tray to avoid paper jams while 
performing this test.  Option Motors—
Tray 1 FeedN/A N/A Single, 
Continuous
Option Motors—
Tray 1 PickN/A N/A Single, 
Continuous
Option Motors—
ElevatorNot applicable Not applicable Forward, 
Reverse Motor testSetup requirements
Values in 
menuNotes
Top cover 
positionLower door 
position 
						

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Tray 4 (if installed)
Tray 5 (if installed)
Multi-Purpose Feeder (if installed)
3.Select Single or Continuous, and press Select (). 
•If Single is selected, a single page is printed.
•If Continuous is selected, printing continues until Stop ( ) is pressed to cancel the test.
If a source is selected that contains envelopes, an envelope test pattern is printed. If Continuous is 
selected, the test pattern is printed only on the first envelope.
Note:  The Print Test Page always prints on one side of the paper, regardless of the duplex setting.
4.Press Back ( ) to return to PRINT TESTS. 
Print quality test pages (Prt Quality Pgs)
The print quality test consists of five pages. Pages one and two contain a mixture of graphics and text. The 
remainder of the pages only contain graphics. The test prints on the media in the default tray.
This test may be printed from either Configuration Menu or the Diagnostics mode. To run the print quality pages 
from the Diagnostics mode, select PRINT TESTS and Print Quality Pgs from the menu. Once the test is 
started, it cannot be canceled. When the test pages print, the printer returns to the original screen.
To run the Print Quality Test Pages, select Prt Quality Pgs from PRINT TESTS, and press Select ( ). The 
message Printing Quality Test Pages is displayed, and the test prints.  
						

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Hardware Tests
Panel Test
This test verifies the operator panel LCD function.
To run the Panel Test:
1.Select HARDWARE TESTS from DIAGNOSTICS, and press Select ().
2.Select Panel Test, and press Select ().
The Panel Test continually executes. Each pixel is activated at the darkest level to the lightest level, and 
then the backlight illuminates and turns off. This is repeated continuously.
3.Press Stop ( ) to cancel the test at any point.
Button Test
This test verifies the operator panel button function.
To run the Button Test:
1.Select Button Test from HARDWARE TESTS from Diagnostics, and press Select ().
2.Press each button one at a time, and an X appears in the box that represents that button.
When you press Stop ( ), the test ends.
Press Stop ( ) to cancel the test.
DRAM Test
This test checks the validity of DRAM, both standard and optional. The test writes patterns of data to DRAM to 
verify that each bit in memory can be set and read correctly.
To run the DRAM Test select DRAM Test from HARDWARE TESTS in DIAGNOSTICS, and press Select (). 
The power indicator blinks indicating the test is in progress.
Note:  If you need to exit the test before it is complete, turn off the printer.
P:###### represents the number of times the memory test has passed and finished successfully. Initially, 
000000 displays with the maximum pass count being 99,999.
F:##### represents the number of times the memory test has failed and finished with errors. Initially, 00000 
displays with the maximum fail count being 99,999.
Once the maximum pass count or fail count is reached, the test is stopped, the power indicator turns on solid, 
and the final results appear. If the test fails, SDRAM Error appears for approximately three seconds and the 
failure count increases by 1.DRAM Test 128M
P:###### F:#####
Button Test 
						

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Serial 1 Wrap
The Serial 1 Wrap Test is used to check the operation of the serial port hardware using a wrap plug. Each serial 
signal is tested.
To perform the Serial 1 Wrap Test:
1.Disconnect the serial interface cable, and install the serial wrap plug.
2.Select HARDWARE TESTS from the Diagnostics Menu, and press Select ().
3.Select Serial 1 Wrap, and press Select ().
The power indicator blinks indicating the test is in progress. The following screens appear
Upon completion of the POR, the following screen is displayed:
P:###### represents the number of times the serial port hardware has passed.
Initially, 000000 is displayed. The maximum pass count is 999,999.
F:###### represents the number of times the serial port hardware has failed.
Initially, 0000 is displayed. The maximum fall count is 999,999.
Any of the following explanations for failure may display:
•Receive Status Interrupt Error
•Status Error
•Receive Data Interrupt Error
•Transmit Data Interrupt Error
•Transmit Empty Error
•Threshold Error
•Receive Data Ready Error
•Break Interrupt Error
•Framing Error
•Parity Error
•Overrun Error
•Data Error
•Data 232 Error
•Data 422 Error
•FIFO Error
•DSR Error
•DSR PIO Error
•DSR Interrupt Error
•CTS Error
•CTS PIO Error
•CTS Interrupt Error Serial Wrap [x] Testing…
Resetting the 
Printer
Serial Wrap
P:###### F:#### 
						

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USB HS Test Mode
1.
Select HARDWARE TESTS from DIAGNOSTICS, and press Select ().
2.Select USB HS Test Mode, and press Select ().
3.Select the port (Port 0, Port 1, Port 2, or Port 3), and press Select ().
4.Select the test for that port from the following list:
Test J
Test K
Test SE0 NAK
Test Packet
Test Force Enable
5.Press Select ().
While the test executes, USB High Speed Testing… displays.
To exit the test, restart the printer.
Duplex Tests
Quick Test (duplex)
Note:  Before you set the duplex top margin, be sure to set the skew and alignment. See “Printhead 
alignment” on page 4-8.
This test prints a duplex version of the Quick Test that can be used to verify the correct placement of the top 
margin on the back side of a duplex page. 
You can run one duplexed page (Single), or continue printing duplexed pages (Continuous) until Stop () is 
pressed. For information about changing the margin, see “Top Margin (duplex)” on page 3-16.
The paper you choose to print the page on should be either Letter or A4.