Lexmark C 746 Service Manual

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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  , and then use   or  to enter the 
setting computed for T. Press   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...

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Motor tests
The motor tests are run to locate noises in the printer and isolate failures between the motors, cables, and 
system board. 
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 the Diagnostics...

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Motor diagnostics
PCU CY – 1 N/A Closed • No motion 
• No error reported
Open • Ok
• Cartridge disconnected from motor
Fuser Closed Closed Ok
Open Possible under-temp 120.04 error
Open N/A Not recommended, fuser errors possible
Cam N/A Closed • Ok
• Front door locks & unlocks
Open • Ok
• Door disconnected from motor
• View gearbox
COD N/A Closed • Ok
• Engages and disengages cartridges
Open • No motion
• No error reported (open while test is running)
Motor...

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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 Menu.
2.Select the media...

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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  or touch Back to return to PRINT TESTS. 
Print quality test pages (Print Quality Pages)
The print quality test consists of five pages. Pages one and two contain a mixture of...

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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 the Diagnostics Menu.
2.Select Panel Test.
Note:  For C748x, 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.
Note:  For C746x, the operator panel display cycles through red, green, blue, white,...

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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.
3.Select Serial 1 Wrap.
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...

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USB HS Test Mode
1.
Select HARDWARE TESTS from the Diagnostics Menu.
2.Select USB HS Test Mode.
3.Select the port (Port 0, Port 1, Port 2, Port 3).
4.Select the test for that port from the following list:
Test J
Test K
Test SE0 NAK
Test Packet
Test Force Enable
5.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...

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To run the Quick Test (duplex):
1.Select Quick Test from DUPLEX TESTS.
2.Select Single or Continuous. 
•The single Duplex Quick test cannot be canceled.
•The printer attempts to print the Quick Test Page from the default paper source. 
•Check the Quick Test Page for the correct offset between the placement of the first scan line on the 
front and back side of a duplexed sheet.
The single test stops automatically when a single duplex sheet is printed, and...

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Skew (duplex)
This setting adjusts the duplex motor speed when it feeds through the aligning roll. It controls the skew between 
the first scan line and the top of the page. Adjustments are made to the image that is facedown in the output 
tray.
To set the Skew (duplex):
1.Select DUPLEX TESTS from the Diagnostics Menu.
2.Select Quick Test.
3.Select Single.
The test page prints.
4.Look at the dotted arrows at the top of the page. If the page is skewed on the...