Lexmark C 746 Service Manual

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7.Select Quick Test in the Cyan menu, and press  .
Two pages print. You may have to print these pages several times until you get T (Top Margin) and 
Z (Skew) aligned. Do not go to step 2 until T and Z are aligned. The first page is similar to the following: 
						

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8.Determine the line under Fine Adjustment that is closest. If the value is beyond the Fine Adjustment scale, 
use either of the Coarse Adjustment scales.
9.Enter the number determined from the Fine Adjustment scale or the Coarse Adjustment scales on the part 
of the page for the “T” value. The current value is automatically entered on the sheet. At this point, it should 
be zero.
10.Enter the “New Cyan T value” on the operator panel using the left and right arrows, and press   to save 
the value. 
11.Reprint the Quick Test, and evaluate whether you are at zero changes. 
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12.Repeat this process for skew (Z). Dont forget to subtract the T value and add the current cyan Z value to 
obtain the new skew (Z) value.
An example is shown below:
13.Continue to follow the directions on the bottom of the first page to find the Cyan Top Margin (T), the 
Skew (Z), and on the second page of the Quick Test page, the Left Margin (L), Right Margin (R), and 
Bow (P).
14.Repeat steps 1 through 13 for yellow and magenta.
Note:  Start each color group by setting the Top Margin, Left Margin, Right Margin, Bottom Margin, Skew, 
and Bow to zero.
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Printhead mechanical alignment (C748)
Skew (black)
1.Turn off the printer.
2.Disconnect the power cord from the electrical outlet.
3.Remove the transfer module and photoconductor units:
a.Disconnect the transfer module cable (A). 
b.Press the two tabs (B) to release the front access cover assembly.
c.Press the two tabs (C) on either side of the transfer module, and lift out the transfer module.
Note:  Leave the photoconductor units on the transport belt when removing. 
To avoid damaging the photoconductor drum, place the transfer module with the photoconductor 
units on a clean surface. Never expose the photoconductor units to light for a prolonged period of 
time. You can place a clean, dry cloth over the transfer module and photoconductor units until they 
are required.
4.Loosen the printhead mounting screws in the following order: D1, D2, and D3.
BC
A
D2D3
D1 
						

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5.Remove the printhead alignment screw cover (E).
6.Reinstall the transfer module with the photoconductor units still attached.
7.Reconnect the transfer module cable. 
8.Replace the toner cartridges. 
9.Close the top access door. 
10.Close the front access door.
11.Plug the electrical cord into the printer.
12.Plug the electrical cord into the outlet. 
13.Align the printhead skew for black. 
a.Enter the Diagnostic menu (turn off the printer, press and hold buttons 3 and 6, turn on the printer, 
and release the buttons when the clock graphic displays).
b.Touch REGISTRATION from the DIAGNOSTICS menu, and then touch Settings.
c.Touch Skew.
d.Set the Skew to zero.
E 
						

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e.Scroll down and touch Quick Test. A page similar to this one prints: 
						

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f.Adjust the printhead alignment screw (G) to change the skew and straighten the image on the 
printout.
If the top right alignment marks are lower than the top left alignment marks, rotate the alignment 
screw counterclockwise a full revolution, and print the Quick Test page. Repeat adjusting the screw 
and printing the Quick Test until the top alignment marks are the same distance from the top of the 
media.
Note: One rotation of the printhead alignment screw equals approximately 0.5 millimeter movement 
of the top edge print alignment marks.
g.When the top right and top left alignment marks are both showing and are even on the page, the 
skew is aligned.
G
Straight Skewed 
						

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14.Tighten the printhead mounting screws.
a.Turn off the printer.
b.Disconnect the power cord from the electrical outlet.
c.Disconnect the transfer module cable. 
d.Press the two tabs on either side of the transfer module, and lift out the transfer module with the 
photoconductor units in place.
e.Remove all of the toner cartridges.
f.Tighten the printhead mounting screws in the following order: H1, H2, and H3.
15.Replace the printhead alignment screw cover.
16.Replace the toner cartridges. 
17.Reinstall the transfer module and the photoconductor units.
18.Connect the transfer module cable. 
H2H3
H1 
						

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Registration (black)
Top Margin
1.Reconnect the power cord to the electrical outlet, but do not turn on the printer yet.
2.Enter Diagnostic mode (press and hold buttons 3 and 6, turn on the printer, and release the buttons when 
the clock graphic displays).
3.Touch REGISTRATION.
4.Touch Quick Test or use the last Quick Test you used to adjust skew.
5.Touch Top Margin.
6.Adjust the values until both top alignment marks are on the top edge of the print. 
•Increasing the value (+) moves the top alignment marks down on the page. 
•Decreasing the value (-) moves the top alignment marks up on the page. 
7.Touch   to save the value. 
8.Print the Quick Test page, and check the top alignment marks. Repeat adjustment of the top margin and 
printing of the Quick Test page until top margin is set.
Bottom Margin
1.Touch Bottom Margin. 
2.Adjust the bottom margin until the points of the bottom margin alignment marks are visible and touching 
the edge of the paper.
•Increasing the value (+) moves the bottom alignment marks up on the page.
•Decreasing the value (-) moves the bottom alignment marks down on the page.
3.Touch   to save the value. 
4.Print the Quick Test page, and repeat this process until the bottom margin is adjusted. 
						

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Left Margin
1.Touch Left Margin.
2.Adjust the left margin until the points of the left alignment marks touch the edge of the page.
•Increasing the value (+) moves the left alignment marks away from the edge of the page.
•Decreasing the value (-) moves the left alignment marks toward the edge of the page.
3.Touch   to save the value. 
4.Print the Quick Test page, and check the left alignment marks each time until you are satisfied.
Right Margin
1.Touch Right Margin.
1.Adjust the right margin until the points of the left alignment marks touch the edge of the page.
•Increasing the value (+) moves the right alignment marks away from the edge of the page.
•Decreasing the value (-) moves the right alignment marks toward the edge of the page.
2.Touch   to save the value. 
3.Print the Quick Test page, and check the results. Repeat if necessary.
4.When the registration is complete, proceed to the color alignment.
Alignment (cyan, yellow, and magenta)
1.
Touch Back until you reach the top menu.
2.Touch ALIGNMENT MENU.
3.Touch Cyan. 
4.Touch Top Margin.
5.Use + and - to set the Top Margin to zero, and then touch   to save the value.
6.Do the same for Left Margin, Right Margin, Bottom Margin, Skew, and Bow. 
It is important to set all the values to zero before starting.