Lexmark C760 Service Manual

							
Repair information4-55
  5060-4xx
Paper size sensing assembly
Go to “Paper size sensing” on page 7-16  for part numbers associated with this assembly.
1.Enter Diagnostics mode. Power up the printer in Diagnostics mode (holding  Go and  Return  until 
Performing Self Test  appears.).
2.Print the Quick Test Page, if possible. Retain this sheet to verify the installation.
a.Select REGISTRATION .
b.Press Go to print the page.
3.Turn the printer off.
4.Remove the inner system board shield. See  “Inner system board shield” on page 4-43 . 
5.Open the waste toner container door and slide the container out.
6.Remove the two screws (A) on the lower shield and remove the ground wire screw (B).
7.Remove screw (C) from the paper size sensing assembly. 
						

							
4-56Service Manual
5060-4
xx   
8.Gently twist and remove the paper size sensing assembly. As shown, the assembly touches at the 
spring (D), the fingers (E), the bottom (F), and the right side (G). This also occurs when replacing the 
assembly.
Replacing the paper size sensing assembly
1.
Press on the back of the paper size sensing assembly fingers (H). 
						

							
Repair information4-57
  5060-4xx
2.Move the assembly down to the bottom of the aligning hole. Be careful with the exposed fingers. Do not 
allow them to press against the black plastic frame.
3.Gently wiggle the entire assembly and press in and around the corner to the right.
4.Grasp the rectangular piece (J) of the paper size sensing assembly and move up and to the left until the 
screw hole (K) lines up.
5.Reinstall the ground screw, inner system board shield, waste toner container, outer system board shield, 
and the covers.
Paper size sensing board
Warning: Whenever the paper size sensing board is removed, customer settings in the NVRAM may be lost. 
The Motor Detect test must be performed if the NVRAM contents are lost during the replacement of 
a paper size sensing board. See  “Motor Detect” on page 3-17. 
Go to  “Paper size sensing” on page 7-16  for part number.
1.Print the Quality Test Pages. See “Prt Quality Pgs” on page 3-9.
Save the margin settings so they can be reentered after replacing the board.
2.Remove the rear cover. See  “Rear cover” on page 4-16.
3.Disconnect the cables. 
						

							
4-58Service Manual
5060-4
xx   
4.Remove the paper size sensing board screws (A).
5.Remove the board.
Replace the new board
1.
Power up the printer in Diagnostics mode (holding  Go and  Return  until Performing Self Test  
appears.)
2.Verify the model name to make sure the correct paper size sensing board is installed.
a.Select  PRINTER SETUP  from the Diagnostics mode.
b.Select Model Name .
The model name should match the model name on the Quick Test Page or on the printer logo. If it 
does not, you have the wrong paper size sensing board.
c.Press  Select  to save the Model Name.
3.Verify or change the serial number to the number on the Quick Test Page or on the printer. 
a.Select  Serial Number  from PRINTER SETUP in the Diagnostics mode.
b.The leftmost digit  blinks, indicating it is the first digit to be changed. To change the value, press  Menu 
until the desired value is displayed. Press  Select to move to the next digit. The digit  blinks. Continue 
modifying each digit using this method. To skip a digit, and keep its current value, press  Select.
4.Perfor m the Motor Detect test.
a.Remove all the print cartridges from the printer and close the cover.
b.Select  Motor Detect  from MISC TESTS.
c.Press Go.
Motor Detection in Progress  is displayed.
The test lasts approximately ten seconds. No buttons are active during detection and the test 
completes automatically.
5.Turn off the printer.
6.Replace the print cartridges.
7.Power up the printer in Diagnostics mode (holding  Go and  Return  until Performing Self Test  
appears.)
8.Set the Configuration ID. See  “Configuration ID” on page 3-33 . The printer will POR.
9.Turn the printer off and power up the printer in Diagnostics mode (holding  Go and  Return  until 
Performing Self Test appears .)
10.Set the registration. See “REGISTRATION” on page 3-14 . Refer to settings on the Quick Test Page you 
printed at the beginning of this removal.
11.Set the alignment. See  “ALIGNMENT MENU” on page 3-15 . Refer to settings on the Quick Test Page. 
						

							
Repair information4-59
  5060-4xx
Pick rolls
Go to “Pick roll tires” on page 7-53  for part number.
Front roll
1.
Wipe any toner or debris from the bottom pan to avoid contaminating the pick rolls.
2.Pull the pick assembly down into the bottom pan and remove the screw.
Note:   Do not attempt to remove either the shaft or the clutch races.
Rear roll
Reach around and depress the latch on the side of the shaft and remove the roll. 
Installation notes:

Replace both rolls at the same time.
When you replace the front roll, make sure the roll is pressed against the shaft and the screw is fastened all 
the way down.
When replacing both the front and back rolls, note the directional markings on the roll and make sure the 
rolls turn clockwise when viewed from the front. Check out the directional arrows in the pictures. Verify the 
rolls turn freely.  
						

							
4-60Service Manual
5060-4
xx   
Printhead removal and adjustments
Identifying the printheads
A color version of this sheet is available in the appendix. See“Identifying the printheads” on page A-4.
Warning: Do not loosen or remove all printheads at the same time. If all printheads are loosened or removed, 
your reference to readjust will be lost.
Notes :
Whenever a printhead is removed, it is necessary to perform the  “Printhead mechanical alignment” on 
page 4-61  and “Printhead electronic alignment” on page 4-63 .
The front cover must be installed and closed before any printhead alignment can be performed. It is not 
necessary to remove the cover to access the printheads.
If there is a protective lens cover on the new printhead, it must be removed before installing the 
replacement printhead. 
						

							
Repair information4-61
  5060-4xx
Printhead mechanical alignment
Warning: Do not loosen or remove all printheads at the same time. If all printheads are loosened or removed, 
your reference to readjust will be lost.
1.Install two printhead alignment assemblies, one in the front and another in the rear (see Figure 2 and 
Figure 3), by aligning the locating pin on the printhead alignment bracket (see Figure 1) with the hole in the 
printer frame.
2.Attach the printhead alignment tool with the provided screw. 
ThumbwheelBracket Locating pin
Figure 1 
						

							
4-62Service Manual
5060-4
xx   
3.Turn the thumbwheel (see Figure 1) until the end of the thumbwheel just touches the printhead mounting 
beam for both the front and rear alignment assemblies.
4.Remove the old printhead and install a new printhead assembly. Do not tighten the printhead screws yet. 
Note:  Make sure the right rear screw goes through the printhead spacer located at the right rear of the 
printer frame. 
5.Bias the new printhead assembly against the front and rear stops. 
6.Tighten the right rear printhead mounting screw. Then, tighten the front screw followed by the left rear 
screw. Make sure the printhead is biased against the thumbwheels when tightening the screws.
7.Securely close the front cover or reattach if previously removed.
8.Turn the printer on and enter the Diagnostics mode.
9.If replacing the black printhead go to step 10. Otherwise, select  Alignment, select color of the printhead 
that was replaced, and set the Z value to zero. Exit  Alignment menu.
10.Select Miscellaneous Test  and Printhead Inst Alignment . 
						

							
Repair information4-63
  5060-4xx
11.Print the Printhead Mechanical Alignment Test page to determine the printhead alignment. 
Note:   To see a printhead mechanical alignment test in color page, see  “Printhead mechanical alignment test 
page” on page B-9 .
12.Loosen the printhead screws before making any adjustments to the thumbwheel.
13.Turn each thumbwheel the appropriate number of  clicks as indicated by the test page. For example, if the 
test page indicates a +10 as the misalignment, turn the thumbwheel 10  clicks in the positive direction 
indicated on the test page. Do this for both the front and rear printhead.
14.Bias the printhead up against both thumbwheels, and hold in place when tightening printhead mounting 
screws.
15.Tighten the right rear printhead mounting screw. Then tighten the front screw followed by the left rear 
screw. Make sure the printhead is biased against the thumbwheels when tightening the screws.
16.Print another Printhead Mechanical Alignment Test Page to verify printhead alignment.
17.If the printhead alignment is within ±5 for both front and rear positions, then proceed to electronic 
alignment procedure. If not, repeat steps 12 through 16, until alignment is within ±5.
Note:   When replacing the black printhead there is no Z value to reset. After the black printhead is mechanically 
aligned to the magenta printhead, it is necessary to electronically align the three color printheads to the new 
black printhead.
Printhead electronic alignment
After completing all mechanical adjustments return to  Alignment Menu. See “ALIGNMENT MENU” on 
page 3-15  to electronically align the cyan, magenta, or yellow printheads to black. 
						

							
4-64Service Manual
5060-4
xx   
Rear bellcrank (cyan, magenta, yellow)
1.Power off the printer.
2.Remove the four toner cartridges and leave the front door open.
3.Remove the ITU assembly. See “ITU assembly” on page 4-44.
4.Check each of the rear bellcranks for cracks or breakage.
5.Remove the spring (A).