Lexmark E 450 Dn Service Manual

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Controller card removal 
Warning:  
•Always touch a ground before touching the card. 
•Handle the card carefully by the edges.
•Never replace the operator panel and controller card at the same time without a successful POR in 
between.
1.Remove the right side cover. See“Right side cover removal” on page 4-5.
2.Remove the controller card cover.
3.Disconnect all the cables from the controller card, and remove cables from the shield housing. 
Warning:  Do not replace the...

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5.Remove the three screws (B) securing the USB port and the parallel ports. 
6.Lift and remove the card.
Re-installation note: When replacing the controller card, make sure to route all of the cables through the 
correct shield opening. Make sure that the ground wire that is being held by the front, upper screw is in the 
correct location before installing. 

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Cover open sensor removal
1.
Remove Tray 1.
2.Open the front cover.
3.Open the right side cover. See steps 1 and 2 of “Right side cover removal” on page 3-5.
4.Remove the controller card cover.
5.Loosen the one screw (A) from the shield that protects the sensor.
6.Disconnect the cable from J6 on the controller card.
Note:  The cable has a toroid. Be sure to remove the toroid before removing the cable.
7.Use a small Phillips screwdriver to remove the screw (B) holding the...

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Developer drive coupling assembly removal
1.
Remove the left side cover. See “Left side cover removal” on page 3-4.
2.Place the machine on its right side.
Note:  Be sure to protect the machine from marring.
3.Remove the six screws (A), the machine screw (B), and the ground cable screw (C).
4.Lift the main motor drive, and disconnect the motor cable (D). 
ABC 

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5.Remove the coupling spring (E). 
6.Remove the developer drive coupling (F).  

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Duplex removal
1.
Remove the right side cover. See “Right side cover removal” on page 3-5.
2.Remove the left side cover. See “Left side cover removal” on page 4-4.
3.Remove the top cover. See “Top cover removal” on page 3-7.
4.Remove the controller card. See “Controller card removal” on page 4-13.
5.Remove the LVPS/HVPS card assembly. See “LVPS/HVPS card assembly removal” on page 3-26.
6.Unhook the media level indicator. See “Media level indicator removal” on page 3-33....

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9.Remove the six screws (D). 
10.Lift the right side (opposite the coupler) and remove the duplex.
Note:  At re-installation, before tightening the screws, locate the duplex unit against the left side frame. (Left side 
relative to the picture above.) 

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Duplex gear drive
1.
Remove the main motor drive. See “Main motor drive removal” on page 3-28.
2.Remove the duplex. See “Duplex removal” on page 4-18.
3.Remove the duplex coupling and gears (A) (the screw and plastic retainer).
4.Remove the duplex coupling (B) and mating link.
Note:  The link (not shown) that connects the duplex and duplex coupling is part of this FRU as well as the 
duplex FRU. 

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Fan removal
1.
Open the right side cover. See steps 2 through 4 of “Right side cover removal” on page 3-5.
2.Remove the two screws (A) holding the fan to the side frame.
3.Unplug the cable from J4 on the controller card.
Note:  Be sure to remove the toroid before removing the cables. When re-installing, be sure to place the toroid 
back over the same cables.
4.Remove the cable from its retainer.
5.Remove the fan.
Flag removal (top cover right)
1.
Remove the top cover....

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Fuser removal
1.
Remove the left side cover. See “Left side cover removal” on page 4-4.
2.Remove the right side cover. See “Right side cover removal” on page 4-5.
3.Remove the rear cover. See “Rear cover removal” on page 4-6.
4.Loosen the top cover by removing the one rear screw above the reverse solenoid. Release the side 
latches, and lift the rear of the top cover.
5.Remove the paper exit guide assembly. The gears of the exit guide must clear the fuser bracket without...