Lexmark X543 Service Manual

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Toner patch sensor (TPS)—left and right removal
The toner patch sensors are similar, but the left sensor includes an extra cable and sensing device. Remove 
them the same way. 
1.Remove the ITU. See “Image transfer unit (ITU)” on page 4-25.
2.Remove the rear shield. See “Rear shield removal” on page 4-7. 
3.Disconnect the toner density sensor cable from JTDS1 connector (A Right) or JTDS2 connector (A Left) on 
the controller board. If you...

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e.Continue entering and pausing.
5.After the 32nd number is entered and becomes solid, the number is automatically entered.
If the number is incorrect, Checksum does not match appears, and the original screen appears to re-
enter the value. 
If the number is correct, Saving changes to NVRAM appears.
Tray present sensor removal
1.Turn the printer on the left side.
2.Unclip the tray present sensor (A) from the right lower frame.
3.Disconnect the...

Repair information4-49
Lexmark confidential until announce7525xxx
USB connector removal
1.Remove the rear shield. See “Rear shield removal” on page 4-7. 
2.Disconnect the USB connector (A) from the controller board.
3.Remove the flatbed assembly. See “Flatbed removal” on page 4-53.
Note:  Do not remove the flatbed covers, or any of the hinges. The flatbed only needs to be removed from 
the print engine.
4.Remove the operator panel from the flatbed assembly.“Operator panel removal” on page 4-76.
5.Remove...

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Wireless network antenna
1.Remove the rear shield. See “Rear shield removal” on page 4-7.
2.Lift to disconnect the wireless card (A) from the controller board.
3.Carefully disconnect the antenna cable (B) from the wireless card at the card.
4.Remove the screw (C) that secures the antenna cover (D) to the frame, and remove the antenna cover and 
antenna. 

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5.Straighten the antenna perpendicular to the cover, push against the cover with your fingers, and gently 
squeeze the fastener (E) with needlenose pliers. Slide the antenna cable and cable through the hole in the 
bracket.
6.If the fastener is damaged, remove the fastener by pressing the tabs on each side.
Note:  Take note of the orientation of the fastener. When reinstalling, place the cover upright, bend the 
antenna as it would be...

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Wireless network card
1.Remove the rear shield. See “Rear shield removal” on page 4-7.
2.Lift to remove the wireless card (A) from the controller board.
3.Carefully disconnect the antenna cable (B) from the wireless card at the card. 

Repair information4-53
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Scanner component removal procedures
Flatbed removal
1.Remove the AIO rear cable cover. See “AIO back cable cover removal” on page 4-8.
2.Remove the rear shield. See “Rear shield removal” on page 4-7.
3.Remove the left cover. See “Left cover removal” on page 4-4.
4.Remove the ADF unit. See “Duplex ADF removal” on page 4-63 or “Simplex ADF removal” on 
page 4-64.
5.Disconnect the CCD cable form JCCD1 on the controller board.
6.Remove the...

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7.Disconnect the ADF cable ground wire (B) from the frame.
8.Disconnect JADF1, and route the cable through the top of the card cage.
9.Disconnect the USB cable from JUSB1, op panel cable from JOPP1, flatbed home sensor cable from 
JHS1, and flatbed motor cable from JFBM1. Route the cables through the right side of the card cage.
10.Disconnect the ground wire (C) connecting the redrive unit to the print engine frame.
B
C 

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11.Disconnect the screw (D) connecting the flatbed to the AIO link on the rear of the MFP. 
12.Carefully disconnect the AIO link from the flatbed.
13.Remove the two screws (E) securing the flatbed hinge to the top cover.
14.Remove the two springs (F) between the flatbed and top cover. 
D
FE 

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15.Gently push the front flatbed hinge (G) towards the front of the top cover to disengage it from the top cover 
guide Pin.
16.Carefully pull the flatbed unit towards the front of the MFP while using your other hand to route the cables 
through the top cover.
17.Remove the CCD ribbon route cover and homing guide attachment.
18.Disconnect the op panel ground termination from the LVPS.
Note:  This completes the removal of the flatbed assembly...