Lexmark X 850 Owners Manual

Repair information4-133
7500-XXX
Scanner top rear cover removal
1.Remove the ADF unit assembly. See “ADF unit assembly removal” on page 4-159.
2.Remove the rear upper cover. See “Rear upper cover removal” on page 4-15.
3.Remove the scanner left cover. See “Scanner left cover removal” on page 4-134.
4.Remove the scanner right cover. See “Scanner right cover removal” on page 4-135.
5.Remove the three screws securing the scanner top rear cover (A) to the scanner unit assembly.
6.Lift the scanner top rear...

4-134MFP Service Manual 7500-XXX
Scanner left cover removal
1.Remove the two screws securing the scanner left cover (A) to the scanner unit assembly.
2.Disengage the rear side of scanner left cover (A) from the scanner unit assembly, and shift the scanner left 
cover (A) rearward. 
3.Release the two hooks securing the front side of scanner left cover (A), and remove the scanner left cover 
(A).
A 

Repair information4-135
7500-XXX
Scanner right cover removal
1.Remove the two screws securing the scanner right cover (A) to the scanner unit assembly.
2.Disengage the rear side of scanner right cover (A) from the scanner unit assembly, and shift the scanner 
right cover (A) rearward. 
3.Release the two hooks securing the front side of the scanner right cover (A), and remove the scanner right 
cover (A).
A 

4-136MFP Service Manual 7500-XXX
Operator panel assembly removal
Warning:  In the event of replacement of any one of the following components:
•Operator panel assembly (universal)
•Operator panel controller card assembly
•RIP card assembly
•Interconnect card assembly
Only replace one component at a time. Replace the required component, and perform a POR before replacing a 
second component listed above. If this procedure is not followed, the printer will be rendered inoperable. Never 
replace two or more...

Repair information4-137
7500-XXX
USB connector removal 
1.Remove the one screw securing the USB connector housing (A) to the operator panel assembly (B).
2.Pull the USB connector housing (A) from the operator panel assembly (B).
3.Remove the connector from the USB connector (C).
4.Remove the USB connector (C) from the USB connector housing (A).
Operator panel user touch screen removal
1.Remove the operator panel assembly. Go to “Operator panel assembly removal” on page 4-136.
2.Remove one screw securing...

4-138MFP Service Manual 7500-XXX
9.Remove the operator panel user touch screen (D).
Note:  Before reinstalling the operator panel user touch screen (D), ensure that all connections are properly 
replaced. 
Note:  Before reinstalling the operator panel assembly (B), ensure that all ground wires (A) are properly 
replaced.
Connectors
E
D
D
B
E
C
A
B
A 

Repair information4-139
7500-XXX
Operator panel controller card assembly removal 
1.Remove the operator panel assembly. Go to “Operator panel assembly removal” on page 4-136.
2.Remove one screw securing the ground wires (A) to the rear of the operator panel assembly (B).
3.Remove the six screws securing the bottom cover (C) to the operator panel assembly (B).
4.Remove the bottom cover (C) from the operator panel assembly (B).
Warning:  Be careful when removing ribbon connections to avoid damage.
5.Remove...

4-140MFP Service Manual 7500-XXX
Operator panel inverter card assembly removal 
1.Remove the USB connector. Go to “USB connector removal” on page 4-137.
2.Remove the operator assembly. Go to “Operator panel assembly removal” on page 4-136.
3.Remove one screw securing the ground wires (A) to the rear of the operator panel assembly (B).
4.Remove the six screws securing the bottom cover (C) the operator panel assembly (B).
5.Remove the bottom cover (C) from the operator panel assembly (B).
6.Remove the two...

Repair information4-141
7500-XXX
Scanner unit assembly removal 
1.Remove the ADF unit assembly. See “ADF unit assembly removal” on page 4-159.
2.Remove the operator panel assembly. See “Operator panel assembly removal” on page 4-136.
3.Remove the scanner left cover. See “Scanner left cover removal” on page 4-134.
4.Remove the scanner right cover. See “Scanner right cover removal” on page 4-135.
5.Remove the rear upper cover. See “Rear upper cover removal” on page 4-15.
6.Remove the scanner top rear...

4-142MFP Service Manual 7500-XXX
Large platen glass removal
1.Remove the two screws securing the large platen glass retainer (A) to the scanner unit assembly.
2.Remove the large platen glass retainer (A).
3.Gently lift the large platen glass (B) upward, and move it rightward in the direction of the arrow.
4.Remove the large platen glass (B).
Warning:  Do not drop the large platen glass (B), or damage will occur.
CAUTION: Avoid touching the underside of the large platen glass (B).
Note:  Before...