Lexmark X 850 Owners Manual

General information1-69
7500-XXX
Exit 2
Exit 2 drive motor
The rotating force of the exit 2 drive motor is transmitted through the gears to components that need mechanical 
driving force as shown below.
The transmitted driving force drives the exit 2 media transport roll assembly and the exit 2 media exit roll 
assembly through the gears.
Exit 2 drive motor
Exit 2 drive gear 19T
Exit 2 drive gear 19/44T
Exit 2 drive gear 19T
Exit 2 media transport roll asmExit 2 drive gear 19T
Exit 2 media exit roll asm 

1-70MFP Service Manual 7500-XXX
Media transport
Media transport path
With the exit 2 installed, media is supplied from the MPF, tray 1, or tray 2 and is transported to the printer along 
the media transport path shown below.
MPF
MPF pick roll
MPF Transport Roll ASM
MPF ASMMedia feed
unit ASMMedia feed
unit ASM Pick roll Pick roll
Separation roll Separation roll
Feed roll
Media transport roll ASM
Registration roll ASM
Transfer roll ASM
PC cartridge Drum
Heat roll
Pressure roll
Fuser unit ASM
Exit 1 media...

General information1-71
7500-XXX
Layout of media transport path
The following figure illustrates the main components directly associated with the media path and transport with 
the exit 2 installed.
Functions of Main Components
Drive motor
The drive motor is a stepping motor driving the transport roll assembly and media exit roll assembly. Forward 
rotation of this motor drives these rollers to feed media to the exit 2 standard bin. Reverse rotation of this motor 
drives the transport roll assembly to...

1-72MFP Service Manual 7500-XXX
Exit interface card assembly (located in the printer)
The exit interface card assembly contains a CPU and controls media feed in the exit 2 upon receiving a 
command from the printer engine card assembly and sensor/switch information.
Exit 2 left door assembly
The left door assembly detects open/close of the exit 2.
Sensor (exit 2)
The sensor (exit 2) detects whether media is remaining in the exit 2.
Sensor (Standard bin full exit 2)
The sensor (exit 2 standard bin full)...

General information1-73
7500-XXX
Exit 2 transport roll assembly and media exit roll assembly 
The exit 2 transport roll assembly and exit 2 media exit roll assembly are rollers used to eject media to the exit 2 
standard bin or to feed media to the duplex.
Tools required for service
Flat-blade screwdriver
#1 Phillips screwdriver, magnetic
#2 Phillips screwdriver, magnetic
#2 Phillips screwdriver, magnetic short-blade
Needle nose pliers
Diagonal side cutters
Spring hook
Analog or digital multi meter...

1-74MFP Service Manual 7500-XXX
Acronyms
2TM 2 Tray Module
AC Alternating Current 
ADF Automatic Document Feeder
APS Automatic Paper Size
ASIC Application Specific Integrated Circuit
CRU Customer Replaceable Unit
CSU    Customer Setup
CCW Counterclockwise
CW Clockwise
DC Direct Current 
DIMM Dual Inline Memory Module
DRAM  Dynamic Random Access Memory
EDO Enhanced Data Out
EP     Electrophotographic Process
EPROM Erasable Programmable Read-only Memory
ESD    Electrostatic Discharge
FRU    Field...

General information1-75
7500-XXX
TVOC Total Volatile Organic Compound
UPR    Used Parts Return
VVolts 
V ac Volts alternating current
V dc Volts direct current 

1-76MFP Service Manual 7500-XXX 

Diagnostic information2-1
7500-XXX
2.  Diagnostic information
Start
CAUTION: Unplug the power cord from the printer or electrical outlet before you connect or disconnect 
any cable or electronic board or assembly for personal safety and to prevent damage to the printer. 
Disconnect any connections between the printer and PC peripherals. 
CAUTION: The MFP weighs approximately 106 kg (233 lb) and requires at least four people to lift it 
safely. Make sure your fingers are not under the MFP when you lift or...

2-2MFP Service Manual 7500-XXX
Confirm the installation status
Be sure to check the following items before starting the troubleshooting procedures.
•With the power cord unplugged from the wall outlet, check that the cord is free from breakage, short-circuit, 
disconnected wire, or incorrect connection in the power cord.
•The printer is properly grounded. Check the power cord ground terminal.
•The printer is not installed at a place subjected to extreme temperature, extreme humidity or rapid changes 
in...