Lexmark C920 Service Manual page 99

Paper has stopped at the registration roller or has not reached the fuser (areas C, E,
250, 24x).
FRU
1 • Registration roller
clutch
• Registration roller
• Transfer belt unit
• Rear paper feed guide
2 • Registration sensor
• Printer controller board
Paper has exited the registration roller and entered the fuser (areas A and B).
FRU
1 • Transfer belt unit
• Rear paper guide
• Discharge brush
• Fuser
2 Fuser separation pawl
Paper has entered the fuser and exited the printer (area B).
FRU
1 Fuser
2 • Fuser exit lower roller
• Fuser exit upper roller
• Face-up exit assembly
3 • Face down exit
assembly
• Face down feed roller
belt
Action
Check these parts for wear or damage. Replace as necessary. Be
sure all guide surfaces in the paper path are free of dirt.
Check the registration roller clutch for continuity. Does the clutch
engage when the printer is printing a job?
Be sure connector CN7 on the CK1 daughter board is connected
properly.
Check for a fluctuation of between 0 V and +5 V between pins 1
and 2 of connector CN6 on the CK1 daughter board while
actuating the sensor. If the voltage fluctuates as stated above,
replace the printer controller board. If the voltage does not
fluctuate, replace the sensor.
Action
Remove any buildup of toner. Replace any damaged or worn parts.
Check the paper exit flag on the fuser for damage. Replace the
fuser if necessary.
Replace the fuser if paper jams cannot be removed.
Action
Remove any toner buildup, and replace any worn or damaged
parts.
Be sure the exit FU/FD solenoid energizes in the correct position
for either face-down or face-up delivery.
Do a continuity check of the solenoid. Be sure connector CN7 is
properly connected to the CK2 daughter board.
Be sure that connector CN4 is properly connected to the controller
board.
Check the face-down feed roller belt.
Check for a fluctuation of between 0 V and +5 V on the printer
controller board between the following pins, when actuating the
sensor:
Paper exit switch–CN7 on the Ck2 daughter board (pins 4 and 5).
5056-XXX
2-57
Diagnostic information