Lexmark C 950 Service Manual

							Diagnostic aids 3-129
  5058-030
Go Back Previous
Next
Tray lifting
Tray lift operation starts automatically when the HCF media tray is inserted with media loaded.
Media is lifted and stops at the feeding position. At the same time, detection of no media and remaining media 
volume becomes available.
Media out detection
This function checks whether media is loaded in the HCF media tray.
When media is present, the media out actuator in the middle of the HCF is raised as media is lifted, and leaves 
the sensing area of the sensor (media out), which makes the sensor light-receivable. The presence of media is 
detected.
On the other hand, if media out occurs when the HCF media tray is at the feeding position, the media out 
actuator comes inside the sensing area of the sensor (media out), which blocks the light transmission of the 
sensor (media out). Media out is detected.
Feed lift gear bracket asm HCF feed lift motor
Bottom plate 
						

							3-130  Service Manual 5058-030  
Go Back Previous
Next
If the HCF media tray is not lifted, the media out actuator remains in the sensing area of the sensor (media out), 
while blocking the light transmission of the sensor (media out). Media out is detected regardless of the presence 
of media in the tray.
Detection of media out is carried out constantly after the lifting operation is completed.
When media out is detected, media transfer from the HCF is inhibited.
If media out is detected during printing, print operation of the next media is stopped. However, when the printer 
is operating in the Auto Tray Select mode and there is media of the same size in another tray, media is 
automatically fed out of the tray.
Sensor (media out) 
Detects whether media is present in the HCF media tray.
When this sensor (media out) is off while the tray is at the feeding position, the presence of media is detected.
Remaining media volume detection
This function determines the media volume remaining in the HCF media tray by using the HCF feed lift motor 
rotation time and the sensor (media level) during the tray lifting time. The printer notifies operators of remaining 
media volume as 25%, 50%, 75%, full, or 0 (zero).
If the remaining media volume becomes zero before no media is detected, the indication remains at (25%).
When the sensor (media level) detects no media, the indication becomes (0) (zero).
When a fault occurs, determination of remaining media volume is carried out as shown below.
•When the interlock is opening during the lifting operation, the remaining media volume is determined 
based on the total of the time it takes for the interlock to open, plus the amount of time that transpires from 
the media feed lift motor forward/reverse rotation until the sensor comes on.
•When the power is turned off and on during the lifting operation, the remaining media volume is determined 
by the lifting time after the power comes on. (The actual volume of media in the tray may differ from the 
indication.)
Sensor (media out)Media out actuator 
						

							Diagnostic aids 3-131
  5058-030
Go Back Previous
Next
•When the power is turned off and on while the tray is at the feeding position, the sensor (media level) is on 
when the power is turned on, and the remaining media volume before the previous power off is regarded 
as the remaining media volume.
•If the sensor (media level) is off when the power is turned on, the HCF regards the HCF media tray as 
having been removed, and determines the remaining media volume based on the time from the media feed 
lift motor forward/reverse rotation until the sensor (media level) comes on.
Sensor (media level)
Detects the media feeding position in the tray in order to control the media position.
While this sensor (media level) is off, lifting the tray is continued until the sensor (media level) turns on.
Sensor (media level)HCF pick solenoid
HCF feed lift motor
Front 
						

							3-132  Service Manual 5058-030  
Go Back Previous
Next 
						

							Repair information 4-1
  5058-030
Go Back Previous
Next
4.  Repair information
Warning:  Read the following before handling electronic parts.
Handling ESD-sensitive parts 
Many electronic products use parts that are known to be sensitive to electrostatic discharge (ESD). To prevent 
damage to ESD-sensitive parts, use the following instructions in addition to all the usual precautions, such as 
turning off power before removing logic boards:
•Keep the ESD-sensitive part in its original shipping container (a special “ESD bag”) until you are ready to 
install the part into the machine.
•Make the least-possible movements with your body to prevent an increase of static electricity from clothing 
fibers, carpets, and furniture.
•Put the ESD wrist strap on your wrist. Connect the wrist band to the system ground point. This discharges 
any static electricity in your body to the machine.
•Hold the ESD-sensitive part by its edge connector shroud (cover); do not touch its pins. If you are removing 
a pluggable module, use the correct tool.
•Do not place the ESD-sensitive part on the machine cover or on a metal table; if you need to put down the 
ESD-sensitive part for any reason, first put it into its special bag.
•Machine covers and metal tables are electrical grounds. They increase the risk of damage, because they 
make a discharge path from your body through the ESD-sensitive part. (Large metal objects can be 
discharge paths without being grounded.)
•Prevent ESD-sensitive parts from being accidentally touched by other personnel. Install machine covers 
when you are not working on the machine, and do not put unprotected ESD-sensitive parts on a table.
•If possible, keep all ESD-sensitive parts in a grounded metal cabinet (case).
•Be extra careful in working with ESD-sensitive parts when cold-weather heating is used, because low 
humidity increases static electricity.
Turning the printer off
Note:  This procedure is performed to preserve the operator panel memory settings.
1.Press the Sleep button to turn off the operator panel.
2.Open the front door and switch off the printer. 
						

							4-2  Service Manual 5058-030  
Go Back Previous
Next
Removal procedures
Notes:  
•Some removal procedures require removing cable ties. You must replace cable ties during reassembly to 
avoid pinching wires, obstructing the paper path, or restricting mechanical movement.
•Remove the waste toner bottle, color toner cartridges, imaging unit, and media tray before removing other 
printer parts. The imagine unit should be carefully set on a clean, smooth, and flat surface. It should also 
be protected from light while out of the device.
•Disconnect all external cables from the printer to prevent possible damage during service.
•Unless otherwise stated, reinstall the parts in reverse order of removal.
•When reinstalling a part held with several screws, start all screws before the final tightening.
CAUTION
Remove the power cord from the 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 PCs/peripherals.  
						

							Repair information 4-3
  5058-030
Go Back Previous
Next
Cover removal procedures
Inner cover removal
1.Remove the printer front door. See “Printer front door removal” on page 4-10.
2.Remove the transfer belt cleaner. See “Transfer belt cleaner removal” on page 4-175.
3.Remove the waste toner box.
4.Rotate the transfer belt lever counterclockwise to the unlock position.
5.Open the printhead retract door.
6.Remove the four photoconductor units.
7.Remove the four toner supplies.
8.Remove the operator panel front cover. 
9.Remove the printhead retract door. See “Printhead retract door removal” on page 4-142.
10.Open the printer left duplex door. 
						

							4-4  Service Manual 5058-030  
Go Back Previous
Next
11.Remove the six screws (A) from the inner cover.
12.Remove the inner cover.
A 
						

							Repair information 4-5
  5058-030
Go Back Previous
Next
Internal rear cover removal
1.Remove the top cover. See “Printer top cover removal” on page 4-12.
2.Remove the two screws (A) from the internal rear cover.
3.Remove the internal rear cover.
A 
						

							4-6  Service Manual 5058-030  
Go Back Previous
Next
Left rear lower cover removal
1.Open the printer left duplex door.
2.Remove the two screws (A).
3.Remove the left rear lower cover.
Left upper cover removal
1.Open the printer left duplex door.
2.Open the upper redrive door.
3.Remove the two screws (A).
4.Remove the left upper cover.