Lexmark C736 Service Manual

							Diagnostic aids3-45
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5.Reinsert tray 1.
6.Press Select ().
240 paper jam
If paper is jammed in Tray 1, 241.xx Paper jam appears. If paper is jammed in any of the optional trays, 24x.xx 
Paper jam appears. 
•If the jammed paper is located in tray 1, follow these steps to remove the paper from tray 1.
1.Open tray 1, and pull the jammed pages straight up and out.
2.If the jam is located in front of the tray, pull the jammed pages up and out.
3.After removing the tray, the front door may need to be opened to access the jam.
4.Close tray 1.
5.Press Select ().
•If the jammed pages are located in one of the optional trays, follow the appropriate steps below to remove 
the pages from an optional tray.
1.Open the specified optional tray, and pull the jammed pages out as illustrated.
2.After removing the tray, the tray above may need to be opened to access the jam.
3.Close the specified optional tray.
4.Press Select (). 
						

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250 paper jam
If paper is jammed in the multipurpose tray, 250.xx Paper jam appears.
1.Press the paper release lever, and then remove the jammed pages from the multipurpose tray.
2.Load new paper into the multipurpose tray.
3.Press Select (). 
						

							Repair information4-1
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4.  Repair information
Safety information
•The safety of this product is based on testing and approvals of the original design and specific 
components. The manufacturer is not responsible for safety in the event of use of unauthorized 
replacement parts. 
•The maintenance information for this product has been prepared for use by a professional service person 
and is not intended to be used by others.
•CAUTION: When you see this symbol, there is a danger from hazardous voltage in the area of the 
product where you are working. Unplug the product before you begin, or use caution if the product 
must receive power in order to perform the task.
Removal and cleaning precautions
Observe the following precautions whenever you service the printer:
•Be sure to unplug the printer from the outlet before attempting to service the printer.
•To reassemble the printer, reverse the order of removal unless otherwise specified.
•Do not operate the printer anytime during removals. If it is absolutely necessary to run the printer with its 
covers removed, use care not to allow your clothing to be caught in revolving parts such as the gears, 
rollers and fan motor.
•Never touch the terminals of electrical parts or high-voltage parts such as the high-voltage power supply.
•After part replacement, ensure the wiring harness is not caught or damaged. 
•Do not attempt to cut or extend the wiring harness. 
•Confirm the wiring harness connector is connected properly.
•Be sure to handle the fuser carefully, as it remains hot for a while after the printer stops running. Always 
unplug connectors by holding the connector housing.
Warning:  Read the following before handling electronic parts.
CAUTION—POTENTIAL INJURY:
The printer weight is greater than 54 lbs (24.5kg), and requires two or more trained personnel to 
lift safety. 
						

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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, follow the instructions below in addition to all the usual precautions, such as 
turning off power before removing electronic cards:
•Keep the ESD-sensitive part in its original shipping container (a special “ESD bag”) until you are 
ready to install the part in the printer.
•Make the fewest 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 printer.
•Hold the ESD-sensitive part by its edge connector shroud (cover); do not touch its pins.
•If you need to put down the ESD-sensitive part for any reason, first put it into its special bag.
•Printer 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 printer 
covers when you are not working on the printer, 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.
Handing the photoconductor unit
The following precautions must be observed when handling the photoconductor unit. The photoconductor unit is 
a supply item you will have to remove during some of the repair procedures:
Transportation/storage
Use the specified carton whenever moving or storing the photoconductor unit.
Handling
•The optical photoconductor roller in the photoconductor unit exhibits the greatest light fatigue after being 
exposed to strong light over an extended period of time. Never expose it to direct sunlight. Cover the 
photoconductor unit when you remove it from the printer. 
•Use care not to contaminate the surface of the optical photoconductor roller with an oil-based solvent, 
fingerprints, and other foreign matter.
•Do not scratch the surface of the optical photoconductor roller.
Parts not to be touched
Any part where the mounting screws are used to meet a printer alignment set at the factory must not be 
removed, disassembled, or adjusted. 
						

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Screw and retainer identification table
The following table contains screw types and retainers, locations, and quantities necessary to service the 
printer. Pay careful attention to each screw type location when doing removals. You must install the correct 
screw type in each location during reassembly.
Sizes are as close to actual as possible, as long as the printout is not scaled or resized.
Screw identification table
P/N Screw type Location Qty
10B1580 #6 panhead Cartridge cooling fan to top cover 2
Cooling fan to top cover 2
1126828 E-clip M3 LR overcenter bellcrank to side frame 1
1126829 E-ring M4 MP feeder gears to right side frame studs 2
18B0832 Taptite M3 L6 
panhead5 V interlock switch to right frame 1
Card support plate to upper plate 2
Card support plate to lower plate 3
Card support plate (and printhead ground) to left frame 5
Card support plate to right frame 4
Cartridge left guide assembly to left plate (interior side of plate assembly) 4
COD (color-on-demand) drive assembly to upper plate 3
COD shaft assembly to upper plate 2
Contacts assembly to left frame next to auger worm gear 2
Contacts assembly to left frame near duct 2
EP drive to right plate (exterior side) 8
Front door ground wire to right frame bracket 1
HVPS to left frame plate 1 
						

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18B0832
(Cont.)Taptite M3 L6 
panheadLaser support plate to lower plate 2
Left camshaft lock assembly to printer frame 2
Left frame assembly to laser support plate 2
Left frame assembly to lower plate 4
Lower plate to left frame assembly 2
LVPS support plate to right plate 4
LVPS to right frame plate and support bracket 5
Motor driver card to EP drive assembly 2
MPF driver cover to right frame 3
Right camshaft lock assembly to printer frame 2
Right frame assembly to laser support plate 2
Right frame assembly to lower plate 3
System board to RIP plate 9
Top cover assembly to printer frame 5
Upper plate to right frame assembly 3
Upper plate to left frame assembly 3
Upper plate to laser support plate 3
18B0939 Plastite M3x6
flatheadGearbox plate assembly to frame 4
18B2302 Machine M2.6 
L3-3.5MP feeder/duplex drive motor to rightside plate 2
18B2315 Machine M3 
panhead L35Printhead 1
27S2836 Taptite M3 L6 
panhead, blackLeft cover to printer frame (next to system board) 1
Rear cover frame to frame 8
Rear left cover to printer frame 1
Rear right cover to printer frame 1
Right cover to printer frame 4 Screw identification table (continued)
P/N Screw type Location Qty 
						

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27S2837 M3.5X1.34 panhead 
8L, blackLeft cover to lower frame 2
Rear left cover through lower swingout frame into left cover 1
Rear right cover to rear upper cover 1
Rear upper cover to top cover 1
Top cover to right cover 1
27S2838 Machine M3X0.5–
6GLContacts assembly to left/front edge of printer frame 2
Fax modem blank plate to left plate 1
ISP blank plate to left plate 2
Second USB connector to left frame 1
System board USB connector to frame 1
USB-A Blank plate to left plate 1
27S2839 Taptite M3 L6 
Taptite slotted hex 
blackRear cover frame to frame 8
88A0003 Machine M3X0.5-
6G 8LPrinthead 3
88A0095 M2.5x10 Machine 5 V interlock switch actuator assembly 1
24 V interlock switch and shield to right frame 1
88A0212 Taptite M3.5x0.6 
PANFuser AC cables ground wire to left plate 1
88A0232 Taptite M3 L6 
PANHDCartridge right guide assembly to rightside plate 10
Lower plate to lower swingout frame assembly 1
Lower swingout frame assembly to left frame assembly 4
Lower frame support to right frame assembly 4
88A0233 Taptite M3 L8 
PANHDLower swingout frame assembly to leftside frame assembly (rearmost 
position)1 Screw identification table (continued)
P/N Screw type Location Qty 
						

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88A0293 Plastite M2.2 L5 Contact spring cap to left guide assembly 4
88A0312 Plastite M2.9 L6 
PANBackup springs to reference edge plate assembly 2
Cartridge cooling fan duct to top cover 2
Cartridge left guide assembly to leftside plate assembly (exterior side of plate 
assembly)4
Cover mount to rightside plate 3
Display detent spring to display back bezel 1
Door straps to front access door cover 2
Door bracket to front access door cover 2
Duplex entry guide to front access door cover 4
Exterior screws attaching cover bracket to front access door cover 2
Front cover bracket to front access door cover 4
Ground terminal/operator panel card to top access door cover CBM 1
Lower frame support to lower left frame assembly 2
Operator panel card to top access door cover CBM 3
Option locator to rightside plate 1
88A0313 Plastite M2.9 L8 
PANContacts assembly to leftside cartridge guide 1
Cover bracket to front access door cover 2
Cover pivot to swingout frame 3
HVPS to transfer contact assembly 3
HVPS to leftside cartridge guide assembly 2
Interior screws attaching cover bracket to front access door cover 2
88A0323 M3.5X1.34 Panhead 
8LDuplex upper guide to top access door cover CBM 9
Ground strap/contact to front door frame 1
Lower right frame to right side plate 3
Pick assembly to lower plate 4
Secures reference edge assembly to door assembly 2
Static brush bracket to top access door cover CBM 1
Torque tube cover to front door frame 6
88A0324 M3.5X1.34 PANHD 
10LEP drive to rightside plate 2
Secures door cap to door assembly 1 Screw identification table (continued)
P/N Screw type Location Qty 
						

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88A0412 M2.9x5.2 Plastite GS COD bellcranks to guide 3
NGS COD bellcranks to guide 3
Top access door assembly to fuser retract link 1
Top cover left link to cover 1 Screw identification table (continued)
P/N Screw type Location Qty 
						

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Adjustments
Printhead alignment
Overview
When aligning the printhead, it is important to keep in mind that the printhead mounting screws should be initially 
loose enough to just hold the printhead in the printer. This allows the pages to be printed that will be used to 
align the black plane to the printer frame and also allows skew adjustment with the printhead alignment screw. 
Once the black skew is adjusted, the mounting screws are fully tightened.
There is one printhead that houses the four color planes. The black plane is aligned to the printer, and the color 
planes are internally aligned to black. Electrical alignment is done to fine tune the alignment of the color planes 
to the black plane once the printhead is installed and skew is adjusted.
The first step in aligning the printhead is to loosen the printhead mounting screws, and to set the skew for black. 
Note:  If you need to replace the printhead, see “Printhead removal, installation, and adjustment” on 
page 4-135. 
Printhead mechanical alignment
Skew (black)
1.Turn off the printer.
2.Disconnect the power cord from the electrical outlet.
3.Remove the transfer module and photoconductor units:
a.Disconnect the transfer module cable (A). 
b.Press the two tabs (B) to release the front access cover assembly.
c.Press the two tabs (C) on either side of the transfer module, and lift out the transfer module.
Note:  Leave the photoconductor units on the transport belt when removing. 
To avoid damaging the photoconductor drum, place the transfer module with the photoconductor 
units on a clean surface. Never expose the photoconductor units to light for a prolonged period of 
time. You can place a clean, dry cloth over the transfer module and photoconductor units until they 
are required.
AC
B