Lexmark C760 Service Manual

							
Diagnostic information2-105
  5060-4xx
AC and DC power service check
Before proceeding with this service check remove or disconnect any options that may be installed. Turn the 
machine on. If it operates correctly, reattach one option at a time until the failing option is located.
Note:  Set the voltage range switch to the proper power setting for the geographic area you are in.
Note:   Before proceeding with this service check turn the printer on and check to see if the Power on LED on the 
system board is turned on.
AC power service check
The printer appears to be inoperative when turned on with the Power on/Status LED off, the LCD 
display is blank, the Fuser lamps do not come on and no motors turn.
Step Actions and questions Yes No
1 Is the LED turned on? Go to  “AC power 
service check” 
on page 2-105 Go to 
“DC power 
service check” 
on page 2-106
Step Actions and questions Yes No 1 Main AC power - Make sure the printer is receiving 
main AC power.
Is the printer receiving AC power? Go to step 2 Inform the 
customer that AC 
power to the 
printer is 
incorrect.
2AC power check (wall outlet) - Check the AC line 
voltage at the AC outlet.
Is the AC line voltage correct? Go to step 3 Inform the 
customer that the 
AC line voltage is 
incorrect
3AC power cord
Is the power cord in good condition and correctly 
installed? Go to step 4 If the cord is in 
poor condition, 
replace the cord
4AC power check (AC line cord) - Check the AC line 
voltage at the end of the AC line cord.
Is the AC line voltage correct? Go to step 5 Replace the line 
cord
5Check the AC voltage range switch (A).
Is the switch set properly? Go to step 6 Set switch to the 
proper voltage. 
						

							
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DC power service check
The machine is partially operative, a motor turns, display is on or the Power On LED may be on or off.
6Low voltage power supply - Turn the power off and 
disconnect the LVPS at J35 on the system board. 
Measure the voltages on J35-3 and J35-4. The voltage 
should measure approximately +5 V dc.
Is there approximately +5 V dc on any of these 
connector pins?Replace the 
“System board” 
on page 4-72
Replace the 
“LVPS 
assembly” on 
page 4-46
Step Actions and questions Yes No 1 Does the printer beep 5 times and the operator panel 
display all diamonds? Go to 
“Operator 
panel LCD/
status LED/
buttons service 
check” on 
page 2-125 Go to step 2
2DC power to system board - Turn the power off and 
disconnect the LVPS cable to J35 on the system board. 
Turn the power on and check the following voltages on 
the LVPS cable:
Note
: All voltages are approximate values.
Are the voltages correct? Go to step 3 Replace the 
“LVPS 
assembly” on 
page 4-46
3Unplug all cables from the system board, except J6, 
J35, J37. See “System board - non-network” on 
page 5-6  or “System board - network” on page 5-7 . 
Does the printer power up and display a message? Go to step 4 Replace the 
“System board” 
on page 4-72.
Step Actions and questions Yes No
J35-1 +3.3 V dc
J35-2 +3.3 V dc
J35-3 +5 V dc
J35-4 +5 V dc
J35-5 +24 V dc
J35-6 +24 V dc
J35-7 +24 V dc
J35-8 +3.3V dc
J35-9 Ground
J35-10 Ground
J35-11 Ground
J35-12 Ground
J35-13 Ground
J35-14 Ground
J35-15 Ground
J35-16 Ground 
						

							
Diagnostic information2-107
  5060-4xx
Autocompensator service check
If the paper fails to feed from Tray 1 or 500-sheet option, go to  “Step A” on page 2-107.
If the autcompensator fails to lower when Tray 1 is installed, go to  “Step B” on page 2-108.
If the autocompensator fails to retract when you attempt to remove Tray 1, go to  “Step C” on page 2-108.
If there is no indication that the media is out or low, go to  “Step D” on page 2-109.
Note:   When feeding paper through the printer to check for autocompensator problems, use the Tray 1 Feed test 
in the Diagnostics Menu. A printed copy is not required.
Step A
4Turn off the printer and plug in the cable for the 
component that is related to the error presented. For 
example, for the 114 Service Printhead error, plug in 
the black printhead J11 and J12. Use connector 
locations on  “System board - non-network” on 
page 5-6  or “System board - network” on page 5-7 .
Repeat this step until the original DC power problem 
occurs.
Does the DC power problem occur? Check the cable 
and component 
that was last 
connected to 
system board for 
short.
If printer comes 
to Ready, 
connect the 
remaining cables 
and print.
Step Action and questions Yes No 1 Use the tray 1 feed test to feed paper from tray 1. 
Check to see if the pick rolls are turning.
Note: Observe the pick rolls by opening the lower jam 
access door assembly.
Do the pick rolls turn? Go to step 2 Go to step 3
2Check the autocompensator pick rolls for 
contamination or damage to the rolls.
Is there any excessive contamination or damage to the 
pick rolls?
Replace the pick 
rolls. Always 
replace both pick 
rolls at the same 
time.Go to step 3
3Verify the autocompensator is not stuck in the up 
position. Verify the output clutch assembly is not 
damaged.
Is the autocompensator stuck or the output clutch 
damaged. Dislodge the 
autocompensator 
assembly. 
If this does not fix 
the problem, go 
to step 4.Replace the 
“Autocompensa
tor pick 
assembly” on 
page 4-20
.
4Check the voltages at J25-9 and J25-10 on the system 
board.
Are the voltages correct? Replace the 
“Autocompensa
tor pick 
assembly” on 
page 4-20Replace the 
“System board” 
on page 4-72
Step Actions and questions Yes No 
						

							
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Step B
Step C
Step Action and questions Yes No
1 Check Tray 1 for damage to the pick arm lift bellcrank 
activation tabs on the rear of the tray.
Is there any damage to the tray? Replace tray 1 Go to step 2
2Check the following parts for damaged, loose, or 
missing parts.
 Pick ar m lift bellcrank
 Bellcrank lift spring
 Tray interlock bellcrank
Are any of the parts broken, loose, or missing? Repair or replace 
parts as 
necessary
Go to step 3
3Verify the autocompensator is not stuck in the up 
position (tires or hub caught on the upper deflector)
Dislodge the 
autocompensator 
assembly.Replace the 
“Autocompensa
tor pick 
assembly” on 
page 4-20
.
Step Action and questions Yes No 1 Can you remove Tray 1 from the printer? Go to step 3 Go to step 2
2Open the lower jam access door and carefully lift the 
autocompensator assembly until it is in its uppermost 
position, and carefully tr y to remove tray 1.
Can you remove Tray 1? Go to step 3 Determine what 
is causing the 
tray to stay in a 
locked position. 
Repair as 
necessary
3Check Tray 1 for damage to the pick arm lift bellcrank 
activation tabs on the rear of the tray.
Is there damage to the tray? Replace tray 1 Go to step 4
4Check for loose or broken parts on the 
autocompensator assembly.
Are there loose or broken parts?Replace the 
autocompen-
sator assembly
Go to step 5
5Check the following parts for any signs of damaged or 
broken parts.
 Pick ar m lift bellcrank
 Pick arm bellcrank lift spring
Are there any damaged or broken parts? Repair or replace 
parts as 
necessary
Determine what 
is causing the 
autocompen-
sator to stay in 
the down 
position. Repair 
as necessary. 
						

							
Diagnostic information2-109
  5060-4xx
Step D
Black only retract (BOR) service check
Step Action and questions Yes No
1 Enter the Diagnostics Mode and select  INPUT TRAY 
TESTS, Sensor Test,  and Tr a y  1 . You can activate the 
paper level sensor inside the printer. The paper level 
sensor is a dual sensor and checks the following levels 
for  Tr ay 1.
The Tray 1 level sensor is a dual sensor assembly that 
senses when tray 1 is empty, nearly empty, or partially 
empty.
Does the Sensor Test pass? Call your next 
level support
Go to step 2
2Paper level sensing assembly - Make sure the 
assembly is not loose or damaged. Make sure the 
bellcrank is not broken.
Are any parts loose or broken? Repair or replace 
parts as 
necessary
Go to step 3
3Check the paper level sensing cable for correct 
installation at J25 on the system board and to the 
paper level sensing dual sensor assembly.
Is the cable connected correctly? Go to step 4 Install the cable 
correctly
4Check the paper level sensing assembly flag for correct 
installation and the flag is not broken or damaged.
Is the paper level sensing assembly installed correctly 
and the flag not broken or damaged? Go to step 5 Install correctly or 
replace the flag if 
damaged or 
broken
5Check continuity of the paper level sensing cable.
Is there continuity? Go to step 6 Replace the level 
sensing cable
6Check the voltage at J25. It should measure 
approximately +5 V dc.
Is the voltage correct? Replace the level 
sensing 
assembly
Replace the 
“System board” 
on page 4-72
Step Action and questions Yes No 1 Using the toggle ITU function in diagnostics Mode, test 
the BOR system. Remove the print cartridges and 
watch the belt while activating the toggle function.
Does the ITU belt move up and down when the ITU is 
toggled? Go to 
“Print 
quality service 
check” on 
page 2-130 .Go to step 2
2Remove the ITU. Locate the BOR gear and manually 
activate the gear. Verify that the front and back BOR 
cams are moving the respective bell cranks.
Do the cams move back and forth properly? Replace in the 
following order:
1. “BOR drive 
assembly” 
on 
page 4-28 .
2. “System 
board” on 
page 4-72 .Determine which 
component is 
preventing the 
proper 
movement. 
						

							
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Close door/HVPS/printhead interlock switch service check
Note:  There are two separate cables that contain microswitches and a cable. These cable/switches provide 
separate interlocks for the printhead and HVPS. One switch in the Printhead/cover open cable is mounted in the 
front access door support and the other switch in the printhead/open cover cable is mounted on the ITU light 
shield assembly. The HVPS/cover open cable only has one switch mounted on the front access door support 
and is routed through the ITU autoconnect. The HVPS/cover open cable is connected to J28 on the system 
board and the printhead/cover open cable is connected to J10 on the system board.
POR incomplete, Close Door constantly displays
This symptom is usually associated with the lower switch mounted on the front access door support and with the 
switch mounted in the ITU light shield.
Note:   When the printer is powered on for some time with this symptom displayed, the printer may then display a 
902 Service Error.
Step Action and questions Yes No 1 Make sure that the ITU light shield is not out of 
position.
Is the ITU light shield out of position? Properly align the 
ITU light shield
Go to step 2
2Make sure the ITU assembly interlock switch actuator 
is not damaged or broken and actuates the switches 
correctly.
Is the actuator damaged or broken? Replace the 
“ITU 
assembly” on 
page 4-44 Go to step 3
3Front cover assembly
Does the front cover close correctly?
Go to step 4 Install the front 
cover correctly or 
repair as 
necessary
4Front cover assembly
Make sure the front cover flag is not broken or 
damaged and actuates the switches correctly.
Is the flag broken or damaged? Replace the 
“Front cover 
assembly” on 
page 4-14
Go to step 5
5Printhead/cover open interlock cable assembly
Make sure that the cable is correctly connected to J10 
on the system board.
Is the cable connected correctly? Go to step 6 Install the cable 
correctly
6Make sure the front cover is closed and the ITU is 
correctly installed. Disconnect J10 from the system 
board and check for continuity between pins J10-1 and 
J10-3.
Do you measure continuity? Replace the 
“System board” 
on page 4-72
Replace the 
printhead 
interlock cable/
switch assembly 
(see 
“Printhead 
interlock cable 
assembly” on 
page 7-22  for the 
part number.) 
						

							
Diagnostic information2-111
  5060-4xx
POR complete, printer feeds blank page
This symptom is usually associated with the upper switch mounted on the front access door support. 
Step Action and Questions Yes No 1 Make sure that the ITU light shield is not broken.
Is the ITU light shield broken? Replace the ITU 
light shield
Go to step 2
2Make sure that the ITU light shield is not out of 
position.
Is the ITU light shield out of position? Properly align 
ITU light shield
Go to step 3
3Make sure the ITU assembly interlock switch actuator 
is not damaged or broken and actuates the switch 
correctly.
Is the actuator damaged or broken? Replace the 
“ITU 
assembly” on 
page 4-44 Go to step 4
4Front cover assembly
Does the front cover close correctly?
Go to step 5 Install the front 
cover correctly or 
repair as 
necessary
5Front cover assembly
Make sure the front cover flag is not broken or 
damaged and actuates the switches correctly.
Is the flag broken or damaged? Replace the 
“Front cover 
assembly” on 
page 4-14
Go to step 6
6HVPS/cover open interlock cable assembly to system 
board - Make sure that the cable is correctly connected 
to J28 on the system board and the ITU autoconnect is 
seated correctly.
Is the cable connected correctly? Go to step 7 Install the cable 
correctly
7HVPS/cover open interlock cable assembly - Make 
sure the front cover is closed and the ITU is correctly 
installed. Disconnect the switch cable from J28 on the 
system board. Check for continuity between J28-1 and 
J28-2 on the cable connector.
Is there continuity? Replace the 
“System board” 
on page 4-72
Replace the 
HVPS/cover 
open interlock 
switch/cable 
assembly (see 
“Printhead 
interlock cable 
assembly” on 
page 7-22
 for 
part number.) 
						

							
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Duplex option service check
Before proceeding with this service check:
1.Check for any pieces of media or obstructions in the duplex paper path that might cause a paper jam.
2.Check for correct installation of the front duplex jam tray and right side clearance tray.
3.Check the duplex option for any signs of loose, damaged, contaminated, or warped parts that might cause 
a jam.
 Duplex not recognized as being installed
Step Action and questions Yes No
1 Is duplex option the only option installed beneath the 
base printer? Go to step 3 Go to step 2
2Except for the duplex option, remove any other paper 
options installed beneath the base printer.
Does the printer recognize the duplex option as being 
installed?The problem is in 
one of the 
option(s) that is 
installed beneath 
the printer. Try to 
isolate which of 
the options is 
causing the 
problem.Go to step 3
3Make sure the duplex option is correctly installed.
Is the duplex option installed correctly?
Go to step 4 Install the duplex 
option correctly
4Make sure the bottom options cable connector is 
snapped firmly into the bottom of the base machine.
Is the cable connector mounted correctly? Go to step 5 Install the cable 
correctly
5Make sure the bottom options cable is installed 
correctly to system board connector J37.
Is the cable installed correctly? Go to step 6 Install the cable 
correctly
6Check the voltages on connector J37 on the system 
board. The voltages are measured with the printer in 
standby mode:
Note: All voltages are approximate values.
Are the voltages correct? Go to step 7 Replace the 
system board
Connector pin Voltage
J37-1 +5 V dc
J37-2 Ground
J37-3 Ground
J37-4 +5 V dc
J37-5 +24 V dc
J37-8 +5 V dc
J37-7 +5 V dc 
						

							
Diagnostic information2-113
  5060-4xx
Top margin on duplexed copy set incorrectly
Go to “Duplex Quick Test” on page 3-24  to adjust the top margin on the back of the duplexed page.
7Check the voltages on the bottom options cable 
connector. The voltages are with the printer in standby 
mode.
Note: All voltages are approximate values.
Are the voltages correct? Go to step 8 Replace the 
bottom options 
cable in the 
printer
8Make sure the upper options cable in the duplex option 
is installed correctly in the duplex frame.
Is the cable installed correctly? Go to step 9 Correctly install 
the cable. If the 
connector is 
damaged, 
replace the cable 
assembly.
9Make sure the upper options cable in the duplex option 
is connected correctly to J11 on the duplex options 
board.
Is the cable connected correctly? Go to step 10 Install the cable 
correctly
10Check continuity of the upper duplex options cable.
Is there continuity? Replace the 
duplex options 
boardInstall the cable 
correctly
Step Action and questions Yes No
Connector pin Voltage
J37-1 +5 V dc
J37-2 Ground
J37-3 Ground
J37-4 +5 V dc
J37-5 +24 V dc
J37-7 +5 V dc
J37-8 +5 V dc 
						

							
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Envelope feeder option service check
Note:  Except for the tray and pick tires, the envelope feeder option is a complete assembly with no other 
internal parts that can be replaced.
If a 24x paper jam (x=envelope feeder) is displayed, go to  “Envelope feeder” on page 2-77. 
The printer does not recognize that the envelope feeder option is installed
Step Action and questions Yes No
1 Is the envelope feeder option the only option that is not 
recognized? Go to step 2 Go to step 6
2Are the other options that are not recognized installed 
below the envelope feeder?Replace the 
envelope feeder 
optionGo to step 3
3Make sure the printer and any option installed above 
the envelope feeder option is installed correctly.
Is the option installed above the envelope feeder 
installed correctly? Go to step 4 Install the printer 
or options 
correctly and 
recheck 
performance
4Check for the correct installation of the lower options 
autoconnect cable for the system board connector J37.
Is the cable installed correctly? Go to step 5 Install the cable 
correctly and 
recheck 
performance
5Autoconnect cable - Check the autoconnect from the 
printer or option installed above the envelope feeder. 
Check for cuts, pinched wiring, or damage to the 
contacts in the connector. Go to the service 
check for the 
option mounted 
above the 
envelope feederReplace the 
envelope feeder
6Disconnect the autoconnect cable from J37 on the 
printer system board. Measure the voltages on J37, the 
voltages are approximate values and should measure:
Are the voltages correct? Go to step 7 Replace the 
system board
7Check continuity of the autoconnect cable.
Is there continuity? Replace the 
envelope feeder 
optionReplace the 
autoconnect 
cable
Connector pin Voltage
J37-1 +24 V dc
J37-2 Ground
J37-4 +5 V dc
J37-5 +5 V dc
J37-7 +5 V dc
J37-8 +5 V dc