Lexmark C760 Service Manual

							
Diagnostic information2-85
  5060-4xx
925 error code
Fuser fan (main fan)
926 error code
VTB Fan service check
Step Actions and questions Yes No
1 Turn the power off and manually spin the fan and check 
that it rotates freely.
Does the fan rotate freely? Go to step 2 Replace the 
“Fuser fan” on 
page 4-38
2Check the fuser fan cable connection to the system 
board, J31 for correct installation.
Is the cable installed correctly? Go to step 3 Install the cable 
correctly
3Disconnect the fuser fan from J31 on the system board 
and check the voltages on J31.
Are the voltages correct? Replace the 
“Fuser fan” on 
page 4-38
Replace the 
“System board” 
on page 4-72
Step Actions and questions Yes No 1 Turn the power off and manually spin the fan and check 
that it rotates freely.
Does the fan rotate freely? Go to step 2 Replace the 
“Vacuum 
transport belt 
(VTB) fan” on 
page 4-79
2Check the VTB fan cable connection to the system 
board, J32 for correct installation.
Is the cable installed correctly? Go to step 3 Install the cable 
correctly
3Disconnect the VTB fan from J32 on the system board 
and check the voltages on J32.
Are the voltages correct? Replace the 
“Vacuum 
transport belt 
(VTB) fan” on 
page 4-79
Replace the 
“System board” 
on page 4-72
Pin Fan on Fan off Fan disconnected
Fan switch onFan discon-
nected
Fan switch 
off
J31-1 +1.6 V dc +3.3 V dc +3.3 V dc +3.3 V dc
J31-20 V0 V0 V 0 V
J31-3 +1.9 V dc 0 V dc 0 V +2 V dc
J31-4 +24 V dc +24 V dc +24 V dc +24 V dc
J31-5 Ground
Pin Fan on Fan off Fan  disconnected
fan switch onFa n  
disconnected
fan switch off
J32-1 +1.6V dc +3.3 V dc +3.3 V dc +3.3 V dc
J32-20 V0 V0 V 0 V
J32-3 +3.1 V dc 0 V dc 0 V +2 V dc
J32-4 +24 V dc +24 V dc +24 V dc +24 V dc 
						

							
2-86Service Manual
5060-4
xx   
927 error code
RIP Fan service check
930 error code
LV P S
This problem with the fuser circuits is usually the zero crossover signal from the LVPS not working correctly.Step Actions and questions Yes No
1 Turn the power off and manually spin the fan and check 
that it rotates freely.
Does the fan rotate freely? Go to step 2 Replace the 
“RIP 
fan” on 
page 4-69
2Check the RIP fan cable connection to the system 
board, J3 for correct installation.
Is the cable installed correctly? Go to step 3 Install the cable 
correctly
3Disconnect the RIP fan from J3 on the system board 
and check the voltages on J3.
Are the voltages correct? Replace the 
“RIP 
fan” on 
page 4-69 Replace the 
“System board” 
on page 4-72
Step Action and questions Yes No 1 LVPS cable - check the LVPS cable to J33 on the 
system board to make sure it is seated correctly. Go to 
“System board” on page 5-8 .
Is the cable seated correctly? Go to step 2 Install the cable 
correctly
2Voltage checks - Disconnect J10 from the system 
board assembly. Go to  “System board” on page 5-8 . 
Check the voltage at J33, on the cable. It measures 
approximately +3.7 V dc.
Is the voltage correct? Go to step 3 Replace the 
following FRUs in 
order:
1. “LVPS 
assembly” 
on page 4-46
2. “System 
board” on 
page 4-72
3Is 930 error still displayed? Replace the 
“LVPS 
assembly” on 
page 4-46Problem solved
Pin Fan on Fan off Fan 
disconnected
Fan switch onFa n  
disconnected
Fan switch off
J3-1 +1.6 V dc +3.3 V dc +3.3 V dc +3.3 V dc
J3-20 V0 V0 V 0 V
J3-3 +1.9 V dc 0 V dc 0 V +2 V dc
J3-4 +24 V dc +24 V dc +24 V dc +24 V dc 
						

							
Diagnostic information2-87
  5060-4xx
940 error code
Cyan toner metering cycle (TMC)
The TMC is where the code and electronics in the printer sense an addition of toner in the cartridge developing 
area. If the printer is expecting a toner addition cycle but one is not detected, a 94x TMC Error is displayed.
Replacement of the cartridge may fix the problem temporarily if the problem is with the printer. Only replace the 
cartridge if there are no problems with the printer or if the cartridge is known to be defective.
Note:  Before proceeding with this service check, observe the error log for repetitive occurrences of a 94 x 
ser vice error.
Step Actions and questions Yes No 1 Check the toner metering cam (A) on the rear of the 
cyan cartridge.
Note:  In some cartridges the toner metering cam is 
black.
Is the cam present on the cartridge? Go to step 2 If the toner 
metering cam is 
not present, 
check the printer 
to make sure it is 
not inside.
Replace the 
damaged 
cartridge.
2Check the TMC pin (B) in the cyan cartridge contact 
assembly to make sure it moves freely.
Does the pin move freely? Go to step 3 Replace the 
“Cartridge 
contact 
assembly” on 
page 4-29.
A
B 
						

							
2-88Service Manual
5060-4
xx   
3Go to “BASE SENSOR TEST” on page 3-30  and 
check the cyan TMC sensor. When you press the TMC 
pin in the cyan cartridge contact assembly make sure it 
actuates the TMC switch on the developer HVPS. 
When the TMC pin is pressed in you hear a  click when 
the switch actuates. Check for mechanical interference 
between the contact block and the developer HVPS.
Note:  You may need to turn the printer off to hear the 
click .
Does the cyan TMC switch on the developer HVPS 
board actuate properly when the TMC pin is pressed? Replace the 
cartridge.
Go to step 4
4Check the developer HVPS board to make sure it is not 
cracked or broken.
Is the developer HVPS cracked or broken?‘ Go to step 6 Go to step 5
5Check the mounting of the developer HVPS. Make sure 
the screws that mount the power supply are properly 
tightened down and the board is positioned and 
mounted correctly.
Is the developer HVPS mounted correctly?Replace the 
developer HVPS 
assembly.
If the board is 
incorrectly 
installed, install it 
correctly. Make 
sure all the 
mounting screws 
are tightened 
down. Recheck 
the printer to see 
if a 940 Error is 
still displayed.
6Make sure the developer HVPS cable is correctly 
installed on the developer board assembly.
Is the cable correctly installed? Go to step 7 Correctly connect 
the cable.
7Make sure the developer HVPS cable is correctly 
installed at J14 on the system board.
Is the cable properly installed? Go to step 8 Correctly connect 
the cable.
8Check the voltage at connector J14-11 on the system 
board while pressing the cyan TMC pin in the cartridge 
contact assembly.
Does the voltage change when the pin is pressed? Replace the 
“System board” 
on page 4-72
.Go to step 9
9Check the voltage at connector J14-11 when the cyan 
TMC switch is pressed.
Does the voltage measure approximately +3.3 V dc? Go to step 10 Go to step 11
10Check the developer HVPS to system board cable for 
damage, broken connections, or wire and shorts 
between adjacent pins.
Are there any signs of damage to the cable?Replace the 
cable.
Replace the 
“Developer 
HVPS board” on 
page 4-31
.
11Disconnect the developer HVPS cable from connector 
J14 on the system board. Measure the voltage on 
connector J14-11 on the system board.
Does the voltage measure approximately 0 V dc? Replace the 
“System board” 
on page 4-72
.Replace the 
developer HVPS 
and developer 
HVPS to system 
board cable.
Step Actions and questions Yes No 
						

							
Diagnostic information2-89
  5060-4xx
941 error code
Magenta toner metering cycle (TMC)
The TMC is where the code and electronics in the printer sense an addition of toner in the cartridge developing 
area. If the printer is expecting a toner addition cycle but one is not detected, a 94x TMC Error is displayed.
Replacement of the cartridge may fix the problem temporarily if the problem is with the printer. Only replace the 
cartridge if there are no problems with the printer or if the cartridge is known to be defective.
Note:  Before proceeding with this service check, observe the error log for repetitive occurrences of a 94 x 
ser vice error.
Step Actions and questions Yes No 1 Check the toner metering cam (A) on the rear of the 
magenta cartridge.
Note:  In some cartridges, the toner metering cam is 
black.
Is the cam present on the cartridge? Go to step 2 If the toner 
metering cam is 
not present, 
check the printer 
to make sure it is 
not inside.
Replace the 
damaged 
cartridge.
2Check the TMC pin (B) in the magenta cartridge 
contact assembly to make sure it moves freely.
Does the pin move freely? Go to step 3 Replace the 
“Cartridge 
contact 
assembly” on 
page 4-29.
A
B 
						

							
2-90Service Manual
5060-4
xx   
3Go to “BASE SENSOR TEST” on page 3-30  and 
check the magenta TMC sensor. When you press the 
TMC pin in the magenta cartridge contact assembly 
make sure it actuates the TMC switch on the developer 
HVPS. When the TMC pin is pressed in you hear a 
click  when the switch actuates. Check for mechanical 
interference between the contact block and the 
developer HVPS.
Note:  You may need to turn the printer off to hear the 
click .
Does the magenta TMC switch on the developer HVPS 
board actuate properly when the TMC pin is pressed? Replace the 
cartridge.
Go to step 4
4Check the developer HVPS board to make sure it is not 
cracked or broken.
Is the developer HVPS cracked or broken?‘ Go to step 6 Go to step 5
5Check the mounting of the developer HVPS. Make sure 
the screws that mount the power supply are properly 
tightened down and the board is positioned and 
mounted correctly.
Is the developer HVPS mounted correctly?Replace the 
“Developer 
HVPS board” on 
page 4-31
. If the board is 
incorrectly 
installed, install it 
correctly. Make 
sure all the 
mounting screws 
are tightened 
down. Recheck 
the printer to see 
if a 941 Error is 
still displayed.
6Make sure the developer HVPS cable is correctly 
installed on the developer board assembly.
Is the cable correctly installed?
Go to step 7 Correctly connect 
the cable.
7Make sure the developer HVPS cable is correctly 
installed at J20 on the system board.
Is the cable properly installed? Go to step 8 Correctly connect 
the cable.
8Check the voltage at connector J14-6 on the system 
board while pressing the magenta TMC pin in the 
cartridge contact assembly.
Does the voltage change when the pin is pressed? Replace the 
“System board” 
on page 4-72
.Go to step 9
9Check the voltage at connector J14-6 when the 
magenta TMC switch is pressed.
Does the voltage measure approximately +3.3 V dc? Go to step 10 Go to step 11
10Check the developer HVPS to system board cable for 
damage, broken connections, or wire and shorts 
between adjacent pins.
Are there any signs of damage to the cable?Replace the 
cable.
Replace the 
“Developer 
HVPS board” on 
page 4-31
.
11Disconnect the developer HVPS cable from connector 
J14 on the system board. Measure the voltage on 
connector J14-6 on the system board.
Does the voltage measure approximately 0 V dc? Replace the 
“System board” 
on page 4-72
.Replace the 
developer HVPS 
and developer 
HVPS to system 
cable.
Step Actions and questions Yes No 
						

							
Diagnostic information2-91
  5060-4xx
942 error code 
Yellow toner metering cycle (TMC)
The TMC is where the code and electronics in the printer sense an addition of toner in the cartridge developing 
area. If the printer is expecting a toner addition cycle but one is not detected, a 94x TMC Error is displayed.
Replacement of the cartridge may fix the problem temporarily if the problem is with the printer. Only replace the 
cartridge if there are no problems with the printer or if the cartridge is known to be defective.
Note:  Before proceeding with this service check, observe the error log for repetitive occurrences of a 94 x 
ser vice error.
Step Actions and questions Yes No 1 Check the toner metering cam (A) on the rear of the 
yellow car tridge.
Note:  In some cartridges the toner metering cam is 
black.
Is the cam present on the cartridge? Go to step 2 If the toner 
metering cam is 
not present, 
check the printer 
to make sure it is 
not inside.
Replace the 
damaged 
cartridge.
2Check the TMC pin (B) in the yellow cartridge contact 
assembly to make sure it moves freely.
Does the pin move freely? Go to step 3 Replace the 
“Cartridge 
contact 
assembly” on 
page 4-29.
A
B 
						

							
2-92Service Manual
5060-4
xx   
3Go to “BASE SENSOR TEST” on page 3-30  and 
check the yellow TMC sensor. When you press the 
TMC pin in the yellow cartridge contact assembly make 
sure it actuates the TMC switch on the developer 
HVPS. When the TMC pin is pressed in you hear a 
click  when the switch actuates. Check for mechanical 
interference between the contact block and the 
developer HVPS.
Note:  You may need to turn the printer off to hear the 
click.
Does the yellow TMC switch on the developer HVPS 
board actuate properly when the TMC pin is pressed? Replace the 
cartridge.
Go to step 4
4Check the developer HVPS board to make sure it is not 
cracked or broken.
Is the developer HVPS cracked or broken?‘ Go to step 6 Go to step 5
5Check the mounting of the developer HVPS. Make sure 
the screws that mount the power supply are properly 
tightened down and the board is positioned and 
mounted correctly.
Is the developer HVPS mounted correctly?Replace the 
developer HVPS 
assembly.
If the board is 
incorrectly 
installed, install it 
correctly. Make 
sure all the 
mounting screws 
are tightened 
down. Recheck 
the printer to see 
if a 942 Error is 
still displayed.
6Make sure the developer HVPS cable is correctly 
installed on the developer board assembly.
Is the cable correctly installed? Go to step 7 Correctly connect 
the cable.
7Make sure the developer HVPS cable is correctly 
installed at J14 on the system board.
Is the cable properly installed? Go to step 8 Correctly connect 
the cable.
8Check the voltage at connector J14-16 on the system 
board while pressing the yellow TMC pin in the 
cartridge contact assembly.
Does the voltage change when the pin is pressed? Replace the 
“System board” 
on page 4-72
.Go to step 9
9Check the voltage at connector J14-16 when the yellow 
TMC switch is pressed.
Does the voltage measure approximately +3.3 V dc? Go to step 10 Go to step 11
10Check the developer HVPS to system board cable for 
damage, broken connections, or wire and shorts 
between adjacent pins.
Are there any signs of damage to the cable?Replace the 
cable.
Replace the 
“Developer 
HVPS board” on 
page 4-31
.
11Disconnect the developer HVPS cable from connector 
J14 on the system board. Measure the voltage on 
connector J14-16 on the system board.
Does the voltage measure approximately 0 V dc? Replace the 
“System board” 
on page 4-72
.Replace the 
developer HVPS 
and developer 
HVPS to system 
board cable.
Step Actions and questions Yes No 
						

							
Diagnostic information2-93
  5060-4xx
943 error code 
Black toner metering cycle (TMC)
Toner metering cycle (TMC) is where the code and electronics in the printer sense an addition of toner in the 
cartridge developing area. If the printer is expecting a toner addition cycle but one is not detected, a 94x TMC 
Error is displayed.
Replacement of the cartridge may fix the problem temporarily if the problem is with the printer. Only replace the 
cartridge if there are no problems with the printer or if the cartridge is known to be defective.
Note:  Before proceeding with this service check, observe the error log for repetitive occurrences of a 94 x 
ser vice error.
Step Actions and questions Yes No 1 Check the toner metering cam (A) on the rear of the 
black cartridge.
Note:  In some cartridges the toner metering cam is 
black. Is the cam present on the cartridge? Go to step 2 If the toner 
metering cam is 
not present, 
check the printer 
to make sure it is 
not inside.
Replace the 
damaged 
cartridge.
2Check the TMC pin (B) in the black cartridge contact 
assembly to make sure it moves freely.
Does the pin move freely? Go to step 3 Replace the 
“Cartridge 
contact 
assembly” on 
page 4-29.
A
B 
						

							
2-94Service Manual
5060-4
xx   
3Go to “BASE SENSOR TEST” on page 3-30  and 
check the black TMC sensor. When you press the TMC 
pin in the black cartridge contact assembly make sure 
it actuates the TMC switch on the developer HVPS. 
When the TMC pin is pressed in you hear a  click when 
the switch actuates. Check for mechanical interference 
between the contact block and the developer HVPS.
Note:  You may need to turn the printer off to hear the 
click .
Does the black TMC switch on the developer HVPS 
board actuate properly when the TMC pin is pressed? Replace the 
cartridge.
Go to step 4
4Check the developer HVPS board to make sure it is not 
cracked or broken.
Is the developer HVPS cracked or broken?‘ Go to step 6 Go to step 5
5Check the mounting of the developer HVPS. Make sure 
the screws that mount the power supply are properly 
tightened down and the board is positioned and 
mounted correctly.
Is the developer HVPS mounted correctly?Replace the 
developer HVPS 
assembly.
If the board is 
incorrectly 
installed, install it 
correctly. Make 
sure all the 
mounting screws 
are tightened 
down. Recheck 
the printer to see 
if a 943 Error is 
still displayed.
6Make sure the developer HVPS cable is correctly 
installed on the developer board assembly.
Is the cable correctly installed? Go to step 7 Correctly connect 
the cable.
7Make sure the developer HVPS cable is correctly 
installed at J14 on the system board.
Is the cable properly installed? Go to step 8 Correctly install 
the cable.
8Check the voltage at connector J14-1 on the system 
board while pressing the black TMC pin in the cartridge 
contact assembly.
Does the voltage change when the pin is pressed? Replace the 
“System board” 
on page 4-72
.Go to step 9
9Check the voltage at connector J14-1 when the black 
TMC switch is pressed.
Does the voltage measure approximately +3.3 V dc? Go to step 10 Go to step 11
10Check the developer HVPS to system board cable for 
damage, broken connections, or wire and shorts 
between adjacent pins.
Are there any signs of damage to the cable?Replace the 
cable.
Replace the 
“Developer 
HVPS board” on 
page 4-31
.
11Disconnect the developer HVPS cable from connector 
J14 on the system board. Measure the voltage on 
connector J14-1 on the system board.
Does the voltage measure approximately 0 V dc? Replace the 
“System board” 
on page 4-72
.Replace the 
developer HVPS 
and developer 
HVPS to system 
board cable.
Step Actions and questions Yes No