Lexmark C760 Service Manual

Diagnostic information2-105
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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...

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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...

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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...

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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...

Diagnostic information2-109
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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...

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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...

Diagnostic information2-111
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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...

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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...

Diagnostic information2-113
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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...

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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...