Lexmark CS748de, Service Manual

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Diagnostic information
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920.10—POST—Three toner sensors not connected error service check
3
1. Remove the left cover. See
“Left cover
removal” on page 4-31
.
2. Reseat and check all the toner level
sensor cables (A) connected to the rear of
the HVPS for damages and if they are
installed correctly.
Does the problem persist?
Go to step 4. Problem resolved.
4
Connect four new toner level sensors outside
the machine and perform a POR.
Note:
Keep track of which sensors change
the error code to reduce the number of failing
sensors. Keep the old sensor which does not
reduce the failing number, leaving three new
sensors and no error reported.
Does the problem persist?
Remove the four new toner
level sensors and go to
step 5.
Replace the failing toner
level sensors. See
“Toner
level sensor removal” on
page 4-171
.
5
Replace the HVPS board. See
“High-voltage
power supply (HVPS) removal” on
page 4-123
.
Does the error clear?
Problem resolved. Go to step 6.
6
1. Install the old HVPS back to the machine.
2. Replace the HVPS cable. See
“High-
voltage power supply (HVPS) cable
removal” on page 4-125
Does the problem persist?
Replace the system board.
See
“System board
removal” on page 4-163
.
Problem resolved.
Step Questions / actions Yes No
1
Turn the printer off, and then remove the rear
frame cover. See
“Rear frame cover
removal” on page 4-47
.
Reseat the cable in connector JHVPS1.
Does the error clear?
Problem resolved. Go to step 2.
2
Check the HVPS cable in connector JHVPS1
for pinch points and any other damage to the
cable or connector.
Is the cable damaged?
Replace the HVPS cable.
See
“High-voltage power
supply (HVPS) cable
removal” on page 4-125
.
Go to step 3.
Step Questions / actions Yes No