Lexmark E 450 Dn Service Manual

Diagnostics information2-15
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Symptom tables
POST symptom table
Note: Investigate any displayed codes before proceeding with these symptoms. For example, a missing toner cartridge will 
prevent POST from completing.Symptom Action
The main motor, cooling fan, and fuser do not come 
on.See “Cover interlock switch service check” on page 2-18. 
POST completes, but LCD does not appear to be 
working.See “Operator panel service check” on page 2-21.
Main motor does not come on. See “Main motor service...

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Printer symptom table
Symptom Action
Dead machine (no power). See “Dead machine service check” on page 2-19.
Fan noisy or fan not working. See “Cooling fan service check” on page 2-18.
Fuser parts melted. See “LVPS/HVPS service check” on page 2-20.
Toner not fused to the media. See“Fuser service check” on page 2-19.
Paper jams. See “Paper feed service checks” on page 2-21.
Main motor noisy or not moving. See “Main motor service check” on page 2-20.
Media skew. See “Paper feed...

Diagnostics information2-17
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Service checks
Service checks which involve measuring voltages on the LVPS/HVPS (low voltage power supply/
high voltage power supply board) should be performed with the printer positioned on its back side. 
Note:  When making voltage readings, always use frame ground unless another ground is 
specified. See the wiring diagram in the back of the book for more information. 
Controller card service check 
Controller card service check
FRU Action
Controller card...

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Cooling fan service check 
Cover interlock switch service check 
Note:  Make sure a print cartridge assembly is installed and the cover closes all the way, engaging the cover 
open switch lever.  LVPS/HVPSVerify main power to controller card
With the printer off, unplug the LPS/HVPS cable at J19 on the controller card. Verify 
grounds on pins 7, 12, and 14 for both the cable and the controller card. If any of these 
grounds are incorrect, check the cable for continuity....

Diagnostics information2-19
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Dead machine service check
CAUTION: Check the AC line voltage. The voltage should be within the following limits:
•100 V ac (volts alternating current) — 127 V ac for the 110 V printer
•200 V ac — 240 V ac for the 220 V printer
Fuser service check 
When toner is partially fused to the media, it is usually caused by low fuser temperature.
The line voltage to the printer must be within the following limits:
•100 V ac—127 V ac for the 110 V model printer
•200 V ac—240 V...

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LVPS/HVPS service check
Main motor service check 
FRU Action
LVPS/HVPSLVPS portion of board 
Fuses that open typically indicate a faulty LVPS/HVPS.
Disconnect the power cable, and open the LVPS/HVPS enough to test the switch. The 
switch will show continuity across the conductors with a meter when the switch is on. If the 
switch is good, see “Dead machine service check” on page 2-19 for more diagnostics.
HVPS portion of board 
Problems with the HVPS are exhibited in the print...

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Operator panel service check
Inspect the operator panel cable for damage. Make sure the cable is plugged in securely. Run POST, and check 
each light for proper operation. See “Power—On Self Test (POST) sequence” on page 2-1. 
Paper feed service checks
Paper jam error indication during POST 
Media picks during POST and/or continuously LCD Operator panel service check
FRU Action
Operator panel (LED)
Controller card 
Warning: Do not 
replace the operator 
panel and...

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Media picks but stops halfway through the printer 
Media never picks 
Media occasionally mispicks or picks multiple sheets at once 
FRU Action
Input/Duplex sensors
(under print cartridge assembly) 
Input sensor (manual)Make sure the input sensors are working properly. 
Check for a broken or stuck flag on the input sensors. 
Make sure the cables are seated on the controller card at J23 (Tray 1 input) and 
J20 (manual input). 
Check for about +5 V dc on pin 6 at J23...

Diagnostics information2-23
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Media skews
Media “trees,” wrinkles, stacks poorly, or curls 
Parallel or USB port service check
1.Perform a print test to make sure the printer prints correctly. Verify that the indicator light is on, then press 
 to print menu settings. 
2.Be sure the printer parallel cable is designed for bidirectional printing.
3.Be sure the user’s application is set up correctly. 
4.If the internal print test page prints correctly, the user’s application/printer driver is set up...

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Print quality service checks
Note:  Ensure the cover closes tightly. A gap in the opening may allow light to expose the photoconductor 
resulting in a ‘dirty’ print. Extreme environmental conditions, temperatures, and humidity will affect the print 
quality.
Using print quality test pages 
To help isolate print quality problems, like streaking, print test pages using the print quality test pages. To print 
the print quality test pages:
1.Enter Configuration Menu.
a.Turn off...