Lexmark 4039 - B/W Laser Printer, Service Manual

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Diagnostic Information
13
4039-1XX
Banding
Banding appears as light and dark horizontal lines on a page that is
supposed to be uniformly gray. It is due to variation in the speed of
the paper as it moves from roll to roll during development or transfer.
It is undetectable when printing text and is most noticeable on fine
dot or horizontal line patterns such as the second page of Print
Test 2 or Print Test 3. Inspect the gear train and the paperfeed rollers
for wear, damage, dirt, or binds.
Background
Areas that are supposed to stay blank are getting small amounts of
toner deposited on them. Clean the erase lamps and the printhead
window.
Run the diagnostic Paper Feed Test and verify that all the erase
lamps turn on. If not, verify that there is +24VDC on pin (10R/12R/
12L/12C) J20-16 (16L) J17-16 (10P) J20-1 and b15 and
+20VDC on pin 15 (pin 2 on 10P). Shorting pin 15 (pin 2 on 10P) to
ground should turn on all the erase lamps. Check the erase lamp
cable continuity. Replace the transfer roll housing if the voltage and
the cable are good.
Inspect the contacts on the HVPS; make sure each spring-loaded
contact returns when pressed and released.
Rough Paper mode can cause background on some papers; if
Rough Paper mode is on, turn it off and run the print test again.
Printing on coated paper or using refilled print cartridges can also
cause background.
Run the print test in continuous mode and check the following
voltages; then stop the test and check the voltages again:
Vertical Void or Streak Vertical Service Check
Banding Banding Service Check
Symptom Action or Service Check