Black Page; Heavy Background - Lexmark E120 Service Manual

4506-1xx

Black page

Note: Incorrect laser exposure or incorrect charging of the photoconductor causes an all black page. Always
verify the same results from a different toner cartridge assembly and developer before proceeding.
FRU
PC kit (not a FRU)
Toner electrodes (not
a FRU)
LVPS/HVPS board
Controller card

Heavy background

Poor development or poorly charged toner particles cause excessive background. This is more noticeable as
the toner cartridge nears end-of-life.
FRU
Toner cartridge (not a
FRU)
PC Kit (not a FRU)
LVPS/HVPS
Controller card
2-34
Service Manual
Action
Check the three electrical contacts at the right rear of the toner cartridge
assembly for contamination or damage. Correct them as necessary.
Check continuity between the spring behind the LVPS/HVPS (DEV, TAR, and
doctor blade) contact tips for the toner cartridge assembly. If continuity fails, call
the next level of service.
Check the contact for the PC kit. No charge on the charge roll will result in a
black page. Try a different PC kit.
With the printer off, disconnect the cable from CN402 on the LVPS/HVPS card.
Turn the printer on, and verify +24 V dc on pins 18, 16, 15, 14, 13, and 12 on the
connector.
With the printer off, verify the ground on pins 2, 4. 6, 8, and 17.
• If the voltage is incorrect, replace the LVPS/HVPS board. See
removal" on page 4-19.
• If voltage is correct and the toner electrodes are good, check continuity on
the cable. Replace the cable if necessary.
As much as possible, check the cable while in plugged position but not
plugged. Flat cables open when bent but close when straightened.
• If voltages are correct and the cable is good, check the controller card. See
"Controller card service check" on page
Action
Check the toner darkness setting in the driver. Try a lower setting.
Make sure the toner cartridge and PC Kit are correctly installed and the high
voltage contacts are clean.
If the toner cartridge and PC Kit are installed correctly, try a new PC Kit first and
then try a new toner cartridge. Check the darkness setting.
Check the contacts for correct installation and contamination where contact is
made between the toner cartridge assembly and the LVPS/HVPS board. Clean
the contacts as necessary.
If this does not correct the problem, replace the following FRUs one at a time in
the order shown:
• LVPS/HVPS board
• Controller card
"LVPS/HVPS
2-24.