Black Page; Heavy Background - Lexmark E250D - E B/W Laser Printer Service Manual

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
Toner electrodes (not a
FRU)
LVPS/HVPS board
Controller card
Miscellaneous cables

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
Action
Check the three rearward electrodes below the toner cartridge assembly for contamination
or damage. Correct as necessary.
Check continuity between the cable (DEV, TAR, and doctor blade) connection PCN3 and on
the contact tips below the toner cartridge assembly.
• If continuity fails, call the next level of service.
With the printer off, disconnect the LVPS/HVPS cable from J19 on the controller card.
Turn the printer on, and verify +24 V dc on pins 8 and 9 of the cable.
Verify ground on pins 7, 12, and 14.
• If the voltage is incorrect, replace LVPS/HVPS board.
• If grounds are incorrect, check ground paths.
• Check confinuity in the cable. Replace the cable if necessary.
• If voltage is correct and the toner electrodes are good, replace the controller card.
"LVPS/HVPS service check" on page 2-42
• See the
check" on page 2-39, if necessary.
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 toner
cartridge.
Check the contacts for correct installation and contamination where contact is made
between the toner cartridge assembly and spring contacts which connect to the LVPS/
HVPS board at PCN3. Clean as necessary.
If this does not correct the problem, replace the following FRUs one at a time in the order
shown:
• LVPS/HVPS board (See
• Controller card
"Black page" on page 3-47
4512-220, -230
"Controller card service
and the
for pin values.)
Diagnostic information
2-47