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4.6.13 Gradation reproduction failure
Scanner section
Section Step Check item Result Remedy
Scanner section 1 Is the shading-sheet located under
the size cover dirty?
Yes Clean or replace CIS, and ad-
just the background level
2 Are the ADF glass and document
glass dirty?
Yes Clean
3 Do the connection from CIS to main
control board remain intact?
No Reconnect / Replace harness.
4 Is the trouble settled with above
steps?
No 1. Adjust the background level.
2. Replace CIS.
3. Replace main control board.
Printer section
Section Step Check item Result Remedy
Drum cartridge 1 Are the developing bias, supply bias
and blade bias contact terminal dirty
or deformed?
Yes Clean / Repair
2 Are the grid bias, charge bias and
drum ground contact terminal dirty or
deformed?
Yes Clean / Repair
Circuit boards 3 Are the connections from LED print
head and from high-voltage board to
main control board in good condition?
(Check plugs firmly plugged and
snapped harness.)
No Reconnect / Replace harness
4 Is the trouble settled with above
steps?
No 1. Replace drum cartridge.
2. Replace LED print head.
3. Replace main control board.
4. Replace high-voltage power
board.