Black Spots - Muratec MFX-2550 Field Engineering Manual

Printer section
Section Step Check item
Paper path 1
Drum cartridge 2
3
Fusing unit 4
Toner cartridge 5
Circuit boards 6
7

4.5.9 Black spots

Scanner section
Section Step Check item
Scanner section 1
(Front side)
2
3
Is paper path dirty with toner?
Is the charge wire dirty?
Is the drum dirty or damaged?
Is the fusing roller or separation
scraper dirty or damaged?
Is the developing roller dirty or
damaged?
Are the connections from LPH to
high-voltage board, and from high-
voltage board to main control board
in good condition?
(Check plugs firmly plugged and
snapped harness)
Is the trouble settled with above
steps?
Are the mirrors, lens, ADF glass and
document glass dirty?
Do the connection from CCD 
Scanner board  Main control board
 LPH board  LPH connect board
 LED unit remain intact?
Is the trouble settled with above
steps?
Result Remedy
YES Clean.
YES Clean.
YES Replace.
YES Clean. / Replace.
YES Replace.
NO Reconnect. / Replace harness.
NO 1. Replace drum cartridge.
2. Replace fusing unit.
3. Replace toner cartridge.
4. Replace LPH.
5. Replace LPH connect board.
6. Replace LPH board.
7. Replace main control board.
8. Replace high-voltage power
board.
Result Remedy
YES Clean.
If the trouble is not settled
by cleaning, adjust the
background level.
NO Reconnect / Replace harness
NO 1. Replace scanner board.
2. Replace main control board.
3. Replace LPH board.
4. Replace LPH connect board.
5. Replace LPH.
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