Gradation Reproduction Failure - Muratec MFX-2550 Field Engineering Manual

4.5.10 Smear on back
Printer section
Section Step Check item
Paper path 1
Fusing unit 2
Transfer section 3
Circuit boards 4
5

4.5.11 Gradation reproduction failure

Scanner section
Section Step Check item
Scanner section 1
(Front side)
2
3
4
Is paper path dirty with toner?
Is the fusing roller or separation
scraper dirty or damaged?
Is the transfer roller dented 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?
Is the shading sheet under the
contact cover dirty?
Are the document glass, back plate,
and ADF 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. / Replace.
YES Replace.
NO Reconnect. / Replace harness.
NO 1. Replace fusing unit.
2. Replace high-voltage power
board.
3. Replace main control board.
Result Remedy
YES Clean.
If the trouble is not settled
by cleaning, adjust the
background level.
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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