Oki C7400 Maintenance Manual page 113

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Dirty Background (Figure 5-2 B )
• Were the image drums exposed to external light for a long time?
Yes Replace the ID unit(s).
• No Is the roller of the fuser unit dirty?
Yes Replace the fuser unit.
• No Correct the PAPER TYPE setting.
Light: 60 g/m
Medium Heavy: 90g/m
No Set the MEDIA TYPE correctly.
• No Are the LED head Assys connected to the junction board (Y71 PWB) properly?
No Connect the LED head Assy(s) to the junction board (Y71 PWB) properly.
• Yes Is +3.8V output to the following power connector pins of the junction board (Y71 PWB)?
+38V: Pins 1 to 8
• Yes Is +3.8V output to the following cable connector pins between the junction board (Y71 PWB)
and the LED head Assys?
YPOW connector pin 3: LED head Assy Yellow
MPOW connector pin 3: LED head Assy Magenta
CPOW connector pin 3: LED head Assy Cyan
KPOW connector pin 3: LED head Assy Black
No Replace the junction board (Y71 PWB).
• Yes Replace the LED head Assy after checking the cable connection.
• No Replace the low voltage power unit after checking the cable connection.
Has the problem been corrected?
Yes End
• No Is 32V supplied to the power connector of the engine board (71K PWB)?
+32V: Pins 7 to 10
No Replace the low voltage power unit after checking the cable connection.
• Yes Is 32V supplied to the power connector pin of the engine board (71K PWB)?
No Replace the engine board.
• Yes Replace the high voltage power unit or the belt cassette Assy after checking the cable
connection. Has the problem been corrected?
Yes End
• No Are the terminals of the ID units connected to the contact Assy properly? (See Figure 5-2.)
No Connect the ID unit terminal(s) to the contact Assy properly.
• Yes Replace the image drum unit(s).
Notes: 1. When replacing the engine board (71K PWB), demount the EEPROM from the board and
mount it on a new board.
2. When the EEPROM is not replaced, see Section 3.2.2.
41316401TH Rev.9
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Medium Light: 67.5 g/m
2
Heavy: 105 g/m
2 2
Medium: 75 g/m
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Ultra Heavy: 120 g/m
Oki Data CONFIDENTIAL
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