Oki C7500n Maintenance Manual page 132

6
Poor Fusing (Ink spreads or peels when touched with fingers)
• Is regulated paper being used?
NO Use regulated paper.
M •
YES Is the contact of the fuser unit connected properly?
NO Connect the contact of the fuser unit properly.
M
• YES Is the roller in the fuser unit dirty?
YES Replace the fuser unit assembly.
M •
NO Is the PAPER THICKNESS (menu 1) selected correctly?
Light: 64 g/m
Medium Heavy: 91 to 104 g/m
Transparency
NO Set [Paper Thickness] properly.
M •
YES Is AC voltage output between CN connector pins 1 and 3 in the low-voltage power unit?
NO Replace the low-voltage power unit.
M
• YES Is the heat roller thermister resistance within the regulated value? (See Fig. 5-1)
(Approx. 180k-980kΩ in room temperature of 0-43 degrees Celsius.)
NO Replace the fuser unit.
M •
YES Is the back-up roller thermister resistance within the regulated value? (See Fig. 5-1)
(Approx. 190k-980kΩ in room temperature of 0-43 degrees Celsius.)
NO Replace the fuser unit.
M •
YES Does the fuser temperature match the set temperature?
Check the fuser temperature in the LCD display of the engine maintenance mode.
Heat roller (upper): 145-155 degrees (5FH-6BH)
Back-up (lower)
NO Replace the fuser unit assembly.
M
• YES Replace the fuser unit assembly.
Note: 1. Remove EEPROM from the old board and set it on the new board upon replacing the
engine board (K7N PWB).
2. If EEPROM is not replaced, refer to section 3.2.2.
3. When replacing the engine board (K7V PWB), upload EEPROM data from the board and
then download it to a new board, using a life counter tool.
41955801TH Rev.8
2
Medium Light: 64 to 74 g/m
2
Heavy: 105 to 120 g/m
: 125-135 degrees (48H-53H)
2 2
Medium: 75 to 90 g/m
2
Ultra Heavy 121 to 203 g/m
Oki Data CONFIDENTIAL
2
132 /