Canon LBP1760P Service Manual page 176

CHAPTER 4
Action: Replace the laser/scanner unit.
I-12. White horizontal lines
<Possible causes>
1. Horizontal scar(s) on the photosensitive drum
Action: Replace the cartridge.
2. Defective fixing film unit
Action: Replace the fixing film unit.
I-13. Poor fixing
<Possible causes>
1. The nip width of the fixing unit is not within the specification.
Action: Replace the fixing unit.
2. Dirty pressure roller
Action: Clean the pressure roller. If the dirt cannot be removed, replace the pressure roller.
3. Scars or dents on the pressure roller surface.
Action: Replace the pressure roller.
4. Scars or foreign materials on the fixing film unit surface.
Action: Replace the fixing film unit.
5. Deterioration of thermistor
Action: Replace the fixing film unit.
I-14. Image distortion
<Possible causes>
1. Poor contact in the connector on the laser/scanner unit
Action: Reconnect J401, J551, and J201 correctly.
2. Poor connection of connector on the engine controller PCB
Action: Reconnect J53 correctly.
3. Defective laser/scanner unit
Action: Replace the laser/scanner unit.
4. Defective engine controller PCB
Action: Replace the engine controller PCB.
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