Brother MFC-L6900DW - Page 142

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Confidential
 Fogging
<User Check>
• Check the usage environment of the machine. Using the machine in
hot-humid or cold-dry conditions can cause this problem.
• Check that the acid paper is not used.
• This problem may disappear after printing multiple sheets of paper.
• Replace the toner cartridge with a new one.
• Replace the drum unit with a new one.
Step Cause Remedy
1
Toner amount detection sensor
PCB (light reception) failure
Replace the toner amount detection sensor
PCB ASSY (light reception).
2 Relay front PCB failure Replace the relay front PCB ASSY.
3
High-voltage power supply PCB
failure
Replace the high-voltage power supply PCB
ASSY.
4 Main PCB failure Replace the main PCB ASSY.
Note:
• This problem tends to occur when the life of the drum unit or toner cartridge is expiring.