Brother DCP-L5500D Service Manual page 84

 Error code 6801
The side thermistor of the fuser unit or internal temperature sensor detected a temperature
higher than the specified value.
<User Check>
• Lower the room temperature.
• Keep the machine away from heating appliances.
Step
Connection failure of the internal
1
temperature sensor harness
Internal temperature sensor
2
failure
3 Fuser unit side thermistor failure Replace the fuser unit.
4 Main PCB failure
 Error code 6901
An error occurred in the fuser unit when the power switch was turned ON or sleep mode was
released.
Error code 6902
Rechecking the error after the power switch was turned OFF and then ON again because an
error was detected in the fuser unit.
(This message is displayed for approximately 15 minutes when the machine is restarted after
error code 6901 has occurred.)
Step
Connection failure of a fuser unit
1
harness
Connection failure of the eject
2
sensor harness
3 Eject sensor PCB failure
4 Fuser unit failure
Low-voltage power supply PCB
5
failure
6 Main PCB failure
Note:
• Turn OFF the power switch. After the fuser unit has cooled sufficiently, turn ON the
power switch again and leave the machine for 15 minutes. This problem may then be
cleared.
• To release the fuser unit error after taking appropriate measures, enter the
maintenance mode once and quit it with the function code 99.
Cause
Reconnect the internal temperature sensor
harness.
Replace the main frame L ASSY.
Replace the main PCB ASSY.
Cause
Reconnect the fuser unit harness.
Reconnect the eject sensor harness.
Replace the eject sensor PCB ASSY.
Replace the fuser unit.
Replace the low-voltage power supply PCB
ASSY.
Replace the main PCB ASSY.
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Remedy
Remedy
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