Brother HL-4140CN Service Manual page 74

■ Error code 5F
WT Box End Soon
The waste toner box near full. (The sensor detected that the waste toner became near full.)
<User Check>
- Prepare a new waste toner box.
Step
1 Harness connection failure of
waste toner sensor
2 Waste toner sensor failure
3 High-voltage power supply PCB
failure
4 Main PCB failure
Cause
2-43
Remedy
Check the harness connection of the
waste toner sensor and reconnect it.
Check the sensor performance following
the procedure described in
32". If any problem occurs, replace the
waste toner sensor.
Replace the high-voltage power supply
PCB ASSY.
Replace the main PCB ASSY.
"Function code
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