Brother HL-4140CN Service Manual page 67

■ Error code 3F
Print Unable 3F
Turn the power off and then back on again.
Write error in engine firmware.
This error does not usually occur in the normal use. The conceivable causes are noise around
the installation site, fluctuation of the power supply voltage, and failures in the software.
<User Check>
- Turn OFF the power switch, and turn it ON again after a while.
Step
1 Engine PCB failure
2 Main PCB failure
■ Error code 40
Print Unable 40
Turn the power off and then back on again.
Error in the high-voltage power supply PCB while the printer is in operation.
Error code 42
Print Unable 42
Turn the power off and then back on again.
High-voltage power supply PCB transfer error.
Step
1 Engine PCB failure
2 Main PCB failure
3 Harness connection failure of
high-voltage power supply PCB
4 High-voltage power supply PCB
failure
Cause
Cause
2-36
Remedy
Replace the engine PCB ASSY.
Replace the main PCB ASSY.
Remedy
Replace the engine PCB ASSY.
Replace the main PCB ASSY.
Check the harness connection of the
high-voltage power supply PCB ASSY
and reconnect it.
Replace the high-voltage power supply
PCB ASSY.
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