Brother HL-5440D Service Manual page 36

4.6 Troubleshooting for Control Panel Problems....................................................... 2-75
4.6.1 Nothing is displayed on the LCD .............................................................. 2-75
4.6.2 LEDs are not activated ............................................................................. 2-75
4.6.3 Control panel is inoperable....................................................................... 2-75
4.7 Troubleshooting for Toner and Drum Problems................................................... 2-76
4.7.1 New toner is not detected......................................................................... 2-76
4.7.2 Cartridge error (toner cartridge cannot be detected)................................ 2-76
4.7.3 Drum error ................................................................................................ 2-76
4.8 Troubleshooting for Fuser Unit Problems ............................................................ 2-77
4.8.1 Fuser unit failure....................................................................................... 2-77
4.9 Troubleshooting for Laser Unit Problems ............................................................ 2-78
4.9.1 Laser unit failure....................................................................................... 2-78
4.10 Troubleshooting for PCB Problems ..................................................................... 2-79
4.10.1 Main PCB failure ...................................................................................... 2-79
4.10.2 High-voltage power supply PCB failure.................................................... 2-79
4.10.3 Low-voltage power supply PCB failure..................................................... 2-79
4.11 Troubleshooting for Other Problems.................................................................... 2-80
4.11.1 Machine is not turned ON......................................................................... 2-80
4.11.2 Main fan does not rotate........................................................................... 2-80
4.11.3 Main motor failure..................................................................................... 2-80
4.11.4 Unusual noise is generated from the machine ......................................... 2-80
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