Follow the procedure below to replace drum unit.

The Brother machine has separate consumables the toner cartridge and the drum unit. Verify you replace only the drum unit and not the toner cartridge. If you want to know their difference, refer to "What is the difference between the toner cartridge and the drum unit?"

1. Press the front cover release button and then open the front cover.
   
2. Reset the drum counter: Press and hold down the Go button for about 4 seconds until all the LEDs light up. Once all four LEDs are lit, release the Go button.
   

   Do not reset the drum counter when you only replace the toner cartridge.

    
    
3. Take out the drum unit and toner cartridge assembly.
   

    

    

   • We recommend that you put the drum unit and toner cartridge assembly on a piece of disposable paper or cloth in case you accidentally spill or scatter toner.
   • To prevent damage to the printer from static electricity, DO NOT touch the electrodes shown in the illustration.

    

    
   

4. Push down the blue lock lever and take the toner cartridge out of the drum unit.

   

    

    

   • DO NOT put a toner cartridge into a fire. It could explode, resulting in injuries.
   • Use neutral detergents when cleaning the printer.
   • DO NOT use cleaning materials that contain ammonia, alcohol, any type of spray, or any type of flammable
     substance to clean the outside or inside of the machine. Doing this may cause a fire or electrical shock.
   • Be careful not to inhale toner.
   • Handle the toner cartridge carefully. If toner scatters on your hands or clothes, wipe or wash it off with cold water at once.
   • To avoid print quality problems, DO NOT touch the shaded parts shown in the illustrations.
    
   
    
5. Unpack the new drum unit.
    

   Wait to unpack a drum unit until immediately before you put it in the printer. Exposure to direct sunlight or room light may damage the drum unit.

    
6. Put the toner cartridge firmly into the new drum unit until you hear it lock into place. If you put the cartridge in properly, the blue lock lever will lift automatically.

    

   

    

   Make sure that you put in the toner cartridge properly, or it may separate from the drum unit.

    
7. Put the drum unit and toner cartridge assembly back in the printer.
   
8. Close the front cover.
9. Make sure that the Drum LED is now off.