MFC-9840CDW BELT DRIVE MOTOR

Your Brother MFC-9840CDW Multifunction Printer is equipped with a precise built-in system, which is constantly monitoring the status/condition of the installed transfer belt. Once the built-in system detects that the installed transfer belt is at the end of its useful life, you will see the following warning message ''Change Parts BELT UNIT'' appearing on the control LCD of your multifunction printer. It is very important the exhausted transfer belt to be replaced soon after the initial appearance of the warning message, in order to be avoided  print quality problems or/and damages to other printer components. The transfer belt replacement in your MFC-9840CDW is a relatively easy procedure, and there are no special tools required for its successful execution. 

The transfer belt used in your Brother MFC-9840CDW Multifunction Printer is located/installed under the drum unit. Therefore, you must turn off the printer's power switch, and then gain access to the drum unit by opening the front cover. After that, you must slightly lift the drum unit, and then pull it out of the printer until it stops. Now, you must unlock the drum unit by pulling the gray lock release lever upwards, and then take the drum unit out of the printer by using both green handles. Please note that you must avoid touching the printer's electrodes (on the inner printer sides) and the black flat surface of the new transfer belt, in order to be avoided damages caused by static electricity. In the next step of the replacement procedure, you must grab the exhausted transfer belt by its front green side and lift it gently up, in order to unlock it from the printer slot, and then take the exhausted transfer belt out of the printer by pulling it towards you. Then, you must unpack the new transfer belt and remove its protective cover and paper. Once the new transfer belt is prepared for installation, you must align the marks on its front side with the marks of the slot, and then insert the new transfer belt into the printer until it stops. Now, you must lock the new transfer belt into place by pushing its front green side down, and then make sure that the gray lock release lever is still in ''upper''/''unlocked'' position. After that, you must insert the drum unit into the printer until it stops, and then push the gray lock release lever back to its original ''locked'' position. In the next step of the new transfer belt installation, you must completely insert the drum unit into the printer, and then push its front side down. Finally, you must close the front cover of your Brother MFC-9840CDW Multifunction Printer, and then reset the transfer belt counter.

Reset of the Transfer Belt Counter

Turn on the printer's power switch, and then navigate to [84. Reset Menu] by pressing [Menu] – [8] – [4].
Select [Belt Unit] by pressing [OK].
Confirm the transfer belt counter reset by pressing [1], and then press [Stop/Exit].