Parts for a brother MFC-7420

Unfortunately, the MFC-7420 doesn't have a physical lock switch. You need to turn off the all-in-one and wait for the unit to clear its memory. If the error recurs after you press the power button again, wait 30 minutes and try again. (Note: you will lose any faxes that are in memory. See the User Guide page 11-5 to save this information.) You can find the manual on the Brother support page for the MFC-7420: https://www.brother-usa.com/support/ModelInfo.aspx?R3ModelID=MFC7420 . Click on the Manuals & Documents tab. Then click on the Manuals on our Online Solution Center for the English version of the manual. The direct link to the User Guide is currently: http://download.brother.com/welcome/doc000387/ALLFB_UsaEngUsr_B.pdf .

You can also try unplugging the all-in-one for several minutes to reset the error codes. If the error persists, contact Brother if the MFC-7420 is still under warranty (1 year). If it isn't under warranty, consider replacing the unit. The repair costs may be unreasonable.

I hope this helps.

Cindy Wells

It could be an issue with the drum unit either being faulty or the internal drum counter having been reset sometime after a new drum was installed. I would recommend removing the currently installed drum unit and trying it in the second printer you mentioned with the toner cartridges that has been confirmed as working.

If the problem persists it is likely to be a froblem with a fuser or another internal part that is not traditionally a consumable item. In which case I would recommend contacting Brother or a printer technician.

Sounds like a bad drum cartridge. Pull the toner/drum cartridge out of the machine and set it down. Press down on a (blue?) tab to release the toner cartridge, and you can lift the toner cartridge out of the drum cartridge. There is a cleaning blade in there - a soft plastic blade that rides against the drum and scrapes off toner that didn't get transferred to the paper. If it gets stuck off the drum surface, images repeat a few inches (one drum circumference) down the page.

A new DR-350 drum unit should fix it. have the machine's power on when replacing it. While the door is open, touch the CLEAR key. The display will read "REPLACE DRUM?" or something like that. Press 1 for Yes.

Please clarify the marks . Usually is due to drum unit, clean it.

http://www.brother-usa.com/downloads/Default.aspx?WT.cg_n=Support&WT.cg_s=Downloads

Here's the software you needed.

helo braxtol! tell me, are you using brother oem toner and drum or are you using a generic brand. you could also have a bad power supply. this is what charges the drum and toner. good luck brother tech

The Brother MFC 7420 is still being sold in major office supply stores. However, there newer version are available as well. The MFC 7440, 7840W, 7820N, 7340, and 7220 are comparable machines

you must have paper port to use the scan part of the machine. if you have the original cd that came with machine it has paper port in it. may be if you go to brother.com you could download this software let me know brother tech

Open the front cover and try to pull it out strongly.
then use the duster to clean the machine.
then you should able to replace your cartridge easily next time.
mightbe too dirty or you use ODM toner? if yes that's the problem issued from.

u have to replaced blade.