Question about Brother MFC 420CN All-In-One InkJet Printer

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Printer keeps turning off,,,error message MN1 in lcd

My brother mfc 420CN keeps turning off and on, and I also get MN1 in the top right side of the lcd. What gives, and how do I fix it???? Thanks

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  • deerslayer Sep 26, 2007

    Doesn't anyone have anny ideas about this problem or know what Mn1 means?

  • deerslayer Sep 28, 2007

    Hi, Mix it up,
    Actually I bought the second printer cheap hoping I could use the parts from one to make at least one working. I haven't done anything with the one with 4F yet, hoping the one with the turning off and on problem (Mn1 message) would be an easy fix. Actually, I haven't had either of them hooked up to my pc yet, as I am somewhat familiar with the general operation of this model since MY personal printer is an MFC 420CN, and I shouldn't have had any problems just printing test pages. I've stocked up on ink for it since it was so inexpensive, and wanted to get one to have as a spare. I'd like to thank you for taking the time to try helping me figure it out, as it can be very frustrating for the (mechanically impared).
    I'm not sure exactly what you mean by (firmware), but my next steps will be to try installing it on my pc, and looking for updates.
    Thanks again, and I'l let you know if I ever get either of them working.


  • dre1219 Feb 28, 2009

    I have a very difficult problem that won't go away. My machine continues to display the "unable to init. See troubleshooting and routine maintenance in user's guide." I have performed all the steps listed there in the user's manual - to no avail!!! Error message won't go away. Please help.



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I realise this is an old question but I recently had a similar issue with our MFC-5860CN not receiving faxes and displaying the "Mn1" code. As it turns out "Mn1" means the machine is set to manual receive and was therefore not automatically receiving faxes. You will need to locate the "Receive Mode" option in the menu and change it to "Fax Only" or "Fax / Tel". Unfortunately I dont know what could have caused the turning off and on that the OP mentioned. I'm a little late to the party but I hope this info can help someone else!

Posted on Jul 07, 2008

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Sorry, havent found any hints within the service man for your printer although they have listed all kinds of errors given by the machine. Did you had a lighting strike the days before? It could be that there was some high voltage which had affected the micro electronics of the pcb (Its just a guess). If so, try to do firmware update from the brother homepage. If your are lucky machine will work again.

Posted on Sep 28, 2007

  • Mix-it-up
    Mix-it-up Sep 28, 2007

    Did you disassemble the printer looking for a answer to 4F?

    Please check all cable connection to the pcb. This could be another hint to your prob.



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