Brother mfc-8120 check cable showing on LCD screen - have cat5 connected - what is the error message indicating and how do I check/fix

SOURCE: printer keeps turning off,,,error message MN1 in lcd

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!

SOURCE: Error message 50

Confirm Success on a 440CN

1) Remove Plastic wire covers from inside printers, and release plastic stay on lower edge, tilt cover to 90 Degrees
2) make a note of where each connector goes
3) release the Ribbon and 3 Multicore cables, removing grounding screw, then remove scanner module by sliding it off the hinges at 90 degrees.
4) Remove Three Front Panel Screws, carefully leaver front panel upwards releasing front side clips.
5) Remove front panel by disconnecting ribbon and wireing on both sides.
6) Remove 6 Screws (2 on back, three at front and one middle right
7) Carefully remove speaker cable (Red Connector) and lift up plastic casing, leaving printer uncovered.
8) Re-Seat Encoder Strip into guide. (The Transparent strip)
9) Re-assemble in reverse and Hey Presto.

All Cured. Hopefully!

Robert McCord

• 70 Answers
• Posted on Mar 23, 2009

SOURCE: ! Unable to print 36

here is the solution according to brothers website
http://www.brother-usa.com/FAQs/Solution.aspx?FAQID=100000012648&Sympt=How+do+I+clear+error+message+Print+Unable+36%3f&Model=1208&ProductGroup=1&ProductID=HL4070CDW

SOURCE: error 46 in brother mfc-440cn

Machine Error 46 ("Unable to Clean") indicates that the wasteink is full. Basicly it gives you two options - have it replaced (a semi-complicated performance which requires buying a spare part and change it yourself) or have it sent to service. If you do not have any warranty on the machine, the more suitable would probably be to just replace the machine instead, since it's relatively cheap compared to both service costs and having the wasteink replaced, but you instead get a full new warranty on your new machine.
Unfortunately, there's nothing you yourself can do to remove this error, without actually changing an item inside the machine.

SOURCE: error message one brother mfc-5440cn

Unplug the printer from power cord.Press and hold the "menu" button, then plug the device.You'll see on the LCD screen a "machine error" code.If this code is 40,41 or 4F the print head is defective.If the error is 50 or 51 there is error in Purge unit and printer require service.If the error is 46 the waste ink tank is full.Follow this:
Enter 80, then scroll down with the arrow down (round) key. You'll find an entry listed as purge count. If number
is over 6000, enter 2 7 8 3.This will reset the purge count value. Then restart the printer, hopefully without the
annoying cannot clean message.