Brother MFC-5840CN All-In-One InkJet Printer "keeps saying change" Questions

...keeps telling me to change ink cartridges or even though they are in the it says no cartridge. as a printer mechanic .i had got many customers coming at my work shop with this problem .and it gets ...

keeps saying "change drum soon" even if we replace the drum, and keeps say drum error and is telling me to move blue tab side to side and i did. i switched the phone cord to a different hook up on the

keeps saying change LC51M two of the four cartridges were low in ink so I put 4 new brother ink cartridges in the machine but it keeps saying "no cartridge" for cyan. doesn't LC51M refer

...Keeps saying add new black ink cartridge, i have and still saying change cartridge When inserting a new cartridge, you may receive a prompt "The installed ink cartridge differs from the original ink ...

I changed my black and yellow ink and the printer keeps reading no cartridge. It also say open scanner cover and reinstall. I have done that and it keeps reading the same thing. can you help me please

...saying to change the yellow press 1 or 2 i have done this and cannot make this stop i tried to clear it so i can change the date. i have even tried to unplug it and plug it in. please help press stop ...

...keeps saying no catriage after I change the cyan color. Its posible there is another ink cartridge that is now empty. Open the cover for the inks and see what it says on the display. If it asks for ...

...keeps turning off and on saying "please wait"...a kind of ding dong sound!!! I have uninstalled and reinstalled 3 times...and works for a while then out of the clear blue..its starts making that ding ...

not able to print envelopes . It keeps saying wrong paper change paper size , and adjust paper holding clip to the size of envelope

ive changed the ink and it still says not enough ink to keep printing. Why? if your not using genuine cartridge this can happen, or you just have a bad cartridge, they have sensors on now.