Machine Error 71 – Brother MFC-8440-8840D-8840DN-DCP-8040-8045D-8045DN
Machine Error 71 – Brother MFC 8440, 8840D, 8840DN DCP 8040, 8045D, 8045DN
The machine error 71  message in the Brother MFC 8440, 8840D, 8840DN, DCP 8040, 8045D, 8045DN  machines  is related to the laser/ scanner unit motor. As the machine gets ready to print the laser / scanner motor starts rotating. Depending on the model they get anywhere between 20,000 and 40,000 RPM’s. The machine watches for the polygon motor to reach its correct RPM’s before the laser starts writing to the drum unit. If the Brother MFC 8440, 8840D,  8840DN, DCP 8040, 8045D, or 8045DN don’t reach that specific speed in a certain amount of time  then they display a 71 machine error on the display.
Troubleshooting the machine error 71 Â on Brother MFC 8440, 8840D, 8840DN, DCP 8040, 8045D, 8045DN machines.
Not much troubleshooting is involved in the machine error 71  on Brother MFC 8440, 8840D, 8840DN, DCP 8040, 8045D, 8045DN  machines. If you’re doing  a call for your customer then I would ask if the machine as been running noisy before the error happenned. Typically the  71 machine error is  a result of the bushings inside the polygon motor getting dried out or dirty. Before the 71  machine error  happens  the motor usually gets really noisy as it gets up to speed. Some customers say it sounds similar to an airplane taking off. Most times the machine goes to a ready state when turned on but once you send a print or copy  job to it it  fails. Hopefully, you can hear the noise then to help verify the issue if the motor hasn’t already siezed up.
Repair the Machine Error 71 Â on Brother MFC 8440, 8840D, 8840DN, DCP 8040, 8045D, 8045DN machines.
There are two ways out there to fix the machine error 71. First, and the way I prefer  to handle the problem, is to replace the laser / scanner unit. The unit is a pain to get out because it is located in the middle of the machine. For an experienced tech it shouldn’t be a big deal but for the average Joe it could be overwhelming. For anybody planning on doing this that hasn’t done one before I would recommend finding a service manual first before disassembly. Your second option is to remove the laser / scanner unit take out the polygon motor (don’t touch mirrors or lenses) clean off the shaft the goes into the motor bushings and using a light oil lubricate the post and bushings. I prefer just replacing the unit for the 71 machine error because it’s not that expensive, it’s a  pain to get out, and the clean and lubricate  repair doesn’t always work. Sometimes it does, other times for a while or not at all. The choice is yours, I replace the  laser unit for a machine error 71  on  Brother MFC 8440, 8840D, 8840DN, DCP 8040, 8045D, 8045DN machines  to protect my reputation and fix it right the first time.
The LSU’s for this unit are becoming increasing hard to find due to the age of the machines. Below I have listed the current replacement Brother models.
