When Brother MFC-7420 printer error in the fuser, the printer shows the error message on the LCD: Unit is too Hot , Fail to Warm up. Currently, multi-function printer Brother MFC-7420 is being used quite extensively. With multiple functions: fax, photocopy, print, scan it helps a lot for a small office area. Brother MFC-7420 printer also has advantages following: print speed, copy speed, sharp pages printed, toner saving and easy to use. However, we can not avoid the damage of the printer as some components of the printer caused in during use. Cause of error in the fuser: - With Unit is too Hot: The fuser unit is too hot. - With Fail to Warm up: The fuser unit is too cold. Instruction to fix fuser error for Brother MFC-7420 Printer(See more details in Samsung Scx-6545N Service Repair Manual) When you turn off the MFC’s power switch its memory will be cleared. - If there are faxes, you need to save them before following the suggestions below. Then, turn off the MFC’s power switch. Check the MFC’s environment. - If it is in a location that is too hot or too cold, try to cool or warm the room by turning on the air conditioner or heater. Or, move the MFC to another location. Then, turn on the MFC’s power switch. You can find solutions fix other errors of Brother MFC-7420 printer in "Samsung Brother MFC-7420 Service Repair Manual". The following is table of message error of Brother MFC-7420 Brother MFC-7420 Service Repair Manual document very important with technician when repair the Brother MFC-7420 printer. "Brother MFC-7420 Service Repair Manual" guide technician remove and install components internal Brother MFC-7420 printer, providing them knowledge intensive the component, how to take apart and fix bugs in the process of using Brother MFC-7420 printer that the user themselves can not repair.