I had the same problem with my first refurbished 8680DN unit I got from Staples. I realized this was a defect, so I returned it for a replacement unit. My replacement unit does not have such a problem.
I have a Brother Multi Function 8680 DN Laser Printer and it operates with Windows XP Home. Although I like the printer my only issue is that Brother Support tells me that the only way for the Date & Time to work is to initially leave the printer on for 48 hours to charge the battery and not shut it off for more than a day or two (leave in sleep mode). If I shut it off for a few days, it resets to a default 1/1/2010 setting and I lose fax logs. Why would any printer with an uninterrupted power source require being on continuously to maintain it's date in time. In an era of trying to cut power consumption, this would seem to be a poor design feature particularly if a large organization had hundreds of printers. Please comment

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