MFC-8840D FAQs & Troubleshooting MFC-8840D Not your product? Sort by: Updated Date Popularity 3 Results 1. 28.01.2013 The keys on the control panel do not respond. 2. 26.08.2011 I heard a beep sound from the UPS (Uninterruptible Power Supply) when I turned on my Brother machine. 3. 26.06.2007 Why does my computer become unresponsive when using the USB interface to connect the Brother machine? Others FAQs & Troubleshooting