MFC-8440 FAQs & Troubleshooting MFC-8440 Not your product? Sort by: Updated Date Popularity 3 Results 1. 01/28/2013 The keys on the control panel do not respond. 2. 08/26/2011 I heard a beep sound from the UPS (Uninterruptible Power Supply) when I turned on my Brother machine. 3. 06/26/2007 Why does my computer become unresponsive when using the USB interface to connect the Brother machine? Others FAQs & Troubleshooting