When the Brother machine is idle for a certain period of time, it will enter Sleep Mode and its display (hereinafter called LCD) on the control panel will be blank.
If you press the LCD, it should light up and display the date and time.
If the LCD remains blank, your Brother machine is not powered on. Go to the next step.
2. Check the power cord and AC power outlet (electrical socket)
If the LCD is blank even after you have pressed it:
Make sure that the machine's power cord is connected directly to the AC power outlet (electrical socket) and that no surge protectors or power switches are used.
Make sure that the socket is working. Disconnect your machine, and try to plug another device directly into the same socket. If that device does not work, connect the Brother machine to a different working socket.