To turn off the sleep mode of your brother machine, at first, you need to press the "Start" and "Options" keys at the same time. When the LCDs the message saying "Sleep Mode: On", press the "Up" or "Down" arrow keys to turn it off. In the end, press the "OK" button followed by Stop/Exit. https://www.brother-support.us/how-to-wake-up-brother-printer-from-deep-sleep/
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To turn off the sleep mode of your brother machine, at first, you need to press the "Start" and "Options" keys at the same time. When the LCDs the message saying "Sleep Mode: On", press the "Up" or "Down" arrow keys to turn it off. In the end, press the "OK" button followed by Stop/Exit.
https://www.brother-support.us/how-to-wake-up-brother-printer-from-deep-sleep/