Brother DCP-L8400CDN Service Manual page 422

1.3.20 Motor reset (Function code 57)
<Function>
When the main PCB or each motor is replaced, the main PCB needs to identify each motor.
If you reset the identification of each motor in the main PCB with this function, when the power
is turned ON next time, a motor identification operation for each motor is performed before the
engine performs a warm-up.
<Operating procedure>
(1) Press the 5 and 7 keys in this order in the initial state of the maintenance mode.
"RESET MOTOR" is displayed on the LCD.
(2) When the Mono Start key is pressed, each motor identification result is reset and "PLZ
POWER OFF/ON" is displayed on the LCD.
(3) Turn OFF/ON the power switch to perform a motor identification operation for each motor
and the machine returns to the initial state of the maintenance mode.
Note:
If "PLZ POWER OFF/ON" is displayed on the LCD, any keys other than the power switch
are not accepted.
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