Brother MFC990CW Service Manual page 322

(14) To adjust the bottom margin, enter the measured value (in units of 0.1 mm) multiplied by
10.
In this example, the bottom margin measured in step (12) is 3.1 mm, so press the 3, 1, and
OK keys. (For models without numerical keypad, enter 3 and 1 using the
keys and then press the OK key again.)
Upon completion of the entry, the machine automatically returns to the initial stage of the
maintenance mode.
(15) Go back to step (11) and print out the bottom margin check pattern again.
(16) Measure the bottom margin on the printed pattern.
If it is within the range from 2.9 to 3.1 mm, the adjustment is completed.
7-24
, and OK
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