Brother MFC5490CN Service Manual page 255

(4) Move the head/carriage unit to the center of its travel with function code 63 (see
Section 9.4.17) using the following key operation.
Press the 6, 3, and Black Start (Mono Start) keys in this order to display "START 63?" on
the LCD. Next, press the * key.
(5) Turn the head skew adjuster knob by the number of divisions specified by the pattern
number you recorded in step (3), using a spanner.
If block +1 is the least uneven print, for example, turn the head skew adjuster knob
clockwise by one division; if block -1, turn it counterclockwise by one division.
Counterclockwise
(6) After completion of the adjustment, press the Stop/Exit key. The head/carriage unit returns
to the home position (head capping position).
Clockwise
Head skew adjuster knob
(head_skew_adjuster_knob_BHM9)
7-13
Chapter 9,
Confidential