Brother MFC620CN Service Manual page 293

(4) On the 2nd sheet, check the printed vertical alignment pattern for 750 dpi and perform the
same operation as in step (2).
The machine automatically returns to the initial stage of the maintenance mode.
NOTE: If #1 or #8 block is fully aligned so that you press the 1 or 8 key (or you enter 1 or 8) in
the above procedure, then go back to step (1) to confirm that #5 block becomes aligned.
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