JUKI MF-7900 Series Engineer's Manual page 97

Adjustment procedures
1. DOWN position
(1) DOWN position of the needle is the position where top end B
of the looper has scooped loop A of the left needle thread.
If it is incorrect, adjust the down position of the needle by func-
tion setting No.122 (DOWN position starting angle compensa-
tion) of SC-921.
* When performing the machine type setting, it is set to be
stopped at a position described above.
2. UP position
(1) UP position of the needle is the position that the mark C on
the machine head side aligns with the mark D (marker line of
upper side) on the handwheel ❶ .
If it is incorrect, adjust the down position of the needle by func-
tion setting No.121 (UP position starting angle compensation)
of SC-921.
* When performing the machine type setting, it is set to be
stopped at a position described above.
Results of Improper adjustment
– 83 –