JUKI MF-7900 Series Engineer's Manual page 109

Adjustment procedures
1. Adjusting the clamp spring
Adjust the leaf spring which clamps the needle thread after the wip-
er operates.
(1) Install clamp spring ❽ on wiper ❺ with screw ❾ so that they
are in parallel to each other.
(2) Fix clamp spring with the screw so that the top end of clamp
spring ❽ does not protrude the slanted section at the top end of
wiper ❺ .
2. Installing the needle thread wiper
(1) Bring the needle bar to the uppermost position.
(2) Make mounting base ❶ level and temporarily fix it by tightening
screw ❷ at the center of the slot.
(3) Adjust so that the lever ❸ is horizontally positioned relative to
mounting base ❶ and a clearance of 4 mm is provided between
them. In this state, tighten screw ❹ .
(4) Adjust wiper ❺ so that its top end is spaced 15 mm from the
center of the needle bar and its height is 8 mm above the top
surface of throat plate ❻ when wiper ❺ is brought to the left-
most position.
(5) Adjust the position of the top end of wiper ❺ by means of screw
❼ and the height of the top end of wiper ❺ by means of screw
 respectively.
(6) After the completion of the adjustment, tighten screws ❷ .
(Caution) When the solenoid operates, the solenoid shaft
moves forward by 0.9 mm while rotating. To adjust
the solenoid, rotate it while pulling lever ❸ toward
you. After the completion of the adjustment, activate
the solenoid to check that it does not interfere with
other parts such as the presser foot and needle in the
operating range of wiper ❺ .
Results of Improper adjustment
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