Janome MC6700P Service Manual page 24

To adjust the upper thread tension release (2)
Upper thread tension disks should open 0.8 mm when the tension release motor operates.
If not, adjust follows.
Base
Setscrew C
Front
Setscrew A Thread tension release
gear
(Fig. 1)
Plate
Setscrew B
Approximately 0.8 mm
Thread tension
release plate
1. Remove the top cover, face plate and thread guide
cover.
2. Set the thread tension dial at "9" and lower the presser
foot lifter.
3. Turn the thread tension release gear counterclockwise
until it stops. (Fig. 1)
4. Check the gap of upper thread tension disks. The
clearance should be 0.8 mm.
If the clearance is smaller than 8.0 mm:
Loosen the setscrews A and B. Tighten the setscrew
B lightly. Remove setscrew C and slide the base to the
front. Tighten the setscrew A and B securely. Tighten the
setscrew C.
If the clearance is larger than 8.0 mm:
Loosen the setscrews A and B. Tighten the setscrew
B lightly. Remove setscrew C and slide the base to the
rear. Tighten the setscrew A and B securely. Tighten the
setscrew C.
NOTE:
Turn the setscrew B with the plate positioned in the front
cover.
5. Attach the thread guide cover, face plate and top
cover.
To check
Make sure that the thread tension release plate has
a play when turning the thread tension release gear
counterclockwise until it stops.
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