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If a sewing trouble occurs due to frequent idling of
bobbin when performing thread trimming, loosen
screw
❹
and adjust the initial position of moving
knife
❶
.
Loosen screw
❹
with a 7-mm spanner.
According to the initial value representing the ini-
tial position of moving knife, the distance from the
top end of throat plate
❷
to the top end of moving
knife link
❸
is 19 mm. Change the initial value to
a value between 19.5 and 20mm.
If the distance from the top end of throat plate
❷
to the top end of moving knife link
❸
is increased excessively, the needle thread and bobbin thread sometimes cannot be
trimmed at a time.
In such a case, decrease the distance from the top end of throat plate
❷
to the top end of
moving knife link
❸
.
CAUTION :
Turn OFF the power before starting the work so as to prevent accidents caused by abrupt start of
the sewing machine.
Thick thread can be guided more smoothly by opening the speed controller since the air
flow is increased by opening it. However, thin thread will be likely to flop when the air
flow is excessively increased.
Thin thread can be guided more smoothly by closing the speed controller since the
air flow is decreased by closing it. However, thick thread will be likely not to be guided
smoothly.
CAUTION :
Turn OFF the power before starting the work so as to prevent accidents caused by abrupt start of
the sewing machine.
The initial adjustment value of the speed controller
has been adjusted to the value which is obtained
by turning it in the reverse direction by seven rev-
olutions from the fully-opened position.
If the remaining thread removal is not carried out
stably according to the type and count of thread,
finely adjust the speed controller.
Speed controller
Remaining thread
guide solenoid valve
2-4. Corrective measure against idling of the bobbin
❹
❸
❶
❷
19 mm
2-5. Adjusting the air flow for the remaining thread guide
