JUKI LK-1900A Series Engineer's Manual page 51

Adjustment Procedures
1. Start the test mode CP-7.
2. Tread on the pedal for needle thread clamp device
3. Press the key twice and set the needle thread clamp support
plate complete in the needle thread clamp position.
4. Confirm that the clearance A becomes 0 between the needle thread
clamp device and the needle thread clamp support plate complete
when the [–] key is pressed 3 to 4 times (for 3 to 4 pulses), and
that both the needle thread clamp device
clamp support plate complete
pressed again.
5. If the clearance A becomes 0 with 5 or more pulses, loosen the set
screw and fix the sensor mounting plate
direction B.
6. If the clearance A becomes 0 with less than 3 pulses, loosen the set
screw and fix the sensor mounting plate
direction C.
7. After the sensor mounting plate
mentioned steps 2. to 4.
8. Using 3 to 4 pulses, repeat the steps 2. to 6. above until the clear-
ance A becomes 0.
9. Tread on the pedal for needle thread clamp device
and define the most advanced position by pressing the
once.
10. Confirm that the distances between the needle thread clamp sup-
port plate complete
1.7 ~ 2.3mm, respectively.
11. If the distance is found to be inadequate, adjust the position toward
the needle according to (35) Needle thread clamp device con-
nection/disconnection. Since then, make the above-mentioned sen-
sor adjustments again.
and the needle thread
move together when the [–] key is
after moving it in the
after moving it in the
has been fixed, check the above-
and the needle are kept at 3 ~ 4mm and
o If there are too many pulses used
origin retrieval.
o If the number of pulses is too small
o If the distance is improper be-
origin retrieval
key
– 47 –
Results of Improper Adjustment
until the clearance A becomes 0,
this can be a cause of unthreading
at the beginning of sewing.
until the clearance A becomes 0,
the resistance toward the needle
thread becomes large and this
can be a cause of thread break-
age at the beginning of sewing.
tween the needle thread clamp
support plate complete
needle , this will give rise to in-
terference between the needle
thread clamp device
needle .
and the
and the