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1. Thread comes off at the start of
1-1) Stitch skipping at the 1st
Decrease the sewing speed at the start of sewing.
sewing
stitch
1-A) Penetration registance of the
Use a thinner needle. (Lower the needle count to be
thread against the cloth is small..
used.)
1-2) Length of thread remaining
2-A) Tension controller No. 1 provides
Properly adjust the tension controller No. 1.
at the needle is not sufficient.
an excessive tension.
2-B) Floating of the AT thread
Adjust the amount of AT thread tension floating.
tension disc is insufficient.
2-C) Stroke of the thread take-up
Adjust the stroke of the thread take-up spring.
spring is excessive.
2-D) The thread take-up spring
Adjust the thread take-up spring tension.
tension is insufficient.
2-E) Level difference between the
Adjust the height of the counter knife.
needle hole guide and the
counter knife is excessively high.
2-F) Needle thread tension is high
Adjust the needle thread tension.
and the thread is excessively
stretched.
2-G)Thread spreading section of
Polish the thread spreading section of the moving
the moving knife has scratches.
knife with buff or replace the knife.
1-3) Length of bobbin thread re-
3-A) Level difference between the
Adjust the height of the counter knife.
maining is not sufficient.
needle hole guide and the
(Otherwise, widen the gap.)
counter knife is excessively high.
3-B) Lower face of the needle hole
Polish the needle hole guide with a buff or replace it.
guide has scratches.
3-C) Thread spreading section of the
Polish the thread spreading section of the moving
moving knife has scratches.
knife with buff or replace the knife.
3-D) Shuttle upper spring has
Polish the shuttle upper race with a buff or replace
scratches.
it.
3-E) The bobbin thread tension is
Adjust the bobbin thread tension.
excessive.
3-F) The bobbin or bobbin case
Polish it with a buff or replace it.
has scratches.
Trouble
Cause (1)
Cause (2)
Check and corrective measures
(2) Troubles and corrective measures (Sewing conditions)
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Summary of Contents for LK-1900A
Page 20: ... 16 10 Hook adjustment Standard Adjustment 0mm 0mm 7 5mm 0 05 0 1mm For DPX5 For DPX17 ...
Page 90: ... 86 Grease Grease Grease Grease Grease 8 Needle thread clamp mechanism area ...
Page 91: ... 87 Grease Grease A Grease Grease Grease Grease 9 LK 1901A relations ...
Page 92: ... 88 10 LK 1903A relations Grease Grease ...
Page 114: ... 111 12 Circuit diagrams 1 Block diagram A ...
Page 115: ... 112 2 Power supply circuit diagram A ...
Page 116: ... 113 3 Power supply circuit diagram B ...
Page 117: ... 114 4 Power supply circuit diagram C ...
Page 118: ... 115 5 Servo motor circuit diagram ...
Page 119: ... 116 6 Sensor pedal VR circuit diagram ...
Page 120: ... 117 7 MAIN PANEL board circuit diagram ...
Page 121: ... 118 8 Motor solenoid circuit diagram Thread trimmer Lifting the work clamp foot motor ...