– 97 –
3. Stitch Skipping
3-1) Too much clearance between
Adjust the clearance between needle and inner hook.
the needle and the inner hook.
3-2) Inadequate timing adjustment
Adjust timing for the needle and the inner hook.
for the needle and the inner hook.
3-3) Inadequate clearance between
Adjust the clearance between needle and shuttle driver.
the shuttle driver and the needle
3-4) Material to be sewn is not
4-A) Too much clearance between
Adjust the work clamp foot height.
properly stretched.
the work clamp foot and
sewing object
Remove the slackness of the sewing object.
3-5) Needle is bent or blunt.
Replace the needle.
3-6) Loop of the needle thread
Attach the needle with the long groove orienting slightly
falls down.
to the right. (Approximately 20
°
)
6-A) Feed timing is too fast.
Change the feed timing by the use of the memory switch.
4. Thread breakage
4-1) Stratches on the inner hook
1-A) Scratches on section
A
After polishing the blade point of the inner hook with
(Contact of the inner hook with
oilstone, polish it with polishing powder. Properly adjust
the needle)
the clearance between the needle and the inner hook.
1-B) Scratches on section
B
After polishing the blade point of the inner hook, polish it
(Scratches occur when the
with polishing powder.
needle is bent or broken.)
1-C) Scratches on section
C
After polishing the blade point of the inner hook, polish it
(Needle scratches the inner hook
with polishing powder.
when removing the inner hook.)
1-D) Scratches on section
D
After polishing the blade point of the inner hook, polish it
with polishing powder.
4-2) Thread enters into the shuttle.
2-A) Position of the shuttle upper
Properly adjust the position of the shuttle upper
spring is wrong.
spring.
2-B) Blade point section
A
of the
Replace the inner hook.
shuttle is round.
2-C) Position of the shuttle is wrong.
Properly adjust the position od the shuttle.
2-D) Needle thread tension is too low.
Properly adjust the needle thread tension.
Trouble
Cause (1)
Cause (2)
Check and corrective measures
A
To the next page
To the next page
A
B
C
D
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 ...
