JUKI LBH-1790 Series Quick start guide

R
ENGINEER’S MANUAL
40006360
No.E352-00
Computer-controlled, High-speed,
Lockstitch Buttonholing Machine
LBH-1790 Series

PREFACE
This Engineer’s Manual is written for the technical personnel who are responsible for the service and maintenance of
the machine.
The Instruction Manual for these machines intended for the maintenance personnel and operators at an apparel
factory contains operating instructions in detail. And this manual describes “Standard Adjustment”, “Adjustment
Procedures”, “Results of Improper Adjustment”, and other important information which are not covered by the Instruction
Manual.
It is advisable to use the relevant Instruction Manual and Parts List together with this Engineer’s Manual when carrying
out the maintenance of these machines.
In addition, for the motor for the sewing machine with thread trimmer, refer to the separate Instruction Manual or
Engineer’s Manual for the motor. And for the control panel, refer to the Instruction Manual for the control panel.
This manual gives the “Standard Adjustment” on the former page under which the most basic adjustment value is
described, and on the latter page “Results of Improper Adjustment” under which stitching errors and troubles arising
from mechanical failures are described together with the “Adjustment Procedures”.

CONTENTS
1. SPECIFICATIONS ............................................................................................. 1
2. STANDARD SEWING SHAPE LIST ................................................................. 2
3. STANDARD ADJUSTMENT ............................................................................. 3
(1) Height of the needle bar.................................................................................................. 3
(2) Needle-to-hook timing..................................................................................................... 3
(3) Adjusting the feed timing belt tension .......................................................................... 5
(4) Knife drop position.......................................................................................................... 5
(5) Adjusting the stroke and initial position of the cloth cutting knife ............................ 7
(6) Adjusting the rotary play of the cloth cutting knife...................................................... 9
(7) Replacing the knife.......................................................................................................... 9
(8) Adjusting the needle thread trimmer........................................................................... 11
1) Adjusting the thread grasping force of the needle thread trimmer.......................................................... 11
2) Adjusting the height of the needle thread trimmer .................................................................................. 11
3) Needle thread trimming adjustment mode.............................................................................................. 13
4) Adjusting the needle thread trimmer origin sensor ................................................................................. 15
5) Lateral adjustment of the needle thread trimmer (start of sewing) ......................................................... 15
6) Longitudinal and lateral adjustment of the needle thread trimmer (at the time of trimming)................... 17
7) Opening amount of the needle thread trimmer....................................................................................... 17
8) Adjusting the needle thread draw-in amount .......................................................................................... 19
(9) Adjusting the bobbin thread trimmer .......................................................................... 19
1) Bobbin thread trimmer adjustment mode ............................................................................................... 19
2) Adjusting the bobbin thread trimming origin sensor ............................................................................... 21
3) Adjusting the position of the trimmer ...................................................................................................... 21
4) Replacing the bobbin thread trimmer ..................................................................................................... 23
5) Open timing and open amount ............................................................................................................... 23
(10) Adjusting the presser lifter......................................................................................... 25
1) Adjusting the backlash of the presser lifter gear..................................................................................... 25
2) Adjusting the presser bar position bracket ............................................................................................. 25
3) Adjusting the presser lifter origin sensor ................................................................................................ 27
1 Adjusting the senor ............................................................................................................................. 27
2 Refer to the adjusting procedure of the presser lifter motor origin compensation .............................. 27
(11) Adjusting the thread tension...................................................................................... 29
1) Adjusting the stroke of the thread tension solenoid................................................................................ 29
2) Adjusting the thread take-up spring tension (purl stitching).................................................................... 29
(12) Adjusting the bobbin winder ...................................................................................... 31
(13) Adjusting the thread breakage detecting plate......................................................... 31
(14) Adjusting the bobbin presser..................................................................................... 33
(15) Adjusting the pedal ..................................................................................................... 35

4. ADJUSTING EACH SENSOR ......................................................................... 37
(1) Adjusting the needle rocking origin ............................................................................ 37
1) Needle rocking motor origin compensation ............................................................................................ 38
(2) Adjusting the feed origin .............................................................................................. 39
1) Feed motor origin compensation ............................................................................................................ 40
5. DISASSEMBLING/ASSEMBLING PROCEDURE .......................................... 41
(1) Disassembling/assembling the main shaft ................................................................. 41
(2) Replacing the timing belt (main shaft)......................................................................... 43
(3) Replacing the timing belt (hook driving shaft) ........................................................... 45
(4) Adjusting the timing belt of main shaft (idler) ............................................................ 47
(5) Disassembling/assembling the face plate section..................................................... 49
(6) Disassembling/assembling the needle rocking motor............................................... 51
(7) Replacing the cloth cutting knife solenoid ................................................................. 53
(8) Replacing the cloth cutting knife solenoid cushion................................................... 55
(9) Replacing the knife return stopper .............................................................................. 57
6. LUBRICATION ................................................................................................ 59
(1) Lubricating oil to oiling tank......................................................................................... 59
(2) Adjusting the lubrication for the sewing hook........................................................... 59
(3) Applying grease.............................................................................................................59
1) Main shaft components .......................................................................................................................... 59
2) Presser and feed components................................................................................................................ 60
3) Needle bar rocking components ............................................................................................................. 61
4) Needle thread trimmer components ....................................................................................................... 62
5) Cloth cutting knife components .............................................................................................................. 63
7. OPERATION PANEL....................................................................................... 65
(1) Structure of the operation panel .................................................................................. 65
(2) Initial value data for each shape table......................................................................... 67
8. VARIOUS DATA LIST ..................................................................................... 68
(1) Sewing data list.............................................................................................................. 68
(2) Memory switch data list ................................................................................................ 74
9. EXPLANATION OF SHAPE ............................................................................ 78
10. DETAILED EXPLANATION OF CONTINUOUS STITCHING....................... 86
11. ERROR CODE LIST ...................................................................................... 87

12. ELECTRICAL COMPONENTS...................................................................... 90
(1) Change of data ROM ..................................................................................................... 90
(2) Adaptation to the high voltage..................................................................................... 90
(3) DIP switch....................................................................................................................... 90
(4) Adaptation to the PK pedal........................................................................................... 91
(5) Fuse list .......................................................................................................................... 92
13. GAUGE COMPONENTS AND OPTIONAL COMPONENTS ........................ 93
14. OTHERS ........................................................................................................ 95
(1) Points of replacement for feed 70 mm and 120 mm................................................... 95
15. TROUBLES AND CORRECTIVE MEASURES............................................. 97
(1) With regard to sewing ................................................................................................... 97
(2) With regard to mechanical components ................................................................... 106
(3) With regard to electrical components ....................................................................... 107
16. TIME CHART ............................................................................................... 123
17. CIRCUIT DIAGRAM .................................................................................... 125
(1) Block diagram A (3-phase 200 to 240V)..................................................................... 125
(2) Block diagram B (Single phase 230V (for CE)) ......................................................... 126
(3) Block diagram C (Single phase 220 to 240V)............................................................ 127
(4) Power circuit diagram (3-phase 200 to 240V) ........................................................... 128
(5) Power circuit diagram (Single phase 220 to 240V)................................................... 129
(6) Power circuit diagram (Single phase 100V) .............................................................. 130
(7) Servo motor circuit diagram....................................................................................... 131
(8) Stepping motor/solenoid circuit diagram.................................................................. 132
(9) Head sensor circuit diagram ...................................................................................... 133
(10) Pedal switch circuit diagram .................................................................................... 134
(11) Connection circuit diagram between control box and head ................................. 135
18. DRAWING OF THE TABLE ........................................................................ 136

−1−
1. SPECIFICATIONS
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
Model
Item
Stitch width*1
Cloth cutting knife size (Knife
length)
Stitch length (max.)*2
Sewing speed
Speed control system
Needle
Needle bar stroke
Thread take-up lever
Hook
Lift of work clamp check
Presser lifting drive system
Bobbin winder
Feed drive method
Needle rock drive system
Clothcutting knife drive system
Adjustment of needle thread
Sewing shape
Number of patterns stored in
memory
Data memory medium
Data communication function
External pattern creation
Change-over of 1/2 stitching
Input voltage classification
(Power consumption)
Motor
Lubrication method
Lubricating oil
Grease
Dimensions
Weight of machine head
Specifications
5 mm (Resolution : 0.05 mm)
6.4 to 31.8 mm (1/4" to 1-1/4")
41 mm
Standard 3,600 rpm Max. 4,200 rpm (Dry hook : Max. 3,300 rpm)
Panel input and variable resistor
DPX5 #11J to 14J
34.6 mm
Link thread take-up lever
DP type full-rotary automatic lubricating hook, (Dry hook : DP type
RP hook : optional)
14 mm (optional setting possible) Max. 17 mm (When reverse
revolution to lift needle function is set.)
Stepping motor system (1-pedal, 2-pedal)
Built-in machine head type (Bobbin winding possible only when sewing
machine rotates)
Stepping motor drive (Timing belt)
Stepping motor drive
Double acting solenoid drive
Active tension method
Digital setting for each section by means of operation panel (Parallel
section tension, bar-tacking section tension, etc.)
Square shape, radial shape, round shape, etc. 30 shapes (selection
by operation panel)
99 patterns
Smart media (When IP-200 is used)
Possible with IP-200
Possible with PM-1
Each pattern can be set.
Domestic : 1ø 100V/ 3ø 200V (1000VA)
Export : 1ø 220 to 240V (CE : Single phase 230V without power
switch) / 3ø 200 to 240V (1000VA)
Compact AC servo motor 450W Direct-drive method
Face plate section : dry Hook section : minute quantity lubrication
(dry hook : no lubrication)
JUKI New Defrix oil No.1 (Equivalent to ISO VG7)
JUKI exclusive grease, TEMPLEX
Width of machine bed : 200 mm, Height : 364 mm, Length : 630 mm
55 Kg
LBH-1790S LBH-1790S
Model classification : S : standard, K : for knit
Stitch width
Sewing length (Max.)
For *1 and 2, stitch width can be changed to max. 10 mm by replacing optional parts.
Besides, for the sewing length, it can be changed to max. 120 mm (70 mm).
Presser type 1
4 mm
25 mm
Presser type 2
5 mm
35 mm
Presser type 3
5 mm
41 mm
Presser type 5
3 to 10 mm (Optional setting)
10 to 120 mm (Optional setting)

−2−
2. STANDARD SEWING SHAPE LIST
(1) Square type (2) Round type (3) Radial square type (4) Radial type (5) Radial straight bar-
tacking type (6) Radial flow bar-tacking type
(7) Eyelet square type (8) Eyelet radial type (9) Eyelet straight bar-
tacking type (10) Eyelet flow bar- tacking type (11) Semilunar type (12) Round square type
(13) Semilunar square
type (14) Semilunar straight bar-tacking type (15) Semilunar flow bar- tacking type (16) Eyelet semilunar type (17) Eyelet round type (18) Square radial type
(19) Square semilunar
type (20) Square round type (21) Square straight bar- tacking type (22) Square radial bar- tacking type (23) Radial semilunar type (24) Radial round type
(25) Semilunar radial type (26) Semilunar round
type (27) Bar-tacking (28) Bar-tacking, right cut (29) Bar-tacking, left cut (30) Bar-tacking, center cut
PANEL
DISPLAY
PANEL
DISPLAY
PANEL
DISPLAY
PANEL
DISPLAY
PANEL
DISPLAY
PANEL
DISPLAY
PANEL
DISPLAY PANEL DISPLAY PANEL DISPLAY PANEL
DISPLAY PANEL DISPLAY PANEL DISPLAY
PANEL
DISPLAY PANEL DISPLAY PANEL
DISPLAY PANEL DISPLAY PANEL DISPLAY PANEL
DISPLAY
PANEL
DISPLAY PANEL DISPLAY PANEL DISPLAY PANEL DISPLAY PANEL DISPLAY PANEL DISPLAY
PANEL
DISPLAY PANEL DISPLAY PANEL DISPLAY PANEL DISPLAY PANEL DISPLAY PANEL DISPLAY

−3−
3. STANDARD ADJUSTMENT
(1) Height of the needle bar
Standard Adjustment
Standard Adjustment
(2) Needle-to-hook timing
Adjust the height of the needle bar so that the distance from the top surface of the throat plate to the
lower end face of the needle bar is 12.0 mm (S : standard) or 11.3 mm (K : knit) when the needle bar
is in the lowest dead point.
Needle
1) Blade point of the hook is aligned with the center of the needle when the
needle bar goes up by 2.5 mm (S : standard) or by 3.0 mm (K : knit) from
its lowest dead point.
At this time, the distance from the top end of the needle eyelet to the
bladepoint ofthe hookis 1.6to 1.8mm (needleis in the central section of
the hole in the throat plate).
2) The clearance provided between the needle and the blade point of the
hook is 0.01 to 0.04 mm (when the needle is rocked to the right of the
hole in the throat plate)
3) Adjustment value of the needle guard is 0 to 0.02 mm (needle is in the
central section of the hole in the throat plate).
Rear plate
(Needle guard section)
1.6 to 1.8 mm
0.01 to 0.04 mm
0 to 0.02 mm
Blade point
of hook
Needle guard
2
1
1
2
4
3
5
0 to 0.02 mm
Loop guide section Inner hook presser
Blade point

−4−
Adjustment Procedures Results of Improper Adjustment
Adjustment Procedures Results of Improper Adjustment
1. Enter timing gauge [1] 1supplied with the machine as
accessories between the throat plate and the lower end of the
needle bar as shown in the figure, fit the needle bar to timing
gauge [1] 1, loosen the setscrew 2in the needle bar
connection, and adjust the height of the needle bar.
(Caution) Adjust the height of the needle bar when the needle
is positioned in the center of the needle hole in the
throat plate.
2. Table of timing gauge
Part No. of timing gauge : 13943402 (S : standard)
13782107 (K : knits)
™For the floppy fabrics, it is
effective when the needle bar is
slightly lowered than the
standard value.
™For the floppy fabrics, it is
effective when the hook timing
is slightly retarded than the
standard value.
(Clraranceprovided between the
upper end of the needle eyelet
and the blade point of the hook
is desired to be approximately
1.0 mm.)
™For the purl stitching, if the hook
timing is advanced, crest of
seam is likely to be improved.
On the contrary, if the hook
timing is retarded, stitch skipping
is improved, but crest of seam
is likely to be slightly
deteriorated.
S (standard)
K (knits)
[1]
12.0 mm
11.3 mm
[2]
14.5 mm
14.3 mm 79NS1 791K
Sub-class type Engraved mark
Timing gauge
1. Turn the hand pulley in the normal direction of rotation, and make a
statethat the needle is in the center of hole in thethroat plateand the
needle bar starts going up from the lowest dead point. Then enter
timing gauge[2] 1between the throat plate and the lower end of the
needle bar as shown in the figure and loosen setscrew 2in the
hook shaft joint to adjust the timing.
2. Loosen setscrew 2in the hook shaft joint and adjust so that
the clearance between the needle and the blade point of the
hook is 0.01 to 0.04 mm when the needle is rocked to the
extreme right of the hole in the throat plate.
3. Adjust with setscrew 5so that the engagement of the top end of
bobbin casepositioning stopper 3andinner hook4is 0 to 0.2 mm.
4. Bend the needle guard and adjust sothat theclearance between the
needle and the needle guard is 0 to 0.02 mm.
(Caution)
1. When adjusting the needle guard, adjust so that there is no
clearance between the inner hook presser and the rear plate.
2. When moving the needle guard to the needle side, put a
screwdriver from the direction of the arrow mark, while
pressing the loop guide, and perform the adjustment.

−5−
Standard Adjustment
(3) Adjusting the feed timing belt tension
Standard Adjustment
(4) Knife drop position
General drawing of feed mechanism
Feed guide shaft
1
2
3
4
5
6
7
1
2
3
5
6
7
Knife should drop in the center of the knife drop groove in the throat plate.
Knife drop groove
Feed stepping motor
Feed shaft
Edge of machine arm
Knife
4
Throat plate
1
2
3

−6−
Adjustment Procedures Results of Improper Adjustment
Adjustment Procedures Results of Improper Adjustment
1. Adjust the position of feed motor installing plate 6so that the
lengthwise feed timing belt tension is applied with 70 to 80N.
2. Temporarily tighten three setscrews 5in feed motor installing
plate 6and adjust the timing belt tension by taking adjusting
screw 1in ond out.
(Caution)
1. Be careful that timing belt 3is not drwan up to one
direction when feed base 2is moved back and forth
several times.
2. Be careful that the cord of feed sensor 7does not come
in contact with timing belt 3.
3. Fix feed motor installing plate 6so that feed follower
shaft 4is parallel to the lengthwise feed motor shaft.
1. Loosen the setscrews, and remove work clamp carrier 2and
throat plate base cover 3.
2. Adjust the logitudinal and lateral positions at the installing
position of throat plate base 1and the direction of rotation at
the installing position of knife bar base 4.
(Caution) When the installing position of throat plate base 1
is adjusted, check the bobbin thread trimmer.
™When the belt tension is low,
correct lengthwise feed pitch
may not be obtained, or tooth-
skipping of belt may occur.
™When the position is improper,
the blade of cloth cutting knife
will wear out earlier.

−7−
Standard Adjustment
(5) Adjusting the stroke and initial position of the cloth cutting knife
General drawing of cloth cutting knife
1
2
3
4
5
6
7
8
9
Machine
arm
Sensor
detecting plate
Sensor
Knife return
spring
Edge of machine arm
0.4 to 0.6 mm
14 mm
Cushion
12
3
4
5
6
8
Knife sensor
Knife bar
Knife bar rotary
stopper
Knife driving lever
Cushion
Knife return spring
10 mm
4±0.5 mm

−8−
Adjustment Procedures Results of Improper Adjustment
1. Make the height of knife return stopper 110 mm from the
work plane of the machine arm and fix it with nut 2. (Adjustment
of initial position of the knife)
2. Adjust the position of solenoid installing base 4so that the
clearance between cloth cutting knife solenoid 3and the
cushion is 14 mm, and fix it with four screws. (Adjustment of
stroke)
3. Fix knife bar bracket 6so that the clearance between knife
bar base 5and the edge of the machine arm is 4±0.5 mm.
(Adjustment of initial position of the knife)
4. Adjust knife installing base 9so that the clearance between
needle bar 7and knife 8is 0.5±0.1 mm.
(Caution)
1. Be careful of the clearance between the throat plate and
knife 8when adjusting knife bar bracket 6, knife bar
base 5and knife installing base 9.
2. Fix solenoid installing base 4so that it is not tilted.
™If the distance of 4 mm is
excessively small, the knife
installing base comes in contact
with the jaw section of the
machine arm and a big noise
occurs.
™If the distance of 4 mm is
excessively large, the knife may
come out under the presser
when the presser is lifted.
™If the distance between cloth
cutting knife and needle bar is
small, the knife comes in contact
with needle bar and abnormal
noise, worn-out of knife or stain
of cloth may occur.
™If the distance between cloth
cutting knife and needle bar is
large, the distance from the front
bar-tacking to knife hole is
increased and the rear bar-
tacking may be cut.

−9−
Standard Adjustment
(6) Adjusting the rotary play of the cloth cutting knife
Standard Adjustment
(7) Replacing the knife
General drawing of cloth cutting knife
Square block base
1
2
3
4
1
3
4
5
Inch /mm conversion table
Knife size (inch indication)
1/4
3/8
7/16
1/2
9/16
5/8
11/16
3/4
13/16
7/8
1
1-1/8
1-1/4
mm indication
6.40
9.50
11.10
12.70
14.30
15.90
17.50
19.10
20.60
22.20
25.40
28.60
31.80
1
2
Knife return stopper
Knife sensor
Cloth cutting knife solenoid
Knife driving lever
Cushion
1 to 2 mm

−10 −
Adjustment Procedures Results of Improper Adjustment
1. Fix knife bar rotary stopper 3and the setscrew of thrust collar
4(from the left side of the machine arm) so that when moving
knife bar 1up or down, it moves smoothly and there is no
rotary play at knife bar base 2.
(Caution) When moving knife bar 1up or down, check that
there is a sufficient clearance between square block
5and knife bar rotary stopper 3both at upper
and lower positions.
Adjustment Procedures Results of Improper Adjustment
When sharpening knife 1or replacing it with a new one 1, perform
as follows.
1. Loosen knife setscrew 2. Knife 1can be simply removed
together with the washer.
2. Adjust so that the distance from knife 1and the top surface of
the throat plate is 1 to 2mm when lightly lowering the knife bar
by hand as shown in the figure. Then tighten it with the washer
without fail.
When the cloth cutting knife 1you have is indicated by inch, set
the cloth cutting length (knife size) to mm indication referring to
the inch /mm conversion table.
™When the rotary play is large,
the cloth cutting knife may
interfere with the throat plate.
This case is very dangerous.
So, be careful.

−11 −
Standard Adjustment
(8) Adjusting the needle thread trimmer
1) Adjusting the thread grasping force of the needle thread trimmer
2) Adjusting the height of the needle thread trimmer
1
2
3
4
1
23
4

−12 −
Adjustment Procedures Results of Improper Adjustment
1. If needle thread trimmer 2fails to provide consistent thread
grasping force, loosen setscrew 1and remove needle thread
trimmer 2.
2. Slightly bend the top end of thread presser spring 3by hand
so that it comes in contact with thread trimming blade of upper
knife4over the length with no clrarance and so that the needle
thread trimmer securely holds the thread regardless of the
position of the thread trimming blade at which the thread is
trimmed.
™When the thread grasping force
of needle thread trimmer 2is
low, slip-off of needle thread at
the start of sewing or thread
grasping failure after thread
trimming occurs.
1. Loosen setscrew 1in the needle thread trimmer and move
the trimmer up or down to adjust the height. Set the clearance
between the trimmer and the presser as low as possible,
provided that they do not come in contact with each other, in
order to minimize the length of remaining thread on the needle
after trimming.
2. Note that the presser tilts when sewing a multi-layered portion
ofthe material. Slightly raise the installing position of the trimmer
so that the presser does not come in contact with the trimmer.
™When the trimmer is set
excessively high, trimmer open
lever 2comes in contact with
needle thread trimmer lower
knife pin 3when trimmer open
lever 2is actuated, and
malfunction may occur. In this
case, loosen setscrew 4and
raise upward the height of
trimmer open lever 2to prevent
the contact.

−13 −
Standard Adjustment
Thread trimming
position (40 pulses)
3) Needle thread trimming adjustment mode
* When entering the adjustment
mode, the position is in the state
of origin position.
Needle thread trimming adjustment mode motion
/Thread holding position /Thread release position /Waiting position /Thread trimming position
Thread release
position (-86 pulses) Thread holding position (0 pulse)
Origin
position
Waiting position
(10 pulses)
Latch
Cam groove
end
Roller
Roller
Cam groove end
Thread release position Thread trimming position

−14 −
Adjustment Procedures Results of Improper Adjustment
1. Press MODE key 4to enter memory switch level 2 of the
adjustment mode.
2. Select K51 with ITEM SELECTION key !0 and press
READY key 2.
3. Every time ITEM SELECTION key !0 is pressed, the
four positions as shown in the figure are repeatedly moved
and can be changed over in order.
4. To change the set value, move the state to the position you
desire to set, and set the value with DATA CHANGE key !1
.
(1) Thread trimming position
1) Longitudinal position of the trimmer at the time of
trimming can be changed.
Locus of the trimmer in terms of needle thread scarcely
changes and the position of trimmer after trimming only
changes. When needle thread is missed, adjust it with
“6) Longitudinal and lateral adjustment of the needle
thread trimmer (at the time of trimming)”.
(2) Thread holding position
1) Fine adjustment of the longitudinal position of trimmer
at the start of sewing can be performed.
(3) Thread release position
1) Escape amount of the trimmer can be adjusted.
Adjust the opening amount of trimmer with “7) Opening
amount of the needle thread trimmer”.
(4) Waiting position
1) Trimmer waits before trimming thread after it is opened.
The longitudinal position can be adjusted.
5. When READY key 2is pressed, origin retrieval can be
performed from any position and the position moves to the
origin position.
6. When RESET key 3is pressed, the respective moving
set values are memorized in EEPROM of the machine head
and the needle thread trimming adjustment mode is completed.
™Thread trimming position
When the number is excessively
increased, the needle thread
trimmingcam groove end comes
in contact with the roller, and
step-out of needle thread
trimming motor may occur.
™Thread release position
When the number is excessively
decreased (minus number is
increased), the needle thread
trimmingcam groove end comes
in contact with the roller, and
step-out of needle thread
trimming motor may occur.
™Waiting position
When the number is excessively
decreased, the latch comes off
during sewing, trimmer and
needle collide with each other,
and needle breakage or trimmer
breakage may occur.

−15 −
Standard Adjustment
4) Adjusting the needle thread trimmer origin sensor
5) Lateral adjustment of the needle thread trimmer (start of sewing)
* Thread holding : “0” pulse
1
2
1
2
1
A
B
0 to 3 mm
Thread release position Thread trimming position