JUKI LBH-1790S User manual

LBH-1790S
INSTRUCTION MANUAL

i
CONTENTS
I. IMPORTANT SAFETY INSTRUCTIONS ..................................................... 1
II. SPECIFICATIONS....................................................................................... 1
1. Specications.........................................................................................................................2
2. Standard sewing shape list...................................................................................................3
3. Conguration .........................................................................................................................4
III. INSTALLATION.......................................................................................... 5
IV. PREPARATION BEFORE OPERATION.................................................. 15
1. Lubrication ...........................................................................................................................15
2. Inserting the needle .............................................................................................................16
3. Threading the needle-thread...............................................................................................17
4. Threading the bobbin case .................................................................................................17
5. Adjusting the bobbin thread tension .................................................................................18
6. Installation of bobbin case..................................................................................................18
7. Installing the knife ...............................................................................................................19
8. Checking the sewing machine in the delivered state.......................................................19
V. OPERATION OF THE SEWING MACHINE.............................................. 20
1. Explanation of the operation panel switch........................................................................20
2. Basic operation of the sewing machine ............................................................................22
3. How to use the pedal ...........................................................................................................23
4. Input of the presser type .....................................................................................................25
5. Performing pattern selection ..............................................................................................26
6. Changing needle thread tension ........................................................................................27
7. Performing re-sewing ..........................................................................................................28
8. Winding bobbin thread........................................................................................................29
9. Using the counter ................................................................................................................31
10. Using the initial value pattern...........................................................................................34
11. Changing sewing data.......................................................................................................35
12. Method of setting sewing data with/without edit ............................................................37
13. Sewing data list..................................................................................................................38
14. Copying sewing pattern ....................................................................................................44
15. How to edit/check the data other than sewing data .......................................................45
16. Using parameter register key ...........................................................................................47
17. Performing continuous stitching .....................................................................................48
18. Performing cycle stitching................................................................................................51
19. How to change the name of cycle/continuous sewing data ..........................................53
20. Explanation of plural motions of knife.............................................................................54
21. Method of changing memory switch data .......................................................................55
22. Memory switch data list ....................................................................................................56
23. How to change the sewing speed while the sewing machine is engaged in sewing.. 60
24. How to adjust the pedal variable resistor........................................................................61

ii
25. How to adjust the contrast................................................................................................62
26. How to set the key lock .....................................................................................................62
27. Communication..................................................................................................................63
28. Production support function ............................................................................................66
VI. MAINTENANCE....................................................................................... 72
1. Adjusting the needle-to-hook relation ...............................................................................72
2. Adjusting the needle thread trimmer .................................................................................73
3. Adjusting the presser bar pressure ...................................................................................74
4. Adjustment of the bobbin presser unit..............................................................................74
5. Thread tension .....................................................................................................................75
6. Replacing the fuse ...............................................................................................................76
7. Disposal of batteries............................................................................................................77
VII. GAUGE COMPONENTS ........................................................................ 78
1. Cloth cutting knife ...............................................................................................................78
2. Throat plate ..........................................................................................................................78
3. Presser..................................................................................................................................78
VIII. ERROR CODE LIST.............................................................................. 79
IX. TROUBLES AND CORRECTIVE MEASURES....................................... 85
X. DRAWING OF THE TABLE...................................................................... 87
XI. INITIAL VALUE DATA FOR EACH SHAPE TABLE ............................... 89

– 1 –
I. IMPORTANT SAFETY INSTRUCTIONS
II. SPECIFICATIONS
Main specications of the LBH-1790S computer-controlled, lockstitch buttonholing machine
1) Never operate the machine unless the oiling tank has been properly lubricated.
2) After the completion of a day's work, remove dust and dirt accumulating on the hook, bobbin thread
trimming knife section and lubricating hole of the oil tank. At this time, also check whether or not the oil
quantity is adequate.
3) Be sure to return the starting pedal to the home position after the machine has started to run.
4) This machine is provided with a machine head tilt detector so that it cannot be operated in the state
that the machine head is tilted. When operating this sewing machine, turn the power switch ON after
setting the sewing machine to the bed base properly.
Subclass S
Major application Buttonholing of cloth such as men’s shirts, blouses,
work uniforms, ladies' wear, etc.
Buttonholing size
Knife size used :
6.4 to 31.8 mm (1/4' to 1-1/4')
Buttonholing sewing length
Standard : Max. 41 mm
Special type part : Max. 120 mm
Standard : Max. 5 mm
Special type part : Max. 10 mm

– 2 –
1. Specications
Sewing speed Standard speed : 3,600 sti/min (Max. : 4,200 sti/min) (Max. : 3,300 sti/
min when dry hook is used)
Needle DP×5 #11J to #14J
Hook DP type full-rotary hook
Needle rocking drive method Drive by stepping motor
Feed drive method Drive by stepping motor
Presser lifting drive method Drive by stepping motor
Lift of presser foot 14 mm (Optional setting available) Max. : 17 mm (At the time of nee-
dle up by reverse run)
Cloth cutting knife drive method Motor-driven crank system
Standard sewing shape 31 kinds
Number of patterns stored in
memory
99 patterns
Weight Machine head 55 kg, Control box 5.5 kg
Power consumption 370 VA
Operating temperature range 5 ˚C to 35 ˚C
Operating humidity range 35% to 85% (No dew condensation)
Line voltage AC220 to 240V ± 10% 50/60 Hz
Motor used Single phase AC220 to 240 V, 370 VA
Noise - Equivalent continuous emission sound pressure level (LpA) at the
workstation :
A-weighted value of 81.0 dB ; (Includes ; KpA = 2.5 dB) ; according
to ISO 10821- C.6.3 -ISO 11204 GR2 at 3,600 sti/min.

– 3 –
2. Standard sewing shape list
(29) Bar-tacking,
left cut
(30) Bar-tacking,
center cut
(31) Basting + Cloth
cutting knife
(1) Square type (2) Round type (3) Radial square
type (4) Radial type
(5) Radial straight
bar-tacking type
(6) Radial taper
bar-tacking type
(7) Eyelet square
type
(8) Eyelet radial
type
(9) Eyelet straight
bar-tacking type
(10) Eyelet taper
bar-tacking type
(11) Semilunar
type
(12) Round
square type
(13) Semilunar
square type
(14) Semilunar
straight bar-tack-
ing type
(15) Semilunar
taper bar-tacking
type
(16) Eyelet semi-
lunar type
(17) Eyelet round
type
(18) Square radi-
al type
(19) Square
semilunar type
(20) Square
round type
(21) Square
straight bar-tack-
ing type
(22) Square taper
bar-tacking type
(23) Radial semi-
lunar type
(24) Radial round
type
(25) Semilunar
radial type
(26) Semilunar
round type (27) Bar-tacking (28) Bar-tacking, right 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
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PANEL
DISPLAY
PANEL
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PANEL
DISPLAY
PANEL
DISPLAY

– 4 –
3. Conguration
The LBH-1790S sewing machine consists of the following parts.
󰿿Power switch
󱀀Machine head (LBH-1790S)
󱀁Operation panel
󱀂Control box (MC-603)
󱀃Presser lifting and starting pedal
󱀄Thread stand device
󱀅Power switch (EU type)
󰿿
󱀀
󱀃
󱀂
󱀁
󱀄
󱀅

– 5 –
(1) Preparation for assembly of the control box
III. INSTALLATION
WARNING :
To prevent possible accidents caused by the fall of the sewing machine, perform the work by two
persons or more when the machine is moved.
1) Fix toothed washers 󱀀 and rubber
cushions 󱀁 on control box 󰿿. (At four
locations)
* Tighten the toothed washers so that their
height becomes 0.8 mm.
2) Fix control box mounting plate 󱀂 with
plain washers 󱀃 and nuts 󱀄. (At four
locations)
* Fix the mounting plate while tting the
screw in the U-groove in the mounting
plate.
󰿿
At four locations
0.8 mm
󱀀
󱀁
󱀄
󱀃
󱀂

– 6 –
(2) Set-up of the table
1) Fix control box 󱢳, power switch 󱢵 and pedal sensor 󱢶 on table 󱢴.
2) Fix power switch 󱢵 with a staple.
3) Pass four bed base xed screws 󱢷 through bed base 󱢸.
4) Set rubber cushions 󱢹 to holes 󱢺 (4 places) for xing bed base and x bed base 󱢸.
5) Fix head support bar 󱢻 on table 󱢴.
6) Place the main unit of the sewing machine on bed base 󱢸. Then, connect the pedal and pedal sen-
sor 󱢶 with connecting rod 󱢼 supplied with the unit.
󱢴
󱢹
󱢸
󱢺
󱢻
󱢷
󱢼
󱢶
󱢳
󱢵

– 7 –
(3) Connecting the power source cord
• Connecting the power cable
Voltage specications are shown on the power indication tag attached on the power cable and on the
rating plate adhered on the power box. Connect the cable which matches the specications.
• Connection of the single-phase power cable
Never use under the wrong voltage and phase.
Power indication tag
Rating plate
(For example: In the
case of 220V)
Table
Brown Brown
Light blue Light blue
Light
blue
Green/Yellow Green/
Yellow
Control box
Green/Yellow
Plug
Power source cord
Power switch
GND
AC
220 V
-240 V
Brown

– 8 –
(4) Installing the sewing machine main unit
1) Place hinge plates 󰿿 and shaft bearings 󱀀-1
(rubber) and 󱀀-2 (metal) in two places on the
head base and x the hinge plates to the ma-
chine head with setscrews 󱀁 in two places.
When the rubber hinge and metal tting
hinge are installed in reverse order, it
is dangerous since the sewing machine
shakes when it is tilted. So, be careful.
󰿿
󱀁
󱀀-1 (rubber)
󱀀-2
(metal)
WARNING :
To prevent possible accidents caused by
the fall of the sewing machine, perform the
work by two persons or more when the
machine is moved.
(5) Tilting the sewing machine head
When tilting the sewing machine head, tilt quiet-
ly the sewing machine until head support bar 󰿿
comes in contact with it.
1. Make sure that sewing machine head
support bar
󰿿
is placed on the table
before tilting the sewing machine.
2. To protect fall-down, be sure to tilt
the sewing machine in a level place.
WARNING :
When tilting/raising the sewing machine head, perform the work so as not to allow your ngers
to be caught in the machine. In addition, to avoid possible accidents caused by abrupt start of
the machine, turn OFF the power to the machine before starting the work.
󰿿

– 9 –
(7) Installing the hook oil shield plate
Install hook oil shield plate 󰿿 onto bed base 󱀁
with setscrew 󱀀.
Attach hook oil shield plate 󰿿 to the
bed base with the sewing machine
raised.
In addition, check to be sure that the
sewing machine does not interfere
with hook oil shield plate 󰿿 when
tilting/raising the former.
Adjust the mounting of the hook oil
shield plate 󰿿 to prevent scattered
from the gap between the bed and
cover pot.
󰿿
󱀀
󱀁
(6) Connecting the machine head tilt detector
Connect machine head tilt detector 󰿿 with
connector 󱀀 located on the machine head
side.
(8) Installing the operation panel
Fix operation panel 󰿿 on the table with four wood-
screws 󱀀. Pass the cable through hole 󱀁 in the
table.
󰿿
󱀀
󰿿
󱀀
󱀁

– 10 –
CN15
Main motor encoder
(9) Connecting the cords
Sewing machine head
Operation panel
1) Loosen four setscrews 󱀀 of control box cov-
er 󰿿. Remove control box cover 󰿿.
2) Connect the cord to the connector on the
MAIN PCB as illustrated in the gure below.
3) Fix the earth cord with setscrew 󱀁.
4) Install control box cover 󰿿.
5) Fix control box cover with the washers,
spring washers and nuts 󱀂.
MAIN circuit board
CN49
MAIN-INT A
CN34
Panel
CN40
MAIN-INT C
CN39
Pedal
CN17
Main motor cord
CN32
MAIN-INT B
CN34
CN39
CN49
CN40
CN32
CN17
CN15
Earth cord
󱀁
Earth cord
󰿿
󱀀
󱀂

– 11 –
(10) Managing the cord
1) Slowly tilting the sewing machine, check
that the cords are not forcibly pulled.
When you tilt the sewing ma-
chine, make sure that the sewing
machine head support bar 󰿿 is
placed on the table.
󰿿
󱀁
󱀀
󱀂
󱀃
2) Bring the cords under the table into the
control box.
3) Put the cord brought into the control box
through cord exit plate 󱀀 and fix cable
clip band 󱀁.
4) Install control box lid 󱀂 with four set-
screws 󱀃.

– 12 –
(11) Installing the eye protection cover
Be sure to install and use eye protection cover 󰿿 and use the sewing machine.
WARNING :
Be sure to attach this cover to protect the eyes from the disperse of needle breakage.
When placed longitudinally When placed horizontally
Operator
Operator
󰿿
󰿿
(12) Fixing the temporary stop switch
The temporary stop switch has been in the state as shown in gure A at the time of delivery.
Loosen setscrew 󰿿 and set the switch in the state as shown in gure B, and x it with setscrew 󰿿 to-
gether with setscrew 󱀀 supplied with the machine.
󰿿
󰿿
󱀀
AB
󰾯

– 13 –
(13) Thread guide rod
Insert the thread guide pin into the insert hole se-
curely so that two lateral holes in the thread guide
pin face the front of the tension controller No. 1 (A).
Thread guide rod
(14) Installing the thread stand
1) Assemble the thread stand, and set
it in the hole in the top right corner of
the machine table.
2) Tighten locknut 󰿿 to x the thread
stand.
󰿿
A
Tension controller No. 1

– 14 –
(15) Installing the auxiliary table
1) Temporarily x two auxiliary table mount-
ing plates 󰿿 on auxiliary table 󱀀 with four
bolts 󱀁.
2) Temporarily fix auxiliary table 󱀀 on the
sewing machine bed with two bolts 󱀂.
3) Fix four bolts 󱀁 while removing a clear-
ance between the sewing machine bed
and auxiliary table 󱀀.
4) Fix two bolts 󱀂 while aligning auxiliary
table 󱀀 with the top surface of the sewing
machine bed.
󰿿
󱀁󱀂
󱀀

– 15 –
󰿿
IV. PREPARATION BEFORE OPERATION
WARNING :
To protect against possible personal injury due to abrupt start of the machine, be sure to start the fol-
lowing work after turning the power o󰀨 and ascertaining that the motor is at rest.
1. Lubrication
1) Lubricating oil to oiling tank
○ Fill the oiling tank with JUKI New Defrix Oil No.1 up to the level indicated by “MAX” 󰿿.
(Caution) When supplying oil to the oil tank through the lubricating hole, take care not to allow
dust to enter the oil tank.
○ Supply oil in the case the oil cannot be visually observed from the front side of the oil tank.
2) Adjusting the lubrication for the sewing hook
○ The amount of oil is adjusted with oil amount adjusting screw 󱀀.
○ Amount of supplied oil is reduced when turning the screws 󱀀 clockwise.
○ When you rst operate your sewing machine after set-up or after an extended period of disuse, re-
move the bobbin case and apply a few drops of oil to the hook race. In addition, apply a few drops oil
from oiling hole 󱀂 in hook driving shaft front metal 󱀁 to soak the inside felt in oil.
󱀀
󱀂
󱀁
Detailed diagram of oil amount adjusting section
Oil pipe
󱀀
Increase Decrease
Increase Decrease
Oil amount
Front
side
Front side

– 16 –
Hold needle with its recessed part facing toward the operator side A,
insert the needle fully into the needle clamping hole, and tighten nee-
dle setscrew 󰿿. Use a DPx5-(#11J, #14J).
When attaching the needle, turn OFF the power to the
motor.
2. Inserting the needle
WARNING :
To protect against possible personal injury due to abrupt start of the machine, be sure to start the fol-
lowing work after turning the power o󰀨 and ascertaining that the motor is at rest.
󰿿
A
* The adequate oil quantity is achieved when the
oil spots are made on paper within a range of 2 to
5 mm in width (oil spots should not be in the form
of lines).
40 mm
100 mm
2 to 5 mm
Approximately
0.5 mm
Approximately
0.5 mm
󱀃
󱀄
3) How to check the hook oil quantity
1. In preparation for checking the hook oil quan-
tity, cut a sheet of paper to make a piece of
paper size of which is approximately 40 mm x
100 mm.
2. After the adjustment of the oil quantity, start
the sewing machine at a high speed (3,600
sti/min) by 100 times or more.
3. Insert the piece of paper prepared in Step 1
into the clearance provided between the hook
cover and the bed base so that it is placed
near the underside of the hook.
As a guide, insert the paper until it comes in
contact with the hook oil shield.
4. Supporting the paper with hand, run the sew-
ing machine by ve cycles using the standard
pattern (3,600 sti/min) and check the splash-
ing oil quantity.
In the case the oil quantity is too much
even after the oil controlling screw is
fully tightened, remove the hook shaft
coupling 󱀃 and cut o󰀨 the excess of
oil wick 󱀄.

– 17 –
Rotating direction of bobbin and threading
1) Fit the bobbin so that it rotates in the direction of the arrow.
2) Pass the thread through thread slit 󰿿, then through under the tension spring 󱀀, again through thread
slit 󱀁, and pull the thread from 󱀂.
3) Threading at 󱀂 for purl stitching is di󰀨erent from that for whip stitching. So, be careful.
4. Threading the bobbin case
3. Threading the needle-thread
Pass the needle thread in the order 󰿿 to 󱢵 as shown in the gures.
The threading can be done easily by using the needle threader supplied with the machine.
Change the thread guide threading method according to the thread to be used.
Synthetic lament thread
Cotton thread, spun thread
Whip stitchPurl stitch
Bobbin case
Bobbin
WARNING :
To protect against possible personal injury due to abrupt start of the machine, be sure to start the fol-
lowing work after turning the power o󰀨 and ascertaining that the motor is at rest.
󰿿
󱀀
󱀃
󱀂
󱀁
󱀄
󱀅
󱀆
󱀇
󱢳
󱢴
󱢵
󰿿
󱀀󱀂
󱀁󱀂