JUKI LBH-1790 Series User manual

E-No.01
40012734
R
INSTRUCTION MANUAL
Computer-controlled, High-speed,
Lockstitch Buttonholing Machine
LBH-1790
NOTE : Read safety instructions carefully and understand them before using.
Retain this Instruction Manual for future reference.

Please do not hesitate to contact our distributors or agents in your area for further information when necessary.
＊The description covered in this instruction manual is subject to change for improvement of the
commodity without notice.
04 · 03 Printed in Japan (E)
R
INTERNATIONAL SALES H.Q.
8-2-1, KOKURYO-CHO,
CHOFU-SHI, TOKYO 182-8655, JAPAN
PHONE : [phone] to 4005
FAX : [phone] • 4914 • 4984
TELEX : J22967
Copyright 狡 2003-2004 JUKI CORPORATION.
All rights reserved throughout the world.

i
IMPORTANT SAFETY INSTRUCTIONS
Putting sewing systems into operation is prohibited until it has been ascertained that the sewing systems in
which these sewing machines will be built into, have conformed with the safety regulations in your country.
Technical service for those sewing systems is also prohibited.
1. Observe the basic safety measures, including, but not limited to the following ones, whenever you use the
machine.
2. Read all the instructions, including, but not limited to this Instruction Manual before you use the machine. In
addition, keep this Instruction Manual so that you may read it at anytime when necessary.
3. Use the machine after it has been ascertained that it conforms with safety rules/standards valid in your
country.
4. All safety devices must be in position when the machine is ready for work or in operation. The operation
without the specified safety devices is not allowed.
5. This machine shall be operated by appropriately-trained operators.
6. For your personal protection, we recommend that you wear safety glasses.
7. For the following, turn off the power switch or disconnect the power plug of the machine from the
receptacle.
7-1 For threading needle(s), looper, spreader etc. and replacing bobbin.
7-2 For replacing part(s) of needle, presser foot, throat plate, looper, spreader, feed dog, needle guard, folder,
cloth guide etc.
7-3 For repair work.
7-4 When leaving the working place or when the working place is unattended.
7-5 When using clutch motors without applying brake, it has to be waited until the motor stopped totally.
8. If you should allow oil, grease, etc. used with the machine and devices to come in contact with your eyes or
skin or swallow any of such liquid by mistake, immediately wash the contacted areas and consult a medical
doctor.
9. Tampering with the live parts and devices, regardless of whether the machine is powered, is prohibited.
10. Repair, remodeling and adjustment works must only be done by appropriately trained technicians or
specially skilled personnel. Only spare parts designated by JUKI can be used for repairs.
11. General maintenance and inspection works have to be done by appropriately trained personnel.
12. Repair and maintenance works of electrical components shall be conducted by qualified electric
technicians or under the audit and guidance of specially skilled personnel.
Whenever you find a failure of any of electrical components, immediately stop the machine.
13. Before making repair and maintenance works on the machine equipped with pneumatic parts such as an air
cylinder, the air compressor has to be detached from the machine and the compressed air supply has to be
cut off. Existing residual air pressure after disconnecting the air compressor from the machine has to be
expelled. Exceptions to this are only adjustments and performance checks done by appropriately trained
technicians or specially skilled personnel.
14. Periodically clean the machine throughout the period of use.
15. Grounding the machine is always necessary for the normal operation of the machine. The machine has to
be operated in an environment that is free from strong noise sources such as high-frequency welder.
16. An appropriate power plug has to be attached to the machine by electric technicians. Power plug has to be
connected to a grounded receptacle.
17. The machine is only allowed to be used for the purpose intended. Other used are not allowed.
18. Remodel or modify the machine in accordance with the safety rules/standards while taking all the effective
safety measures. JUKI assumes no responsibility for damage caused by remodeling or modification of the
machine.
19. Warning hints are marked with the two shown symbols.
Danger of injury to operator or service staff
Items requiring special attention

ii
FOR SAFE OPERATION
1. In case nothing is displayed in the operation panel even when the power switch is
turned ON, turn OFF the power switch and check the power voltage and phase.
2. To avoid personal injury, never put your fingers under the thread take-up lever, cloth
presser, cloth cutting knife, or needle when you turn the power switch ON or operate
the sewing machine.
3. To protect against possible accidents due to abrupt startup of the machine, turn
OFF the power switch before tilting the machine head or removing the motor cover.
4. To avoid personal injury, never bring your fingers, hair or clothing close to V belt,
cloth cutting knife or motor during operation, and never place anything on any of
these parts.
5. To avoid personal injury, never operate the machine with the motor cover, eye
protection cover, or any other safety devices removed.
6. To avoid personal injury, be careful never to allow your fingers to go inside the
machine when tilting or raising the machine head.
7. To prevent possible accidents due to electric shocks or damaged electrical
component(s), always turn OFF the power switch before connecting or disconnecting
the power plug.
8. During thunder and lightning storms, stop your work and disconnect the power
from the outlet to ensure safety and prevent possible accidents due to damaged
electrical component(s).
9. If the machine is suddenly moved from a cold place to a warm place, dew
condensation may result. If this occurs, be sure to confirm that there are no potentially
dangerous water drops in the machine before turning it on in order to prevent possible
accidents due to damaged electrical component(s).
10. In the event of a power failure, be sure to turn OFF the power to the machine to
protect against damaged electrical components.
11. This is a Class A product. In a domestic environment this product may cause radio
interference in which case the user may be required to take adequate measures.
1. To prevent possible accidents due to electric shocks, neither open the cover of
motor electrical box nor touch the component(s) inside the electrical box.
2. Make sure of the needle entry after changing the pattern. Should the pattern protrude
from the work clamp check, needle interferes with the work clamp check resulting in
the danger of occurrence of needle breakage or the like. In addition, check that the
work clamp check which has been set corresponds to that which has been installed
on the sewing machine.

iii
CONTENTS
蠢. IMPORTANT SAFETY INSTRUCTIONS ....................................................................... 1
蠡. SPECIFICATIONS ......................................................................................................... 1
1. Subclass ................................................................................................................................................ 1
2. Specifications ........................................................................................................................................ 1
3. Standard sewing shape list .................................................................................................................. 2
4. Configuration ........................................................................................................................................ 3
蠱. INSTALLATION ............................................................................................................. 4
蠶. PREPARATION BEFORE OPERATION ..................................................................... 12
1. Lubrioation .......................................................................................................................................... 12
2. Inserting the needle ............................................................................................................................ 12
3. Threading the needle-thread .............................................................................................................. 13
4. Threading the bobbin case ................................................................................................................ 13
5. Adjusting the bobbin thread tension ................................................................................................ 14
6. Installation of bobbin case .................................................................................................................14
7. Installing the knife .............................................................................................................................. 15
蠹. OPERATION OF THE SEWING MACHINE ................................................................. 16
1. Explanation of the operation panel switch ....................................................................................... 16
2. Basic operation of the sewing machine ........................................................................................... 18
3. How to use the pedal .......................................................................................................................... 18
4. Input of the presser type .................................................................................................................... 20
5. Performing pattern selection ............................................................................................................. 21
6. Changing needle thread tension ....................................................................................................... 22
7. Performing re-sewing ......................................................................................................................... 23
8. Winding bobbin thread .......................................................................................................................24
9. Using the counter ...............................................................................................................................25
10. Using the initial value pattern ............................................................................................................26
11. Changing sewing data ........................................................................................................................27
12. Method of setting sewing data with/without edit ............................................................................. 28
13. Sewing data list ................................................................................................................................... 29
14. Copying sewing pattern ..................................................................................................................... 35
15. Using pattern register key.................................................................................................................. 36
16. Using parameter register key ............................................................................................................ 37
17. Performing continuous stitching ....................................................................................................... 38
18. Performing cycle stitching .................................................................................................................40
19. Explanation of plural motions of knife.............................................................................................. 42
20. Method of changing memory switch data ........................................................................................43
21. Memory switch data list ..................................................................................................................... 44
蠧. MAINTENANCE .......................................................................................................... 48
1. Adjusting the needle-to-hook relation .............................................................................................. 48
2. Adjusting the needle thread trimmer ................................................................................................ 49
3. Adjusting the presser bar pressure .................................................................................................. 50
4. Adjustment of the bobbin presser unit .............................................................................................50
5. Thread tension .................................................................................................................................... 52
6. Cleaning the filter ................................................................................................................................ 52
7. Replacing the fuse ..............................................................................................................................52
蠻. GAUGE COMPONENTS ............................................................................................. 53
1. Cloth cutting knife ..............................................................................................................................53
2. Throat plate ......................................................................................................................................... 53
3. Presser ................................................................................................................................................. 53
衄. ERROR CODE LIST .................................................................................................... 54
衂. TROUBLES AND CORRECTIVE MEASURES ........................................................... 57
衒. DRAWING OF THE TABLE ......................................................................................... 59
衙. INITIAL VALUE DATA FOR EACH SHAPE TABLE .................................................... 60

−1 −
1. IMPORTANT SAFETY INSTRUCTIONS
1) Never operate the machine unless the oiling tank has been properly lubricated.
2) Be sure to remove any dust from the hook or bobbin thread cutting knife section at the end of the day,
and check the amount of oil remaining.
3) Be sure to return the activating pedal to the home position after the machine has started to run.
4) A safety switch is installed so that this sewing machine can not 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.
2. SPECIFICATIONS
1. Subclass
Computer-controlled, high-speed, lockstitch buttonholing machine, LBH-1790, has the subclass machines below.
Subclass
Major
application
Buttonholing
size
S
Buttonholing of cloth
such as men’s shirts,
blouses, work uniforms,
ladies' wear, etc.
2. Specifications
Sewing speed
Needle
Hook
Needle rocking drive
method
Feed drive method
Presser lifting drive
method
Lift of presser foot
Cloth cutting knife
drive method
Standard sewing
shape
Number of patterns
stored in memory
Motor used
Noise
Standard speed : 3,600 rpm (Max. : 4,200 rpm) (Max. : 3,300 rpm when dry hook is used)
DPX5 #11J to #14J
DP type full-rotary hook
Drive by stepping motor
Drive by stepping motor
Drive by stepping motor
14 mm (Optional setting available) Max. : 17 mm (At the time of needle up by reverse run)
By double-acting solenoid drive
30 kinds
99 patterns
Single phase 220/230/240 V, 3-phase 200 to 240 V, 1000 VA
Workplace-related noise at sewing speed
n = 4,000 min–1 : LPA ≦83 dB(A)
Noise measurement according to DIN 45635-48-A-1.
Standard : Max. 5 mm
Special type part : Max. 10 mm
Buttonholing sewing length
Standard : Max. 41 mm
Special type part : Max. 120 mm
Knife size used :
6.4 to 31.8 mm (1/4' to 1-1/4')
K
Buttonholing of knits
such as knitted
underwear, sweaters,
cardigans, jersey, etc.

−2 −
3. 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 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-tacking type
(15) Semilunar taper 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 taper 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
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PANEL
DISPLAY
PANEL
DISPLAY
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DISPLAY
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DISPLAY
PANEL
DISPLAY
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DISPLAY
PANEL
DISPLAY
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DISPLAY
PANEL
DISPLAY
PANEL
DISPLAY
PANEL
DISPLAY
PANEL
DISPLAY
PANEL
DISPLAY
PANEL
DISPLAY
PANEL
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PANEL
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PANEL
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DISPLAY
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PANEL
DISPLAY

−3 −
4. Configuration
LBH-1790consists of the following components.
qPower ON/OFF switch
wMachine head (LBH-1790)
eOperation panel
rControl box (MC-601)
tPresser lifting pedal
yStarting pedal
uThread stand device
q
w
t
r
e
y
u

−4 −
(1) Set-up of the table
3. 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) Securely install control box wand power switch eon table q.
2) Securely fix the respective power cables of power switch e.
3) Pass four bed base fixed screws !1 through bed base r.
4) Set rubber cushions tto holes y(4 places) for fixing bed base and fix bed base r.
5) Fix head support bar uon table q.
6) After placing the sewing machine main unit on bed base r, connect pedal (right side) to pedal switch
o, and pedal (left side) to pedal sensor !0 respectively with connecting rods iwhich have been
supplied as accessories.
Adjust the positions of the pedals so that connecting rods iand control box wdo not
come in contact with each other.
q
w
t
r
e
y
u
i
!0
!1
o

−5 −
(2) Connecting the power source cord
• Voltage specifications
Power source specifications are indicated on the
voltage indication seal. (3-phase type only)
For other type machines, power source specifications
are indicated on the voltage caution seal and the
rating label.
Connect the cord in accordance with the
specifications.
Table
Brown Brown
Brown
Light blue Light blue
Light
blue
Green/Yellow Green/
Yellow
Control box
Green/Yellow
Plug
Power source cord
Power switch
GND
AC200 V
AC220 V
AC230 V
AC240 V
Voltage indication seal (3-phase type only)
• Connecting single phase 200V, 220V, 230V and 240V
Table
Red
Black
Green /
Yellow
White
Control box
Power source cord
Plug
Power switch
GND
AC200 V
AC220 V
AC240 V
• Connecting three phase 200V, 220V and 240V
Green/Yellow
Voltage caution seal
Red
White
Black
Green /
Yellow
Red
Black
White
Rating label
1. Never use under the wrong voltage and phase.
2. When changing the voltage, refer to the item of "Changing the voltage of 100 /
200V".