JUKI LBH-1790A Series User manual

LBH-1790A Series
INSTRUCTION MANUAL

vii
CONTENTS
I. IMPORTANT SAFETY INSTRUCTIONS ..................................................... 1
II. SPECIFICATIONS....................................................................................... 1
1.Specications.......................................................................................................................1
2. Standard sewing shape list.................................................................................................2
3.Conguration .......................................................................................................................3
III. INSTALLATION.......................................................................................... 4
IV.PREPARATIONBEFOREOPERATION.................................................. 14
1. Lubrication .........................................................................................................................14
2. Inserting the needle ...........................................................................................................14
3. Threading the needle-thread.............................................................................................15
4. Threading the bobbin case ...............................................................................................15
5. Adjusting the bobbin thread tension ...............................................................................16
6. Installation of bobbin case................................................................................................16
7. Installing the knife .............................................................................................................17
8. Checking the sewing machine in the delivered state.....................................................17
V.OPERATIONOFTHESEWINGMACHINE.............................................. 18
1. Explanation of the operation panel switch......................................................................18
2. Basic operation of the sewing machine ..........................................................................20
3. How to use the pedal .........................................................................................................21
4. Input of the presser type ...................................................................................................23
5. Performing pattern selection ............................................................................................24
6. Changing needle thread tension ......................................................................................25
7. Performing re-sewing ........................................................................................................26
8. Winding bobbin thread......................................................................................................27
9. Using the counter ..............................................................................................................28
10. Using the initial value pattern...........................................................................................30
11. Changing sewing data .......................................................................................................31
12. Method of setting sewing data with/without edit ............................................................32
13. Sewing data list..................................................................................................................33
14. Copying sewing pattern ....................................................................................................39
15. How to edit/check the data other than sewing data .......................................................40
16. Using parameter register key ...........................................................................................42
17. Performing continuous stitching .....................................................................................43
18. Performing cycle stitching................................................................................................46
19. How to change the name of cycle/continuous sewing data ..........................................49
20. Explanation of plural motions of knife.............................................................................50
21. Method of changing memory switch data .......................................................................51
22. Memory switch data list ....................................................................................................52
23. How to adjust the pedal variable resistor........................................................................56

viii
24. How to adjust the contrast................................................................................................57
25. How to set the key lock .....................................................................................................57
26. Communication..................................................................................................................58
VI.MAINTENANCE....................................................................................... 61
1. Adjusting the needle-to-hook relation ...............................................................................61
2. Adjusting the needle thread trimmer .................................................................................62
3. Adjusting the presser bar pressure ...................................................................................63
4. Adjustment of the bobbin presser unit..............................................................................63
5. Thread tension .....................................................................................................................64
6. Replacing the fuse ...............................................................................................................65
VII.GAUGECOMPONENTS ........................................................................ 66
1. Cloth cutting knife ...............................................................................................................66
2. Throat plate ..........................................................................................................................66
3. Presser..................................................................................................................................66
VIII.ERRORCODELIST.............................................................................. 67
IX.TROUBLESANDCORRECTIVEMEASURES....................................... 72
X. DRAWING OF THE TABLE...................................................................... 74
XI.INITIALVALUEDATAFOREACHSHAPETABLE ............................... 76

– 1 –
I. IMPORTANT SAFETY INSTRUCTIONS
II. SPECIFICATIONS
Main specications of the LBH-1790A computer-controlled, lockstitch buttonholing machine
1.Specications
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) 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.
Sewing speed Standard speed : 3,600 sti/min (Max. : 4,200 sti/min) (Max. : 3,300 sti/min when dry hook is used)
Needle DPX5 #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 needle 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
Motor used 3-phase 200 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.
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 –
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
DISPLAY
PANEL
DISPLAY
PANEL
DISPLAY
PANEL
DISPLAY
PANEL
DISPLAY

– 3 –
3.Conguration
LBH-1790A consists of the following components.
❶Power switch
❷Machine head (LBH-1790A)
❸Operation panel
❹Control box (MC-602)
❺Presser lifting and starting pedal
❻Thread stand device
❼Power switch (EU type)
❶
❷
❺
❹
❸
❻
❼

– 4 –
(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 reinforcing plates ❷on control box ❶
with bolts ❸. (At eight locations)
* Only in the case the reinforcing plates are
supplied with the unit as accessories.
2) Fix toothed washers ❹and rubber cush-
ions ❺on control box ❶. (At four loca-
tions)
* Tighten the toothed washers so that their
height becomes 0.8 mm.
3) Fix control box mounting plate ❻with plain
washers ❼, spring washers ❽and nuts
❾. (At four locations)
* Fix the mounting plate while tting the
screw in the U-groove in the mounting
plate.
0.8 mm
❹
❺
❻
❼❽
❾
❶
❷
❸

– 5 –
(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.
󱢴
󱢹
󱢸
󱢵
󱢺
󱢻
󱢷
󱢼
󱢶
󱢳

– 6 –
(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.
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 Red
White
Black
Green /
Yellow
Red
Black
White
Never use under the wrong voltage and phase.
Power indication tag
Rating plate
(For example: In the
caseof200V)

– 7 –
(4) Installing the sewing machine main unit
1) Place hinge plates ❶and shaft bearings ❷-1
(rubber) and ❷-2 (metal) in two places on the
head base and x the hinge plates to the ma-
chine head with setscrews ❸in 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.
❶
❸
❷-1 (rubber)
❷-2
(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 ❶
comes in contact with it.
1. Make sure that sewing machine head
support bar
❶
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.
❶

– 8 –
(7) Installing the hook oil shield plate
Install hook oil shield plate ❶onto bed base ❸
with setscrew ❷.
Attach hook oil shield plate ❶to 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 ❶when
tilting/raising the former.
Adjust the mounting of the hook oil
shield plate ❶to prevent scattered
from the gap between the bed and
cover pot.
❶
❷
❸
(6) Connecting the machine head tilt detector
Connect machine head tilt detector ❶with
connector ❷located on the machine head
side.
(8) Installing the operation panel
Fix operation panel ❶on the table with four wood-
screws ❷. Pass the cable through hole ❸in the
table.
❶
❷
❸
❶
❷

– 9 –
CN15
Main motor encoder
(9) Connecting the cords
Electric bobbin winding device (optional)
Sewing machine head
Operation panel
1) Loosen four setscrews ❷of control box cov-
er ❶. Remove control box cover ❶.
2) Connect the cord to the connector on the
MAIN PCB as illustrated in the gure below.
3) Fix the earth cord with setscrew ❸.
4) Install control box cover ❶.
5) Fix control box cover with the washers,
spring washers and nuts ❹.
MAIN circuit board
CN49
MAIN-INT A
CN34
Panel
CN40
MAIN-INT C
CN39
Pedal
CN17
Main motor cord
CN32
MAIN-INT B
CN44
CN34
CN39
CN49
CN40
CN32
CN17
CN15
Earth cord
❸
Earth cord
❶
❷
❹

– 10 –
(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 ❶is
placed on the table.
❶
❸
❷
❹
❺
2) Bring the cords under the table into the
control box.
3) Put the cord brought into the control box
through cord exit plate ❷and fix cable
clip band ❸.
4) Install control box lid ❹with four set-
screws ❺.

– 11 –
(11) Installing the eye protection cover
Be sure to install and use eye protection cover ❶and 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
❶
❶
(12) Fixing the temporary stop switch
The temporary stop switch has been in the state as shown in gure Aat the time of delivery.
Loosen setscrew ❶ and set the switch in the state as shown in gure B, and x it with setscrew ❶to-
gether with setscrew ❷supplied with the machine.
❶
❶
❷
AB
➡

– 12 –
(13) Thread guide rod
Securely t the thread guide rod so that two side
holes in the thread guide rod face the thread
guide.
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 ❶ to x the thread stand.
❶

– 13 –
(15) Installing the auxiliary table
1) Temporarily x two auxiliary table mount-
ing plates ❶on auxiliary table ❷with four
bolts ❸.
2) Temporarily fix auxiliary table ❷on the
sewing machine bed with two bolts ❹.
3) Fix four bolts ❸while removing a clear-
ance between the sewing machine bed
and auxiliary table ❷.
4) Fix two bolts ❹while aligning auxiliary
table ❷with the top surface of the sewing
machine bed.
❶
❸❹
❷

– 14 –
IV.PREPARATIONBEFOREOPERATION
Hold needle with its recessed part facing toward the operator side
A, insert the needle fully into the needle clamping hole, and tighten
needle setscrew ❶. 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
following work after turning the power off and ascertaining that the motor is at rest.
1) Lubricating oil to oiling tank
○ Fill the oiling tank with New Defrix Oil No.1 up to the level indicated by “MAX” ❶.
2) Adjusting the lubrication for the sewing hook
○ The amount of oil is adjusted with oil amount adjusting screw ❷.
○ Amount of supplied oil is reduced when turning the screws ❷clockwise.
○ When you first operate your sewing machine after set-up or after an extended period of disuse,
remove the bobbin case and apply a few drops of oil to the hook race. In addition, apply a few drops
oil from oiling hole ❹in hook driving shaft front metal ❸to soak the inside felt in oil.
WARNING :
To protect against possible personal injury due to abrupt start of the machine, be sure to start the
following work after turning the power off and ascertaining that the motor is at rest.
Detailed diagram of oil amount adjusting section
Oil pipe
1. Lubrication
❷
❷
❶
Increase Decrease
Oil amount
Increase Decrease
❶
A
❹
❸

– 15 –
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 ❶, then through under the tension spring ❷, again through thread
slit ❸, and pull the thread from ❹.
3) Threading at ❹for purl stitching is different 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 ❶to 󱢵 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
following work after turning the power off and ascertaining that the motor is at rest.
❶
❷
❺
❹
❸
❻
❼
❽
❾
󱢳
󱢴
󱢵
❶
❷❹
❸❹

– 16 –
5. Adjusting the bobbin thread tension
6. Installation of bobbin case
1) Lift up and hold bobbin case latch lever between
two ngers.
2) Push the bobbin case into the hook so that it is
supported by the hook shaft ❶and then snap in
the latch lever.
Press the bobbin case until the predetermined
position is reached, and it will click.
1. If the bobbin case is out of the
predetermined position, it can jump
out from the hook to cause the
needle thread to tangle on the hook
shaft. Check to be sure that the
bobbin case is properly installed in
the correct position.
2. There is a difference in the shape of
bobbin case between the standard
hook and the dry one. They have
nothing in common with each other.
Adjust the bobbin thread tension as given below when the bobbin thread is pulled up at the position where
thread slit ❶of bobbin case comes up.
Purl stitch
Whip stitch
0.05 to 0.15N
0.15 to 0.3N
To such an extent that bobbin case quietly comes down when holding
thread end coming from bobbin case and shaking it quietly up and
down.
To such an extent that bobbin case barely comes down when holding
thread end coming from bobbin case and shaking it somewhat
strongly.
WARNING :
To protect against possible personal injury due to abrupt start of the machine, be sure to start the
following work after turning the power off and ascertaining that the motor is at rest.
Turning tension adjust screw ❷clockwise will increase bobbin thread tension, and turning it
counterclockwise will decrease the tension.
Adjust the bobbin thread tension to lower for synthetic lament thread, and to higher for spun thread.
The thread tension is higher by approximately 0.05N when the bobbin case is set to the hook since idle-
prevention spring is provided.
When bobbin thread tension is adjusted, check the needle thread tension setting of the
memory switch. (Refer to "V-22.Memoryswitchdatalist"p.52.)
❶
❷
❶

– 17 –
7. Installing the knife
Inch →mmCONVERSIONTABLE
When the cloth cutting knife you have is indicated in
inch, set the cloth cutting length (knife size) in mm
using the inch →mm conversion table. (Refer to "V-
13. Sewing data list" p.33.)
When replacing the knife with a new one, perform as
follows.
1) Knife
❶can be easily removed together with the
washer when removing knife retaining screw ❷.
2) Lower the knife bar by hand. Now, push the knife
bar down so that the knife goes below the top
surface of the throat plate by 1 to 2 mm, as illus-
trated in the gure. In this state, place the wash-
er and tighten the setscrew.
WARNING :
To protect against possible personal injury due to abrupt start of the machine, be sure to start the
following work after turning the power off and ascertaining that the motor is at rest.
Knife size Indication of mm
1/4 6.40
3/8 9.50
7/16 11.10
1/2 12.70
9/16 14.30
5/8 15.90
11/16 17.50
3/4 19.10
13/16 20.60
7/8 22.20
1 25.40
1 1/8 28.60
1 1/4 31.80
1 3/8 34.90
1 1/2 38.10
❶
❷
1 to 2 mm
8. Checking the sewing machine in the delivered state
If the work clamp is in its upper posi-
tion when it is delivered to your work-
shop, it is necessary to lower the work
clamp before turning on the power to
the sewing machine.
When lowering the work clamp, take
care not to place your hands near the
knife.
If the power is turned ON with the
work clamp raised and the ready key
is pressed, "E998 Work clamp devia-
tion error" can occur.