juki LK-1900A, LK-1901A, LK-1902A, LK-1903A INSTRUCTION MANUAL

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Computer-controlled High Speed Bar Tacking Industrial Sewing Machine

LK-1900A Series

ENGINEER’S MANUAL

40014262

No.E357-00

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 in 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. This manual gives the “Standard Adjustment” on the former page under which the most basic adjustment value is described and on the latter page the “Results of Improper Adjustment” under which stitching errors and troubles arising from mechanical failures and “How To Adjust” are described.

1. Specifications ......................................................................................................... 1

2. Configuration........................................................................................................... 2

(1) Names of main unit ................................................................................................................... 2

(2) Names and explanation of switches on the operation panel................................................ 3

3. Standard adjustment ..............................................................................................4

(1) Main shaft connection/disconnection..................................................................................... 4

(2) Removal of the main shaft motor and coupling..................................................................... 6

(3) Crank connecting rod connection / disconnection ............................................................... 8

(4) Crank balancer positioning.................................................................................................... 10

(5) Lower shaft backlash adjustment and connection/disconnection .................................... 10

(6) Oscillator gear positioning..................................................................................................... 12

(7) Adjustment of hook oil amount ............................................................................................. 12

(8) Large hook connection / disconnection and oil wick piping .............................................. 14

(9) Adjusting the height of the needle bar.................................................................................. 14

(10) Hook adjustment ................................................................................................................... 16

(11) Thread trimmer cam position adjustment and connection / disconnection ................... 18

(12) Thread trimmer and presser foot origin sensor adjustment............................................. 18

(13) Adjusting the lift of the work clamp foot ............................................................................ 20

(14) Adjusting the thread trimmer sensor .................................................................................. 20

(15) Adjustment of the moving knife and counter knife position ............................................ 22

(16) Adjusting the height of the moving knife and counter knife ............................................ 22

(17) Inclination of the blade point of the counter knife............................................................. 24

(18) Floating amount of the thread tension disk ....................................................................... 24

(19) Second thread tension connection / disconnection.......................................................... 26

(20) AT unit connection / disconnection .................................................................................... 28

(21) Position of the mechanical origin........................................................................................ 30

(22) Adjusting the Y origin sensor ..............................................................................................30

(23) Adjusting the X origin sensor ..............................................................................................32

(24) Adjusting the wiper position................................................................................................ 32

(25) Adjusting the wiper spring (LK-1903A only) ...................................................................... 34

(26) Adjusting the position of the X feed motor and the Y feed motor

(Adjusting the backlash of the driving gear)..................................................................... 34

(27) Installing the feed plate support plate ................................................................................ 36

(28) Installation of the feeder bar rear cover.............................................................................. 36

(29) Adjustment of the bobbin winder driving wheel position ................................................. 38

(30) Adjusting the bobbin winder amount.................................................................................. 38

(31) Adjustment of the hook upper spring position .................................................................. 40

(32) Shuttle felt.............................................................................................................................. 40

(33) Shape of the shuttle race ring.............................................................................................. 42

(34) Adjustment of the thread take-up spring............................................................................ 42

(35) Needle thread clamp device connection / diconnection ................................................... 44

(36) Adjusting the needle thread clamp sensor......................................................................... 46

(37) Adjusting the needle thread clamp notch........................................................................... 48

4. Sub-class information .......................................................................................... 50

(1) Models classified by button sizes (LK-1903A) ..................................................................... 50

(2) Table of Standard Patterns (LK-1903A)................................................................................. 51

5. Memory switches .................................................................................................. 52

(1) Memory switch start and change .......................................................................................... 52

(2) Table of memory switch functions ........................................................................................ 53

6. Test mode .............................................................................................................. 57

(1) Test mode start........................................................................................................................ 57

(2) Display output test.................................................................................................................. 58

(3) Method of confirmation according to each test program No. ............................................ 59

7. Miscellaneous........................................................................................................ 64

(1) Various printed wiring boards ...............................................................................................64

(2) LK1900 data ROM.................................................................................................................... 71

(3) Dipswitch setting .................................................................................................................... 71

(4) Table of standard pattern specifications .............................................................................. 72

(5) Table of standard patterns ..................................................................................................... 73

8. Optional features................................................................................................... 75

(1) Connection of PK-57............................................................................................................... 75

(2) Table of optional parts ............................................................................................................ 76

(3) Table of the work clamp foot.................................................................................................. 78

9. Maintenance .......................................................................................................... 80

(1) Replacing the fuse .................................................................................................................. 80

(2) 100V

(3) Greasing parts......................................................................................................................... 81

(4) Parts to which grease is applied ........................................................................................... 82

(5) Grease-up procedures for the specified position ................................................................ 89

↔↔

↔ 200V voltage specification changeover.................................................................. 80

↔↔

10. Table of errors ..................................................................................................... 90

11. Troubles and corrective measures .................................................................... 93

(1) Mechanical parts ..................................................................................................................... 93

(2) Sewing conditions .................................................................................................................. 95

(3) Electrical components.......................................................................................................... 103

12. Circuit diagrams.................................................................................................111

(1) Block diagram A.....................................................................................................................111

(2) Power supply circuit diagram A........................................................................................... 112

(3) Power supply circuit diagram B .......................................................................................... 113

(4) Power supply circuit diagram C .......................................................................................... 114

(5) Servo motor circuit diagram ................................................................................................ 115

(6) Sensor – pedal VR circuit diagram...................................................................................... 116

(7) MAIN • PANEL board circuit diagram .................................................................................. 117

(8) Motor • solenoid circuit diagram ......................................................................................... 118

13. Table drawings .................................................................................................. 119

(1) Table type for longitudinal Installation ............................................................................... 119

(2) Table type for lateral Installation ......................................................................................... 120

1. Specifications

No. Application

Item 1 Application Bartacking 2 Sewing area 3 Button size Type: Round-shaped, flat button

4 Max. sewing * 3000rpm max. * 3000rpm max. * 2700rpm max.

speed 5 Stitch length 0.1mm to 10.0mm (adjustable in 0.1mm step)

Feed motion of work clamp foot 7 Meddle bar stroke 41.2mm 45.7mm 8 Needle DPX5 #14 DPX17 #14

9 Work clamp lifting Pulse motor

system

10 Lifting (lift) amount Standard 14mm, Max.17mm (In the reverse-rotation needle-up Max. 13mm

of work-clamp foot function)

11 Number of standard 50 patterns 3 patterns 6 patterns 50 patterns

patterns

12 Wiper system Interlockly with work clamp foot lifter by pulse motor 13 Needle thread Standard: General 0 Standard: Disable 1

clamp device (Caution) 1.

Needle thread tension

15 Hook

16 Lubrication Hook : minute-quantity lubrication

Model name

LK-1900A LK-1901A LK-1902A LK-1903A

Eyelet buttonhole bartacking

X-Direction (right, left) 40mm; Y-Direction (forward, backward) 30mm

(*2700rpm fo the 2-fold semi-rotary hook)

DPX5#11 (F, M) (DPX17#21

(DPX17#21 heavy-weight material)

Standard semi-rotary hook

(2-fold semi-rotary hook)

(When sewing pitches are less than 5mm in X-direction and 3.5mm in Y-direction)

intermittent feed (2-shaft drive by stepping motor)

Active tension (electronic thread tension control mechanism)

Belt-loop attaching

heavy-weight material)

Standard semi-rotary hook

Lock stitch button sewing

ø 8 to ø32mm, Standard (ø8 to ø20mm)

17 Lubricating oil JUKI NEW Defrix oil (equivalent to ISO VG32) (Lubrication system) 18 Grease 1. Penetration No. 2 lithium grease, 2. Templex N2, 3. Juki Grease A, 4. Juki Grease B (Caution)2.

19 Memory medium EEP-ROM (128Kbyte) EP-ROM (32Kbyte) 20

Number of stitches that

can be stored in memory

21 Enlarging/Reducing X-Direction, Y-Direction: 20 ~ 200% each (1% step)

facility

Enlarging/Reducing method

Sewing speed limits 450 ~ 3000rpm (100rpm step) (2700rpm max. for the 2-fold semi-rotary hook)

Material clrawing amount

Pattern selector facility

Bobbin thread counter

Sewing machine motor

External dimensions

29 Weight Machine head (include motor): 42kg, Control box: 16.5kg 30

Power consumption

Working temperature range

Working humidity range

Pattern enlargement/reduction can be done by increasing/decreasing the stitch length

Max. 3mm

Pattern No. designation system (1 ~ 200)

450W compact AC servomotor (direct-drive system)

W: 1200mm, L: 660mm, H: 1100mm (standard table stand applied)

35% ~ 85% (no dew condensation permissible)

Max. 20,000 stitches

400 ~ 2700rpm (100rpm step)

Up/Down method (0~9999)

320W

5°C~35°C

* Maximum sewing speed should be reduced according to the sewing conditions.

(Caution) 1. LK-1903A is set to needle thread clamp prohibited (no motion) with memory switch No. 35 at

the time of standard delivery.

2. Grease type, refer to (3) Greasing parts of [9] Maintenance.

– 1 –

2. Configuration

(1) Names of main unit

Sewing machine head Work clamp foot Thread stand Operation panel Power switch Control box Pedal switch

– 2 –

(2) Names and explanation of switches on the operation panel

“Ready” key

This key changes over the setting state from the panel

Item selection LED

LEDs of the selected items light up. to the sewing state where the sewing machine actually operates.

Sewing LED

Pattern No. X scale Y scale

This LED goes off at the time of setting state and lights up at the time of sewing state. Changeover can be performed with “Ready” key.

“Reset” key

This key is used for canceling error or returning the

Max. speed Sewing counter Bobbin winder

limitation

set value to the initial value.

“Mode” key

This key makes the setting mode of the memory switch.

“+ / Feed forward” key, and “- / Feed backward” key

This key is used for changing pattern No. and X/Y scale, and feed forward/feed backward.

“Selection” key

This key selects the item to be set. Item selection LED of the selected item and the set value are displayed.

Data indication LED

This LED indicates the set values of the selected items such as pattern No., X/Y scale, etc.

Work clamp foot Thread tension

lowering

Needle thread clamp ON/OFF key

This key selects effective/ineffective of needle thread

clamp. When it is effective, needle thread clamp

disply LED lights up. (Note) 1.

Needle thread clamp display LED

When this LED lights up, needle threas clamp

operaters.

Pattern registration key

This key registers the pattern. When this key is

pressed, the pattern registered here can sew imme-

diately.

X/Y scale, sewing position, ets. can be changed and

registered.

(Note) 1. LK-1903A is set to needle thread clamp prohibited (no motion) with memory switch No. 35 at the

time of standard delivery.

– 3 –

3. Standard adjustment

(1) Main shaft connection/disconnection

Procedures of disassembling

1. Loosen the set screw of the main shaft counterbalance through the screwdriver hole A, then remove the taper screw .

2. Loosen the two set screws

(through the screwdriver hole B), and also the two each of and . At that time, loosen the second set screw first. The first set screw should be removed completely from the flat part of the main shaft

3. Remove the main shaft motor . Refer to “(2) Removal of the main shaft motor and coupling.”

4. Loosen the two set screws . Pay attention to possible injury at that time because the balancer begins to turn when the set screw

is loosened.

5. Loosen the two set screws . At that time, the first set screw of the set screw should be removed completely from the flat part of the main shaft .

6. Loosen the two set screws and the two set screws .

7. Draw out the main shaft in the direction of the Arrow C.

Main shaft taper hole

No. 2 screw

No. 1 screw

Screwdriver hole B

No. 2 screw

No. 1 screw

Screwdriver hole A

No. 2 screw

– 4 –

No. 1 screw

Procedures of assembling

1. Insert the crank rod , balancer , hand pulley gear A , bobbin winder driver wheel , and the main shaft counterbalance in the main shaft in this order, and mount the assembly on the frame.

2. Insert the taper screw in the taper hole of the main shaft, and tighten it. Then, tighten the set screw to fix the main shaft counterbalance .

3. Lightly press the main shaft counterbalance in the direction of the arrow D and also the middle metal in the direction of the arrow E. Then, tighten the two set screws . (Tighten the first screw so that it touches flatly on the main shaft . Then, tighten the second one. Same procedures followed hereafter.)

4. Tighten the two each set screws and , respectively. (Make sure that the first screw touches flatly on the main shaft .)

5. Push the hand pulley in the direction of the arrow F so that the hand pulley gear A is meshed with that the hand pulley gear B . In this state, fix the pulley with the two set screws .

6. Mount the main shaft motor and the coupling . Refer to [(2) Removal of the main shaft motor and coupling].

7. Fix the crank rod with the two set screws . Refer to [(3) Crank connecting rod connection/disconnection].

8. Fix the balancer with the two set screws ( . Refer to [(4) Crank balancer positioning].

9. Fix the bobbin winder driver wheel with the two set screws . Refer to [(29) Adjustment of the bobbin winder driving wheel position]. * Try to turn the main shaft and confirm that there is no torque.

– 5 –

(2) Removal of the main shaft motor and coupling

Procedures of disassembling

1. Removal of the main shaft motor together with coupling Loosen the two set screws on the main shaft side of the coupling . Then, remove the four motor set screws .

2. To remove the coupling

from the main shaft motor , loosen the two set screws on the main shaft side.

(Caution) Turn the main shaft

seen first is the No. 1 screw. Loosen the screws, starting with the No. 2 screw. Tightening should be done, starting with the No. 1 screw.

in the direction of forward rotation

No. 2 screw

No. 1 screw

Flat section

No. 1 screw

0.5mm

. The screw (hole) that can be

– 6 –

Code

Procedures of assembling

1. Mounting of the main shaft motor together with the coupling

1) Tighten the four motor set screws . Then, tighten the two set screws on the main shaft side of the

coupling .

2) The cords of the main shaft motor should be positioned in the sidewise direction.

2. Incorporation of the coupling in the main shaft motor

1) Provide a clearance of 0.5mm between the coupling and the main shaft motor .

2) Apply the No. 1 screw of the coupling to the shaft flat section of the main shaft motor , and fix it.

3. Meshing of the coupling

1) Apply the set screw (No. 1 screw) of the main shaft motor side to the section between the two set screws

of the main shaft, and get them meshed.

– 7 –

(3) Crank connecting rod connection / disconnection

Procedures of disassembling

1. Remove the two set screws and four set screws . Then take out the lengthwise feed motor and the crosswise feed motor mounting plate .

2. Loosen the three set screws and the two set screws . At that time, the second screws should be loosened first for the set screws and . The first screws of the set screws and should be arranged so that they can come completely off the flat section of the oscillator shaft .

3. Pull out the oscillator shaft in the direction of the arrow A.

4. Remove the main shaft according to [(1) Main shaft connection/ disconnection]. Then, take out the crank rod unit .

34.1~34.6mm

No. 2 screw

Face B

No. 1 screw

No. 2 screw

No. 1 screw

– 8 –

Procedures of assembling

1. Mount the main shaft according to [(1) Main shaft connection/ disconnection]. Assemble the crank rod unit .

2. Adjust the clearance to 34.1 ~ 34.6mm between the under-cam of the crank rod unit and Plane B (middle metal bearing mounting plane) of the frame. Fix the cam with the set screw . (Tighten the first screw so that it touches flatly on the main shaft . Then, tighten the second one. Same procedures followed hereafter.)

3. Mount the frame while the oscillator is passed through the oscillator shaft .

4. Pass the thrust collar through the oscillator shaft . Lightly push the oscillator shaft in the direction of the arrow C and the thrust collar in the direction of the arrow D. Tighten the two set screws . (Make sure that the first screw touches flatly on the oscillator shaft .)

5. Fix the large pendulum according to [(6) Oscillator gear positioning].

6. Mount the lengthwise feed motor and the crosswise feed motor mounting plate , using the two set screws and four set screws . Refer to [(26) Adjusting the position of the X feed motor and the Y feed motor (Adjusting the backlash of the driving gear)].

(Cautions) 1. Try to turn the main shaft and confirm that there is no torque.

2. In the case of connection/disconnection or positioning of the crank rod unit or positioning of the oscillator , grease-up treatment is always needed for the specified places (2 positions) and the gear area E of the oscillator .

3. After the completion of positioning of the crank rod unit (under-cam ), actions must be taken, without fail, according to [(6) Oscillator gear positioning]. Inadequate positioning of the under-cam and the oscillator can cause of the frictional wear or lock-up.

– 9 –

(4) Crank balancer positioning

Standard Adjustment

[Rotating direction]

When the needle bar lowers and the clearance between the needle bar connecting and the needle bar bushing, lower is 4.6mm, the two set screws of the crank balancer assume the horizontal condition.

[Axial direction]

Keep the close contact with the main shaft eccentric cam and the crank balancer .

4.6mm

(5) Lower shaft backlash adjustment and connection/disconnection

Standard Adjustment

1. Size of lower shaft backlash is 0.1mm at the tip of the driver . The shaft is required to rotate smoothly.

2. Define the stop position of the lower shaft so that the set screw settles almost in the center of the flat section of the lower shaft .

0.1mm or less

Face A

– 10 –

Adjustment Procedures

Results of Improper Adjustment

If the main shaft eccentric cam is not fixed, this adjustment should be carried out after defining its position and fixing it.

1. Loosen the two set screws of the crank balancer .

2. Using the four set screws , remove the crank rod cover .

3. Turn the main shaft in the direction of forward rotation A so that the needle bar lowers and the clearance between the needle bar connecting and the needle bar bushing, lower is 4.6mm.

4. In the state that the two set screws of the crank balancer assume the horizontal condition and they are moved in the direction of the arrow mark B, keep the close contact with the main shaft eccentric cam and tighten the two set screws . When tightening these two set screws , the screws should be tightened reciprocally.

o If the angle for fixing the crank

balancer is inadequate, vibration of sewing machine operation will be intensified.

o If the sewing machine is used for

a long time while the fixing position is inadequate, the operational life of the main shaft bearing may be shortened.

o If the crank balancer is not

moved in the direction of the arrow mark B, there may be interference with the sewing machine frame.

Adjustment Procedures

1. Lower shaft backlash

1) Loosen the two set screws .

2) Turn the lower shaft rear metal in the direction of the arrow and adjust

the backlash, keeping the metal to contact closely with Face A. Size of backlash is 0.1mm at the tip of the driver . The shaft is required to rotate smoothly.

3) Tighten the two set screws .

(Caution) When eliminate the backlash, the direction of rotation

should always be kept in the direction of the arrow.

2. Lower shaft connection/disconnection

1) Loosen the two set screws .

2) The lower shaft can be taken out if it is pulled in the direction

of the arrow.

3) When mounting the lower shaft , insert it in the lower shaft rear

metal and the lower shaft gear . Apply one of the set screws

to the flat section of the lower shaft and tighten it approxi-

mately in the center. Tighten the remaining set screw .

* Connection and disconnection of the lower shaft become easy if

the above-mentioned backlash has been relieved in advance. In this case, backlash adjustment must be done after the lower shaft has been installed.

Results of Improper Adjustment

o If the backlash is excessive, the

hook noise will be increased.

o If backlash is too small, the lower

shaft gear or the oscillator will give rise to frictional wear. In addition, this can be a cause of crank rod lock-up.

o If the front or rear position of the

lower shaft rear metal is displaced at the time of backlash adjustment, this can also be a cause of the lock-up of oscilator or the crank rod.

– 11 –

(6) Oscillator gear positioning

Standard Adjustment

1. When the oscillator is lightly swung by a finger in the direction of the arrow, the oscillator is fixed in the center position of swinging.

No. 2 screw

No. 1 screw

(7) Adjustment of hook oil amount

Standard Adjustment

– 12 –

Adjustment Procedures

Results of Improper Adjustment

1. Loosen the two set screws and increase the backlash of the lower shaft gear .

(Caution) 1. If the lower shaft gear has insufficient backlash,

the oscillator does not swing correctly. In such a case, refer to [(5) Lower shaft backlash adjustment and connection/disconnection] and provide a sufficient backlash.

2. The three set screws should have been loosened in advance. In this case, the second screw of the set screws should be loosened first. Then, the first one can be loosened.

3. Lightly swing the whole body of the oscillator with a finger in the direction of the arrow. Decide the positioning of the oscillator so that it stays in the center of swinging.

4. Loosen the three set screws and then fix them so that the oscillator is not displaced from the center of swinging. (Tighten the first screw first so that it comes in contact flatly with the oscillator shaft . Then, tighten the second one.)

5. Make backlash adjustment for the lower shaft gear , according to [(5) Lower shaft backlash adjustment and connection/ disconnection].

(Cautions)1. In the case of disassembly and adjustment, grease-

up treatment is always needed for the specified places (2 positions) and the gear area A of the oscillator .

2. When the crank rod (under-cam) is removed, actions for under-cam positioning must be taken, without fail. Refer to [(3) Crank connecting rod connection/ disconnection].

o If the position for fixing the

oscillator is inadequate, this can also be a cause of the frictional wear or lock-up of the oscillator pin, crank rod lid, undercam, and the crank rod.

Adjustment Procedures

1. Loosen the set screw and remove it.

2. When the adjusting screw is tightened, the quantity of oil can be regulated for the lubrication pipe left .

3. After adjustments, tighten the set screw to fix it.

(Cautions) 1. In the state of standard shipping, the hook lubrica-

tion reducer is positioned so that it is lightly tightened and then return-loosened by 4 turns.

2. When reducing the oil amount, the screw should not be tightened up fully. Tighten the hook lubrication reducer and then return it by two turns. In this position, wait for half a day to see how it goes. Too much reduction can be a cause of hook wear.

Results of Improper Adjustment

o If the amount of hook lubricant is

reduced too much, this can be a cause of frictional wear of the hook race plane or lock-up.

– 13 –

(8) Large hook connection / disconnection and oil wick piping

Procedures of disassembling

1. Loosen the four set screws .

2. Cut the harness bands and .

3. Remove the set screw and pull the oil tank in the direction of the arrow A.

4. Pull Part B upwards of the two lubrication pipes . Take them out of the oil tank .

5. Release the cord clamp from the rear side of the bed of the oil drain pipe .

6. Loosen the set screw and take out the driver .

7. Loosen the set screw .

8. Remove the set screw and pull out the shuttle race adjust shaft .

9. Pull the shuttle in the direction of the arrow C and take it out.

(9) Adjusting the height of the needle bar

Standard Adjustment

Engraved line for DP x 5

: Upper engraved line

Engraved line for DP x 17

is for H type only.

– 14 –

Procedures of assembling

1. Pass the two lubrication pipes and the oil drain pipe through the frame, and mount the shuttle .

2. Hold the lubrication pipe with the lubrication pipe holder plate and fix it with the set screw . At that time, make sure not to let the lubrication pipe come in contact with the thread cutter connector

rod.

3. Pass the lubrication pipe through the cord clamp and fix it with the set screw At that time, the needle thread clamp sensor cord should be passed beneath the lubrication pipe and the oil drain pipe . If the needle thread clamp sensor cord is located above them, this can be a cause of abrasion or cable breakage in the crosswise feed main .

4. Using the harness band and the lubrication pipe holder , stretch and fix the lubrication pipe along the wall side of the frame. At that time, make sure not to permit the lubrication pipe to touch the needle thread clamp connector link.

5. Bundle the needle thread clamp sensor cord , the lubrication pipe , and the oil drain pipe with the harness band .

6. Pass the two oil drain pipes through the cord clamp and fix them with the set screw .

7. Insert the two oil drain pipes (part B) in the oil tank . Fix the oil tank to the frame with the set screw

8. Fix the oil drain pipe to the rear side by means of the cord clamp.

9. Fix the shuttle and mount the driver . Refer to [(10) Hook adjustment].

* Harness bands and : Part No. EA9500B0100

Adjustment Procedures

Bring needle bar to the lowest position of its storoke. Loosen needle bar connection screw and adjust so that upper marker line engraved on the needle bar aligns with the bottom end of needle bar bushing lower .

(Caution) After the adjustment, make sure that there is no uneven

torque.

Results of Improper Adjustment

* When stitch skipping occurs in accordance with the sewing condi-

tions, adjust the height of the needle bar so as to lower it by 0.5 to 1mm from the neddle bar engraved line .

– 15 –

(10) Hook adjustment

Standard Adjustment

For DPX5

For DPX17

0.05~0.1mm

0mm

7.5mm

– 16 –

Adjustment Procedures

1. Turn the handwheel by hand. When needle bar has gone up, adjust

so that lower marker line engraved on the needle bar aligns with the bottom end of the needle bar bushing , lower.

2. Loosen setscrew in the driver . Open inner hook pressers to

the right and left, and remove inner hook presser .

(Caution) At this time be careful not to let inner hook come off

and fall.

3. Adjust so that the blade point of inner hook aligns with the center

of needle , and that a clearance of 0 mm is provided between the front end of the driver and the needle as the front end face of driver receives the needle to prevent the needle from being bent. Then tighten setscrew of the driver .

4. Loosen setscrew of the shuttle, and adjust the longitudinal posi-

tion of the shuttle. To do this adjustment, turn shuttle race adjusting shaft clockwise or counterclockwise to provide a 0.05 to 0.1 mm clearance between needle and the blade point of inner hook .

5. After adjusting the longitudinal position of the shuttle, further adjust

to provide a 7.5 mm clearance between the needle and the shuttle by adjusting the rotating direction. Then tighten setscrew of the shuttle.

Results of Improper Adjustment

(Caution) Apply a small amount of oil to race section and oil

wick , and use the sewing machine after an extended period of disuse or cleaning the periphery of hook portion.

– 17 –

(11) Thread trimmer cam position adjustment and connection / disconnection

Procedures of disassembling

1. Loosen the two set screws of the thread trimmer cam (cam hereafter) .

2. Loosen the two set screws and remove the sensor slit .

3. Remove the four set screws and take out the presser lifting motor in the direction of the arrow. In some cases, the bearing and the motor shaft seem to be tightly coupled. Pull out the motor shaft in the direction of the arrow straightforward in order not to hurt the bearing . At that time, the cam may come down. Handle it with care, not to damage it.

Flat section

(12) Thread trimmer and presser foot origin sensor adjustment

Standard Adjustment

In the state of origin retrieval (Start Switch ON) in the test mode CP-6, the standard holes A and B of the sewing machine frame come to coincide with the standard hole C of the thread trimmer and presser bar lifter cam .

– 18 –

Procedures of assembling

1. Apply a proper amount of grease (Juki Grease A) to the grooved cam block of the cam , the peripheral cam block, and the rollers of the presser bar lifter link and the thread trimmer link . Refer to “9.-(4) Parts to which grease is applied.”

2. While the cam is being inserted in the shaft of the presser lifting motor , mount the assembly on the sewing machine frame and tighten the four set screws . The insertion of the cam should be done gently in order not to hurt the bearing .

3. Clearance B toward the presser bar lifter link and Clearance A toward the thread trimmer link should be equally distributed. For this purpose, adjust the position of the cam and fix it with the use of the two set screws . (Apply the screws to the flat section at both ends of the shaft.) * If it is difficult to examine Clearance B, Clearance A should be adjusted to 0.5mm ~ 0.7mm during assembly.

4. Mount the sensor slit with the two set screws so that the end plane of the motor shaft can approximately coincide with that of the sensor slit . (Join the flat section for installation.) * Confirm that the slit plate of the sensor slit does not interfere with the presser bar lifter sensor.

5. Refer to “(12) Thread trimmer and presser foot origin sensor adjustment” and make sensor adjustments.

Adjustment Procedures

1. Start the test mode CP-6.

2. Tread on the pedal for the retrieval of the thread trimmer and presser bar lifter (cam) origin.

3. Using a bar or the like, confirm that the standard holes A and

of the sewing machine frame coincide with the standard hole C of the thread trimmer and presser bar lifter cam .

4. If the standard hole C of the thread trimmer and presser bar lifter cam stays in the upper E direction, loosen the set screw to move the sensor mounting plate in the lower D direction and then fix it. If the standard hole C of the thread trimmer and presser bar lifter cam stays in the lower D direction, loosen the set screw to move the sensor mounting plate in the upper E direction and then fix it. After the sensor mounting plate has been fixed, tread on the pedal for the retrieval of the thread trimmer and presser bar lifter (cam) origin to confirm whether the standard holes coincide with each other.

5. Repeat the above steps 2 to 4 until the coincidence is confirmed.

(Caution) Confirm that there is no mutual interference between the

sensor slit plate and the sensor before tightening the set screw .

Results of Improper Adjustment

o If there is no coincidence of the

standard holes, such a condition is regarded as a thread cutting timing error. This can be a cause of trouble in thread breakage or unthreading at the beginning of sewing.

– 19 –

(13) Adjusting the lift of the work clamp foot

Standard Adjustment

Max. 17mm

(14) Adjusting the thread trimmer sensor

Standard Adjustment

After the completion of origin retrieval in the test mode CP-6 (Start Switch ON), try to press the + key 6 to 8 times. At that time, the thread trimmer sensor is turned ON. (The digit display at the operation panel: [10] → [00])

– 20 –

Adjustment Procedures

1. With the machine in stop mode, remove six setscrews of the top cover, and take off top cover .

2. Apply L-shaped wrench to socket bolt of clamp , and loosen the socket bolt.

3. Push down L-shaped wrench to increase the lift of the work clamp hoot, or pull it up to decrease the lift.

4. After the adjustment, securely tighten socket bolt .

5. If the right and left work clamp feet are not levelled, loosen fixing screw and adjust the position of the work clamp foot lever support plate to level them.

(Caution) At this time, be careful not to cause work clamp foot

lever support plate to interfere with feed bracket . If the work clamp foot levers support plate interferes with the wiper, readjust the height of the wiper using setscrew

in the wiper installing base.

Results of Improper Adjustment

Adjustment Procedures

1. Start the test mode CP-6.

2. Tread on the pedal to perform origin retrieval for the thread trimmer cam. (Confirm that the origin is in the correct position. Then, proceed to the procedures shown below. Refer to “(12) Thread trimmer and presser foot origin sensor adjustment.”)

3. Press the ] key . Confirm that the display of the operation panel is changed over from [10] → [00] when the key is pressed within the range of 6 to 8 times.

4. If the display changeover occurs deviating from the range of 6 times to 8 times, or if the display changeover does not occur at all, loosen the set screw and make fine adjustments of the sensor slit in the directions of the arrow.

5. After the sensor slit has been fixed, tread on the pedal and make origin retrieval for the thread trimmer cam. Examine the sensor changeover position in the steps 3 and 4 above.

6. Repeat the steps 2 ~ 5 above until the coincidence is secured.

(Caution)During adjustments, check the clearances A, B, and C of

the sensor slit and the sensor . If the clearances seem to be insufficient, use the set screws and to correct the gradient. While taking this action, continue to work on the steps above.

Results of Improper Adjustment

o If the thread trimmer sensor

changeover takes place outside the range, the moving knife may interfere with the needle. This will be a cause of injury or the breakage of parts.

o If the thread trimmer sensor

changeover does not take place, Error 305 occurs and the sewing machine fails to start operating.

o If the sensor slit has no clear-

ance against the sensor , this can be a cause of destruction in the sensor slit or the sensor

– 21 –

(15) Adjustment of the moving knife and counter knife position

Standard Adjustment

Counter knife position : The clearance between the counter knife and the needle hole guide is 0.5mm. Moving knife position : Before thread trimmer operation (standby state), the distance from the throat plate

front end to the tip of the thread cutter lever (small) is 18.5mm.

18.5mm

0.5mm

Moving knife link

(16) Adjusting the height of the moving knife and counter knife

Standard Adjustment

Moving knife : The amount of mesh of the needle hole guide with the moving knife is 0.15mm. Counter knife : The height between the needle hole guide and the blade of the counter knife is 0.1 ~

0.15mm.

0.1~0.15mm

(Throat plate)

0.15mm

– 22 –

Adjustment Procedures

Results of Improper Adjustment

1. Counter knife position Loosen the counter knife set screw to adjust the position.

2. Moving knife position Loosen the screw to adjust the position.

(Cautions)1. In normal operation, the moving knife passes in-

side the needle hole guide , as illustrated in

2. The throat plate is the appropriate item for the LK-1900A Series (40006721).

o If the clearance is less than

0.5mm, thread may be cut by the counter knife blade when the thread is pulled with the moving knife . In this case, upper and lower threads are cut into short pieces.

o If the clearance is more than

0.5mm, the residual thread length after thread cutting operation becomes longer beneath the work.

Adjustment Procedures

1) Adjusting the height of the moving knife Adjustments should be based on the plate thickness of the washer

in the above illustration. If the height seems to be inadequate,

select and use the parts as specified below.

Part No. Name of part Thickness B242328000A Moving knife washer 0.4mm B242328000B Moving knife washer 0.5mm B242328000C Moving knife washer 0.6mm B242328000D Moving knife washer 0.7mm B242328000E Moving knife washer 0.8mm

2) Adjusting the height of the counter knife Adjust the height by prying Part A with a screwdriver or the like.

Results of Improper Adjustment

o If the step is too small (0.25 ~

0.3mm) between the moving and counter knives, trouble in thread cutting may occur.

o If the step is too large (0.1 ~

0.15mm) between the needle hole guide and the counter knife , thread may be cut by the counter knife blade when the thread is pulled with the moving knife . In this case, upper and lower threads are cut into short pieces.

– 23 –

(17) Inclination of the blade point of the counter knife

Standard Adjustment

To cut the two threads (needle thread and, bobbin thread) uniformly, the blade face of the counter knife is made to have an inclination of 0.2mm.

0.5mm

0.2mm

(18) Floating amount of the thread tension disk

Standard Adjustment

When the sewing machine power supply is turned off (AT solenoid is OFF), the gap between AT thread tension discs is 0.6 ~ 1mm.

Close contact

0.6~1mm

– 24 –

Adjustment Procedures

Results of Improper Adjustment

1. If the thread on Side B cannot be cut, grind Side C. If the thread on Side C cannot be cut, grind Side B.

(Caution) When grinding the side, make the angle more acuter than

90 degrees.

Secure an acute angle.

Adjustment Procedures

1. Turn off the power supply and look for any close contact between the AT solenoid and the thrust collar .

2. Loosen the three set screws and remove the thread tension cap

3. Hold the tension releasing pin adjust collar not to let it rotate, and loosen the nut .

4. Turn the tension releasing pin adjust collar and adjust the gap between the thread tension discs . (Adjustment of thread tension disc floating)

o When less than 0.2mm

Thread on Side C cannot be cut.

o When more than 0.2mm

Thread on Side B cannot be cut.

Results of Improper Adjustment

o If the amount of disc floating is too

less, the residual thread length can be changed or shortened when the thread is thick.

o If the amount of disc floating is too

much, the tension discs cannot close completely and normal thread tension may fail to be chosen. This can be a cause of imperfect sewing.

5. Hold the tension releasing pin adjust collar and tighten the nut . Mount the thread tension cap by means of the set screw .

6. Turn on the power supply and set up the thread tension. Confirm that the thread tension discs are closed.

– 25 –

(19) Second thread tension connection / disconnection

Procedures of disassembling /assembling

1. Loosen the set screw .

2. Remove the two set screw .

3. Move the AT link unit (front) downwards (in the direction of the Arrow A), and pull out the pin block from the hole of the thread tension releasing pin of the second thread tension .

4. Pull out the second thread tension to remove it. (Arrow B)

5. For reassembly, follow the steps of 4) to 1) above.

– 26 –

Cautions for disassembly and reassembly

1. When pulling out the second thread tension , confirm that the pin block of the AT link unit (front) has been displaced from the hole of the thread tension releasing pin . If this action is taken forcedly with the pin block left connected, this can be a cause of breaking the second thread tension .

2. When tightening the set screw , this fixing action should be taken after the AT link unit (front) has been moved to the left side (in the direction of the arrow C). If it is not moved to the left side (in the direction of the arrow C), the amount of tension disc floating may fail to be adjusted normally.

3. After reassembly, follow the steps for the adjustment of thread tension disc floating and thread take-up spring stroke. (Refer to the instruction manual.)

– 27 –

(20) AT unit connection / disconnection

Procedures of disassembling /assembling

1. Remove the set screw of the A T link unit (front) and take out the second thread tension . ((19) Refer to “Second thread tension connection / disconnection.”)

2. Draw out the cotter pin from the pin block of the AT link unit (rear) . Be careful not to drop the washer at that time.

*Work becomes easier if the main shaft motor is removed.

3. Lift the joint block of the AT unit upwards and take it off the pin block of the AT link unit (rear) .

4. Draw out the AT link unit (front) from the plane side (in the direction of the arrow E) and remove it.

5. Remove the two set screws and take out the AT solenoid unit .

6. For reassembly, follow the steps of 5. to 1. above.

Close contact

Solenoid side

– 28 –

Cautions for disassembly and reassembly

1. When incorporating the AT solenoid unit , the solenoid cable should be laid beside the AT solenoid. If this solenoid cable is positioned in the vicinity of the AT link unit (rear) , this will be a cause of AT solenoid malfunction.

2. The center-to-center distance is 358mm between the AT joints of the AT connector rod . In cases of disassembly and reassembly of the AT joints , the center-to-center distance must be secured correctly. In addition, the parallelism of the two front and rear joints must also be secured, without fail. If the correct distance and parallelism are lost, this can be a cause of AT malfunction and normal sewing tension cannot be obtained.

3. Upon the completion of all reassembly work, confirm that there is a close contact between the thrust collar and the AT solenoid unit . If any clearance is perceived, loosen the two set screws and assemble the AT solenoid unit after it has been moved to the left side (in the direction of the arrow F). * If the above-mentioned center-to-center distance is great between the AT joints , the clearance will be

opened wider.

358mm

Secure parallelism between plane and plane.

– 29 –

(21) Position of the mechanical origin

Standard Adjustment

A : 147mm (LK-1900A, 1902A)

: 146mm (LK-1901A, 1903A)

B : 61mm (LK-1900A, 1902A)

: 62mm (LK-1901A, 1903A)

C : 74mm (LK-1900A, 1902A)

: 73mm (LK-1901A, 1903A)

(22) Adjusting the Y origin sensor

Work feed plate

Standard Adjustment

– 30 –

Adjustment Procedures

Results of Improper Adjustment

1. The position of the mechanical origin is shown in the illustration at left.

2. In the horizontal direction, the needle hole center <center of the horizontal feed fulcrum shaft > and the center of the vertical feed fulcrum shaft are aligned on a straight line.

3. Adjustments should be carried out according to 1) (22) Adjusting the Y origine sensor and (23) Adjusting the X origin sensor.

o The maximum area cannot be

secured.

Adjustment Procedures

1. Select the test mode No. 2 (CP-2) origin retrieval.

2. Origin retrieval is conducted each time the pedal is trodden on. Loosen the sensor slit set screw and shift the position of the sensor slit plate . Apply the work feed plate to the origin position. Refer to “ (21) Position of the mechanical origin.”

(Caution) After adjustments, confirm that the sensor slit plate

does not interfere with the sensor .

Results of Improper Adjustment

– 31 –

(23) Adjusting the X origin sensor

Standard Adjustment

(24) Adjusting the wiper position

Above 1.5mm

Standard Adjustment

Amm

– 32 –

Adjustment Procedures

1. Select the test mode No. 2 (CP-2) origin retrieval.

(Caution) After adjustments, confirm that the sensor slit plate

does not interfere with the sensor .

Results of Improper Adjustment

Adjustment Procedures

1. Loosen the screw to adjust the clearance between the wiper and the needle so that this clearance attains 1.5mm or more. Loosen

2. Loosen the screw to adjust Distance A between the wiper end plane and the needle center until this distance attains the values specified below. After adjustments, tighten the screw firmly.

Distance A between the needle center and the wiper end plane (Amm) Other thanLK-1903A : 23mm to 25mm

LK-1903A only : 15mm to 17mm

* The needle stays in the position of the end of sewing and stop.

Results of Improper Adjustment

o If Distance A is too small, the

presser bar may tread on the needle thread when the presser bar is lowered. At that time, the needle thread may be caught by the wiper and the needle may be broken. In particular, this must be taken into consideration when a thin needle (#11 or less) is used.

– 33 –

(25) Adjusting the wiper spring (LK-1903A only)

Standard Adjustment

(26) Adjusting the position of the X feed motor and the Y feed motor (Adjusting the back-

lash of the driving gear)

Standard Adjustment

1. Fix the Y feed motor by pressing it in the direction of the arrow C.

2. Fix the X feed motor by pressing it in the direction of the arrow B.

– 34 –

Adjustment Procedures

After thread cutting, the wiper spring is used to hold the needle thread with the aid of the wiper . Adjust the wiper spring and fix it with the set screw so that the intensity of the spring force becomes 30g (somewhat stronger than that of the bobbin thread that is protruded from the bobbin case).

1. Remove the set screw and take out the wiper spring from the

wiper .

2. Adjust the wiper spring and mount it on the wiper again by

means of the screw .

(Caution) 1. If the holding force is too strong, the thread may be

protruded above the button.

2. If the holding force is insufficient, needle thread castoff may occur.

3. If the wiper spring position is inadequate, the needle thread cannot be held correctly and this can be a cause of needle breakage.

Results of Improper Adjustment

Adjustment Procedures

1. Loosen the two set screws and four set screws of the Y feed motor and the two set screws of the X feed motor mounting plate .

2. Pressing it in the direction of the arrow C, tighten the two upper set screws in the first place. Then, tighten the two remaining set screws

and another two set screws , X feed motor mounting plate .

3. Loosen the four set screws of the X feed motor . Pressing it in the direction of the arrow B, tighten the set screw .

Results of Improper Adjustment

o If the pressing force is insufficient,

feed gear backlash becomes too much and needle location accuracy may be decreased. This can also be a cause of feed error, needle breakage, etc.

– 35 –

(27) Installing the feed plate support plate

Standard Adjustment

Machine bed

(28) Installation of the feeder bar rear cover

Standard Adjustment

The clearance between the feeder bar rear cover and the upper surface of the work feed presser bar is about 1mm. When the feeder bar is moved in the direction of the arrow A, there must be a clearance at the notch part of the sewing machine frame .

Clearance

1mm

– 36 –

Adjustment Procedures

Results of Improper Adjustment

1. Loosen the Y feed arm set screw .

2. Push the Y feed shaft in the direction of the arrow A ⇒.

3. Loosen the setscrews (3 pcs.) of the work feed acceptor plate. Moving the Y feed arm in the direction of the arrow , fix the Y feed shaft to the guide and also fix the work feed acceptor plate in the position where no torque is generated.

4. Let the end planes A of the Y feed shaft and the Y feed arm coincide with each other. Fix the Y feed arm set screw .

o The feeding load becomes too

much and this can be a cause of feed error.

Adjustment Procedures

1. Loosen the two set screws .

2. Make vertical adjustments of the feeder bar rear cover and secure a clearance of about 1mm toward the upper plane of the work feed presser bar . Then, tighten the two set screws .

3. Move the feeder bar in the direction of the arrow A and confirm that there is a clearance at the notch part of the sewing machine frame . If there is no clearance and there is interference with the sewing machine frame , the steps of 1. ~ 2. above should be repeated again.

(Caution) 1. When tightening the set screws , the feeder bar rear

cover may be moved vertically . Hold the feeder bar rear cover firmly while the set screws are tightened.

Results of Improper Adjustment

o If the clearance is too small

between the feeder bar rear cover

and the upper plane of the work feed presser bar , the feeder bar rear cover will come in contact with the work feed presser bar due to the effect of vibration during sewing operation. This will cause noise and abrasion.

o If there is no clearance between

the feeder bar rear cover and the notch part of the sewing machine frame , the feeder bar rear cover will come in contact with the sewing machine frame

, causing feed error during sewing operation.

– 37 –

(29) Adjustment of the bobbin winder driving wheel position

Standard Adjustment

The distance is 10mm between the measuring plane B of the bobbin winder driving wheel and the cover mounting plane A of the sewing machine frame .

10mm

(30) Adjusting the bobbin winder amount

Standard Adjustment

The position of the bobbin winder lever is based on the standard that it is 14mm apart from the bobbin winder shaft . Try to perform bobbin winding actually and make fine adjustments in the directions of the arrows A and B so that the amount of thread winding becomes adequate (recommended value: 80 ~ 90% of the bobbin).

14mm

– 38 –

Adjustment Procedures

Results of Improper Adjustment

1. Adjust the position of the bobbin winder driving wheel and fix it with two set screws .

o If the distance of 10mm is

insufficient, rubber ring wear may occur in the bobbin winder unit. In addition, the bearing life may be reduced in the bobbin winder unit.

o If the distance of 10mm is exces-

sive, normal thread winding may fail. In addition, this will also cause rubber ring slippage in the bobbin winder unit and give rise to wear.

Adjustment Procedures

1. Loosen the set screw of the bobbin winder lever and adjust the distance to 14mm between the bobbin winder lever and the bobbin winder shaft . After that, tighten the set screw of the bobbin winder lever.

2. Start the sewing machine and wind the thread at the bobbin winder. Confirm the amount of winding.

1) If the amount of winding seems to be too much, adjust the bobbin

winder lever in the direction of the arrow A.

2) If the amount of winding seems to be too less, adjust the bobbin

winder lever in the direction of the arrow B.

3. If the winding state of the thread around the bobbin winder seems to be uneven, loosen the nut and adjust the height of the thread tension control . (Example) If the amount of the wound thread is less on the upper

side of the bobbin winder as illustrated, adjust the thread tension control upwards.

Results of Improper Adjustment

o If too much thread is wound

(thread protruded from the bobbin

), the thread will come in contact with the inside of the bobbin case and this can be a cause of sewing deficiency.

o If the amount of thread winding is

uneven at top and bottom of the bobbin winder , stitch perforation may become irregular.

– 39 –

(31) Adjustment of the hook upper spring position

Standard Adjustment

For the right and left positions, the needle center is made to coincide with the center of the groove width C. For the front and rear positions, the needle rear end is made to coincide with the corner part A.

(Caution) If Par t

thread, etc. Therefore, this part should be polished by the use of a buff or the like. In particular, the rear side should be handled with care.

B1815210000

is damaged, this is the cause of thread breakage, hangnail of thread, stain on

(32) Shuttle felt

Standard Adjustment

Two pieces of the shuttle felt are inserted in the holes of the shuttle race . Confirm that the shuttle felts are not overloaded when the inner hook is set and turned along the shuttle race .

Shuttle

– 40 –

Adjustment Procedures

Results of Improper Adjustment

1. Remove the work feed bar, feed plate, and the throat plate. Make adjustments with the screw .

(Caution) The right and left positions can also change during (10)

hook adjustments. Position adjustment for the large hook upper spring should be done after the completion of standard hook adjustment, without fail.

o If there is a front and rear

displacement or a right and left displacement, needle thread biting may occur into the hook. Too much motion to the rear side will cause the moving knife to fail to hook the needle thread.

o Too much motion to the rear side

will cause the moving knife to fail to hook the needle thread.

o Too much motion to the left side

will cause the moving knife to fail to hook the bobbin thread.

Adjustment Procedures

1. If the shuttle felt seems to be protruded or it has been replaced with a new one, push it in by means of tweezers or the like.

(Caution) Do not push it in excessively. Align the height and the

plane of the shuttle race .

Results of Improper Adjustment

o If the shuttle felt is protruded,

this will be turned into a rotary load of the inner hook, causing a sewing error.

o If the shuttle felt is missing or

pushed in too much, this will result in hook lubrication deficiency , causing hook overheating and wear.

– 41 –

(33) Shape of the shuttle race ring

Standard Adjustment

If wear seems to be too much around the pointed tip of the inner hook, release the shuttle race ring and confirm that the dimensions of the hatched area on the rear side are 0.3 x 8mm.

0.3mm

8mm

Dimension A

(34) Adjustment of the thread take-up spring

Standard Adjustment

– 42 –

Adjustment Procedures

1. If the dimensions of 0.3 x 8mm are not secured, retouching is required with the aid of an oil stone.

Results of Improper Adjustment

Dimension A

(mm)

0.8 14103253 Shuttle race ring A

1.3 14103352 Shuttle race ring B

1.7 14103659 Shuttle race ring C

1.9 B1817210DAD Shuttle race ring D Optional

Part No. Name of part Remarks

Conforming to Specifications F and M as standard

Conforming to Specifications S as standard

Conforming to Specifications H as standard

Adjustment Procedures

The standard stroke of thread take-up spring is 8 to 10mm, and the pressure at the start is 0.1 to 0.3N.

1) Adjusting the stroke Loosen setscrew , and turn thread tension asm. . Turning it clockwise will increase the moving amount and the thread drawing amount will increase.

2) Adjusting the pressure To change the pressure of the thread take-up spring , insert a thin screwdriver into the slot of thread tension post while screw is tightened, and turn it. Turning it clockwise will increase the pressure of the thread take-up spring . Turning it counterclockwise will decrease the pressure.

Example of the thread tension

When using the sewing machine for the first time, adjust the thread tension referring to the table below.

Thread Material Needle thread Thread take-up spring moving Strength

tension setting amount [ Thread drawing amount] Tetoron thread #50 Wool 30 to 35 10mm [13mm] 0.1N Spun thread #50 Wool 50 to 55 10mm [13mm] 0.2N Spun thread #60 T/C broad 30 to 35 8 to 10mm [11 to 13mm] 0.1N

(Thread clamp OFF) Cotton thread #50 Denim 35 to 45 10mm [13mm] 0.1N Cotton thread #20 Denim 35 to 45 8 to 10mm [11 to 13mm] 0.1N

Results of Improper Adjustment

– 43 –

(35) Needle thread clamp device connection/disconnection

Procedures of disassembling

1. Remove the hinge screw . * If the hinge screw cannot be seen from the open part of the needle thread clamp device , try to

move the needle thread clamp connector link by hand in the direction of A or B.

2. Remove the four set screws of the needle thread clamp base and take out the needle thread clamp device .

Open part

– 44 –

Procedures of assembling and adjustment procedures

1. Push the needle thread clamp device in the direction of A and fix it with the four set screws . Tighten the hinge screw .

2. Turn on the power supply and press the key twice so that the needle thread clamp support plate complete is positioned at the far advanced end. Confirm that the distance between the needle thread clamp support plate complete and the needle is

3.3 ~ 3.7mm and 1.7 ~ 2.3mm, respectively.

3. If the distance seems to be inadequate, loosen the four set screws and move the needle thread clamp device for adjustment.

(Caution) For the prevention of injury, the distance should be checked only if the sewing LED is unlit.

(Press the key twice after the power supply has been turned on.)

4. After the completion of the above-mentioned reassembly, make adjustments according to “(36) Adjusting the needle thread clamp sensor.”

3.3~3.7mm

1.7~2.3mm

– 45 –

(36) Adjusting the needle thread clamp sensor

Standard Adjustment

When the needle thread clamp support plate complete is withdrawn by 3 to 4 pulses from the needle thread clamp position (Caution) 1., the clearance A toward the needle thread clamp device becomes 0.

(Caution) 1. The needle thread clamp position is known to be the one that is one step returned from the

most advanced position when the key is pressed in the test mode CP-7.

1.7~2.3mm

3~4mm

– 46 –

Adjustment Procedures

Results of Improper Adjustment

1. Start the test mode CP-7.

2. Tread on the pedal for needle thread clamp device origin retrieval.

3. Press the key twice and set the needle thread clamp support plate complete in the needle thread clamp position.

4. Confirm that the clearance A becomes 0 between the needle thread clamp device and the needle thread clamp support plate complete

when the [–] key is pressed 3 to 4 times (for 3 to 4 pulses), and that both the needle thread clamp device and the needle thread clamp support plate complete move together when the [–] key is pressed again.

5. If the clearance A becomes 0 with 5 or more pulses, loosen the set screw and fix the sensor mounting plate after moving it in the direction B.

6. If the clearance A becomes 0 with less than 3 pulses, loosen the set screw and fix the sensor mounting plate after moving it in the direction C.

7. After the sensor mounting plate has been fixed, check the abovementioned steps 2. to 4.

8. Using 3 to 4 pulses, repeat the steps 2. to 6. above until the clearance A becomes 0.

9. Tread on the pedal for needle thread clamp device origin retrieval and define the most advanced position by pressing the key once.

o If there are too many pulses used

until the clearance A becomes 0, this can be a cause of unthreading at the beginning of sewing.

o If the number of pulses is too small

until the clearance A becomes 0, the resistance toward the needle thread becomes large and this can be a cause of thread breakage at the beginning of sewing.

o If the distance is improper be-

tween the needle thread clamp support plate complete and the needle , this will give rise to interference between the needle thread clamp device and the needle .

10. Confirm that the distances between the needle thread clamp sup-

port plate complete and the needle are kept at 3 ~ 4mm and

1.7 ~ 2.3mm, respectively.

1 1. If the distance is found to be inadequate, adjust the position toward

the needle according to (35) Needle thread clamp device connection/disconnection. Since then, make the above-mentioned sensor adjustments again.

– 47 –

(37) Adjusting the needle thread clamp notch

Standard Adjustment

1. Needle thread clamp notch R position

1) When the needle thread clamp link complete

is pushed in Direction A and Part B of the needle thread clamp support plate complete and the needle thread clamp device begins to open, the distance between the needle thread clamp device and the needle thread clamp base becomes 21mm.

Contact

21mm

2. Needle thread clamp notch F position

1) When the needle thread clamp link complete

is pushed in Direction C and Part B of the needle thread calmp support plate complete and the needle thread clamp device begins to open, the distance between the needle thread clamp device and the needle thread clamp base becomes 23mm.

23mm

Contact

– 48 –

Adjustment Procedures

Results of Improper Adjustment

1. Needle thread clamp notch R adjustment

1) Loosen the two set screws .

2) Push the needle thread clamp link complete in Direction A so that the distance between the needle thread clamp device and the needle thread clamp base becomes 21mm. Move the needle thread clamp notch R in Direction D, lightly push it toward the needle thread clamp cam plate , and tighten the two set screws .

2. Needle thread clamp notch F adjustment

1) Loosen the two set screws .

2) Push the needle thread clamp link complete in Direction C so that the distance between the needle thread clamp device and the needle thread clamp base becomes 23mm. Move the needle thread clamp notch F in Direction E, lightly push it toward the needle thread clamp cam plate , and tighten the two set screws .

o If the distance between the needle

thread clamp device and needle thread clamp base comes to leager than 21mm, release timing turns so early that unthreading at the beginning of sewing is caused.

o If the distance between the needle

thread clamp device and needle thread base comes to smaller than 21mm, release timing turns so slowly that needle thread remains on the back side of the material is caused.

o If the distance between the needle

thread clamp device and needle thread clamp base comes to larger than 23mm, clamp timing turns so early that needle thread remains on the back side of the material or jamming of needle thread in to the needle thraed clamp device is caused.

o If the distance between the needle

thraed clamp device and needle thread clamp base comes to smaller than 23mm, clamp timing turns so slowly that needle thread clamp error is caused.

– 49 –

4. Sub-class information

(1) Models classified by button sizes (LK-1903A)

Model name LK-1903A-301 LK-1903A-302 Optional

Button size classification For Extra-small button For large buttons

Outside diameter that can be adjusted (mm)

Sewing size (mm) Lengthwise (Y) 0~2.5 0~3.0 0~3.5 0~3.5 0~4.5 0~6.5

Crosswise (X) 0~2.5 0~3.0 0~3.5 0~3.5 0~4.5 0~6.5

Thickness (2.2) (2.2) (2.2) (3.2)

(mm) (2.7) (2.7)

Button clamp jaw lever Right (MAZ158070BA) F

(combination) — —

Part No.

Left (MAZ158080BA) F

Needle hole guide

(mm)

ø C

ø B

Feed plate MAZ15502000(8.5) ←

A (1.8) (1.8)

B ø2.8 (ø3.5) ø3.5 ø3.5 C ø1.6 (ø1.6) ø2.0 ø2.0

Part No. (14149900) (14149603) MAZ15601000 MAZ15701000

ø8~ø9 ø9~ø10 ø10~ø15 ø10~ø20 ø10~ø20 ø15~ø32

1.7 1.7 2.0 2.7

MAZ158070BB G 14148852 K 14149058 L MAZ157070BB D

——

MAZ158080BB G 14148951 K 14149157 L MAZ157080BB D

—— ——

1.6 1.6 1.6 1.4

MAZ15801000 (MAZ15501000)

— *(D2426284Y00)

For small buttons

(accessories)

*(0.9)

Engraving

(MAZ155070B0)B(MAZ155070B0)B(MAZ157070BA) (MAZ156070B0)C(MAZ156070B0) *(B25553720A0)

(MAZ155080B0)B(MAZ155080B0) (MAZ156080B0)C(MAZ156080B0) *(B25573720A0)

*(1.1)

For medium-sized

buttons

Engraving

—— — ——

MAZ15602000(10)

Engraving

C——

MAZ157080BA)

C——

MAZ15702000(12.5)

Engraving

ⓦ Items in ( ) are optional. ⓦ * For common use

Model name Option (LK-1903A-305)

Button type For shank buttons

Max. Sewing speed 1, 500rpm

Button configuration

Configuration

of shank

Sewing pattern number

Outside

diameter Diameter

of hole in

button

Position of

hole in

button

B (mm)

18, 19, 20, 21, 22

ø8~ø20

ø1.5 or more

149 338 5—7

1.5mm or more

A (mm)

Min. Max.

Optional parts for shank button

Part No. Names of part 14146054 Pick-up device complate D1401M1YC0A Needle bar (for TQ-1) MAZ160170A0 Wiper (asm.) 40015434 Moving plate link A 14148209 Bushing SL6030892TN (2 pcs.) Screw MAZ16015000 Button support link SD0640321TP Hinge screw 40010103 Connecting link SL6040892TN (2 pcs.) Screw MAZ16021000 Needle hole guide MTQ300B1400 Needle TQx3 #14

– 50 –

(2) Table of Standard Patterns (LK-1903A)

The number of stitches and the standard sewing lengths X and Y are as specified in the table below.

Pattern Stitch

No. sape (pcs.) X (mm) Y (mm) No. Sape (pcs.) X (mm) Y (mm)

1•34 6-6 18•44 6

2•35 8-8 19•45 8

3 10-10 20 10 3.4 0

4 12-12 21 12

5•36 6-6 22 16

6•37 8-8 23•46 6

7 10-10 24 10 0 3.4

8 12-12 25 12

Sewing thread

Standard length Standard length

Pattern Stitch

Sewing thread

Standard length Standard length

9•38 6-6 26•47 6-6

10•39 8-8 3.4 3.4 27 10-10

11 10-10 28•48 6-6

12•40 6-6 29 10-10

13•41 8-8 30•49 5-5-5

14 10-10 31 8-8-8

15•42 6-6 32•50 5-5-5

16•43 8-8 33 8-8-8

17 10-10

3.4 3.4

3.0 2.5

* Standard sewing lenghts X and Y given above are given assvming that the scale is 100.

Use the patterns No. 34~50 with hole diameter ø1.5mm or less.

– 51 –

5. Memory switches

The sewing machine operation can be changed by changing the setting of the memory switch.

(1) Memory switch start and change

1. When the key is pressed in the state that the sewing LED is turn off, the user level setting mode is assumed for the memory switches. When the key is continuously pressed for 6 seconds, the service level setting mode is assumed for the memory switches.

(Caution)In the case of continued pressing, the buzzer sounds

after 3 seconds and 6 seconds, respectively . The buzzer sound after 3 seconds indicates that the test mode has become effective.

2. The memory switch number can be modified with the and keys.

3. Select a required number of memory switch by pressing the key, then fix the number by pressing key to turn on the LED.

4. Change the contents of the memory switch with the and keys.

5. The factory shipment values can be recovered with the key.

6. The contents of modification can be registered by pressing the key. In this case, the sewing LED is turn off and the select condition of the memory switch number is recovered.

7. When the key is pressed, the memory switch setting mode is finished and normal operating conditions are recovered.

The upper 3 digits are used for the memory switch number.

The upper 2 digits are used for the contents of setting.

– 52 –

(2) Table of memory switch functions

Some initial values for shipment may change according to models. The contents are divided into two categories of user level (U) and service level (S).

Indication Level Functions Setting range Remarks

U Max sewing speed 400~3000rpm 3000 To be set at 2700 for the

(Setting possible in the unit of 100rpm)

U Sewing speed for the first stitch 400~1500rpm 1500

(with needle thread clamp) (Setting possible in the unit of 100rpm)

U Sewing speed for the second stitch 400~3000rpm 3000

(with needle thread clamp) (Setting possible in the unit of 100rpm)

U Sewing speed for the third stitchj 400~3000rpm 3000

(with needle thread clamp) (Setting possible in the unit of 100rpm)

U Sewing speed for the 4th stitchj 400~3000rpm 3000

(with needle thread clamp) (Setting possible in the unit of 100rpm)

U Sewing speed for the 5th stitch 400~3000rpm 3000

(with needle thread clamp) (Setting possible in the unit of 100rpm)

U Thread tension for the first stitch 0~200 200

(with needle thread clamp)

U Thread tension at the time of 0~200 0

thread trimming

State when

delivered

LK-1900AW and LK-1903A.

U Changeover timing of thread ten- –6~4 0

sion at the time of thread trimming (~–1:32°, 0:28°, 1:24°~)

U Sewing speed for the first stitch 400~1500rpm 400

(with needle thread clamp) (Setting possible in the unit of 100rpm)

U Sewing speed for the second stitch 400~3000rpm 900

(with needle thread clamp) (Setting possible in the unit of 100rpm)

U Sewing speed for the third stitch 400~3000rpm 3000

(with needle thread clamp) (Setting possible in the unit of 100rpm)

U Sewing speed for the 4th stitch 400~3000rpm 3000

(with needle thread clamp) (Setting possible in the unit of 100rpm)

U Sewing speed for the 5th stitch 400~3000rpm 3000

(with needle thread clamp) (Setting possible in the unit of 100rpm)

U Thread tension for the first stitch 0~200 0

(with needle thread clamp)

U Changeover timing of thread ten- –5~2 0

sion at the sewing start (~ –1: 64°, 0: 60°, 1: 56°~) operation becomes faster in the (with needle thread clamp) unit of 4°.

Display of Pattern No., XY enlargement/ reduction scale rate, and max. 1: Inoperative speed limits; change enabled/disabled memory switch, pressing M key, turn

U Counter operation 0: Production counter (addition) 0 (Standard operation panel)

U Selection of pedal 0: Standard pedal 0

0: Operative 0

1: Bobbin thread counter (subtraction)

1: Standard pedal (2-step stroke) 2: Optional pedal 3: Optional pedal (2-step stroke)

1: Optional pedal

When the setting value isincreased, eration becomes faster in the unit of 4°.

When the setting value is increased,

In case of setting 1, use of M key is prohibited as well. When changing

ON the power switch. (Standard operation panel)

op-

– 53 –

Indication Level Functions Setting range Remarks

Standard pedal, clamp switch position

Standard pedal, 2-step stroke switch position

Standard pedal, start switch position

50~200 70

50~200 120

50~200 185

State when

delivered

When the setting value is increased, the amount of pedal tread becomes larger.

U Optional pedal 1 operated 0: OFF when trodden again 0

U Optional pedal 2 operated 0: OFF when trodden again 0

U Height of work clamp foot at the 50~90 70

time of 2-step stroke

S Clamp lowering speed during pedal 100~4000pps 4000

operation (Setting possible in the unit of 10pps)

S Clamp rising speed during pedal 100~4000pps 1500 Too much rise in the setting

operation (Setting possible in the level may result in malfunction. unit of 10pps)

S Thread trimmer clamp rising spped 100~4000pps 3000 Too much rise in the setting

at the end of sewing (Setting level may result in malfunction. possible in the unit of 10pps)

U Pattern’s enlargement / reduction 0: Origin 0 The enlargement / reduction

reference point 1: Sewing start point point in the pattern data is

t is possible to stop sewing machine

operation with panel’s reset key. 1: Panel’s reset key

U Buzzer sound can be prohibited. 0: No buzzer sound 2

U No. of stitches for needle thread 1 ~ 7 stitches 2

clamp release

1: OFF when released

Height is lowered when the set value is increased.

effective only for 0 setting.

0: Disabled 0 2: External switch

1: Panel’s operation sound 2: Panel’s operation sound + Error sound

U Clamping timing of needle –10~0 0 Delayed in negative direction

thread clamp (~–1:84°, 0:80°) in the unit of 4°.

U Needle thread clamp control 0: Normal 0 Set at 1 for LK1903A.

disabled 1: Disabled

U Selection of feed operation timing. –8~16 12

Set in negative direction when the (~11:64°, 12:60°, 13:56°~) tightness of stitches is adverse.

U State of work clamp foot after 0: Work clamp foot goes up 1 LK-1903A/BR-35 to be set at 0

completion of sewing can be after moving at the sewing selected start.

1: Work clamp foot goes up immediately after the end of sewing 2: Work clamp foot goes up by pedal operation after moving attne sewing start. LK1903A

S Sewing is possible only with the 0: Normal 0

start switch, without raising the work 1: Work clamp foot rise clamp foot. disabled.

U Each time sewing is finished, origin 0: No origin retrieval 0

retrieval is possible. (Except for the 1: Origin retrieval enabled cycle sewing)

U Origin retrieval setting is possible 0: No origin retrieval 0

after cycle sewing. 1: Origin retrieval after the end

of one pattern. 2: Origin retrieval after the end of one cycle.

Delayed in negative direction in the unit of 4°. If set at extreme negative, there is danger of needle breakage. Significant when handling heavy materials.

– 54 –

Indication Level Functions Setting range Remarks

U State of work clamp foot when 0: Work clamp foot goes up. 0

machine stopped by temporary 1: Work clamp foot goes up stop command can be selected. with work clamp foot switch.

2: Lift of work clamp foot is prohibited.

U Needle bar stop position is set. 0: Up position (53°) 0 Needle bar rotates the reverse

1: Upper dead point (22°) direction after the UP position stop

S Selection of sewing machine 0:400rpm 1

rpm during thread trimming 1:800rpm thread spreading by moving knife.

S Selection of whether the thread 0: Feeding disabled. 1

is moved in the direction of easy 1: Feeding enabled. trimming.

S Needle hole guide diameter when 16~40 16

feeding is moved for thread cutting. (1.6mm~4.0mm) (1.6mm) (Setting possible in the unit of 0.2mm)

U Thread trimming can be disabled 0: Normal 0 After tentative stoppage, thread

at the end of sewing. 1: Thread trimming disabled trimming is not disabled.

State when

deivered

and stops when upper dead point stop is set.

This is the sewing machine rpm of the When the sewing machine has

stopped, thread trimmer is function.

When the setting value is increased, the amount of feeding becomes larger.

S Thread trimming can be disabled. 0: Normal 0 All thread trimming operation is

U The origin reset route can be 0: Linear reset 0

selected with the reset key. 1: Pattern returning

U Bobbin winding speed can be set 800~2000rpm 1600

(Setting possible in the unit of 100rpm)

U Operation timing of material 0: Output prohibited 2 For the machines other than

closing is selected. 1: (LK1901A only) comes down. indicated.

U Wiper operation method can be 0: Without wiper at the time of

selected. thread trimming on the way

S Magnet wipe-out time 10~500ms 50 Effective only if the magnet

(Setting possible in the unit of 10ms)

S Magnet wipe-in time 10~500ms 100

(Setting possible in the unit of 10ms)

S Wipe-out timing at the time of 0: Sewing machine returned 0 Effective only if upper dead

upper dead point stop and upper dead point stop point stop is selected.

U The stitching at the start of sewing 0: The stitching effective 0 For the machines other than LK-

of the pattern for button sewing 1: Tie stitching ineffective 1903A, thus function is not indican be prohibited. For LK-1903A only cated.

S Moving limit range in +X direction –20~20mm 20 In the state of shipment, no clamp

(right side) configuration is considered.

1: Thread trimming disabled disabled.

Operation when work clamp foot

Operation at the time of start

1: With wiper at the time of 1 thread trimming on the way

2: With wiper at the time of th- memory switch, wiper operation read trimming on the way 3: Magnet wiper

after wiper operation in up position. 1: Wiper operation after upper dead point stop

LK-1901A, this function is not

Without return of the last wiper

With return of the last wiper

(When the setting No. 37:1 of the method can not be used.)

wiper has been selected.

S Moving limit range in –X direction –20~20mm –20 In the state of shipment, no clamp

(left side) configuration is considered.

S Moving limit range in +Y direction –20~10mm 10 In the state of shipment, no clamp

(back side) configuration is considered.

S Moving limit range in –Y direction –20~10mm –20 In the state of shipment, no clamp

(front side) configuration is considered.

S Jump feed speed of XY 100~4000pps 2000

(Setting possible in the unit of 10pps)

– 55 –

Indication Level Functions Setting range Remarks

S XY feed forward / back speed 100~4000pps 500

(Setting possible in the unit of 10pps

S When the power supply is turned on, 0: Normal 0

oautomatic preparation is possible 1: Automatic preparation is without pressing the READY key. operated when the power

S While the needle stays in an upper 0: Holding disabled 0

position, a current is maintained in 1: Holding enabled the main motor to make the needle hard to down.

U Method of XY enlargement/reduction 0: % setting 0 Displayed only for the IP200

scale rate setting (IP200 only) 1: Size setting operation panel.

U The origin is moved toward the 0: Standard 0 This setting is needed when

front by 5mm. 1: 5mm closer to the front using the LK1904 presser foot

S No. of pulses for work clamp foot 30~60 45

interlock wiper operation

S The head falling detector switch 0: Normal 0

can be disabled. 1: Head falling detector switch

U This function sets whether or not 0: Calling inoperative Setting dep- Standard pattern Nos. 1 to 64

the calling of the pattern data is 1: Calling operative ends on the can be individually set operative.

S Initialization of model’s specifications 0:LK1900ASS Setting Contents of the memory switches

is executed. 1:LK1900AHS values are are initialized to the state when

U Grease-up error The number of stitches is Only clearing possible with the

)

supply is ON.

disabled

2:LK1900AFS specified delivered. 3:LK1900AMS at left 4:LK1901ASS according pattern is initialized to the state 5:LK1902ASS to models. when delivered. 6:LK1902AHS All the registrations patterns 7:LK1903ASS-301 and cycles are deleted. 8:LK1903ASS-302 9:LK1903ASS-311/BR35 10:LK1903ASS-312/BR35 11:LK1900AWS

counted based on drive, RESET key. sewing machine. Clearing should be done after

State when

delivered

and patterns.

model used. (Standard operation panel)

The thread tension of each standard

the completion of grease-up action.

U Pattern registration is carried out.

Cycle sewing registration is carried out.

S Test mode is assumed.

– 56 –

6. Test mode

When the test mode is started, it is possible to carry out maintenance and inspection.

(1) Test mode start

1. When the key is continuously pressed for 3 seconds in the state that the sewing LED is turn off, the buzzer sounds and test mode start can be selected, with the user level setting mode of the memory switch kept effective.

(Caution) The test mode cannot be selected unless the key is pressed

for more than 3 seconds.

2. Change the memory switch No. with the , keys to select the test mode.

3. Press the key. The selected test mode is assumed and a display output test can be started. In regard to the contents of the display output test, refer to (2) Display output test.

4. Press the key. The display output test is finished and operation moves to the selection of another test feature.

5. Select the test program No. by the use of the , keys.

Test program No. Test program Descriptions

Input signal check The conditions of switches and sensor inputs

are displayed at the LED.

XY motor / origin sensor check Inching operation of the X/Y motor, operation

of origin retrieval, and the status of X/Y origin sensors are displayed.

Continuous operation After the setting of continuous operational con-

ditions, the continuous operation mode is assumed.

Main motor rpm check The sewing machine is started based on the

preset rpm, and the measured rpm number is displayed.

Output check Output is maintained for the LK1901A material

drawing magnet.

Presser foot and thread trimmer Inching operation of the presser foot and thread motor and origin sensor check trimmer motor, operation of origin retrieval,

and the status of presser origin and presser sensors are displayed.

Needle thread clamp motor and Inching operation of the needle thread clamp motor, origin sensor check operation of origin retrieval, and the status of

needle thread clamp origin and needle thread clamp sensors are displayed.

Software version display The software versions of the MAIN and SDC

boards are displayed.

6. Press the key and define the test program number.

7. For each program, the test program can be closed when the key is pressed. The condition of 5. recovered. However, the continuous operation mode cannot be canceled if it is once assumed. To close this mode, it is necessary to turn off the power supply.

– 57 –

(2) Display output test

After moving to the test mode, the display output test is started. At the intervals of one second, the LEDs shown below are turn on.

– 58 –

(3) Method of confirmation according to each test program No.

1) CP-1 (Input signal check)

It is possible to check the input conditions of the respective operation panel keys, pedal switches, and various sensors.

Input No. display When the and keys are pressed simultaneously, the input number is updated by +1.

Item select LED turn on/turn off is used to display the input status. In regard to the contents of display, refer to the table shown below.

Contents of display for each input No.

Input No.

Pattern LED X enlarge LED Y enlarge LED Speed LED Counter LED

1 key key key key key key

2 ( key) key key key key key

3 DIPSW2-4 DIPSW2-3 DIPSW2-2 DIPSW2-1 (Pedal SW) Optional Optional› Optional

4 Pedal SW 8Pedal SW 7Pedal SW 6Pedal SW 5Pedal SW 4Pedal SW 3Pedal SW 2Pedal SW 5 Presser motor Y motor X motor

origin sensor origin sensor origin sensor

6 Upper needle Lower needle Lower needle Upper needle TG Feeding

7 Main motor

Phase Z (0~180°)

(Temporary stop)

dead point dead point position position (45 times/ standard

(5~30°) (185~215°) (80~123°) (40~62°) revolution) (125~155°)

Needle thread

clamp

origin sensor

Thread trimmer Needle thread

motor sensor clamp sensor

Bobbin winder LED

Clamp 2 SW Start SW Clamp SW

Head fall SW

Threading LED Tension LED

(Thermal sensor)

Turn on

DIPSW2 denotes a dipswitch on the MAIN board. Pedal SW 1 ~ 8 are lit up in the direction of 1 to 8 according to the amount of treading-on. [Pedal position = 128 x 8 + 64 x 7 + 32 x 6 + 16 x 5 + 8 x 4 + 4 x 3 + 2 x 2 + 1 x 1]

– 59 –

2) CP-2 (XY motor / origin sensor check)

Inching operation of the X/Y motor, operation of origin retrieval, and the status of X/Y origin sensors are displayed.

1. Preparation At first, press the key to start origin retrieval for needle thread clamp and work clamp foot/thread trimmer

motors. The presser foot assumes the lowering condition. After the completion of preparation, the sewing LED is turn on.

2. Operation

According to the conditions of the selected X/Y origin sensors, “0” or “1” is displayed. Changeover is possible by pressing the key.

Using the and keys, the selected X/Y motors are driven in the directions of +/- in 0.1mm steps.

(Caution) Because of circular interpolation, even the mo-

tors not selected are also driven.

Used to display whether the X motor (X origin sensor) or the Y motor (Y origin sensor) is selected. Changeover is possible by pressing the key. X enlargement / reduction scale rate LED lit: X motor (X origin sensor) Y enlargement / reduction scale rate LED lit: Y motor (Y origin sensor)

Used to change over the selective condition of the X motor (X origin sensor) or the Y motor (Y origin sensor) with the key.

Using the Start SW, origin retrieval of X/Y motors is effected for both shafts.

3) CP-3 (Continuous operation)

After the setting of continuous operation, the condition moves to the continuous operation mode. Turn off the power supply to close the continuous operation mode.

1. Rest time setting Press the and keys to set up the rest time. Setting is possible within the range of 0 ~ 9900ms in the unit of 100ms. (Initial value: 2000ms) After the completion of setting, press the key.

2. Origin retrieval enable/disable setting at the end of sewing Press the and keys to set up whether origin retrieval is enabled or disabled at the end of sewing.

A0: Disable (Initial value) A1: Every 100 sewing cycles A2: Every sewing cycle

After the completion of setting, press the key to recover ordinary display.

3. Continuous operation After the completion of setting, set up the pattern numbers, etc., in the same manner as that for ordinary operation. After the completion of sewing, origin retrieval of the X/Y/work clamp foot/thread trimmer/needle thread clamp motors is conducted if “origin retrieval enabled” has been set as per 2. above. In this case, automatic sewing operation is restarted after the lapse of the rest time specified as per 1. above. To stop continuous operation, press ON the Start SW during the rest time. [E 50] is displayed and operation is suspended.

– 60 –

4) CP-4 (Main motor rpm check)

Used to set up the sewing machine rpm. Only the main motor is driven at the preset rpm and the actually measured rpm number is displayed.

1. Preparation At first, press the key to start origin retrieval for needle thread clamp and work clamp foot/thread trimmer motors. After the completion of preparation, the sewing LED is turn on.

2. Operation

When the key is pressed, the sewing machine motor begins to run at the preset rpm. If the rpm setting is changed on sewing machine operation, speed change is possible to the preset rpm by pressing the key.

When the key is pressed, sewing machine operation stops.

The preset rpm number or the actually measured rpm number is displayed. Changeover is possible by pressing the key.

Using the and keys, it is possible to change the rpm number within the range of 400 ~ 3000rpm. This setting is possible even when the machine is presently driven.

The speed LED is turn off when the displayed rpm is maintained at the preset figure. It is turn on when the actually measured figure is displayed. Changeover is possible by pressing the key .

Using the key, the rpm display can be changed over between preset rpm and actual rpm.

5) CP-5 (Output check)

Output check is carried out for the material drawing magnet of the LK1901A.

1. Operation

While the key is pressed, the material drawing magnet ON output is generated.

– 61 –

6) CP-6 (work clamp foot/thread trimmer motor/origin sensor check)

Inching operation of the work clamp foot/thread trimmer motors, operation of origin retrieval, and the status of origin and thread trimmer sensors are displayed.

1. Preparation In the first place, the key is pressed to carry out origin retrieval of needle thread clamp. After operation for preparation, the sewing LED is turn on.

2. Operation

According to the status of the thread trimmer sensor, “0” or “1” is displayed.

According to the status of the work clamp foot origin sensor, “0” or “1” is displayed.

Using the and keys, the work clamp foot/thread trimmer motors are driven in the directions of +/- for each pulse.

Using the key, the work clamp foot/thread trimmer motor is driven to each specified position.

Work clamp foot rising position

Work clamp foot lowering position (lowering position during pedal operation)

Thread trimmer position

Work clamp foot lowering position (lowering position after thread trimming)

Wipe-out position Driving in reverse rotation is conducted when the key is pressed with the key kept pressed.

(Caution) This feature is available after the completion of ori-

gin retrieval of the work clamp foot/thread trimmer motors with the Start SW.

Origin retrieval of the work clamp foot/thread trimmer motors is carried out by the use of the Start SW.

7) CP-7 (Needle thread clamp motor / origin sensor check)

Inching operation of the needle thread clamp motor, operation of origin retrieval, and the status of needle thread clamp origin sensor and needle thread clamp sensor are displayed.

1. Operation

According to the status of the needle thread clamp sensor, “0” or “1” is displayed. According to the status of the needle thread clamp origin sensor, “0” or “1” is

displayed.

Using the and keys, the needle thread clamp motor is driven in the directions of +/- for each pulse.

Using the key, the needle thread clamp motor is driven to each specified position.

Standby position (front side)

Needle thread bending position

Needle thread clamp position

Refuge position (rear side)

(Caution) This feature is available after the completion of

origin retrieval of the needle thread clamp motor with the Start SW.

Origin retrieval of the needle thread clamp motor is carried out by the use of the Start SW.

– 62 –

8) CP-8 (Software version display)

The software versions of the MAIN and SDC boards are displayed. Each version comes in the type description of RR-VV-LL-xx. “xx” is used for the specifications of special ordering. It is not displayed usually. (Example: 01-01-01, 01-01-02, 01-02-01)

1. Operation

According to the item selection LED, RR-VV-LL-xx of the MAIN and SDC boards is respectively displayed. Changeover is possible by pressing the key. Contents of the display are shown in the table below.

Display changeover is possible with the key in the order of RR → VV → LL → (xx) → for the MAIN board and RR → VV →LL → (xx) → for the SDC board.

RR-VV-LL-xx display for the MAIN and SDC boards for each item selection LED

Pattern LED X enlarge LED Y enlarge LED Speed LED Counter LED

MAIN board MAIN board MAIN board MAIN board SDC board SDC board SDC board SDC board

RR VV LL xx RR VV LL xx

Bobbin winder LED

Threading LED

Tension LED

– 63 –

7. Miscellaneous

(1) Various printed wiring boards

1) FLT-T board Single-phase 100V~120V 3-phase 200V~240V Single-phase 200V~240V

Pulse generation is carried out for the purposes of power supply rectification, noise reduction, and the detection of a momentary interruption

Voltage changeover

CN1 : Power input ← Power switch

In the signal-phase mode, the power supply is connected to Pins 4-5. In the 3-phase mode, the power supply is connected to Pins 4-5-6.

Connected to 100V side for 100V~120V or to 200V side for 200V~240V.

CN3: Momentary interruption detection signal → MAIN board

CN2 : Power output → MAIN board

– 64 –

2) FLT-S board Single-phase 200V~240V Pulse generation is carried out for the purposes of power supply rectification, noise reduction, and the detection

of a momentary interruption

CN1: Power input ← Power switch

Since single-phase specifications are adopted, the power supply is connected to Pins 4-5.

CN3: Momentary interruption detection signal → MAIN board

CN2 : Power output → Main board

– 65 –

3) SDC board The power supply is generated and error check is carried out. Main shaft control is effected, receiving the com-

mands from the MAIN board.

F1: 5A Time lag fuse For +85V

F2: 3.15A

F4: 4A Fuse fixed to the board For +85V source primary

F5: 4A Fuse fixed to the board For +33V source primary

LED4: For power supply check

CN10: 24V for the fan

CN11: Power connector → MAIN board +5V, +12V, +24V, +33V, +85V

LED3: For operation and error check

Time lag fuse For +33V

F3: 2A Quick-action fuse For +24V

CN17: For power supply ← FLT board

CN16: For Main shaft motor power →Main shaft motor

CN15: For MAIN communication → Main board

CN14: For Main shaft encoder → Main shaft motor

DIPSW 2-1: For writing-off 2-2: For mode setting-off 2-3: For mode setting-off 2-4: For mode setting-off

CN13: For momentary interruption detection ← FLT board

DIPSW 1-1: For testing-off 1-2: For testing-off 1-3: For testing-off 1-4: Penetration force-off

– 66 –

4) LED3 for SDC board error check

No. of LED3 flashes Error description Display of operation panel Remarks Turn on Nil Dimly turn on in ordinary state 1 Main shaft motor lock E007 Failure in revolving for 2 seconds 2 Error in phase Z E303 Failure in phase Z detection 3 Error in phases A and B E730 Failure in phases A and B detection 4 5 IPM error E901 Error output generation from IPM 6 Undervoltage E813 Source voltage -20% or more 7 Motor reverse rotation E733 Irregular motor revolutions 8 Overvoltage E811 Source voltage +20% or more 9 Power interruption Display disabled Power interruption of 40ms or more 10 Not used 11 +85V power system error E903 SDC board fuse F1 blow-off 12 +33V power system error E904 SDC board fuse F2 blow-off 13 Overheasting E905 Radiator panel of SDC boaed heated

14 Not used 15 Communication erroe E916 Failure in comminication with the

Motor position sensor error

E731 Logical error in U, V, W

at 85°C or higher

MAIN board

– 67 –

5) MAIN board Overall controls are carried out, such as pulse motor driving for shafts, control of active tension, etc., memory

switch control, etc.

CN32: For the SDC board

CN49: Temporary stop (for OP)

CN45: Needle thread clamp PM (yellow)

CN47: Material drawing MG (LK-1901A)

CN46: For air (for OP)

CN36: For BR35

CN34: For the panel

CN38: For the INT board (head)

U11: LK-1900 PROM 27C256

CN44: Clamp PM (red)

CN39: Active tension

CN40: Pedal sensor

CN31: Power ← SDC board +5V, +12V, +24V, +33V, +85V

CN42: X feed PM (white)

CN41: Foot pedal (for OP)

CN43: Y feed PM (blue)

– 68 –

6) INT board The INT board repeats the head sensor signals and transfers the head model data to the MAIN board.

CN64: Presser bar lifter origin (black)

CN66: Thread trimmer operation (red)

CN65: Needle thread clamp origin Needle thread clamp operation (yellow)

CN62: X feed origin (red)

CN63: Y feed origin (yellow)

CN67: Fall switch (red)

Face F

The head model type (Memory switch No. 241), corrected value of the active tension, the number of stitches for grease-up (Memory switch No. 245), etc. are stored.

– 69 –

7) PANEL board The PANEL board accommodates the display LEDs, switches, buzzer, etc. together with the control CPU.

7-segment LED

Switch

Face F

CPU: IC socket mounted

Face R

Buzzer

– 70 –

(2) LK1900 data ROM

(3) Dipswitch setting

SDC board

SW1

The data ROM for the LK-1900 is used by inserting it in the IC socket that is located on the MAIN board.

(Cautions)1. Pay attention to the direction of inser-

tion.

2. EEPROM cannot be used.

3. If the pattern number is the same as that of the standard pattern, the pattern in the data ROM is in higher preference.

Available ROM

27C256 EPROM

JUKI part No.: HL008423000

1. The penetration force is increased when “4” of Dipswitch SW1 is turned ON on the SDC board

2. If the penetration force is insufficient for thick materials, this switch should be turned ON.

3. All other dipswitches should be turned OFF.

MAIN board

(Caution)Dipswitch changeover should be done af-

ter the power supply has been turned off.

4. All dipswitches on the MAIN board are turned OFF.

SW2

SW3

– 71 –

(4) Table of standard pattern specifications

1900A 1901A 1902A

NO Lengthwise Crosswise

1 (51) 2.0 16 42 Large size bartacking *

2 2.0 10 42 Large size bartacking * 3 2.5 16 42 Large size bartacking * 4 3.0 24 42 Large size bartacking 5 2.0 10 28 Large size bartacking * 6 2.5 16 28 Large size bartacking * 7 2.0 10 36 Large size bartacking * 8 2.5 16 36 Large size bartacking *

9 3.0 24 56 Large size bartacking 10 3.0 24 64 Large size bartacking 11 2.5 6 21 Small size bartacking * *

12 2.5 6 28 Small size bartacking * *

13 2.5 6 36 Small size bartacking * *

14 2.0 8 14 Knit goods bartacking * * 15 2.0 8 21 Knit goods bartacking * * 16 2.0 8 28 Knit goods bartacking * * 17 0 10 21 Straight line bartacking * * 18 0 10 28 Straight line bartacking * * 19 0 25 28 Straight line bartacking 20 0 25 36 Straight line bartacking 21 0 25 41 Straight line bartacking 22 0 35 44 Straight line bartacking 23 20 4.0 28 Lengthwise bartacking 24 20 4.0 36 Lengthwise bartacking 25 20 4.0 42 Lengthwise bartacking 26 20 4.0 56 Lengthwise bartacking 27 20 0 18 28 10 0 21 29 20 0 21 30 20 0 28 38 2.0 8 28 Knit goods bartacking * *

Number of stitches

Pattern S, F, H , W M S S, H

(eyelet)

Lengthwise straight line bartacking Lengthwise straight line bartacking Lengthwise straight line bartacking Lengthwise straight line bartacking

In the condition of delivery from the factory, the pattern sewing with * marks can be made. When using the standard patterns other than the patterns with * marks, refer to “Setting whether the calling of the pattern data is operative or not” described in the item of the how to use the memory switch.

– 72 –

(5) Table of standard patterns

Num-

(51)

Stitch diagram

ber of

stitches

Sewing size

(mm)

Length-

Cross-

wise

2.0 16

(Note) 2

No. of work clamp foot

1 2

Stitch diagram

Number of

Length-

stitches

Sewing size

(mm)

Cross-

wise

010

(Note) 2

No. of work clamp foot

1 2

Large size bartacking

2.0 10

2.5 16

3.0 24

2.0 10

2.5 16

2.0 10

2.5 16

3.0 24

010

2 1

025

7 1

Straight line bartacking

025

1 2

6 7 6 7

7 1 4

035

(Note) 3

(other side)

(This side)

20 4.0

(other side)

(This side)

20 4.0

6 7 6

Lengthwise bartacking

(other side)

(This side)

(Tis side)

20 4.0

Small size bartacking

Knit goods bartacking

2.5 6

2.0 8

(other side)

(This side)

(other side)

(This side)

(other side)

Lengthwise linear bartacking

(other side)

(This side)

20 0

10 0

20 0

(Note) 1. Se win g si ze shows the dimensions when

the scale rate is 100%.

2. Refer to the work-clamp type table indicated in the figure 8.-(3) in the separate sheet hereto.

3. For No. 22, process the work clamp foot blank for use.

4. Use the patterns with *marks for sewing denim.

5. No. 51 is for the machine used without thread clamp device.

– 73 –

Stitch diagram

Number of

stitches

Sewing size

(mm)

Length- Cross-

wise wise

710

Stitch diagram

Number of

stitches

Sewing size

(mm)

Length- Cross-

wise wise

20 2.5

Semilunar bartacking

712

610

612

10 7

324

Lengthwise bartacking

25 2.5

30 2.5

Large size bartacking

Knit goods

bartacking

Round

ø12

bartacking

(Note) 1. Patterns Nos. 41 to 46 are arranged for the

optional presser bar (No. 12).

2. The origin is different by 5mm from that of the lengthwise bartacking patterns Nos. 23 to 26.

Radial bartacking

148

164

30 2.5

ø8

– 74 –

8. Optional features

(1) Connection of PK-57

1. Connect PK-57 change cable with CN41 of MAIN circuit board .

2. Connect the cord of PK-57 with the PK-57 change cable at the rear face of the control box. Then clamp two places with adhesive clamp . In addition, tighten with a screw the PK-57 ground cable as illustrated in the figure.

PK-57 change cable : Part No. M90135900A0 PK-57 : Part No. GPK570010B0 Adhesive clamp : Part No. E9607603000

3. Set the memory switches as follows.

Memory Switch No. Set value

19 2 20 1 24 1

Ground cable

– 75 –

(2) Table of optional parts

Name of parts Type Part No. Remarks

Feed plate blank Without knurl/Processed 14120109 For the stitich size

30 x 20

With knurl/Processed 14120307 For the stitich size

30 x 20

t=1.2

Without knurl/stainless steel 14120505 t=0.8

For the stitich size 30 x 20

Work calmp foot face plate (asm.) 14121263 Face plate for

presser blank

Presser blank With knurl/processed 14121701 For the stitich size

(right) 30 x 20

With knurl/processed 14121800 For the stitich size

t=3.2

(left) 30 x 20

Needle hole guide A=1.6 B=2.6 With relief slit B2426280000 Standard type

A=1.6 B=2.0

Without relief slit

D2426282C00 F and M types

A=2.3 B=4.0

øB

øA

A=2.7 B=3.7

Without relief slit

14109607 For heavy-weight

D2426MMCK00 For extraheavy-

Finger guard (1) A=56.5 B=64 13533104

A=59 B=74 13548300 For large size

material

weight material

bartacking

– 76 –

Name of parts Type Part No. Remarks

Finger guard (2) A=66.5 B=43 14135305 For lengthwise

bartacking

Finger guard (3) A=21.5 B=35.5 14120000 For specially

ordered work clamp

SM8040302TP

– 77 –

(3) Table of the work clamp foot

No. of the work clamp foot

Work clamp foot

Feed plate

12345

13518659 (asm.) 13548557 (asm.) 13542964 (asm.)

14116107 14116404 14116800 14116305 14116206

(Without knurl) (Without knurl)

Sewing specification

SFFHM

* Finger guard 13533104

Remarks

Standard accessory Optional Optional Standard accessory for S (standard) for M (knit goods) type machine type machine head. head.

Spplied with F (foundation) type machine head. (Depends on the destination)

* Install a finger guard suitable for each work clamp foot when replacing the work clamp foot.

– 78 –

No. of the work clamp foot

6 7 8 9 10 11 12*

Work clamp foot

13548003 13554803 14116602 14116503 14116909 14116701 14137707

Feed plate

Sewing specification

13548151 (asm.)

13542451 (asm.)

13571955 (asm.)

13561360 (asm.)

14137509 (Right) 14137608 (Left)

( Without knurl) ( Without knurl) ( Without knurl) ( Without knurl)

SHSFFFF

* Finger guard

Remarks Optional Optional Optional Optional Optional

13548300 13533104 14135305

Standard accessory for H (heavyweight material) type machine

Standard accessory for F (foundation) type machine head.

head.

* Install a finger guard suitable for each work clamp foot when replacing the work clamp foot. * The presser bar No. 12 (optional) should be used for the standard patterns Nos. 41 to 46 (lengthwise

bartacking).

– 79 –

9. Maintenance

(1) Replacing the fuse

The machine uses the following three fuses:

For pulse motor power supply protection 5A (time-lag fuse) For solenoid and pulse motor power supply protection

3.15A (time-lag fuse) For control power supply protection 2A (fast-blow type fuse)

(2) 100V

3-phase 200/220/240V type and single-phase 100/110/120V type can be changed over by changing the power source cable and changing over of the jumper.

Changeover of jumper

200V setting

100V setting

↔↔

↔ 200V voltage specification changeover

↔↔

Change over the jumper in accordance with the voltage used. For the change of the connection of power source cable, refer to the item (Instruction manual (2)) of “Connecting the power source cord”.

(Caution) When a wrong connection such as putting

Jumper

200V type voltage at the time of setting 100V type or the like is performed, the printed circuit board is broken. Perform the change of connection after checking the voltage used.

– 80 –

(3) Greasing parts

(1) When the parts for greasing and grease sealing-in are disassembled and the operational frequency seems to be

higher than usual around these parts, grease should be replenished once every two years.

(2) Recommendable grease

This sewing machine uses four types of grease as specified below. The recommendable brands of grease are listed in (4) Parts to which grease is applied. According to this information, replenish the most applicable grease to these parts. * Use 1Lithium Type Consistency No. 2 for the parts where “Grease” is simply specified in (4) Parts to which grease is applied.

Penetration No. 2 lithium grease This type of grease is used in general sliding parts.

Maker name Brand name Esso: Listan 2, Beacon 2 Shell: Albania Nippon Oil Co., Ltd.: Multinok 2, Epinok 2 Kyodo Oil Co., Ltd.: Lisonix 2 Idemitsu Petrochemical Co., Ltd.: Coronex 2

Templex N2 --- Used for the feeding gear block. 10g tube JUKI Part No.: 13525506

Juki Grease A --- Used for high-speed sliding parts and their peripheral parts. 10g tube JUKI Part No.: 40006323

Juki Grease B --- Used, in particular, for the specific areas with highly loaded parts. Important: this grease must be replenished at the specified intervals of period, according to “(5) Grease-up procedures for the specified position.”

10g tube JUKI Part No.: 40013640

(3) Method of greasing

If no grease pump is available, fill a plastic oilcan with grease. Otherwise, an injector without a needle can be conveniently used.

– 81 –

(4) Parts to which grease is applied

1) Presser bar lifter area

Grease

2) Wiper area

Grease

Grease (Juki Grease A)

Grease

– 82 –

3) Thread tension area

4) Thread trimmer area

Grease

Grease (Juki Grease A)

– 83 –

Grease (Juki Grease A)

Grease

5) Feed area

Grease

(TemplexN2)

Grease

– 84 –

Grease (Templex N2)

6) Needle bar and main shaft area

Grease (Juki Grease A)

7) Lower shaft area

Grease (Juki Grease B)

Grease (Juki Grease A)

Grease (Juki Grease B)

– 85 –

Grease (Juki Grease A)

8) Needle thread clamp mechanism area

Grease

– 86 –

9) LK-1901A relations

Grease

– 87 –

Grease

10) LK-1903A relations

Grease

– 88 –

(5) Grease-up procedures for the specified position

Grease joint 40013451

When sewing operation is repeated for a certain time period, Error Code No. E220 is displayed at the operation panel when the power supply is turned ON. This error code is used for the indication of the grease replenishing time for the specified parts. When you see this error code, replenish the grease specified below, without fail. After greasing, call the memory switch No. 245 and set up “0” with the reset key. Even after the display of Error Code No. E220, this error code can be canceled by pressing the reset key and the machine can be used continuously. Since then, however, this Error Code No. E220 is displayed each time the power supply is turned on. When the sewing machine is used further for the specified time period after the display of Error Code No. E220, Error Code No. E221 is then displayed. In this case, this error code cannot be canceled even though the reset key is pressed, and the sewing machine cannot work anymore. Therefore, when this Error Code No. E221 is displayed, replenish the grease, without fail, to the parts specified below. Start the memory switch and set up the Memory switch No. 245 at “0” with the reset key.

Juki Grease B (10g contained) 40013640

Cautions: 1. If the memory switch No. 245 is not reset at “0” after the replenishment of grease, Error No.

E220 or No. E221 will be displayed again.

2. For the replenishment of grease to the parts specified below, use the attached Juki Grease B (Part No. 40013640). If any grease other than the specified item is replenished, this can be

a cause of destruction of parts.

1) Greasing to the eccentric cam area

1. Open the upper cover and take out the grease cover .

2. Remove the rubber cap that is located beside the

eccentric cam . Feed the specified grease (Juki Grease B ).

2) Greasing to the oscillator pin area

1. Lay down the sewing machine body and remove the

grease cover .

2. Remove the set screw of the oscillator gear

and screw in the Juki Grease B into the threaded hole. This grease tube is attached with an accessory grease joint . Then, the grease can be replenished. (The amount of grease to be replenished is 0.74 grams.)

3. After the grease has been replenished, firmly fasten

the set screw that has been removed.

– 89 –

10. Table of errors

Indication Name of error Description of error Corrective measure Remarks

Machine lock error The main shaft of the sewing machine Turn OFF the power switch and remove

does not rotate due to some troubles. the cause of troubles.

– 90 –

Pattern No. error Back-up pattern No. has not been registered

in the data ROM, or it is set to readout Check the contents of memory switch No. 201. inoperative. Pattern No. is set at “0”.

Needle bar UP position Needle bar is out of the needle UP position. Turn the hand pulley to return the needle error bar to its UP position.

Sewing area over The sewing area is beyond the limit. Press the reset switch and check the This error is output when

Enlargement error The sewing pitch is beyond 10mm. Press the reset switch and check the

Pattern data error The pattern data cannot be adopted. Turn OFF the power switch and check the

Temporary stop Temporary stop by operating the reset switch Re-start or return-to-origin after thread

while the sewing machnine is running. trimming by means of the reset switch (For (Refer to memory switch No. 31.) the details, refer to the item “Using the

Notice for the grease Indicates that it is the time to replenish Replenish the grease to the specified part 9. Refer to Maintenance replacement time grease to the specified parts. and set the memory switch No. 245 at [0] (5) “Replenishment of

Grease replenishment alarm The sewing machine stopped due to the Replenish the grease immediately and set 9. Refer to Maintenance error expiration of grease replenishment time to the memory switch No. 245 at [0] with the (5) “Replenishment of

the specified parts. reset key. grease-up procedures for the

Head tilt error Head tilt detection switch is turned ON. The sewing machine cannot be operated

Press the reset switch and check the pattern No.

pattern and X/Y scale rate. max. sewing area, 30 x 40

is over. Interference of the work clamp foot with needle is not protected

pattern and X/Y scale rate.

data ROM.

temporary stop function”, P.29.)

with the reset key. If the grease cannot be grease-up procedures for the fed soon in the middle of sewing work, the specified position.” error can be canceled by means of the reset key .

specified position.”

withe the head tilted. Return the sewing machine head to its proper position.

– 91 –

Indication Name of error Description of error Corrective measure Remarks

Z phase detection error Detection of the upper dead point of the Turn OFF the power switch and check whether

sewing machine cannot be performed. CN14 of SDC circuit board is disconnected

or loose.

Presser foot and thread Presser foot and the thread trimmer is not Turn OFF the power switch and check whether trimmer position error in the proper position. CN66 of INT circuit board is discoonected

or loose.

Needle tread clamp The needle thread clamp device is not in Turn OFF the power switch and check whether position error the proper position. CN65 of INT circuit board is disconnected

or loose.

Encoder trouble A Encoder A or B phase cannot be detected. Turn OFF the power switch and check whether

Cn14 is loose or disconnected.

Encoder trouble B Encoder U, V or W phase connot be Turn OFF the power switch and check whether

detected. CN14 i s l o o s e o r d isconnected.

Reverse rotation motor The motor is reversing. Turn OFF the power switch and check whether

coupling of the main motor is loose.

Overvoltage error Power source voltage is beyond the Check the power source voltage.

specified value.

Low voltage error Power source voltage is short. Check the power source voltage.

Motor driver trouble Error from the motor driver is detected. Turn OFF the power switch and turn ON the

power switch again after some time..

Stepping motor power Power source of the stepping motor is not Turn OFF the power switch and check F1 Check the cause of blownsource trouble output. fuse of SDC circuit board. out of the fuse.

Solenoid power source Power source of the solenoid is not output. Turn OFF the power switch and check F2 Check the cause of blowntrouble fuse of SDC circuit board. out of the fuse.

SDC circuit board Overheat of SDC circuit board Turn OFF the power switch and turn ON the overheat power switch again after some time.

MAIN circuit board Overheat of MAIN circuit board Turn OFF the power switch and turn ON the overheat power switch again after some time.

X origin retrieval error X origin sensor does not change. Turn OFF the power switch and check whether

CN62 of INT circuit board or CN42 of MAIN circuit board is disconnected or loose.

Indication Name of error Description of error Corrective measure Remarks

Y origin retrieval error Y origin sensor does not change. Turn OFF the power switch and check whether

CN63 of INT circuit board or CN43 of MAIN circuit board is discoonected or loose.

Work clamp foot origin Work clamp foot origin sensor does not Turn OFF the power switch and check whether retrieval error change. CN64 of INT circuit board or CN44 of MAIN

circuit board is discoonected or loose.

Needle thread clamp origin Needle thread clamp origin sensor does Turn OFF the power switch and check whether retrieval error not change. CN65 of INT circuit board or CN45 of MAIN

circuit board is discoonected or loose.

Feed trouble error Timing lag between feed and main shaft Turn OFF the power switch and check whether

has occurred. coupling of the main motor is loose.

– 92 –

Communication error between panel and MAIN MAIN cannot be performed. CN34 of MAIN circuit board is loose.

Communication error between panel and SDC cannot be performed. CN32 of MAIN circuit board or CN15 of SDC

MAIN memory write-in Memory write-in of MAIN circuit board Turn OFF the power switch and check the instrouble cannot be performed. rtion of ROM of U22 of MAIN circuit board.

INT memory write-in Memory write-in of the head circuit board Turn OFF the power switch and check whether trouble cannot be performed. CN38 of MAIN circuit board is disconnected

(No display) Abnormal power source Power source voltage type is different. Turn OFF the power switch and check the

Disconnection of connector The connector is disconnected. power source voltage and check whether

Comminication between the panel and Turn OFF the power switch and check whether

Comminication between MAIN and SDC Turn OFF the power switch and check whether

circuit board is disconnected or loose.

or loose

CN3 of FLT circuit board or CN13 of SDC circuit board is disconnected or loose.

11. Troubles and corrective measures

(1) Troubles and corrective measures (Mechanical parts)

Trouble Cause (1) Cause (2) Check and corrective measures

1. Wiper cannot spread a thread 1-1)Interference between wiper 1-A)Wiper mounting position is Adjust the wiper position.

2. Abnormal noise 2-1)Backlash between the oscillator Check oscillator gear positioning and adjust the

– 93 –

3. Deformation in sewn patterns 3-1)Too much backlash in the 1-A)Backlash is too much in the Adjust backlash of motor base.

and needle inadequate.

1-2)Displacement of front-rear 2-A) Wiper mounting position is Adjust the wiper position.

wiper position inadequate.

1-3)Thread holding before wiper 3-A)

action is inadequate. (insufficient

and the shuttle driver shaft is lower shaft gear backlash. large.

2-2)Too much clearance between Adjust the clearance between the shuttle and the

shuttle and shuttle driver shuttle driver.

Y feed gear Y feed arm and the motor base.

3-2)Too much backlash in the Adjust backlash of the X feed gear.

X feed gear

3-3)Travelling torque in X direction 3-A)The motor is pressed against Adjust backlash of the motor.

is excessive. the X feed arm too strongly.

The right left wiper mounting position distance to the needle).

Backlash is too much in the Y feed

1-B)

pulse motor and the motor base.

Adjust the wiper position

Adjust backlash of Y feed pulse motor.

3-4)Travelling torque in Y direction 4-A)The pulse motor is pressed Adjust backlash of the feed motor gear.

To the next page

3-B)The feed plate or the work Tighten the set screw further for the needle hole guide.

clamp foot is caught by the needle hole guide.

is excessive. against the Y feed shaft too

strongly.

4-B)Friction is excessive between Install the cloth feed support plate.

the Y feed arm and the cloth feed support plate.

4-C)The feed plate or the work Tighten the set screw further for the needle hole guide.

clamp foot is caught by the needle hole guide.

Trouble Cause (1) Cause (2) Check and corrective measures

From the previous page

3-5)Inadequate adjustment of the Adjust the X sensor position correctly.

X sensor position

3-6)Inadequate adjustment of the Adjust position of the Y slit plate correctly.

Y slit plate

4. Sewing machine locked 4-1)Large needle compared with Replace the needle hole guide.

5. Severe vibration 5-1)Inadequate crank balancer Define the correct crank balancer position.

6. Malfunction of vertical movement 6-1)Looseness of thread trimmer Define the thread trimmer cam position and fix the cam. of work clamp foot cam screw

– 94 –

the hole diameter of the needle hole guide

positioning

6-2)Presser pulse motor malfun- 2-A) Defective the presser pulse Replace the presser pulse motor.

ction motor.

2-B)The presser pulse motor is Check the connector connections.

wrongly connected.

6-3)Defective circuit board 3-A)Circuit board programming Replace the circuit board.

flaw.

3-B)Connector connections are Check the connector connections.

wrongly made.

(2) Troubles and corrective measures (Sewing conditions)

Trouble Cause (1) Cause (2) Check and corrective measures

1. Thread comes off at the start of 1-1) Stitch skipping at the 1st Decrease the sewing speed at the start of sewing. sewing stitch

1-A)Penetration registance of the Use a thinner needle. (Lower the needle count to be

thread against the cloth is small..

used.)

– 95 –

1-2) Length of thread remaining 2-A)

at the needle is not sufficient. an excessive tension.

1-3)Length of bobbin thread re- 3-A)

maining is not sufficient. needle hole guide and the (Otherwise, widen the gap.)

Tension controller No. 1 provides

2-B) Floating of the AT thread Adjust the amount of AT thread tension floating.

tension disc is insufficient.

2-C)Stroke of the thread take-up Adjust the stroke of the thread take-up spring.

spring is excessive.

2-D)The thread take-up spring Adjust the thread take-up spring tension.

tension is insufficient.

2-E) Level difference between the Adjust the height of the counter knife.

needle hole guide and the counter knife is excessively high.

2-F)Needle thread tension is high Adjust the needle thread tension.

and the thread is excessively stretched.

2-G)Thread spreading section of Polish the thread spreading section of the moving

the moving knife has scratches. knife with buff or replace the knife. Level difference between the

counter knife is excessively high.

3-B)Lower face of the needle hole Polish the needle hole guide with a buff or replace it.

guide has scratches.

3-C)

Thread spreading section of the moving knife has scratches. knife with buff or replace the knife.

Properly adjust the tension controller No. 1.

Adjust the height of the counter knife.

Polish the thread spreading section of the moving

To the next page

3-D)Shuttle upper spring has Polish the shuttle upper race with a buff or replace

scratches. it.

3-E)The bobbin thread tension is Adjust the bobbin thread tension.

excessive.

3-F)The bobbin or bobbin case Polish it with a buff or replace it.

has scratches.

– 96 –

Trouble Cause (1) Cause (2) Check and corrective measures

From the previous page

1-4)Material to be sewn is not Remove the slack of the material to be sewn.

properly stretched.

1-5)Unstable needle thread clamp 5-A) Thread tends to be extended Increase the needle thread clamp needle number to

or sliding efficiency is worse. 3~4 stitches.

Lower the speed of the first stitch. (600 ~ 1000rpm)

5-B)

Pitch of the first stitch is too small.

1-6)Threading the needle bar Refer to the item “Threading the needle bar thread

thread guide is wrong. Guide”.

1-7)Bobbin runs idle and the bobbin Use a stronger idling prevention spring.

thread is drawn out.

7-A)Initial positioning of the mov- Adjust the initial position of the moving knife.

ing knife is inadequate.

Lower the needle thread tension of the first stitch. Increase the pitch of the first stitch.

2. Needle breakage 2-1)Inadequate clearance between Adjust the clearance between needle and shuttle driver. the shuttle driver and the needle

2-2)Inadequate clearance between Adjust the clearance between the needle and the

the needle and the inner hook. inner hook.

2-3) Feed timing is defective 3-A)Feed timing is slow in regard

to the work pressure.

2-4)Needle coming in contact Adjust the moving knife position.

with the moving knife

2-5)Needle coming in contact Adjust the wiper position.

with the wiper

2-6)Needle is bent 6-A) The needle thread tension is Adjust the tension to a proper level.

too high.

6-B)The presser bar treads on the Increase the crosswise clearance between the wiper

needle thread at the beginning and the needle. 23 ~ 25mm of sewing and the wiper is caught.

2-7) Needle is too thin.

Change the feed timing by the use of the memory switch.

Adjust the work clamp foot (feed bracket) position.

Change the needle No. to the suitable one to the material.

juki LK-1900A, LK-1901A, LK-1902A, LK-1903A INSTRUCTION MANUAL

Specifications and Main Features

Frequently Asked Questions

User Manual

PREFACE

CONTENTS

1. Specifications

2. Configuration

(1) Names of main unit

(2) Names and explanation of switches on the operation panel

3. Standard adjustment

(1) Main shaft connection/disconnection

(2) Removal of the main shaft motor and coupling

(3) Crank connecting rod connection / disconnection

(4) Crank balancer positioning

(5) Lower shaft backlash adjustment and connection/disconnection

(6) Oscillator gear positioning

(7) Adjustment of hook oil amount

(8) Large hook connection / disconnection and oil wick piping

(9) Adjusting the height of the needle bar

(10) Hook adjustment

(11) Thread trimmer cam position adjustment and connection / disconnection

(12) Thread trimmer and presser foot origin sensor adjustment

(13) Adjusting the lift of the work clamp foot

(14) Adjusting the thread trimmer sensor

(15) Adjustment of the moving knife and counter knife position

(16) Adjusting the height of the moving knife and counter knife

(17) Inclination of the blade point of the counter knife

(18) Floating amount of the thread tension disk

(19) Second thread tension connection / disconnection

(20) AT unit connection / disconnection

(21) Position of the mechanical origin

(22) Adjusting the Y origin sensor

(23) Adjusting the X origin sensor

(24) Adjusting the wiper position

(25) Adjusting the wiper spring (LK-1903A only)

(27) Installing the feed plate support plate

(28) Installation of the feeder bar rear cover

(29) Adjustment of the bobbin winder driving wheel position

(30) Adjusting the bobbin winder amount

(31) Adjustment of the hook upper spring position

(32) Shuttle felt

(33) Shape of the shuttle race ring

(34) Adjustment of the thread take-up spring

(35) Needle thread clamp device connection/disconnection

(36) Adjusting the needle thread clamp sensor

(37) Adjusting the needle thread clamp notch

4. Sub-class information

(1) Models classified by button sizes (LK-1903A)

(2) Table of Standard Patterns (LK-1903A)

5. Memory switches

(1) Memory switch start and change

(2) Table of memory switch functions

6. Test mode

(1) Test mode start

(2) Display output test

(3) Method of confirmation according to each test program No.

1) CP-1 (Input signal check)

2) CP-2 (XY motor / origin sensor check)

3) CP-3 (Continuous operation)

4) CP-4 (Main motor rpm check)

5) CP-5 (Output check)

6) CP-6 (work clamp foot/thread trimmer motor/origin sensor check)

7) CP-7 (Needle thread clamp motor / origin sensor check)

8) CP-8 (Software version display)

7. Miscellaneous

(1) Various printed wiring boards

1) FLT-T board Single-phase 100V~120V 3-phase 200V~240V Single-phase 200V~240V

2) FLT-S board Single-phase 200V~240V Pulse generation is carried out for the purposes of power supply rectification, noise reduction, and the detection

3) SDC board The power supply is generated and error check is carried out. Main shaft control is effected, receiving the com-

4) LED3 for SDC board error check

5) MAIN board Overall controls are carried out, such as pulse motor driving for shafts, control of active tension, etc., memory

6) INT board The INT board repeats the head sensor signals and transfers the head model data to the MAIN board.

7) PANEL board The PANEL board accommodates the display LEDs, switches, buzzer, etc. together with the control CPU.

(2) LK1900 data ROM

(3) Dipswitch setting

(4) Table of standard pattern specifications

(5) Table of standard patterns

8. Optional features

(1) Connection of PK-57