JUKI MB-1800, MB-1800A Engineer's Manual

Page 1

Dry-head Type, High-speed, Computer-controlled, Single Thread, Chainstich Button Sewing Machine (with Automatic Thread Trimmer and Knot-tying Mechanism)

MB-1800 MB-1800A

ENGINEER’S MANUAL

29345105

No.00

Page 2

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 Adjutment”, and other important information which are not covered by the Instruction Manual. It is advisable to use the revevant Instruction Manual and Parts List together with this Engineer’s Manual when carrying out the maintenance of these machines.

Page 3

CONTENTS

1. SPECIFICATIONS...................................................................................................................................1

2. NAME OF EACH COMPONENT.............................................................................................................2

(1) Name of the main unit ................................................................................................................................................. 2

3. OPERATION OF THE SEWING MACHINE ............................................................................................3

(1) Names of the operation panel switches .................................................................................................................... 3

(2) Pattern table ................................................................................................................................................................. 4

(3) How to operate and use the memory switch (User level) ........................................................................................ 5

4. STANDARD ADJUSTMENT ...................................................................................................................6

(1) Height of the needle bar.............................................................................................................................................. 6

(2) Positioning the needle and the looper....................................................................................................................... 6

(3) Timing the travel of the yoke slide............................................................................................................................. 8

(4) Timing of the tension disc No. 2 ................................................................................................................................ 8

(5) Lift and pressure of the button clamp ..................................................................................................................... 10

5. ADJUSTMENT OF THE THREAD TRIMMING MECHANISM ..............................................................10

(1) The mechanism and the name of each component of the thread trimmer .......................................................... 10

(2) Adjusting the position of the moving knife............................................................................................................. 12

(3) Adjusting the height of the thread separating claw of the moving knife ............................................................. 12

6. PROCEDURES IN DISASSEMBLING AND ASSEMBLING ................................................................14

(1) Name of each component ......................................................................................................................................... 14

(2) Disassembling the circuit board .............................................................................................................................. 16

(3) Disassembling the machine arm and bed ............................................................................................................... 18

(4) Disassembling the looper shaft ............................................................................................................................... 20

(5) Disassembling the driving shaft .............................................................................................................................. 22

7. ADJUSTMENT OF THE SENSORS......................................................................................................26

(1) Adjusting the starting sensor................................................................................................................................... 26

(2) Adjusting the presser lifter sensor .......................................................................................................................... 26

(3) Adjusting the feed origin sensor ............................................................................................................................. 28

(4) Adjusting the presser lifter stopper......................................................................................................................... 28

8. HOW TO OPERATE AND USE THE MEMORY SWITCH (SERVICE LEVEL) ....................................30

(1) Memory switch function table .................................................................................................................................. 31

9. HOW TO OPERATE AND USE THE INPUT CHECK MODE FUNCTION ........................................... 33

(1) INPUT CHECK CORRESPONDENCE TABLE .......................................................................................................... 34

10. HOW TO OPERATE AND USE THE ALL CLEAR FUNCTION ........................................................... 35

11. PARTS TO BE GREASESD..................................................................................................................36

12. ERROR LIST .........................................................................................................................................37

13. CHANGE-OVER OF THE POWER SOURCE VOLTAGE .................................................................... 38

14. CAUSE OF TROUBLES AND THE CORRECTIVE MEASURES.........................................................39

(1) Thread trimming troubles and the corrective measures ....................................................................................... 39

(2) Cause of troubles and the corrective measures for MB-1800 ............................................................................... 40

15. CIRCUIT BOARD DIAGRAM ................................................................................................................41

(1) MAIN circuit board..................................................................................................................................................... 41

(2) PWR circuit board ..................................................................................................................................................... 42

(3) PANEL circuit board.................................................................................................................................................. 42

16. BLOCK DIAGRAM 1/2 ..........................................................................................................................43

17. CONNECTION DIAGRAM AND CIRCUIT DIAGRAM ..........................................................................45

(1) Power connection diagram....................................................................................................................................... 45

(2) Sensor connection diagram ..................................................................................................................................... 46

(3) Motor circuit diagram ................................................................................................................................................ 47

(4) Encoder circuit diagram ........................................................................................................................................... 48

(5) Solenoid circuit diagram........................................................................................................................................... 48

18. DRAWING OF THE TABLE ..................................................................................................................49

Page 4

−1−

1. SPECIFICATIONS

1) Sewing area : X (lateral) direction 10 mm Y (longitudinal) direction 6.5 mm (0.2 mm pitch)

2) Max. sewing speed : 1,800 rpm

3) Feed motion of button clamp : Intermittent feed (2-shaft drive by stepping motor)

4) Needle bar stroke : 48.6 mm

5) Needle : TQx7, TQx1 (TQx7 #16 at the time of delivery)

6) Button size : 10 to 28 mm

7) Lift of button clamp : Standard 10 mm Max. 14 mm

8) Memory of pattern data : EEP-ROM (32K byte)

9) Enlargement/reduction system : Increase/decrease of stitch length system

10) Limitation of sewing speed : Sewing speed can be optionally limited to 400 to 1,800 rpm with the up/down key. (Adjustable in 100 rpm unit)

11) Pattern selection function : 1 to 99 patterns can be specified by selecting the pattern Nos.

12) Memory back-up : In case of a power interruption, the pattern being used will be automatically stored in memory.

13) Sewing machine motor : 100W servo motor (direct-drive)

14) Dimensions of machine head : W : 240 mm L : 550 mm H : 360 mm

15) Mass : 25 kg

16) Power consumption : 150 W

17) Operating temperature range : 5 to 35˚C

18) Operating humidity range : 35 to 85% (no dew condensation)

19) Line voltage : Rated voltage ±10% 50/60 Hz

20) Noise : Workplace - related noise at sewing speed n= 1,800 min-1 : LPA ≦ 80 dB(A) Noise measurement according to DIN 45635-48-B-1.

＊ Reduce the max. sewing speed in accordance with the sewing conditions.

Page 5

−2−

2. NAME OF EACH COMPONENT

(1) Name of the main unit

• Machine head

• Electrical components

• Operation panel

• Thread stand

• Button tray

• Power switch

• Starting pedal

Page 6

−3−

3. OPERATION OF THE SEWING MACHINE

(1) Names of the operation panel switches

1 Set ready switch

This switch is used when making the sewing machine from setting status to sewing possible status.

2 Button clamp lifting switch

This switch performs up/down of the button clamp.

3 Stitch shape selection LED

4 Stitch shape selection switch

This switch is used when changing the stitch shape.

5 ＋/ Forward switch

This switch increases the set value or performs traveling forward when confirming the feed.

6 −/ Backward switch

This switch decreases the set value or performs traveling backward when confirming the feed.

7 Item selection switch

This switch is used when selecting the item desired to be changed.

8 Item selection LED

9 Reset switch

This switch returns the various set values to the original status or performs release when an error occurs.

!0 Display section A

Page 7

−4−

(2) Pattern table

Three same sewing sizes and numbers of stitches for each stitch shape have been stored in pattern Nos. 1 to 51 at the time of delivery. By selecting sewing size and number of stitches from the table below, the stitch shape can be changed to the three different kinds of patterns of the same stitch shape and be stored in memory.

Pattern No.

1 2 3

4 5 6

7 8 9

10 11 12

13 14 15

16 17 18

19 20 21

22 23 24

25 26 27

28 29 30

31 32 33

34 35 36

37 38 39

40 41 42

43 44 45

46 47 48

49 50 51

4-holed ( , crossover stitch : with)

4-holed ( , crossover stitch : without)

4-holed ( X, crossover stitch : with)

4-holed ( X, crossover stitch : without)

4-holed ( Z, crossover stitch : with)

2-holed (crosswise)

2-holed (lengthwise)

4-holed ( , crossover stitch : with)

4-holed ( , crossover stitch : without)

3-holed ( )

2-holed (crosswise) label attaching

Wrapped-around (crosswize size : 4 mm)

Wrapped-around (crosswise size : 5 mm)

Wrapped-around (crosswise size : 6 mm)

Initial value

2.6

10.0

2.6

Range

2.0 to 6.5

2.6, 2.8, 3.0

6.0, 8.0, 10.0

0.0 to 6.5

Unit

0.2

2.0

0.2

Initial value

Range

15, 19, 23, 27

16, 20, 24, 28

15, 19, 23, 27

16, 20, 24, 28

15, 19, 23, 27

8, 10, 12, 14

15, 19, 23, 27

16, 20, 24, 28

17, 23

5, 7

6, 10, 16

Stich size (mm) Number of stitches

Stich shape

Page 8

−5−

(3) How to operate and use the memory switch (User level)

1) The speed up to 3rd stitch can be set so that the sewing speed at the start of sewing is controlled and the stitch is stabilized.

2) Effective/ineffective of the knot-tying functon can be selected.

3) Operating/non operating of the wiper can be selected. In case the wiper is installed and set to the non-operating setting, when the pattern without crossover thread is selected, the wiper works only when the crossover thread is trimmed, and it does not work after thread trimming at the time of completion of sewing. In case of the pattern with crossover thread as well, the wiper does not work after thread trimming at the time of completion of sewing with this setting. In case of the setting of operating the wiper, the wiper always works at the time of thread trimming.

1 Starting of the memory switches

In the state that ＋/− switches 2 are simultaneously pressed, turn ON the power, and the memory switches are in the state of setting.

At this time, “ ” is displayed in display section A 3. Press set ready switch 5 and all 5 stitch shape selection LEDs 9 flash on and off. This state means

that the memory switches are being inputted.

2 Setting procedure of the memory switches

There are the memory switches 1 to 8. Switch N0. “ ” is displayed in the display section A 3 and item selection LED !0 of the pattern No.

lights up. In this state, press item selection switch 4, and the memory switch No. and the description are alternately displayed in display section A 3.

In the state that the memory switch No. is displayed, press the ＋ switch 8 and the memory switch No. increases by one. When the description of the memory switch is displayed, item selection LED !0 of the pattern No. goes off.

When setting is completed, turn OFF the power. Return ON the power to return to the normal setting state.

Remarks 400 to 1,800 rpm 400 to 1,800 rpm

400 to 1,800 rpm

400 to 1,800 rpm 400 to 1,800 rpm

400 to 1,800 rpm

Switch No.

1 2 3 4 5 6 7 8

Description Speed of 1st stitch of soft start Speed of 2nd stitch of soft start Speed of 3rd stitch of soft start Speed of 1st stitch after trimming crossover thread Speed of 2nd stitch after trimming crossover thread Speed of 3rd stitch after trimming crossover thread Knot-tying function 0 : Ineffective 1 : Effective Wiper operation 0 : Non operating 1 : Operating

Initial setting 18＊ 100 [rpm] 18＊ 100 [rpm] 18＊ 100 [rpm] 18＊ 100 [rpm] 18＊ 100 [rpm] 18＊ 100 [rpm]

1 (Operating)

0 (Non operating)

Setting range

4 to 18 4 to 18 4 to 18 4 to 18 4 to 18 4 to 18

0.1

Page 9

−6 −

(1) Height of the needle bar

The upper engraved line of the two engraved lines for TQx1 and TQx7 should be aligned with the bottom of the lower bushing when the needle bar is at its lowest position.

4. STANDARD ADJUSTMENT

(2) Positioning the needle and the looper

1) Looper timing When the needle bar is ascending from its lowest position and the lower engraved line on the needle bar is aligned with the bottom of the lower bushing, the looper’s blade point should coincide with the center of the needle. (When the needle bar is ascending.)

2) Clearance between the needle and looper The clearance is 0.05 to 0.1 mm when the looper’s blade point coincides with the center of the needle.

3) Clearance between the needle guide and needle The clearance between the needle guide and needle is 0.05 to 0.1 mm when the needle bar is at its lowest position.

Height of the needle bar

For TQx1

Engraved line (upper engraved line)

Lower bushing

Looper timing

Lower bushing

Engraved line

Looper’s blade point coincides with center of needle.

Clearance between needle and looper

0.05 to 0.1 mm

Looper’s blade point

Clearance between needle guide and looper

Needle guide

0.05 to 0.1 mm

Screw

Standard Adjustment

Page 10

−7 −

™ If the needle bar is too high, skipped

stitches will be produced. If the needle bar is too low, the needle will come in contact with the looper.

1) Adjusting the looper timing ™ Loosen the two screws 3 in the looper and cam sleeve

and adjust in the rotating direction of the looper and cam sleeve so that the looper’s blade point aligns with the center of the needle when the lower engraved line of the needle bar is aligned with the bottom of the lower bushing. Then tighten the screws 3.

2) Clearance between the needle and looper

Loosen two screws 4 in the looper support ring and adjust in the longitudinal position of the looper when the looper’s blade point is aligned with the center of the needle. Then tighten the screws 4.

3) Clearance between the needle guide and needle

Loosen the screw 2 in the needle guide 1 and adjust in the longitudinal position of the needle guide 1 so that the clearance between the needle guide 1 and needle should become 0.05 to 0.1 mm when the needle bar is at its lowest position. Then tighten the screw 2.

™ If the clearance between the needle

and looper is too excessive, it is likely to produce skipped stitches. If the clearance is too small, in accordance with the material used, the needle will come in contact with the looper resulting in needle breakage and looper’s blade point breakage.

™ For thick materials and overlapped

sections, adjust the clearance between the needle guide and needle so that the needle guide touches the needle by 0.1 to 0.2 mm.

1) Slightly loosen knob 1 and turn cover 2 in the direction

of the arrow and you will find hand pulley 3.

2) Turn the hand pulley by hand, loosen setscrew 4 in the

needle bar thread-take up lever and adjust so that the upper engraved line of the two engraved lines on the needle bar aligns with the bottom of the lower bushing when the needle bar is at its lowest position.

Adjustment Procedures Results of Improper Adjustment

Page 11

−8 −

(3) Timing the travel of the yoke slide

1) Crosswise travel timing of the yoke slide

The height of the descending needle bar is 53 to 58 mm when the yoke slide advances and begins to travel from the right to the left (TQx7). (In case of TQx1, 43 to 48 mm)

2) Lengthwise travel timing of the yoke slide

The yoke slide should go back immediately after the blade point of the looper has passed the thread triangle. And, it is good for the looper to go back like a slant line of the movement of the triangle.

3) Lengthwise positioning of the yoke slide

Position the yoke slide so that the blade point of the looper passes through the center of the thread triangle. (Use a 4-hole button, 9 or 10 stitches for positioning.)

(4) Timing of the tension disc No. 2

The tension disc No. 2 should float when the height of ascending needle bar becomes 54 to 57 mm. (In case of TQx1, 44 to 47 mm)

Needle bar

53 to 58 mm

Advances and begins to travel from right to left.

It is good for the looper to go back like a slant line.

Yoke slide

(Begins to travel from right to left.)

Blade point of looper

54 to 57 mm

Begins to float

Screw driver

Needle bar

Standard Adjustment

Page 12

−9 −

™ For adjusting the timing of the travel of the yoke slide,

align the engraved marks of the loop positioning finger cam and the triangle loop positionig finger cam with the engraved mark of the cam and looper sleeve after completing the adjustment of looper so that the engraved marks are on a straight line. Then temporarily tighten the screw.

1) Adjust the crosswise travel timing of the yoke slide in the

rotational direction of the triangle loop positioning finger cam. When the timing is higher than 58 mm (48 mm), adjust the timing in the rotational direction of the cam. And when it is lower than 53 mm (43 mm), adjust in the reverse rotational direction. The center of the cam is aligned with the center of the yoke slide support in the longitudinal position of the cam.

2) Adjust the lengthwise travel timing of the yoke slide in the

rotational direction of the loop positioning finger cam. For the triangle movement of the yoke slide, it is good for the yoke slide to go back in a slant line. When the yoke slide goes back like a swollen line, adjust the cam in the reverse rotational direction, and when it goes back like a hollow line inside, adjust the cam in the rotational direction.

3) Adjust the longitudinal position of the yoke slide by moving

the loop positioning finger cam in the lengthwise direction.

™ If the triangle loop positioning finger

cam begins to travel too late, thread breakage, thread remaining, baloon stitch, and insufficient tightness of stitches will result. On the contrary, if it begins to move too early, the needle will come in contact with the yoke slide.

™ If the loop positioning finger cam

begins to go back too early, the retreat of the yoke slide will become like a swollen line and the looper will hook the thread twice.

™ On the other hand, if it begins to retreat

too late, its retreat will become like a hollow line and the needle will come in contact with the yoke slide.

™ If the longitudinal position of the yoke

slide is improper, the looper will hook the thread twice or the needle will come in contact with the yoke slide.

™ Loosen the adjusting nut of the tension post No. 2 and

insert a screwdriver into the tension post No. 2 to adjust the timing. The timing of the start of floating is when the thread tension is lost after passing the thread through the thread tension No. 2, holding it with fingers and turning the handwheel by ha

™ If the thread tension is released too

early, thread remaining and/or poor tightness of stitches will result. On the other hand, if the timing of thread tension release is too late, thread will break.

Looper

Engraved points

Triangle loop positioning finger cam

Cam and looper sleeve

Loop positioning finger cam

Yoko slide retreats like a swollen line.

Yoko slide retreats

like a hollow line.

Screw driver

Timing of start of floating is when thread tenshon is lost at the time of needle bar ascending.

Nut

Adjustment Procedures Results of Improper Adjustment

Page 13

−10 −

(5) Lift and pressure of the button clamp

1) Lift of the button clamp A Standard : 12 mm

Max. : 9 mm

2) Pressure of the button clamp

Adjust the position of the pressure adjusting nut to 4 to 5 mm.

4 to 5 mm

5. ADJUSTMENT OF THE THREAD TRIMMING MECHANISM

(1) The mechanism and the name of each component of the thread trimmer

Throat plate

Presser lifter solenoid

Thread trimming arm

Thread trimming lever

Presser lifter sensor

Presser lifter link

Presser lifter lever

Standard Adjustment

Page 14

−11 −

1) The knife moves in accordance with the lifting of the button

clamp. Therefore, the length of the remaining thread on the wrong side of a fabric depends upon the height of the button clamp at which the thread is trimmed. For the adjustment, insert something of 10 mm thick into section A and make a state that button clamp jaw levers 1 are lifted . Loosen screw 2 and tighten screw 2 to fix the button clamp in the state that lifting hook 3 is pressed to the lower side.

Make adjustment by turning the pressure adjusting nut 1.

™ Increasing the lifting amount of the

button clamp will increase the length of the remaining thread. Especially in case of MB-372, thread tightness becomes strong at the end of sewing resulting in thread breakage and thread slip-off.

™ If the lifting amount of the button clamp

is too low, the length of the remaining thread will become short resulting in thread slip-off.

™ If the pressure of the button clamp is

too low, the thread end at the start of sewing will come out on the wrong side of the fabric unevenly by 10 to 20 mm.

Adjustment Procedures Results of Improper Adjustment

Page 15

−12 −

(2) Adjusting the position of the moving knife

Adjust the position so that the distance between the thread trimming connecting plat (front) and the edge of the slot in the throat plate should be 12 to 13 mm when the button clamp is at its highest position.

(3) Adjusting the height of the thread separating claw of the moving knife

Make adjustment so that the clearance between the thread separating claw 1 and the looper 2 should become 0.5 to 0.7 mm.

0.5 to 0.7 mm

Top end of thread separation nail

Standard Adjustment

Page 16

−13 −

1) Remove cover 1 with setscrew 2.

2) In order to place thread trimming connecting plate A 9 to

the most advanced position, lift the presser lifter lever to such an extent that roller 4 and hook 5 of presser lifter lever 3 come in contact with each other and insert spanner 6 as shown in the figure on the left.

3) Insert gauge 7 into the end face of the throat plate groove,

loosen screws 8, make the top end of thread trimming connecting plate A 9 come in contact with gauge 7, and tighten screws 8.

™ If the thread separating claw is too high,

the claw may fail to separate the thread on the needle from that on a fabric. As a result, thread may not be trimmed, or the both threads are trimmed together, causing thread slippage from the needle in the subsequent stitching start.

™ If this dimension is excessively large,

the thread trimming timing is delayed and the remaining thread on the wrong side of cloth is lengthened. If the dimension is excessively small, the thread trimming timing

becomes too

early, thread trimming

failure such as poor tightness of stitche (easily frayed) at the last stitch, simultaneous thread trimming of two threads due to the failure of thread separation, no thread trimming, etc. is apt to occur.

™ Make adjustment by bending the thread separating claw

Adjustment Procedures Results of Improper Adjustment

Page 17

−14 −

6. PROCEDURES IN DISASSEMBLING AND ASSEMBLING

(1) Name of each component

Feed needle bearing

Needle bar upper bushing

Needle bar clamp

Needle bar lower bushing

Yoke slide

Triangle loop positioning finger cam

Loop positioning finger cam

Needle bearing

Thrust bearing

Rocking rod fulcrum shaft

Screw gear

Crank rod hinge screw

Crank rod

Procedures in disassembling and assembling

Page 18

−15 −

Cautions in disassembling Cautions in assembling

Page 19

−16 −

(2) Disassembling the circuit board

1) Cover components

2) Circuit board components

Control box cover

Side cover

POWER circuit boardMAIN circuit board

POWER circuit board

Setscrew 1

MAIN circuit board

Setscrew 3

Circuit board installing plate

Collar

Setscrew 3

Setscrew 2

Procedures in disassembling and assembling

Page 20

−17 −

Disassembling and assembling of the circuit board Disassembling

1) Remove the control box cover and the side cover. Remove all connectors connected to the circuit board.

2) Loosen setscrews 1 by 2 to 3 mm.

3) Remove setscrews 2, hold the circuit board installing plate by hand and draw it out in the direction of the arrow and you can remove the circuit board in the state that it is connected to the circuit board installing plate.

4) Remove 8 setscrews 3, and MAIN circuit board and POWER circuit board can be removed.

Assembling

1) Assemble in the order of MAIN circuit board, collar, circuit board installing plate, collar and POWER circuit board.

Cautions in disassembling Cautions in assembling

Page 21

−18 −

(3) Disassembling the machine arm and bed

1) Bed components

2) Arm components

• Rubber base • Crank rod

Stud

Base cover

Rubber base

• Starting spring • Throat plate

Starting lever spring

Setscrew

Bed connecting bolt

Procedures in disassembling and assembling

Page 22

−19 −

Disassembling and assembling the machine arm and bed Disassembling

(Note) When disassembling the machine arm and bed,

remove the whole set of the circuit board. For removing procedure of the circit board, see the item “Disassembling the circuit board” P.16.

1) Tilt the machine head, remove the rubber base, stud and setscrews, and remove the cover and packing.

2) Remove the screws in the crank rod.

3) Again, directly attach four studs to the machine bed and place the rubber base.

4) Raise the machine head, loosen four setscrews in the throat plate and remove the throat plate.

(Note) At this time, if the screws in the thread trimming

connecting plate are removed, it is necessary to again adjust the position of the moving knife when assembling.

5) Remove the starting lever spring.

6) Remove the arm/bed connecting bolts and remove the machine arm while rocking and lifting it. Finally, remove the knock pins.

Assembling

1) Hold the machine arm and place it on the surface of the machine bed so that the thread trimming connecting plate and the crank

rod are placed in the

predeterminded

positions on the

machine bed.

2) After entering the knock pins and determining the position, enter the connecting bolts to fix the machine arm.

3) Hook the starting lever spring.

4) Install the throat plate.

5) Tilt the sewing machine, remopve the rubber base and studs, enter the base cover and packing and again assemble it. At this time, move the sensor slit attached to the stepping motor to the position as shown in the figure below.

6) Raise the sewing machine and assemble the circuit board. Refer to the item of “Circuit board” P.16.

Fig.

Cautions in disassembling Cautions in assembling

Page 23

−20 −

(4) Disassembling the looper shaft

1) Disassembling

2) Screw gear components

3) Adjustment

Screw gear

Looper support screw

Oil seal

Loop positioning finger cam setscrew

Needle bearing

Thrust collar

Looper installing shaft

Triangle loop positioning finger cam

Looper shaft

Thrust collar

Thrust bearing

Needle bearing

Thrust bearing

Loop positioning finger cam

Thrust collar

0.01 to 0.5 mm

43.5 mm

0.01 to 0.5 mm

Procedures in disassembling and assembling

Page 24

−21 −

Disassembling and assembling the looper shaft Disassembling

1) Disassemble the machine arm and bed. Refer to the item “Disassembling the machine arm and bed” P.18.

2) Remove the throat plate and remove the components related to the yoke slide and the looper. (Same components as those of MB-373)

3) Loosen the setscrews of the screw gear and tilt the machine bed.

4) Loosen the setscrews of the thrust collars and draw out the looper shaft in the direction of the arrow mark (f).

Assembling

1) Fully apply grease to the inside of the bushing. (It is not necessary when filling grease with grease gun or the like from the grease hole on the surface of the machine bed after setting up.)

2) Enter two thrust collars and the screw gear on the looper shaft.

3) Fit the thrust collars at the position where the dimension from section A to top end B of looper shaft is 43.5 mm.

4) The thrust collar in the front side is for prevention of slip-off of the needle bering. Press the looper shaft backward (in the direction of the arrow a) and fix it so that a clearance of 0.1 to 0.5 mm is provided between the thrust collar and the bushing.

5) Raise the sewing machine and tighten the screw gear. At this time, adjust the thrust play of the looper shaft to 0.01 to 0.5 mm.

6) Assemble the components related to the looper and the yoke slide. (Same adjustment as that of MB-373)

Cautions in disassembling Cautions in assembling

Page 25

−22 −

(5) Disassembling the driving shaft

• Disassembling

1) For the removing procedure of the circuit board, base cover and crank rod, see P.18.

2) Bushing and stator setscrew

4) Motor cover 5) Driving shaft (asm.) 6) Encoder

7) Stator 8) Rotor 9)

Setscrew and bushing of screw gear

• Assembling

1) Screw gear 4) Rotor 5) Stator

8) Bushing

Motor cover

Ball bearing

Encoder

Driving shaft bushing, left

Ball bearing

Servo-motor

Stator setscrew

Bushing setscrew

Screw gear

Crank rod

Thrust bearing

Driving shaft bushing, right

Ball bearing

4 to 4.2 mm

7.6 to 7.8 mm

Stator setscrew

Stator

Thrust bearing

Screw gear

Hand pulley

Bushing, rightBushing, left

7.7 mm

Procedures in disassembling and assembling

Page 26

−23 −

Disassembling and assembling of the driving shaft

(Note) Do not disassemble the driving shaft except

when it has broken since since the motor is built in.

Disassembling ＊＊ Prepare before disassembling a clean board which is

not affected by magnetism and a piece of clean cloth so that the rotor is not directly touched by hand.

1) Remove the circuit board. See the item “Circuit board” P.16. Tilt the sewing machine, remove the base cover and remove the setscrews in the crank rod.

2) Loosen setscrews in the bushing, setscrews in the stator and loosen the hand pulley.

3) Assemble again the studs and the rubber base, and raise the sewing machine.

4) Remove setscrews in the motor cover and draw out the whole driving shaft.

5) Put the driving shaft which has been drawn out on a clean board which is not affected by magnetism.

＊＊ Once again pay attention to the following matters before

disassembling the driving shaft which has been drawn out. 1 Chech whether there is anything such as iron powder

or the like which is attracted by the magnet in the neighbourhood.

2 Check whether there is any electronic apparatus

which is easily affected by the magnetism.

3 Prepare a piece of clean cloth to wrap the rotor. 4 Wash the hands to make them clean.

6) Loosen setscrews and draw out the encoder together with the motor cover.

7) Draw out the stator from the driving shaft. Pressing the driving shaft, slowly draw out the stator with force on the board since the stator is pulled by the strong magnetism from the rotor located inside the stator.

(Note) If the force is quickly applied, the stator and the

rotor come off suddenly at the position where the magnetism is lost. As a result, the parts may be dropped. So, be careful.

8) Hold the rotor so that it is wrapped in a piece of clean cloth, loosen the setscrew, and draw it out from the driving shaft. Wrap the rotor which has been drawn out in a piece of cloth.

(Note) The black section of the rotor is a strong

magnet. If there is a screwdriver or a screw in the neibourhood, it is attracted to the manet with force. As a result, it may be broken by the shock. So, be careful.

9) Loosen the setscrew in the screw gear, and remove bushings, right and left, thrust bearing and hand pulley.

Assembling

1) Install the screw gear. (Clearance : 4 to 4.2 mm)

2) Enter the thrust bearing and the bushings, and install the hand pulley.

3) Install the rotor. Hold it so that the screw section comes out and install it so that there is no clearance in the thrust direction.

4) In this state, enter the rotor in the machine bed. Do not take the cloth covering the rotor.

5) Next, enter the stator. Set the direction of the cord as shown in the figure and slowly enter the stator while pressing the driving shaft. When the magnetism of the rotor works, the stator enters with force as if it is absorbed. On the contrary, the driving shaft tries to jump out. Accordingly, hold the driving shaft by hand.

6) Install the motor cover. Keep the setscrew in the encoder held loosened.

7) Tilt the sewing machine.

8) First, determine the position of the bushing on the right-hand side. Fix it so that the dimension from the end face of the machine bed is 7.7 mm.

9) Next, fix the bushing on the left-hand side while making the driving shaft come in contact with the bushing on the right-hand side.

10) Fix the crank rod.

11) Remove the studs and the rubber base and again assemble them together with the base cover and the packing. At this time, move the sensor slit attached to to the stepping motor. For the position of the sensor slit, refer to the figure on P.19.

Cautions in disassembling Cautions in assembling

Page 27

−24 −

(5) Disassembling the driving shaft

• Assembling and adjusting procedure of the servo-motor

15) Stator setscrew 16) Cord outlet 17) Operation panel

18) Panel display 20) Fixing stator 21) Encoder

23) Encoder setscrew 24) Encoder “0” display

Stator setscrew

Cord outlet

Encoder installing screw

Driving shaft setscrew

Procedures in disassembling and assembling

Page 28

−25 −

12) Raise the sewing machine and install the circuit board. Refer to the item “Circuit board”. P.16.

13) Connect all connectors with the side cover removedand install the control box cover.

14) Tilt the sewing machine. Turn the hand pulley to bring the needle bar to its lowest position.

15) Check that the stator setscrew is loosened.

16) Enter the stator cord so that it comes to the cord outlet. At this time, do not fix the stator.

17) Pressing three buttons (arrow mark, “-”, and arrow mark from the top) located on the left end of the operation panel, turn ON the power.

18) [no] is displayed in the display section of the operation panel.

19) In this state, the stator is in the excitation mode, and the rotor and the stator are fixed. At this time, “W” phase and “V” phase of the rotor are excited. Excitation duty is 20% and current value is approximately 4 [A].

20) In this state, turn again the hand pulley and adjust so that the needle bar is brought to its lowest position. Fix the stator in this state. The rotor and the stator have come to the most proper position since they are pulling each other.

21) Raise the sewing machine. Enter the hexagonal wrench key when the encoder setscrew is at the position as shown in the figure. (Encoder should be temporarily tightened in the center of the slot.)

22) Pressing the three buttons located on the left side of the operation panel, turn ON the power.

23) Loosen the driving shaft setscrews of the encoder and fix them at the position where the setscrew No. 1 comes almost just above. (The position just above overlaps with the encoder screw. Tighten the screw at the slighly front side.) Hand tightening

24) Loosen the encoder setscrews, adjust the position to “0” while observing the operation panel. Then tighten the setscrews. (The value varies –9 to +9.) 20 to 40 kgf

25)Turn OFF the power and install the side cover.

26) Tighten the stator setscrew.

Cautions in disassembling Cautions in assembling

Page 29

−26 −

(1) Adjusting the starting sensor

7. ADJUSTMENT OF THE SENSORS

(2) Adjusting the presser lifter sensor

Needle

Presser lifter sensor plate setscrew

Presser lifter lowering sensor LD1

Presser lifter lifting sensor LD4

Moving knife

Setscrew

Presser lifter sensor

Thrust collar

Starting lever

Sensor slit

Starting sensor

Sensor slit

Starting sensor plate setscrew

Starting lever

Starting lever bracket setscrew

Starting sensor

Starting lever stopper

Starting lever bracket

Standard Adjustment

Page 30

−27 −

(1) Adjusting the starting sensor

1) Loosen the starting sensor plate setscrews.

2) In the state that the starting lever comes in contact with the starting lever stopper, adjust so that the sensor slit does not pass the sensor and is as high as the sensor, and fix the starting sensor plate setscrews. (20 to 30 kgf)

3) For the crosswise direction, loosen the starting lever bracket setscrews and adjust so that the sensor slit of the starting lever passes the center of the sensor.

4) When the aforementioned adjustment cannot complete the adjustment, loosen the sensor slit setscrews and adjust the position of the sensor slit.

(2) Adjusting the presser lifter sensor

1) Remove the top cover and the control box cover.

2) Tilt the sewing machine. (When the machine is put in this state, the sewing machine does not rotate if the starting pedal is depressed by mistake when adjusting with the power switch ON.)

3) Turn ON the power switch and press the presser lifter switch, and loosen presser lifter sensor plate setscrews 1 with the presser lifted.

4) When the sewing machine is in the starting possible position (position where moving knife does not come in contact with needle), adjust so that LD1 on the MAIN circuit board goes out, then lights up, and fix the sensor with the setscrews.

5) Check that LD4 on the MAIN circuit board goes out, then lights up when the presser is lifted by 2 to 3 mm from the throat plate with the knot-tying adjusting plate.

Adjustment Procedures Results of Improper Adjustment

Page 31

−28 −

(3) Adjusting the feed origin sensor

Sensor slits are in the same direction.

(4) Adjusting the presser lifter stopper

Sensor slit

Setscrew

Origin sensor

Origin sensor installing plate setscrew

Origin sensor, left LD2

Origin sensor, right LD3

10 mm

Standard Adjustment

Page 32

−29 −

(3) Adjusting the feed origin sensor

1) Remove the hinge screw attached to the machine arm, enter the sensors in the hole of the feed plate, and fix them with the screw hole in the bed.

2) Tilt the sewing machine.

3) Turn ON the power switch. (Remove the control box cover.)

4) Loosen the origin sensor installing plate setscrews.

5) Fix the left-hand sensor as observed from the front of the sewing machine at the position where LD2 on the MAIN circuit board goes out, then lights up. (30 to 40 kgf)

6) Fix the right-hand sensor as observed from the front of the sewing machine at the position where LD3 on the MAIN circuit board goes out, then lights up. (30 to 40 kgf)

(4) Adjusting the presser lifter stopper

1) Loosen the nut and adjust so that the distance from the end face of the machine arm to the end face of the presser lifter stopper should be 10 mm.

Adjustment Procedures Results of Improper Adjustment

Page 33

−30 −

8. HOW TO OPERATE AND USE THE MEMORY SWITCH (SERVICE LEVEL)

The operation to adapt the various specifications, more stabilized stitching, etc. can be performed by selecting or changing the various operations, various timings, time, etc. of the sewing machine.

1) Pressing – /Backward switch and + /Forward switch, turn ON the power, and the display section becomes as shown below. Then the mode will be the display model of the user level. At this time, all of the stitch shape selection LED and the item selection LED flash on and off.

2) In this state, keep pressing – /Backward switch and + /Forward switch for 5 seconds. Then the display section becomes as shown below, and the mode will be the display mode of the service level. At this time, all of the stitch shape selection LED and the item selection LED flash on and off.

3) When the display mode of the service level appeared, press Set ready switch . Then the display section becomes as shown below, and the memory switch No. 1 is displayed. The mode becomes the setting mode of the service level. At this time, all of the stitch shape selection LED flash on and off and only the pattern No. LED of the item selection LED lights up.

4) Here, select the memory switch No. desired to be changed by pressing down – /Backward and + /Forward switches. In this state, press Item selection switch and the display section becomes as shown below (when the memory switch No. 1 is selected). Then set value corresponding to the memory switch No. is displayed. At this time, all of the stitch shape selection LED flash on and off, and the pattern No. LED of the item selection LED goes out. In addition, when Item selection switch is pressed again, the state of step 3) will appear.

5) In this state, set the value to the one desired to be changed by pressing down – /Backward and + /Forward switches. When the setting has been completed, turn OFF the power.

Display section

(Flashing display)

Display section

(Flashing display)

Display section

(Light-up display)

[Memory switch No. 1]

[Soft-start speed setting]

Display section

(Light-up display)

[Set value of memory switch No. 1]

Page 34

−31 −

(1) Memory switch function table

Unit

x100 [rpm]

0 : Ineffective 1 : Effective

x10 [deg]

[sec]

x10 [msec]

Setting range

4 to 18

0/1

0 to 40

0 to 10

0 to 20

2 to 20

Setting level

User

Service

Setting

initial value

Memory

switch No.

Soft start speed setting (1st stitch at the sewing start)

Soft start speed setting (2nd stitch at the sewing start)

Soft start speed setting (3rd stitch at the sewing start)

Soft start speed setting (1st stitch at the sewing start after trimming crossover thread)

Soft start speed setting (2nd stitch at the sewing start after trimming crossover thread)

Soft start speed setting (3rd stitch at the sewing start after trimming crossover thread)

Knot-tying function selection

Wiper function selection

Knot-tying solenoid ON timing angle setting (When memory switch No. 7, knot-tying function is selected)

Knot-tying solenoid OFF timing time setting (When memory switch No. 7, knot-tying function is selected)

Wiper solenoid ON timing time setting (When memory switch No. 8, wiper function is selected)

Wiper solenoid ON hold time setting (When memory switch No. 8, wiper function is selected)

Speed of 1st stitch at the sewing start can be limited.

Speed of 2nd stitch at the sewing start can be limited.

Speed of 3rd stitch at the sewing start can be limited.

Speed of 1st stitch at the sewing start after trimming crossover thread can be limited.

Speed of 2nd stitch at the sewing start after trimming crossover thread can be limited.

Speed of 3rd stitch at the sewing start after trimming crossover thread can be limited.

Drawing out thread at the sewing end is stopped and thread can be knotted.

When the without-crossover thread device is mounted, needle thread after thread trimming can be wiped. In case the without-crossover thread device is mounted and the pattern without crossover thread is selected at setting “0” : ineffective, needle thread is automatically wiped only after trimming crossover thread (medium thread trimming).

Knot-tying solenoid ON timing angle (upper dead point of one stitch before the last stitch is regarded as 0˚) can be changed.

Period of time of

Knot-tying solenoid OFF timing can be changed.

Period of time from thread trimming to wiper solenoid ON timing can be changed.

Period of holding time from wiper solenoid ON can be changed. As the number is increased, the operating time of wiper becomes longer.

Setting item

Contents of setting

Page 35

−32 −

Unit

x10 [deg]

x10 [msec]

–

[msec]

–

x10 [msec]

Pulse

x10 [msec]

–

[deg]

0 : Hole position 1 : Medium position

Setting range

0 to 40

0 to 20

0 to 10

30 to 90

0 to 10

10 to 40

-9 to 9

5 to 20

0 to 10

-9 to 9 0/1

Setting level

Service

Service Service

Service

Setting

initial value

6 0

Memory

switch No.

45 46 47

Thread trimming operation setting (1)

Thread trimming (presser lifting) solenoid ON timing time setting

Presser lifting holding force setting

Thread trimming operation setting (2)

[Crossover thread trimming when without crossover thread pattern is selected (medium thread trimming), or thread trimming when memory switch No. 8, wiper function is selected.]

Thread trimming operation setting (3)

[Crossover thread trimming when without crossover thread pattern is selected (medium thread trimming), or thread trimming when memory switch No. 8, wiper function is selected.]

Thread trimming operation setting (4)

[Crossover thread trimming when without crossover thread pattern is selected (medium thread trimming), or thread trimming when memory switch No. 8, wiper function is selected.]

Thread trimming position setting (1)

Thread trimming position setting (2)

Thread trimming operation setting (1) [For BR]

Thread trimming operation setting (2) [For BR] Feed pulse delivery timing setting

Thread trimming position function selection

Thread trimming (presser lifting) solenoid ON timing angle (upper dead point of one stitch before the last stitch is regarded as 0˚) can be changed. As the number is increased, the thread trimming timing is delayed. As the number is decreased, thread trimmer may interfere with needle. So, be careful.

Do not change.

Holding force when the presser goes up can be changed. As the number is increased, the holding force is strengthened.

Thread trimming operation can be adjusted. As the number is increased, operating force of thread trimming is strengthened. However, the presser foot may rise. So, be careful.

Do not change.

Thread trimming position can be adjusted. Thread trimming position is determined by the set value of memory switch No. 40, thread trimming position setting (1) or No. 41, thread trimming position setting (2).

Thread trimming operation can be adjusted. As the number is increased, operating force of thread trimming is strengthened.

Do not change. Do not change.

Thread trimming position can be selected.

Setting item

Contents of setting

Page 36

−33 −

9. HOW TO OPERATE AND USE THE INPUT CHECK MODE FUNCTION

Troubles, defects, etc. of the printed circuit boards and elements can be checked by displaying the input state of the various sensors and switches.

1) Pressing Set ready switch and Reset switch, turn ON the power. (“Function No. 1” is displayed.)

2) When Item selection switch is pressed down, the state of input assigned to “Function No. 1” is displayed.

3) In this state, when the feed mechanism, detecting plate, etc. are moved, the display changes in accordance with the input state of the origin sensor. In this case, when the display is “1”, the origin sensor is in the input state of OFF and when the display is “0”, the origin sensor is in the input state of ON.

4) When performing checking of other function No, press down Item selection switch again and the display becomes the display state of step 1). In this state, select the function No. you desire to check by ptressing down – /Backward and + /Forward switches and perform the operation of step 2).

Display section

(Flashing display)

Display section

(Light-up display)

[Example of display]

(Caution) Input of the origin sensor of feed stepping motor is assigned to “Function No. 1”. In this case,

left-hand side (10th digit) of the display section, as observed from the front of the sewing machine, is the input state of the origin sensor of left-hand side stepping motor, and righthand side (1st digit) of the display section, as observed from the front of the sewing machine, is the input state of the origin sensor of right-hand side stepping motor.

Page 37

−34 −

(1) INPUT CHECK CORRESPONDENCE TABLE

Function

No.

Left-hand side of display section

(10th digit)

Origin detection sensor (Left stepping motor)

: ON, : OFF [CN20-2]

Presser lifting detection sensor

: ON, : OFF [CN30-2]

Pedal start SW

: ON, : OFF [CN22-2]

STMG (Input signal for BR)

: ON, : OFF [CN24-2]

Pedal start SW

: ON, : OFF [CN28-2]

Not used.

[CN27-2]

Operation panel : Reset SW

: ON, : OFF [CN25-17]

Operation panel : − /Backward SW

: ON, : OFF [CN25-19]

Operation panel : Set ready SW

: ON, : OFF [CN25-22]

Not used.

[CN25-24]

SW1-1 (DIP SW)

: ON, : OFF

SW1-3 (DIP SW)

: ON, : OFF

SW1-5 (DIP SW)

: ON, : OFF

SW1-7 (DIP SW)

: ON, : OFF

Right-hand side of display section

(1st digit)

Origin detection sensor (Right stepping motor)

: ON, : OFF [CN21-2]

Presser lowering detection sensor

: ON, : OFF [CN30-5]

Not used.

[CN23-2]

WMG (Input signal for BR)

: ON, : OFF [CN24-4]

Pedal presser SW

: ON, : OFF [CN28-5]

Not used.

[CN27-5]

Operation panel : Stitch shape selection SW

: ON, : OFF [CN25-18]

Operation panel : ＋ /Forward SW

: ON, : OFF [CN25-20]

Operation panel : Presser SW

: ON, : OFF [CN25-23]

Overheat monitoring sensor

: ON, : OFF [CN29-1]

SW1-2 (DIP SW)

: ON, : OFF

SW1-4 (DIP SW)

: ON, : OFF

SW1-6 (DIP SW)

: ON, : OFF

SW1-8 (DIP SW)

: ON, : OFF

Page 38

−35 −

10. HOW TO OPERATE AND USE THE ALL CLEAR FUNCTION

All of the data (size, number of stitches, etc.) of each pattern No. and the set value of the memory switch can be cleared and returned to the set value at the time of delivery. However, when this operation is performed, all the up-to-date data are deleted. So, be careful

1) Pressing Presser lifting switch and Reset switch, turn ON the power and the display section becomes as shown below.

2) In this state, press Reset switch and the display section becomes as shown below. Then data deletion operation starts.

3) When the data deletion operation has been completed, the display section becomes as shown below, and the flashing is changed to light-up state. At this time, turn ON the power again after turning OFF the power, and the set value is returned to the one at the time of delivery.

Display section

(Flashing display)

Display section

(Light-up display)

Display section

(Light-up display)

Page 39

−36 −

11. PARTS TO BE GREASESD

Apply or fill up grease to the following parts.

Crank rod hinge screw

Rocking rod fulcrum shaft

Needle bar upper bushing

Needle bar clamp

Needle bar lower bushing

Yoke slide

Triangle cam

Loop positioning

finger cam

Needle bearing

Thrust bearing

Screw gear

Crank rod

Feed needle bearing

Page 40

−37 −

12. ERROR LIST

Error No.

01 02

05 06 07

09 10

16 17 18

30 31 32 33

Item

Trouble of sewing data Trouble of 24V voltage

Dislocation of needle up-position

Dislocation of presser down detection

Trouble of presser solenoid Trouble of servo encoder Servo motor lock

System trouble Trouble of stepping motor origin 1

Trouble of stepping motor origin 2

Overload of servo motor

Trouble of nember of revolution Trouble of servo voltage Trouble of temperature

Overcurrent of servo motor

Trouble of external ROM Trouble of external ROM Trouble of external ROM Trouble of external ROM

Temperature rise

Trouble of memory

Description

Pattern has not been inputted in the program of cycle stitching. Trouble of power voltage, trouble of load on main shaft of machine head, trouble of

PWR circuit board Trouble of load on main shaft of machine head, trouble of encoder,or loosenes of

encoder fixing screw Foreign materials under presser, dislocation of presser down sensor, or defective

down sensor Defective solenoid, dislocation of presser up sensor, or defective up sensor Defective encoder or improper fixing of encoder Trouble of load on main shaft of machine head, or defective servo motor

Defective control circuit board or defective program ROM Trouble of origin sensor 1, dislocation of sensor, or trouble of load on stepping

motor 1 (left side of operator) Trouble of origin sensor 2, dislocation of sensor, or trouble of load on stepping

motor 2 (right side of operator) Trouble of load on main shaft of machine head (short time), or defective servo

motor Trouble of load on main shaft of machine head (long time), or defective servo

motor

Defective control circuit board, defective encoder, or defective servo motor Defective PWR circuit board Cleaning of fan filter, excessive load on main shaft, or trouble of control circuit

board (high temperature of pre-driver) Defective servo motor, or improper timing of encoder

ROM formatting error Number of stitches (99) is over. Moving amount of one stitch (lengthwise : 6.5 mm, crosswise : 10 mm) is over. Outside of sewing possible area

Cleaning of fan filter, defective fan operation, or defective control circuit board (temperature detection)

Defective control circuit board (EEPROM)

Error LED located on the left side of the reset switch flashes on and off or lights up when an error occurs. When the LED lights up, the setting state will be made by pressing the reset switch and the error will be released. Error No. will be displayed in the display section A.

(Note) Error Nos. 01, 03, 04, 31, 32, and 33 return to the state before the occurrence of the error by pressing

the reset switch.

Page 41

−38 −

13. CHANGE-OVER OF THE POWER SOURCE VOLTAGE

This sewing machine has been connected to the power source of 200V to 240V in the state of delivery from the factory. When using the machine with the power source of 100V to 120V, perform the work of change-over of voltage in the order of the procedures below.

1) Remove the cover in the rear of the sewing machine and replace from 200V to 100V the connector of connector No. CN32 (blue 2-pin) on the right side PWR circuit board as observed from the front side. See the figure below.

2) Install the cover.

3) Connect the power plug to the receptacle.

4) Completion of the work.

(Caution)1. Perform the change-over after confirming the voltage of the place where the sewing machine

is set and the voltage in the sewing machine.

2. Do not connect the power plug to the receptacle.

CN32 connector section

Page 42

−39 −

14. CAUSE OF TROUBLES AND THE CORRECTIVE MEASURES

(1) Thread trimming troubles and the corrective measures

Troubles Causes Corrective measures

Correct the position of the moving knife at the time of completion of the stop motion. Refer to the item “5. (2) Adjusting the position of the moving knife”.

2. Both the thread on the needle and that on the wrong side of a fabric are trimmed.

The trimming timing of the moving knife is bad.

1. Thread is not trimmed.

The thread separating claw of the moving knife fails to separate the thread on a fabric from that on the needle.

Adjust the position of the moving knife. Refer to the item “5. (2) Adjusting the position of the moving knife”.

The needle does not come down into the correct point of a button hole.

Make readjustment by the button clamp holder.

The final stitch is skipped. Correct the position on the looper.

Refer to the item “4. (2) Positioning the needle and the looper”.

The height of the thread separating claw of the moving knife is not correct.

Correct the height of the thread separating claw of the moving knife. Refer to the item “5. (3) Adjusting the height of the thread separating claw of the moving knife”.

Improper position of the moving knife

3. The trimmed thread on the wrong side of a fabric is too long.

Improper height of the thread separating claw of the moving knife.

Correct the height of the thread separating claw of the moving knife. Refer to the item “5. (3) Adjusting the height of the thread separating claw of the moving knife”.

The lift of the button clamp is too large.

Correct the position of the moving knife. Refer to the item “5. (2) Adjusting the position of the moving knife”.

Readjust the lift to 10 mm. Refer to the item “4. (5) Lift and pressure of the button clamp”.

(Caution) Adjust the position of the moving knife within a range of 10 to 15 mm.

If the position of the moving knife is readjusted to less than 10 mm, the thread separating claw comes in contact with the counter knife or the yoke slide insert, resulting in damaged thread separating claw of the moving knife. On the other hand, if it is readjusted to more than 15 mm, the thread separating claw may come in contact with the positioning finger yoke slide while the machine is running, also causing breakage of the thread separating claw.

Page 43

−40 −

Troubles Causes Corrective measures

(2) Cause of troubles and the corrective measures for MB-1800

1. The machine fails to sew at the start of sewing.

Length of remaining thread is too short.

Adjust the thread adjusting thread guide.

Speed is fast. Use the soft-start function.

The needle is too thick for the diameter of the hole in the button.

Replace the needle with a thinner one.

The thread tension post No. 2 fails to release the thread at correct timing.

Make the thread releasing timing slightly earlier.

The needle does not enter the center of the holes in the button.

Adjust the position of the button clamp jaw lever holder.

2. Thread breakage

The needle does not enter the center of the holes in the button.

Adjust athe position of the button clamp jaw lever holder.

The thread tension post No. 2 fails to release the thread at correct timing.

Make the thread releasing timing slightly earlier.

The thread tension post No. 2 does not give sufficient tension.

Increase the tension of the thread tension post No. 2.

Buttons are not sewn tightly.

The last stitch skips. Adjust the looper.

The moving knife does not separate the thread on the fabric with its thread separating claw.

Adjust the position of the moving knife.

The needle does not enter the center of the holes in the button.

Adjust the position of the button clamp jaw lever holder.

4. Thread cannot be trimmed.

The moving knife does not separate the thread on the fabric with its thread separating claw.

Adjust the height of the thread separating claw.

The moving knife does not separate the thread on the fabric with its thread separating claw.

Adjust the position of the moving knife.

The moving knife separation nail is too high or too low.

Adjust the height of the thread separating claw.

5. Needle thread is cut in two places.

Page 44

−41 −

15. CIRCUIT BOARD DIAGRAM

(1) MAIN circuit board

Page 45

−42 −

(2) PWR circuit board

(3) PANEL circuit board

Page 46

−43 −

16. BLOCK DIAGRAM 1/2

PANEL pcb asm.

CN41

26P

Feed 1

stepping motor

Feed 2

stepping motor

Servo-motor

Servo-encoder

PWR pcbasm.

CN17

15P

CN19

CN18

CN24

CN26

CN16

26P

CN25

Interface for BR

Serial interface

CN11

CN29

CN33

CN35

Control box power cord asm.

CN26

Power switch

Power cord asm.

CN32

Input change-over cord asm.

(Change-over 100V/200V)

Temperature

sensor cord asm.

MAIN pcb A asm.

Presser sensor cord asm.

Starting cord asm.

CN27

CN28

CN23

CN22

CN152PCN14

CN12

CN13

CN203PCN21

CN30

Thread tension relay cord asm.

CN58

3P3P 3P3P

CN51

CN52

CN53

CN54

CN55

Feed origin cord asm.

Pedal switch asm.

Pedal cord asm.

CN563PCN57

Presser lifter

solenoid asm.

Knot-tying

solenoid asm.

Wiper solenoid

asm.

Thread tension

solenoid asm.

Feed 1 origin

sensor

Feed 2 origin

sensor

Starting switch

Presser lifting

sensor

Presser

lowering sensor

Fan asm.

Presser switch

Start switch

@4@5

Page 47

−44 −

Block diagram 2/2

Sensor connection diagram Solenoid circuit diagram Power connection diagram Power connection diagram Sensor connection diagram Sensor connection diagram Sensor connection diagram Motor circuit diagram Motor circuit diagram Motor circuit diagram Encoder circuit diagram Power connection diagram Power connection diagram Solenoid circuit diagram Solenoid circuit diagram Solenoid circuit diagram Solenoid circuit diagram Sensor connection diagram Sensor connection diagram Sensor connection diagram Sensor connection diagram Sensor connection diagram Power connection diagram Sensor connection diagram Sensor connection diagram Sensor connection diagram Sensor connection diagram

MAIN circuit board A asm. PWR circuit board asm. PANEL circuit board asm.

Temperature sensor cord asm. Thread tension relay cord asm. Input change-over cord asm. Control box power cord asm. Feed origin cord asm. Starting cord asm. Presser sensor cord asm. Feed 1 stepping motor Feed 2 stepping motor Servo-motor Servo-encoder Power switch Power cord asm. Presser lifter solenoid asm. Knot-tying solenoid asm. Wiper solenoid asm. Thread tension solenoid asm. Feed 1 origin sensor Feed 2 origin sensor Starting switch Presser lifting sensor Presser lowering sensor Fan asm. Pedal switch asm. Pedal cord asm. Presser switch Start switch

1 2 3 4 5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

M8601630AA0 M86046300A0 M86026300A0

M85026300A0 M85196300A0 M85236000A0 M85046300A0 M85056300A0 M85066300A0 M85076300A0 M8901630000 M8901630000 M8903630000 M8904630000 HA004250000 M90245800A0 M85086300A0 M85096300B0 M85176300A0 M85186300A0 HD00057000A HD00057000A HD00057000A HD000570000 HD000570000 M85405900A0 M85205900A0 M90115900A0A HD001930000 HD001930000

No.

Part No. Name of part Circuit diagram

Page 48

−45 −

17. CONNECTION DIAGRAM AND CIRCUIT DIAGRAM

(1) Power connection diagram

1 1

2 2

CN31

Power cord asm.

Green

Red

White

Black

Power SW

L1T1L2T2L3

Light blue

Brown

Green/Yellow

Control box power cord asm.

FG1

FG2

AC IN

1 1

2 2

1 1

2 2

White

CN32 (100V)

100V

RTN

CN32 (200V)

PWR pcb asm.

MAIN pcb A asm.

1 1

2 2

3 3

FAN asm.

N.C

12345

N.C

CN34

+15V 1

+15V 1RET

+15V 2

+15V 2RET

+15V 3

+15V 3RET

1 1

2 2

3 3

4 4

5 5

6 6

1 1

2 2

3 3

4 4

5 5

6 6

+24V

+5V

PGND

GND

CN11CN33

+24V

+5V

PGND

GND

DC power cord asm.

Orange

Red

White

CN23

+24V

GND

N.C

Black

Red

Page 49

−46 −

(2) Sensor connection diagram

OPTIONAL

123456789

+5V

PRESSER

GND

+5V

START

GND

+5V

N.C

GND

CN28

BLUE

BROWN

BLACK

BLUE

BROWN

BLACK

123

456

+5V

FEED 1 ORIGIN

GND

123

CN20

BLUE

BROWN

BLACK

+5V

FEED 2 ORIGIN

GND

123

CN21

+5V

STARTING

GND

123

CN22

+5V

PRESSER LIFT

GND

CN30

+5V

PRESSER LOWER

GND

BLUE

BROWN

BLACK

BLUE

BROWN

BLACK

CN29

TEMP. DETECT

GND

WHITE

BLACK

RED

WHITE

BLACK

GREEN

YELLOW

BROWN

321

CN52

321

CN52

321

CN53

321

CN53

321

CN54

321

CN54

321

CN55

321

CN55

321

CN56

321

CN56

321

CN57

321

CN57

321

CN51

321

CN51

BLUE

BROWN

BLACK

BLUE

BROWN

BLACK

BLUE

BROWN

BLACK

BLUE

BROWN

BLACK

BLUE

BROWN

BLACK

RED

WHITE

BROWN

GREEN

YELLOW

CN35

WHITE

BLACK

PWR PCB

FEED 1 ORIGIN SENSOR

FEED 2 ORIGIN SENSOR

STARTING SW

PRESSER

LIFTING SENSOR

PRESSER

LOWERING SENSOR

PRESSER SW

START SW

TEMPERATURE SENSOR

85˚

Page 50

−47 −

(3) Motor circuit diagram

L1-A

+24V

L1-A L1-B

+24V

L1-B

3 2

6 4

CN16

YELLOW

ORANGE

BLUE RED

WHITE

BLACK

L2-A

+24V

L2-A L2-B

+24V

L2-B

5 3 2 6 4

YELLOW

ORANGE

BLUE RED

WHITE

BLACK

CN17

FEED 1 STEPPING MOTOR

FEED 2 STEPPING MOTOR

SERVO-MOTOR

PGND

CN18

RED

WHITE

BLACK

N.C

Page 51

−48 −

(4) Encoder circuit diagram

(5) Solenoid circuit diagram

-U

-V

-W

-B

-A

-Z

+5V

GND

SHIELD

1 2 3 4 5 6

7 8

9 10 11

13 14 15

BLACK

BROWN BROWN/BLACK

GRAY

WHITE WHITE/BLACK

GRAY/BLACK

GREEN GREEN/BLACK BLUE BLUE/BLACK YELLOW YELLOW/BLACK

RED BLACK

CN19 SERVO ENCODER

TS5207N530

+24V

PRESSER

LIFTER

+24V

KNOT-

TYING

+24V

WIPER

+24V

THREAD

TENSION

1 2

WHITE WHITE

WHITE BLACK

CN15

CN14

CN13

CN12

WHITE

1 2

CN58 CN58

THREAD TENSION

PRESSER LIFTER

KNOT- TYING

WIPER

Page 52

−49 −

18. DRAWING OF THE TABLE

(6)

R30

570

500

R30

120

525

980

810

220

390

360

105

115

190

112

21 26

1050

160

110

160

78.5

2 drilled hole, depth 10 (bottom surface)

Installing position of stopper for drawer

30 drilled hole

3-8 drilled hole

JUKI logotype

2 drilled hole, depth 10 (bottom surface)

Installing position of drawer

2-2 drilled hole, depth 10 (bottom surface)

Main switch installing position

40 drilled hole

4-2 drilled hole, depth 10 (bottom surface)

Stand installing hole

17 drilled hole

3. Painting inside of cut portion is not necessary.

2. Do not peel the protection sheet from the surface of table.

(Note) 1. Tolerance of hole without indication is ± 0.7 and that of others ± 1.0.

Page 53

Please do not hesitate to contact our distributors or agents in your area for further information when necessary.

＊ The description covered in this engineer’s manual is subject to change for improvement of the

commodity without notice.

00 · 04 Printed in Japan (E)

INTERNATIONAL SALES DIVISION

8-2-1. KOKURYO-CHO. CHOFU-SHI. TOKYO 182-8655. JAPAN

PHONE : (81)3-3430-4001 to 4005 FAX : (81)3-3430-4909 • 4914 • 4984 TELEX : J22967