ELNA E9020 Service Manual
E9020
SERVICE MANUAL
CONTENTS
[1] Product specifications for E9020....................................................................................................................1
[2] Technical explanation......................................................................................................................................4
[3] Index by troubles (mechanical troubles) .....................................................................................................11
[4] How to disassemble the frame components ...............................................................................................15
[5] Adjustment......................................................................................................................................................17
1. Main unit of sewing machine ................................................................................................................................................ 17
2. Embroidering device.............................................................................................................................................................. 40
3. Service mode .......................................................................................................................................................................... 43
[6] Circuit board connection diagram................................................................................................................49
1
[1] Product specifications for E9020
(1) Speed control device
™ Slide control system (soft start) and optional controller system
™ Straight stitching................................................. 115 to 850 rpm
™ Bobbin winding .....................................................Up to 600 rpm
™ Zigzag pattern ......................................................Up to 700 rpm
™ Bartacking on both sides of buttonholes ..............Up to 525 rpm
™ Large pattern sewing, making key
hole buttonholes, lateral feed pattern sewing...... Up to 300 rpm
™ Embroidering At high speed .................. 410 to 800 rpm
At medium speed ..............Up to 410 rpm
At low speed......................Up to 245 rpm
The maximum speed can be set in four stages according to the position of the
slide variable resistor. (800, 750, 600 and 410 rpm)
[In case of embroidering, the sewing speed (rpm) changes over according to the
travel anount of embroidering device STM (two : X and Y), and at medium speed
and low speed, the sewing speed is fixed regardless of the slide controller.]
™ Soft start ................... 115 rpm for approximately 1 second
(2) General mechanism
1. Thread take-up lever............... One-touch utility thread eyelet link thread take-
up lever
2. Hook........................................ Vertical-axis, full rotary hook. The inner hook
is equipped with an idling prevention device.
3. Drop feed ................................ Slide lever type
4. Lighting ................................... Built in the face plate cover and in the center of
main body.
Lamp ... Halogen lamp
5. Needle thread spool rest rod .. Horizontal type
6. Bobbin winder ......................... Slide-type bobbin winder shaft Starts and stops
using the start switch and the stop switch.
7. Needle thread eyelet............... One-touch utility thread eyelet
8. Presser foot............................. Exclusive transparent presser foot Exclusive
presser foot is denoted by the square frame .
9. Power switch........................... Exclusive to the power to the main unit
10. Lubrication .............................. No lubrication is required under the general
operating conditions.
11. Power cord.............................. The power cord is 1.9 m long from the red mark.
(3) Needle throwing mechanism
1. Needle bar rocking system ..... Pendulum + Circular arc
2. Straight stitching ..................... Center stitch base line and right stitch base line
3. Zigzag width............................ 7 mm
4. Zigzag width adjustment......... In increments of approximately 0.3 (0.333) of
0, 0.3, 0.6, 1.0, 1.3, 1.6, 2.0, 2.3, 2.6, 3, 3.3,
3.6, 4.0, 4.3, 4.6, 5, 5.3, 5.6, 6.0, 6.3, 6.6 and 7
5. Needle throwing motion .......... By a stepping motor
actuating method
2
(4) Feed mechanism
1. Feed amount........................... 0 to 5 mm (in increments of 0.1 mm in the range from 0.2 to 1.0 mm, and 1.5 mm, 2.0 mm, 2.3 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4 mm, 4.5
mm and 5.0 mm)
2. Reverse stitching length.......... 0 to 5 mm (for straight stitch) Fixed at 0.5 mm (for the other patterns)
3. Feed amount adjustment ........ By the manual switch mounted on the LCD
Feed amount (pitch) is given on the LCD.
4. Reverse stitching .................... The machine performs reverse stitching at low speed (115 rpm) while the reverse stitching switch is ON.
5. Lateral feed............................. Fixed at 2 mm when a lateral feed pattern is specified.
6. Descending of feed dog.......... Automatically comes down when the embroidering device is set on the machine.
(5) Special-purpose mechanism
1. Automatic thread tension controller
By the thread-feeding stepping motor Manual switch for increasing/decreasing the amount of needle thread of the automatic thread tension controller by a material
thickness sensor (to increase/decrease the amount of thread in 8 steps)
2. Automatic thread trimmer
Lateral STM is actuated by pressing the thread trimming switch so as to bring the thread trimming mechanism in the standby state. Then the hook driving shaft turns one
and a half times (when the machine has stoped with its needle down) or two times (when the machine has stopped with its needle up) by the sewing machine drive motor
and the main shaft is disengaged at the first turn. The machine actuates the thread trimming knife to cut the thread (115 rpm) and stops with its needle up. Disengagement
of the main shaft is released before stop.
3. Automatic backtack sewing
By pressing key after selecting the pattern, backtack sewing is performed at beginning and end of sewing, and the needle and bobbin threads are cut finally.
4. Helpful pictograph
Operation lever, bobbin winder, buttonholing set, running out of needle thread, pattern selection display, inoperative key display, limit of pattern memory display, pattern
in storing, calling display (when the embroidering device is set), needle raising indication, embroidery frame installing indication, embroidery frame changing indication,
embroidery card inserting indication, difference of embroidery carc indication, pattern clearing indication, and bobbin thread remaining amount indication
5. Automatic needle threading mechanism
When setting thread to the thread retaining section of the thread transfer body, threading from the section to needle is automatically performed by pressing the key of
the operation panel.
6. Automatic buttonholing
Auto-return type fully-automatic buttonholing
Buttonhole size detection, automatic stop after backtacking at thge sewing end (backtacked (L ans S) key hole). Buttonholing plate is provided.
7. Bobbin thread remaining amount
Bobbin thread remaining amount is detected by the LED sensor when the bobbin thread is running out, and the message is shown on the LCD. Then the sewing
machine stops.
8. Limit sensor
In order to prevent the bobbin from being excessively wound when automatically winding bobbin, the sensor monitors during bobbin winding and detects that the bobbin
is wound more than the specified amount. Then bobbin winding automatically stops.
3
9. Pattern selection
Direct selection of patterns through a transparent touch panel and indication of selected pattern on LCD.
10. Number of patterns
Practical patterns 53, Continuous patterns 34, Adherence one point 34, One point 168, Lettering characters 4 fonts 450, large pattern 31, practical one point 51
11. Constant-position needle bar stopper
The machine stops with its needle up or down using the synchronizer shield plate and detector (photo-interrupter) mounted on the main shaft.
When the thread trimming presser is raised, when the embridering device is used or when the bobbin is to be wound, the machine stops with its needle up. In a case
other than those described above, the machine stops with its needle down.
12. Prevention of wrong-setting of needle
It is designed so as not to insert the needle in the wrong direction.
13. Operation guide
How to operate the sewing machine, advice and how to sew are indicated on LCD.
14. Prevention of overheat of motor
If the sewing machine motor shaft is locked, the power supplied to the motor is automatically turned OFF after 1 to 1.5 seconds.
If the motor becomes extraordinarily hot in such cases as the sewing machine cotinuously runs at high speed, the thermal sensor built in the motor detects and stops
the machine operation. (The power is turned ON again after the motor has cooled down.)
15. Automatic bobbin winder
When performing the embroidering, exclusive bobbin thread can be wound to bobbin without removing bobbin. In addition, after bobbin winding, threading to bobbin
thread tension spring and thread cutting are performed. Then sewing can continue.
(6) Microcomputer and ROM
32-bit microcomputer .......... 1
Gate array ........................... 1
Flash ................................... ROM 32MB
Flash (patterns)................... ROM 8MB
Embroidering card............... Available from 4MB to 128MB (Smart media)
* Gate array
A large scale and original circuit is necessary for the computer sewing machine. The circuit is built in the IC which is the exclusive one produced for this model only.
(7) Outer dimensions and weight
Main unit ............................. 47.9 cm (width) X 32.4 cm (height) X 21.5 cm (depth) Weight : 12.4 kg
Main unit with case ............. 49.5 cm (width) X 33.0 cm (height) X 23.5 cm (depth) Weight : 13.7 kg
Embroidering device ........... 33.5 cm (width) X 13.0 cm (height) X 32.0 cm (depth) Weight : 2.3 kg
(8) Power consumption
Sewing machinemain unit ... North America territory: 120V 60 Hz
(Lamp only) Mainly Europe territory: 230V 50 Hz
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[2] Technical explanation
Sewing speed Max. sewing speed in high speed operation ................For straight stitching .........................................................850 ± 50 rpm
For embroidering (at high speed) .....................................800 ± 50 rpm
Low sewing speed in high speed operation .................For bobbin winding ...........................................................750 ± 50 rpm
Max. sewing speed in medium-high speed operation ..For zigzag pattern .............................................................700 ± 50 rpm
When bartacking buttonholes on both sides.....................525 ± 15 rpm
Max. sewing speed in medium speed operation ..........For embroidering (at medium speed) ...............................410 ± 10 rpm
Low sewing speed in medium speed operation ...........For key hole buttonholes, lateral feed patterns, etc. .........300 ± 10 rpm
For patterns which are to be sewn with the needle bar disengaged.
High sewing speed in low speed operation ..................For embroidering (at low speed).......................................245 ± 10 rpm
Low sewing speed in low speed operation..............................................................................................................115 ± 10 rpm
Extra low speed operation.........................................................................................................................................70 ± 10 rpm
™ In case of embroidering, the sewing speed automatically changes over according to travel amount of X-feed and Y-feed of embroidery STMs regardless of the slide
controller. (800, 750, 410 and 245 rpm) Max. sewing speed (800 rpm) is limited according to the position of slide variable resistor.
Start/stop of sewing machine by means of the start/stop switch
(Hereinafter the start/stop switch is called S/S SW.)
™ When a pattern has not been specified, the machine will not start even by turning ON the S/S SW. In this case, the relevant error message will be given with a buzzer.
™ When the S/S SW is used to stop the machine, the machine stops with its needle down in the normal stitching or with its needle up in embroidering.
Start/stop of sewing machine by means of the controller
™ Depress the controller to start the sewing machine. Release the controller to stop it.
™ When the controller is depressed for the first time after turning ON the powwer to the machine, the machine starts with the soft start function. When the controller is
depressed for the second time and beyond, the sofy start function does not work.
™ After the machine has started with the soft start function, the sewing speed gently increases according to the depressing depth of the controller.
™ The sewing machine stops with its needle down if detaching the controller from the receptacle while the sewing machine is turned by operating the controller.
™ While the controller is used, it is impossible to start the sewing machine using the S/S SW. (The switch can be used to stop the sewing machine.)
™ The controller is ineffective during embroidering.
850
750
525
375
115
Sewing speed
rpm
Soft
start
Sewing speed
gently increases.
(At the time of starting the machine)........................................................................ (At the time of stopping the machine)
Low speed (approx. 115 rpm)
Extra low speed
Stop
S/S SW
5
Automatic thread trimmer
™ In case of thread trimming, the machine stops with its needle up after turning the amount equivalent to make one and a half stitches (when the machine has stopped
with its needle down) or two stitches (when the machine has stopped with its needle up). (115 rpm)
™ Make the machine perform steps 1 through 2 using the lateral feed STM, then the sewing machine drive motor will rotate and the thread trimmer will cut the needle
and bobbin threads.
- STM operation steps First step 1 Disengage the drawing roller from the auxiliary roller.
Second step 2 Disengage the knife.
3 The sewing machine runs at low speed (115 rpm), and the moving knife cuts the needle and bobbin threads.
4 Disengagement of the main shaft is released and the sewing machine stops with its needle up.
Thread trimming cannot be performed while the sewing machine is in rotation or is ready to stop.
Bobbin winding
1 Set the bobbin winder shaft lever to the bobbin winding position, and the sewing machine motor rotates by turning ON the bobbin winding switch, turning ON the S/
S SW, or depressing the controller. The main shaft is disengaged at the fixed position of the first rotation. The sewing machine is in the state of stopping with its
needle up and only the bobbin winder shaft rotates. (The hook driving shaft rotates.) (Upper limit 600 rpm)
2 While the bobbin winding switch is ON, the relevant message is shown on the display. In this state, any switch other than the S/S SW is not accepted.
Presser foot lift
When the presser foot is raised and S/S SW is turned ON, the relevant message is shown on the display.
Turning ON the S/S SW makes the machine rotate by the amount equivalent to make a half stitch or one stitch and stop with its needle up. At this time, the relevant
message appears on the display.
Pattern selection
The pattern selector switch consists of the analog-type transparent touch-panel, and the range of switch is set tocorrespond with the LCD indication on the rear side.
Press the pattern selector switch, and a group of patterns which corresponds to the switch pressed is shown on the pattern LCD.
If the number of patterns contained in the group is too large to display all of them at a time, the patterns on the LCD can be changed by operating the pattern selector
key, previous screen key or next screen key.
The table below shows the acceptable conditions for embroidering key and selector keys other than the embroidering key.
™ When the utility key is turned ON, straight stitch patterns are selected and they are shown on the memory LCD.
At this time, the patterns stored in memory are cleared.
Effectiveness of the selector key
Effective
Ineffective
Effective
Ineffective
Ineffective
Ineffective
Effective
Effective
Kind of key
Embroidering key
Pattern selector keys
except embroidering key
Installation of embroidering device
£
X
£
X
£
£
X
X
Installation of memory card
£
£
X
X
£
X
£
X
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Needle throwing
The needle throwing motion is controlled by transmitting an angle of rotation of the needle throwing STM shaft to the needle bar frame by way of link. The time to
compensate the origin of STM is when the needle throws to the left stitch base line as long as the power to the machine is ON.
When the STM is turned beyond the right stitch base line, the needle bar disengaging mechanism actuates.
[Performance of the needle throwing STM]
Material feed (longitudinal)
An angle of rotation of the longitudinal feed STM is transmitted to the cloth feed mechanism as an inclination of the feed adjuster shaft by way of a gear so as to cause
the feed mechanism to feed the material according to the feed amount programed for each kind of stitching pattern.
The feed mechanism is controlled also when the sewing machine is turned by hand.
[Performance of the longitudinal fedd STM]
Lateral feed
The machine performs lateral feed of the material by directly transmitting an angle of rotation of the lateral feed STM (commonly works to control thread trimming) to the
feed dog by way of a link.
[Performance of the lateral feed STM]
Reverse stitching
1) Regular patterns (excluding lateral feed straight stitch patterns, zigzag patterns and embroidery patterns)
Turn ON the reverse stitching switch, and the sewing machine rotates at low speed. The longitudinal feed STM moves the feed adjuster to the reverse stitching
position to move the feed backward. Turn OFF the switch, and the machine stops with its needle down.
The feed amount employed in reverse feed stitching for straight stitching is sama as normal feed stitching.
For a pattern other than straight stitch patterns, the reverse feed amount is fixed at -0.5 mm.
2) Lateral feed patterns (lateral feed straight stitch patterns and lateral feed zigzag patterns)
Turn ON the reverse stitching switch, and the sewing machine rotates at low speed. At this time, the longitudinal feed STM moves to the position at which the feed
mount is set to 0 mm. Now, the lateral feed STM actuates to feed the material in the reverse direction.
Thread tension release 1
Knife is disengaged.
Lateral feed
Origin
Thread tension
release 2
Right-hand side
of feed dog
Left-hand side of feed dog
-5 mm
+5 mm
Longitudinal feed
Origin
Needle throw
Main shaft is is
disengaged.
Left stitch base line (origin)
Right stitch
base line
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Embroidring device
1) The machine is fed, when embroidering, by the X feed STM and Y feed STM. An angle of rotation of each STM is transmitted, by means of a gear and belt, to the
embroidery frame as a linear travel amount in X/Y direction. This causes the machine to sew an embroidery pattern.
2) When a large, medium or small embroidery frame is installed on the machine, three frame detection switches are turned ON or OFF, and the machine determinates
the possible range of layout of the patterns that can be sewn in accordance with the size of embroidery frame, i.e., large, medium or small, installed.
In addition, the number of patterns and letters that can be stored in memory is automatically restricted in accordance with the embroidery frame installed.
3) When the embroidering device is used with the machine, the controller is rendered ineffective and the reverse stitching switch is inoperative.
The maximum speed can be changed over in four steps with the slide variable resistor.
4) If the presser foot is in the lowest position after the power to the machine has been turmed ON, the pictograph "raise presser foot" will be given on the display. If the
needle is in the lowest position, the pictgraph "raise needle" will be shown. The S/S SW is rendered ineffective.
5) If you turn the machine by hand after having selected a pattern, the machine will not perform pattern sewing. Once the S/S SW is turned ON, you are allowed to turn
the machine by hand so as to make the machine perform pattern sewing until the machine completes the pattern. After the completion ofthe pattern sewing, it is
impossible to make the machine perform pattern sewing by turning the machine by hand.
6) The sewing speed automatically changes over, during embroidering, in accordance with the travel amount of the embroidery feeding frame. (800, 750, 410 and 245 rpm)
7) To move the needle by a distance as long as 11 mm (jump) during embroidering, the sewing machine is stopped and only the embroidery frame is moved by the
distance.
8) The micro-switch is used for the detection of the origin.
9) A micro-switch is mounted on the ejection lever, and it informs the micro-computer to cut the power supply to the embroidering device STM before the terminals of
the embroidery and the main unit are drawn. This is a protective circuit not to badly affect the electronic components when the terminals are improperly connected
or they are drawn during sewing.
In addition, when the ejection lever is improperly inserted, the embroidering device does not work. So, be careful.
Automatic thread tension control
1) The automatic thread tension control is carried out by the following.
1 Pattern data (Zigzag width and feed amount are automatically specified by making a choice of a pattern to be sewn.)
2 Material thickness detecting potentiometer
3 Thread drawing stepping motor
Based on the data provided by 1 and 2, the optimum drawing amount of needle thread for every rotation of the sewing machine is calculated by a microcomputer.
The set amount drawing stepping motor rotates, draws the needle thread put between the drawing roller and the auxiliary roller and controls the amount of thread to
be used for sewing the material.
2) Rotate the machine by the amount equivalent to the sewing of several stitches by turning ON the S/S SW or operating the machine by hand, and the slack of thread
will be removed. The automatic thread tension control function works when the thread breakage detection photo-sensor becomes open.
3) For overedging, embroidering, and two color stitching, the thread drawing amount is computed using the respective operation expressions to allow the machine to
adapt to the respective sewing patterns.
4) To correct error in the actual feed amount of the material feed mechanism, sew a straight stitch pattern with the feed amount indication set to 2 mm and measure the
actual feed amount. Then adjust the feed compensating switch in accordance with the difference between the specified amount and the measured feed amount. This
corrects the operation expression used by the microcomputer.
8
Memory
1) When a pattern or a letter is selected, it is automatically stored in memory.
2) The maximum number that can be stored in memory is 120. For the embroidery patterns, the number of patterns to be sewn changes in accordance with the size of
the frame or the size of the patterns stored in memory, and the limit ofthe number of patterns stored in memory is automatically computed and set.
3) The one-point pattern stitching pattern cannot be stored in memory or retained as the continuous pattern mode or the pattern mode.
Pattern selection + continuous key + pattern selection
Pattern selection + continuous key + retaining key
* For the retaining key, refer to the next page.
4) The vertical writing mode can be used for kana letters, Chinese characters and numerals. The embroidery patterns are effective for all patterns stored in memory.
File (save) and calling keys
1) The saving function saves a series of patterns stored in memory after the power to the machine is turned OFF. Once the power is re-turned ON, the saved patterns
can be called for sewing.
Turn ON the pattern case key to select and turn ON the save key. Then the patterns that have been stored in memory for the patterns other than embroidering
and the combined patterns for the embroidering are stored in the file of the specified No. in non-volatile memory (flash memory), and the data are saved even after
the power to the machine is turned OFF.
The condition of patterns which has been simultaneously stored in memory with the patterns such as inversion, increase, decrease, two colors, small letter, vertical
writing, vertical setting, rotation, letter interval, layout condition, etc. and the kind of embroidery frame are saved.
The file that has been saved once cannot save other patterns until the patterns saved in the file are erased.
2) If the embroidery frame installed on the machine, when calling the pattern with the calling key, is smaller than the one when it has been saved in the memory, editing
can be performed by the edit screen. Sewing cannot be performed, however, unless re-editing is peformed so that the pattern can enter inside the frame. In this case,
the error message will appear on the display.
3) Saving and calling under the embroidering mode is effective regardless of the patterns, kind of the embroidery card, built-in patterns or card patterns.
Disengagement of main shaft
1) Disengagement of the main shaft is performed by actuating the main shaft disengaging link by means of the needle throwing STM to disengage the rotation power
to the main shaft.
2) When the data of disengagement of main shaft occurs (70˚), the needle throwing STM starts driving from 287˚ and completes the motion by 0˚.
3) By the step 2) motion, the main shaft disengaging link moves to the disengaging position. (The STM completes the motion by 0˚.)
4) When the main shaft turns in the normal direction in the state that the main shaft disengaging link is in the disengaging position, the main shaft disengaging cam
slides by the main shaft disengaging link. The main shaft hand wheel and the main shaft are disengaged from each other, and the rotation power is cut.
: In this case, error message is given.
9
5) The main shaft which has been disengaged stops at 40˚ to 50˚ by the main shaft disengaging stopper.
6) Main shaft returns from disengagement when the data other than the disengagement of main shaft occur (70˚), the needle throwing STM starts driving at 287˚ and
the main shaft disengaging link moves to the waiting position.
7) The main shaft disengaging cam slides by the main shaft disengaging cam spring and comes in contact with the main shaft hand wheel.
8) When the main shaft rotates by 30˚ to 70˚ in the normal direction in the state that the main shaft comes in contact with the main shaft disengaging cam, the main shaft
disengaging cam slides further by the main shaft disengaging stopper and the main shaft hand wheel is joined together with the main shaft. As a result, the rotation
power is connected.
Automatic needle threading of machine head
1) Automatic needle threading mechanism is actuated by the exclusive threading stepping motor and the lateral feed stepping motor.
2) The automatic needle threading is carried out by the following.
1 Thread transfer body section ........transfers the needle thread from the waiting position located on the upper side of the sewing machine.
2 Needle eyelet threading section ...passes the needle thread which is drawn in front of the needle eyelet to the needle eyelet, and puts the thread on the needle
clamp thread guide.
3 Threading section of thread take-up spring .... puts the needle thread which is drawn by the thread transfer body to the thread take-up lever and the the thread
take-up spring.
3) The possible range of automatic needle threading is 36˚ to 54.5˚. When the needle threading key is pressed within this range, the automatic needle threading
mechanism starts working. A series of motions is as described below.
1 Interlocking with the rotation of the lateral feed stepping motor, the drawing roller and the auxiliary roller separate from each other.
At the same time, the drawing stepping motor is joined together with the threading body.
2 The thread transfer body comes down and rotates. (The threading STM starts rotating in the normal direction.)
3 The needle eyelet threading section comes down following the descending thread transfer body.
4 The thread transfer body stops in the state that the needle thread is drawn in front of the needle eyelet.
At this time, the needle threading hook stops descending at the position of needle eyelet as well.
5 The needle threading hook rotates and enters the needle eyelet. At the same time, the needle clamp thread hook arm catches the needle thread and pushes the
needle thread to near the entrance of the needle clamp thread guide.
6 By the rotation of the drawing STM, the threading body catches the needle thread and rotates. Then the threading body stops at the entrance of the thread take-
up spring. (The threading body detects the stop position by opening the needle thread breakage detection shield plate.) At this time, the needle thread is put to
the thread take-up lever and the drawing roller.
7 The threading STM starts rotating in the reverse direction. The thread transfer body rotates and goes up.
At the same time, a) the needle threading hook catches the needle thread and psasses it to the needle eyelet.
b) The needle clamp thread hook arm returns to its home position after leaving the needle thread in the needle clamp thread guide.
8 When the lateral feed stepping motor returns to its home position, interlocking of the threading body with the drawing stepping motor is released and the
threading body returns to its home position by means of the force of the spring. At this time, the needle thread is left in the the thread take-up spring.
9 The thread transfer body stops at the upper waiting position (origin) and the automatic needle threading completes.
10
Automatic bobbin winding
™ Automatic bobbin thread winding from the exclusive thread (for embroidering only)
Guide the exclusive bobbin thread which has been set to the front panel to the bobbin in the hook, rotate the bobbin and wind the thread. After completing the bobbin
winding, threading to the inner hook and cutting of the needle thread are performed by means of the reverse rotation of the outer hook. This is thread winding
exclusive for for embroidering, and the applicable thread is limited to SHAPPESPAN #90.
(1) Automatic bobbin thread winding (exclusive thread) is carried out by the following.
1 Driving section of thread retaining plate ........... This section catches needle thread and drives the thread retaining plate which guides the needle thread to
bobbin.
2 Transmitting section of rotation of bobbin ......... Change-over of transmission and release of joint of driving of rotation of bobbin.
3 Re-retaining section of thread retaining............ After completing winding, thread is stretched between the bobbin and the thread retaining plate when the thread
retaining plate travels backward up to the re-retaining position. This thread is pushed in the retaining section at
the top end of thread retaining plate by means of the inclined plane on the hook of outer hook. (For next bobbin
thread winding)
4 Threading section of inner hook ....................... After completing bobbin winding, threading to bobbin thread tension spring is performed with the hook of outer
hook which is fixed on the outer hook.
5 Bobbin thread utting section ............................. After completing threading the inner hook, bobbin thread is cut with the outer hook fixed knife which is fixed on
the outer hook.
6 Control section of amount of bobbin winding.... Setting of [S] or [M] of the amount of bobbin winding is controlled by the number of times of bobbin winding and
when [L] is set, bobbin winding is executed until the winding diameter sensor detects the amount. There is the
upperlimitation on amount of bobbin winding even when [L] is set, and bobbin winding stops before the sensor
detects when the limitation on amount is reached.
(2) Conditions of start of automatic bobbin winding
• Main shaft timing ......... 36˚ to 54.5˚
• Presser foot................. Lower position
(3) Performance
Operator performs threading to the thread retaining plate for the exclusive bobbin thread using the threading guide supplied as an accessory.
1 Press the bobbin winding start button and the sewing machine rotates after the main shaft has been disengaged. Then checking whether thread remains in the
bobbin is executed.
2 When bobbin thread does not remain, the thread retaining plate enters on the inner hook while retaining the exclusive thread.
Lift the bobbin driving gear to rotate bobbin. Then the exclusive thread which has been retained by the thread retaining plate is induced into the bobbin slit to be
wound in the bobbin.
3 When the specified amount of bobbin winding is reached, bobbin winding completes. The thread retaining plate travels backward and moves to the re-retaining
position.
At this position, the bobbin driving gear keeps the joined state.
4 Thread is stretched between the bobbin and the thread retaining plate, and the thread is pushed in the retaining section at the top end of of thread retaining plate
by means of the inclined plane of the hook of outer hook through the normal rotation of the outer hook.
5 Outer hook rotates in the reverse direction. The hook of outer hook catches the thread connecting from the bobbin to the thread retaining plate and draw it around
in the reverse direction of rotation. Then the thread is put on the inner hook thread guide.
6 At the timing when the inner hook threading is completed, the outer hook fixed knife which is attached to the outer hook cuts the thread between the hook of outer
hook and the thread retaining plate.
7 Bobbin thread winding completes in the state that it is possible to continue sewing.
11
Item to be checked
P-17 (2) Height of the presser foot P-20 (5) Inner hook detent
P-20 (6) Height of the feed dog P-21 (8) Base tensio P-46 W. Adjusting the material thickness
P-43, A Adjusting the actual feed amount P-26 (17) Bobbin thread tension
P-17 (2) Position of the presser foot P-18 (3) Height of the needle bar P-18 (3) Needle-to-hook timing
P-19 (4) Clearance between the needle and the hook P-26 (18) Timing belt
P-18 (3) Height of the needle bar P-18 (3) Needle-to-hook timing P-20 (5) Inner hook detent plate
P-17 (1) Needle entry
P-17 (2) Height of the presser bar P-20 (6) Height of the feed dog
P-17 (1) Needle entry P-19 (4) Clearance between the neeedle and the hook
P-26 (18) Timing belt
P-27 (20) Disengaging the main shaft P-45 E Longitudinal feed and lateral feed P-27 (21) Main shaft disengaging stopper
P-21 (8) Base tension P-23 (12) Adjusting the knife disengagement P-24 (13) Lateral position of the thread trimmer cam
P-24 (14) Moving knife guide (Upper) P-25 (15) Moving knife guide (Lower)
P-25 (16) Height of the looper P-26 (17) Bobboin thread tension P-26 (18) Timing belt
P-26 (18) Timing belt P-28 (22) Motor belt
P-27 (19) Buttonhole
P-33 (25) Automatic bobbin winding device
P-28 (23) Needle threader
P-40 1 Replacing procedure of the motor P-41 2 Adjusting the belt P-41 3 Adjusting the origin
[3] Index by troubles (mechanical troubles)
Phenomenon
Defective thread tension
Stitch skipping
Thread breakage
Hitched stitch
Defective feed of the material
Contact of the needle
Pattern shape
Automatic thread trimmer
Noise
Buttonhole
Bobbin winder
Needle threader
[Embroidering device]
12
Trouble
Needle thread comes off the
thread retaining section when
the transfer body rotates and
comes down.
Thread fails to pass the needle
eyelet.
Thread is not caught by the
needle clamp thread guide.
Needle thread fails to enter the
fork end.
The needle clamp thread guide
fails to catch thread.
Thread deflects to the inside of
the thread guide and cannot be
caught.
The needle clamp thread guide
fails to catch thread.
Thread deflects to the outside
of the thread guide and cannot
be caught.
1
2
3
-1
3
-2
3
-3
Automatic needle threading (trouble and corrective measure)
Cause
The set needle thread does not enter up
to the root of shaft and is narrowly retained
at the top end.
The retaining pressure does not become high.
Turn OFF the power, and turn the driving shaft
counterclockwise. The retaining pressure changeover plate works and the spring is compressed to
increase the retaining pressure.
Height of the threading hook is improper.
Thread tensed in front of needle is not in the center of needle eyelet at the
lower position of the transfer body.
Longitudinal position of the transfer body in terms of needle is not proper at
the lower position of the transfer body.
Thread retaining section is open at the lower
position of the transfer body.
The base tension is open when threading.
The base tension is open when threading.
The position of needle clamp threading arm is too high.
The transfer body is attached to the left side.
Longitudinal position of the transfer body is
improper. Front and rear
The transfer body is attached to the left side.
The position of needle clamp threading arm is too high.
The thread path control plate is attached to the left side.
The transfer body is attached to the right side.
The position of needle clamo threading arm is too low.
The thread path control plate is attached to the right side.
Corrective measure
Adjust the retaining pressure at the upper position referring to
(24)-1-3).
When the spring is not compressed, check the adjustment of the
retaining pressure change-over link referring to (24) -2-4).
Check the adjustment of the needle threader referring to (23).
Check the vertical adjustment of the lower position referring to
(24)-2-3).
Check the longitudinal adjustment of the lower position referring
to (24)-2-2).
Check the adjustment of the retaining pressure change-over link
referring to (24)-2-4.
Check the adjustment of the base tension referring to (8).
Check the adjustment of the base tension referring to (8).
Check the adjustment of the height of needle clamp threading
arm referring to (24)-3.
Check the lateral adjustment of the transfer body referring to
(24)-4.
Check the longitudinal adjustment of the lower position referring
to (24)-2-2).
Check the lateral adjudstment of the transfer body referring to
(24)-4.
Check the adjustment of the height of needle clamp threading
arm referring to (24)-3.
Adjust the thread path control plate referring to (24)-5.
Check the lateral adjustment of the transfer body referring to
(24)-4.
Check the adjustment of the height of needle clamp threading
arm referring to (24)-3.
Adjust the thread path control plate referring to (24)-5.
(a)
(b)
(a)
(b)
(c)
(d)
(e)
(a)
(b)
(c)
(d)
(a)
(b)
(c)
(a)
(b)
(c)
Front and rear
Needle thread
13
4
Cause
Malfunction of the threading body
Malfunction of the base tension
Malfunction of the mis-threading preventing plate
Rising amount of the auxiliary roller cover
Corrective measure
• Installing position of the face plate is improper.
• The face plate inside cover is moved to the right.
(The face plate installing plate is slantly attached.)
• Defective change-over of STM
• Check the motion of the base tension.
• Check the motion of the mis-threading preventing plate.
Trouble
Defective threading to the
thread take-up spring and
thread take-up lever
(a)
(b)
(c)
(d)
14
1
2
3
4
Cause
The hook cocer is not attached.
Threading to the thread retaining plate is not correct.
Retaining force of the thread retaining spring is too low.
After starting thread winding, the thread which has come out of the bobbin slit
passes the upper side of “U” letter at the top of thread retaining plate A and
comes off the thread retaining spring.
Bobbin fails to rotate.
There is a scratch on the inner hook and thread is caught with it.
Thread is caught with the inner hook detent plate and runs around.
Threading has not completed and the bobbin thread is removed by the needle
thread.
Threading has completed, but the thread cannot be drawn out since thread
end is drawn in and comes out from the entrance side.
There is a scratch on the inner hook and thread is caught with it.
Thread is caught with the inner hook detent plate and runs around.
The outer hook fixed knife is dull.
The bobbin thread tension is too low.
Tension on the side of spool for exclusive thread is too low.
Thread slackens when pushing the thread with the hook of outer hook.
A scratch on the hook of outer hook
Tension of thread retaining plate A is too high.
Corrective measure
• Attach the hook cover.
• Check whether threading to the thread retaining plate is as
shown in the threading diagram.
• Check whether threading is made to the lower side of thread
retaining plate hook.
• Adjust the height of thread retaining plate A referring to (25) -1.
Check the deflecion of thread retaining spring.
• Check the retaining force of thread retaining plate A (asm.) only.
0.64 to 0.88N (65 to 90g) wax coated thread #80.
• Check the position of thread retaining plate A hook.
• Malfunction of the gear connecting link
• Deformation of the gear connecting link plate spring.
• Correct the inner hook.
• Correct or replace the inner hook detent plate.
• Adjust the inner hook detent plate (longitudinal direction)
referring to (6). If it is excessively moved to the forward direction,
thread is caught with it.
• Same as (a) and (b) above.
• The hook cover pile is excessively tilted.
• Same as (a), (b) and (c) above.
• The feed bar pile fails to retain thread.
• Correect the inner hook.
• Correct or replace the inner hook detent plate.
• Adjust the inner hook detent plate (longitudinal direction)
referring to (6). If it is excessively moved to the forward direction,
thread is caught with it.
• Replace the outer hook fixed knife.
• Adjust the bobbin thread tension referring to (17).
• Check the thread winding tension plate or bobbin thread guide.
• The position of gear connecting link stopper is improper and
the bobbin driving gear is disengaged.
• Bobbin rises and the gear is disengaged.
• Check the inclined plane of the hook of outer hook.
• Check the retaining force of thread retaining plate A (asm.) only.
0.64 to 0.88N (65 to 90g) wax coated thread #80.
Trouble
Thread fails to be wound in
bobbin.
Thread is not caught by the
inner hook thread guide.
Bobbin thread fails to cut.
Thread is not retained to thread
retaining plate A after completing
thread winding.
(a)
(b)
(c)
(d)
(e)
(a)
(b)
(c)
(d)
(a)
(b)
(c)
(d)
(e)
(a)
(b)
(c)
Automatic bobbin winding (trouble and corrective measure)
Bobbin thread winding from the exclusive bobbin thread
15
D. Under cover
• Loosen screws 1 and 2.
B. Belt cover
• Remove screws 1, slantly insert
a thin screwdriver into the hooking section C and push in the direction of arrow mark to remove
the cover.
A. Face plate cover
• Loosen screws 1 and 2.
• Remove claw section A and B
using a thin screwdriver or the
like.
[4] How to disassemble the frame components
C. Free arm bottom cover
• Loosen screws 1 and 2.
E. Front panel
• Loosen screws 1 and remove the needle plate.
• Remove screws 2 and loosen screw 3.
• Drawing section A in the -> direction, insert a thin screwdriver into section C and
remove the claw.
• Applying force to section A in the -> direction, insert a thin screwdriver into section D
and remove the claw.
• Remove claw section E located at the jaw section while lowering the rear panel.
• Remove connectors 4, 5, and 6 connected from the front panel to the microcomputer circuit board.
• When drawing out the flexible card connector 7, draw it out after lock of connector
6 has been released.
• Remove connector 8 connected to the inverter circuit board.
A
B
E
C
A
B
C
2
1
1
1
2
1
2
3
4
5
6
7
2
2
D
1
8
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