juki FLS-350N, FLS-350NA, FLS-350NB, FLS-351NA INSTRUCTION MANUAL

1. SPECIFICATIONS

No.

1

Model

2

Sewing speed

3

Stitch length
(Max. total length of
top/bottom stitches)

4

Reverse feed stitching

5

Stitch specifications

6

Needle *

7

Thread
(Thread recommended
by JUKI)

8

Thread length

9

Type of stitch

Item

Specifications

FLS-350N

120 to 400 rpm
(300 rpm or less for
synthetic thread)

Actuated by push-button (Stitch length is fixed at 1 to 2 mm for both top / bottom stitches)

1-needle, 1-thread, special stitching (handstitching type)

ORGAN DPN-1032B/38
FUJIX Co. KING handstitching machine thread
(for light-weight materials)
FUJIX Co. KING FIT #60 (Synthetic thread)

Sewing thread 1,200 mm or less

Short-long stitch Saddle stitch

FLS-350NA

140 to 400 rpm
(300 rpm or less for
synthetic thread)

0.6 mm to 8 mm
(Up to 16 mm)

FLS-350NB

140 to 300 rpm

ORGAN DPN-1032B/49
ACE CROWN
Tetoron #8

Sewing thread 1,000
mm or less

FLS-351NA

140 to 300 rpm
(250 rpm or less for
easing in of fullness)

0.6 mm to 8 mm
(Up to 16 mm)
In case of easing in of
fullness with synthetic
thread : 0.6 mm to 3 mm
(Up to 6 mm)

ORGAN DPN-1032B/32
KANAGAWA
Co. KNK400mZ
FUJIX Co. KING FIT #60
(Synthetic thread)
Sewing thread 1,200 mm
or less

10

Feed type

11

Change-over of upper
and lower stitch
mechanism (Cloth
feed mechanism)

12

Threading

13

Presser foot lifting
method

14

Presser foot lift

15

Material thickness

16

Safety mechanism

17

Lubricating oil

18

Grease

19

Dimensions

20

Weight of machine

21

Input power voltage

22

Power consumption

23

Motor

Change of upper and lower stitch feed amount by a stepping motor

7 mm (when the knee-lifter lever is used)

Drum cover open / close protection switch (when opening the drum cover, the sewing machine is not
actuated even when the foot pedal is depressed.)

JUKI New Defrix Oil No. 2 (equivalent to ISO VG32)

ESSO TEMPLEX Grease N2 containing 10g (Part No. 13552206)
Main unit : 1,070 mm (width) X 660 mm (depth) (FLS-350N : 715 mm) X 1,120 mm (height)
Table : 1,200 mm (width) X 800 mm (depth) X 870 to 910 mm (height)

Single phase :
100V, 200V 50 / 60 Hz

SC-1 SC-380

Single phase : 200V, 220V, 230V, 240V, 380V, 50 / 60 Hz
3-phase : 200V, 220V, 230V, 240V, 380V, 50 / 60Hz

Top and bottom feed type

Manual operation

By a knee-lifter lever

Max. 2.5 mm

300Kg

700W

* It is necessary to change the needle bar when changing the needle size.

− 1 −

2. EXPLANATION OF UNITS

(1) Configuration

!3

!2

!0

31

!4

@2

@1

!5

2

1

@6

@7

@4

@5

@8

4

@3

5

!6

6

9

!9

@0

!7

!1

!8

8

7

1 Operation panel
2 Reverse stitch switch

™ The machine perfomes reverse stitching as long as the push-button is held pressed. The machine resumes

normal stitching when the push-button is released.

(Caution) Reverse stitching should be carried out at the lowest speed within the range of 1 to 3 stitches.

3 Sewing machine light

™ It lights up when turning the knob mounted on the top of the lamp.
™ The lamp support rod is flexible and can be tilted as desired.

(Caution) Unless the power switch is turned ON, the lamp will not light up since the lamp is not energized.

4 Handle

This handle can be operated manually.

5 Main power switch

™ Press the “1” side of the switch, and the control circuit will be energized.

The indicator lamps on the control panel will light up, and the motor that controls the feed mechanism and
the sewing machine will be actuated to retrieve the origin.

™ Press the “0” side of the switch, and the power to the machine will be turned OFF.

6 Knee-lifter lever

Shift the lever to the right, and the presser foot will go up.

7 Drum cover opening/closing knob

When loosening the knob and opening the cover, the safety device will be actuated, and the sewing machine
will not be actuated even when the foot pedal is depressed.

@9

− 2 −

8 Sewing machine foot pedal

™ The machine changes the sewing speed from low to high by gradually increasing depressing the front part

of the foot pedal.

™ After releasing the foot pedal, the needle will stop at the intermediate resting position in its stroke. (The

needle has two different intermediate resting positions.)

™ When this side of the foot pedal is depressed, the needle will stop at the upper position.
™ The lowest speed is fixed at 140 rpm (120 rpm) (Depending on the specifications).

9 Table fixing clip

™ It is used when opening/closing or fixing the machine table.

!0 Presser lifter fixing knob

™ The presser foot and the top feed dog can be fixed with this knob.

!1 Slide plate

™ The drum and underside of the throat plate can be observed by shifting the slide plate.

!2 Thread trimming blade

™ The blade is used to cut and hold the thread.

!3 Table
!4 Head cover

™ Open the head cover when replacing the needle.
™ Open the head cover when disassembling the needle bar for cleaning.

!55 Eye-guard

™ It is a cover that protects eye from a broken needle that jumps out of position.

!6 AC servo-motor
!7 Control box
!8 Needle threading lever

™ It is used to thread the needle.

!9 Caster
@0 Adjusting bolt
@1 Thread stand (packed in the accessory box)
@2 Thread guide

™ This is a guide that works when drawing thread placed on the spool rest rod.

@3 Stitch ruler

(2) Operation panel (1 Operation panel)

@4 Sewing speed LED indicator

The LED lights up to indicate the sewing speed specified by the setting variable resistor locating on the right of
the LED.

@5 Stitch length LED indicator

The LED lights up to indicate the stitch length specified by the setting variable resistor locating on the right of
the LED.

@6 Sewing speed setting variable resistor

Turning this variable resistor clockwise will increase the number of revolutions.

@7 Stitch length setting variable resistor

Turning this variable resistor clockwise will increase the stitch length.

@8 Right side/wrong side stitch indicator

This indicates whether the stitch length is on the upper side or on the lower side.

@9 Stitch selector switch

Pressing the push-button switch changes the right side stitches to the wrong side stitches.

− 3 −

− 4 −

3. EXPLANATION OF STITCH LENGTH COMPENSATION FUNCTION

(1) Function

When changing over the upper stitch length or the lower stitch length (turn ON/OFF the stitch length changing
switch.), it is ideal if the stitches are as illustrated in the figure below.

Change-over of
stitch length

Upper stitch

Upper stitch

Lower stitch

a = a’

aa’

Lower stitch

However, there may rarely be some machines, which make the sticthes as shown in the figure below when the
short sticth length is changed to upper stitch or lower stitch.

1) In case the upper stitch becomes small

(b)

Upper stitch
Lower stitch

Upper stitch
Lower stitch

Change-over of
stitch length

In case of a > a’

a

a’

a

2) In case the upper stitch becomes large

(b)

Upper stitch
Lower stitch

a

Change-over of
stitch length

In case of a < a’

Upper stitch
Lower stitch

a’

a

As shown in the above figure, the upper stitch is not the same as the lower stitch when the stitch length is
changed.
At this time, adjust the stitch length changing variable resistor so that the upper and lower stitches become the
same by adding the stitch length of section (b) of the above figure.

(2) Operation

1) In case of a > a’

Stitch length
change switch

Up

Down

Small

Stitch length change
variable resistor

Large

1 In case of a > a’, the lower stitch is larger than the
upper stitch. Add the compensation amount to the
upper stitch length.
In this case, press up the stitch length change switch,
and adjust the stitch length change variable resistor
so that the lower stitch becomes the same as the upper
stitch.

2) In case of a < a’
2 In case of a < a’, add the compensation amount to
the lower stitch length as the upper stitch is larger than
the lower stitch.
In this case, press down the stitch length change
switch, and adjust the stitch length change variable
resistor so that the lower stitch becomes the same as
the upper stitch.

− 5 −

4. NEEDLE BAR CURVE AND TIMING ADJUSTMENT CHART

10˚ 20˚ 30˚ 40˚ 50˚ 60˚ 70˚ 80˚ 90˚ 100˚ 110˚ 120˚ 130˚ 140˚ 150˚ 160˚ 170˚ 180˚

Needle bar
(upper)

2˚

Needle bar
(lower)

42˚

29.4˚

72.4˚ 75.4˚

12 438

90˚

Points to be adjusted for each timing

1

• Adjusting the home
position (5.-(2))

• Adjusting the needle bar
groove cam and the left
looper cam (5.-(3))

• Adjusting the lower feed
(5.-(12))

• Adjusting the feed
eccentric boss and the
lifting cam (5.-(12)-1)

• Adjusting the presser
(5.-(14))

• Adjusting the height of
the upper needle bar
support cylinder
(5.-(4)-1))

• Adjusting the height of
the lower needle bar
support cylinder
(5.-(4)-2))

• Adjusting the timing of
transferring the needle
(5.-(4)-3))

• Centering the needle bar
(5.-(4)-4))

2

3

• Adjusting the needle and
the needle guide claws
(5.-(5)-1))

• Adjusting the timing of
opening/closing the
tubular cam of the needle
guide claw (5.-(5)-3))

• Adjusting the thread
tension of the needle
guide claws
(5.-(5)-2))

4

• Adjusting the lower
looper (5.-(20))

− 6 −

180˚ 190˚ 200˚ 210˚ 220˚ 230˚ 240˚ 250˚ 260˚ 270˚ 280˚ 290˚ 300˚ 310˚ 320˚ 330˚ 340˚ 350˚ 360˚

252.4˚

209.4˚

255.4˚

270˚

360˚

222˚

182˚

56 7

360˚

5

• Adjusting the thread haul
lever (5.-(7))

6

• Adjusting the thread path
guide (5.-(6))

• Adjusting the hook finger
(5.-(9))

• Adjusting the hook finger
to release the thread
tension

(5.-(10))

7

• Adjusting the left looper
(5.-(16))

• Adjusting the right looper
cam (5.-(17))

• Adjusting the right looper
(5.-(18))

(8)

• Adjusting the brush cam
(5.-(8))

− 7 −

5. STANDARD ADJUSTMENT

(1) Before making the adjustments

Standard Adjustment

FLS-350N

Gear box frame

Handle

Arrow mark

Angle board

Main unit table

FLS-350NA • NB
FLS-351NA

(2) Adjusting the home position (adjusting the graduation)

Standard Adjustment

FLS-350N FLS-350NA • NB

Handle

Handle

Lower stop
section

Aluminum plate

Upper dead point

252.4˚

FLS-351NA

1

255.4˚

Upper stop section

270˚

2˚

240˚210˚180˚

−8 −

330˚ 0˚300˚270˚

(Home position)

Adjustment Procedures Results of Improper Adjustment

Adjustment of the respective functions is indicated by angle board
affixed to the surface of the handle.
Angle indicated by the arrow mark on the gear box cover is the angle
shown in the respective adjustment procedures.

Adjustment Procedures

The home position is indicated by “ 0˚ ”, and the standard of all timing
adjustments. The home position alignment is performed by
determining the 2˚ position.

Adjustment procedure

1) Turn the handle, and stop the needle bar when it starts coming
down from the upper stop position. At this time, loosen the
setscrews (6 pcs.) in the angle board 1 so that the arrow mark
points to 2˚. After adjusting the position, fix the angle board.
The upper stop position is slightly lower than the upper dead point,
and located at a place where the height of the needle bar does
not change for a certain section. Be careful not to mistake it for
the upper dead point.

2) Turn the handle. The place where the arrow mark points to “ 0˚ ”
is the home position.

™ If the home position shifts, the timing

adjustment cannot be made.

−9 −

(3) Adjusting the needle bar groove cam and the left looper cam

Standard Adjustment

FLS-350N

ø8

Setscrew B

C

Gear box cover

Angle board

V belt

Left looper cam

Setscrew A

125mm

120 mm

Left looper cam
configuration

Groove cam wheel

4-ø9

Positioning
hole ø8

Fixing holes

Cord

F

FLS-350NA • NB
FLS-351NA

Setscrew D

Guide metal
fitting

C

Gear box cover

Cord

Angle
board

V belt

Setscrew D

Guide metal
fitting

F

−10 −

Adjustment Procedures Results of Improper Adjustment

Disassembly procedure

1) Loosen setscrew C, and remove the gear box cover.

2) Loosen setscrew F, and turn the guide metal fitting fixing the
synchronizer. Then remove the synchronizer.

3) When loosening setscrew D located inside the angle board, the handle
and synchronizer can be removed together.

4) Remove the V belt.

5) Remove setscrew B in the groove cam wheel, and draw out the groove
cam wheel from the center shaft.

6) Loosen setscrew A, and remove the left looper cam.

Assembly procedure
In case of FLS-350N

1) Bring the left looper cam setscrew tap to the up and down position of the
rotating shaft.

2) Install the left looper cam as illustrated in the figure, and tighten setscrew
A. (Place the left looper cam fixing holes and the tap at the same positions
as when they were removed.)

3)

When attaching the groove cam wheel, insert a ø8 pin supplied as an
accessory into the hole in the groove cam wheel. After adjusting the position
of the groove cam wheel and the left looper cam, tighten setscrew B.
When setting the groove cam wheel on the left looper cam, first fit it over
the center shaft. Then fit the cam follower in the groove of the groove
cam while pressing the lower cam follower outward (the upper cam
follower can be easily fitted in the groove).
After both cam followers have been properly fitted in the groove, position
them quietly taking care not to allow them to come in contact with each
other. When attaching the handle, allow the ø8 positioning hole in the
left looper cam to face exactly toward the right-hand side, and allow the
0˚ scale of the angle board to face upward. Refer the adjustment to item
5-(2) “Adjusting the home position”.)
★ When the positioning holes of the left looper cam and the groove

cam wheel are faced exactly toward the right-hand side, the upper
end section becomes “ 0˚ ”.

In case of FLS-350NA • NB and FLS-351NA

1) Bring the left looper cam setscrew tap to the up and down position of the
rotating shaft.

2) Install the left looper cam as illustrated in the figure, and tighten setscrew
A. (Place the left looper cam fixing holes and the tap at the same positions
as when they were removed.)

3)

When attaching the groove cam wheel, insert a ø8 pin supplied as an
accessory into the hole in the groove cam wheel. After adjusting the position
of the groove cam wheel and the left looper cam, tighten setscrew B.
When setting the groove cam wheel on the left looper cam, first fit it over
the center shaft. Then fit the cam follower in the groove of the groove
cam while pressing the lower cam follower outward (the upper cam
follower can be easily fitted in the groove).
After the both cam followers have been properly fitted in the groove,
slowly place the groove cam until it will go no further taking care not to
allow them to come in contact with each other. When attaching the
handle, allow the ø8 positioning hole in the left looper cam to face exactly
toward the right-hand side, and allow the 0˚ scale of the angle board to
face upward. Refer the adjustment to item 5-(2) “Adjusting the home
position”.)
★ When the positioning holes of the left looper cam and the groove

cam wheel are faced exactly toward the right-hand side, the upper
end section becomes “ 0 ˚ ”.

™ If the position shifts, the timing

between the left looper cam and the
needle bar shifts, and they come in
contact with each other.

−11 −

(4) Adjusting the needle bar

Standard Adjustment

1) Adjusting the height of the support cylinder of the upper needle bar

Locknut

Needle bar

Elevating boss

Bush

Support cylinder of
the upper needle bar

Upper eccentric pin

Crank slide block

Upper eccentric pin

Arm

Setscrew A

12 ± 0.2 mm

Gauge

Surface of the
throat plate

A

2) Adjusting the height of the support cylinder of the lower needle bar

Support cylinder of the
upper needle bar

Setscrew B

Upper needle bar

Arm

Support sleeve

Gauge

B

23.2 ± 0.2 mm

Support cylinder of
the lower needle bar

Setscrew A

Lower eccentric pin

Setscrew B

Lower needle bar

−12 −

Adjustment Procedures Results of Improper Adjustment

Bring the support cylinder of the upper needle bar to its lower stop
position (within the range of 42˚ to 209.4˚). Loosen two setscrews A,
and adjust so that a distance of 12 ± 0.2 mm is obtained between the
throat plate and the support cylinder. When finely adjusting the
distance, loosen setscrew B, and turn the upper eccentric pin.
Dimension A of the gauge is 12 mm.

™ If the height shifts, needle

transferring cannot be properly
made, causing needle breakage.

Adjust so that the distance from the support cylinder of the upper
needle bar to the support cylinder of the lower needle bar is 23.2 ±

0.2 mm when they come closest to each other in their stroke (35˚ to
37˚).
Loosen setscrew A, and using the gauge adjust the height of the
support cylinder of the lower needle bar. When finely adjusting the
height of the support cylinder of the lower needle bar, loosen setscrew
B, and turn the lower eccentric pin.
Apply the minus tolerance when adjusting the distance between the
support cylinders when they come closest to each other in their stroke
Open the throat plate on the left-hand side, and use the gauge with
turned upside down.
Dimension B of the gauge is 23 mm.
* Perform this adjustment after checking that 4-(4)-1) “Adjusting the

height of the support cylinder of the upper needle bar” has been
performed.

™ If the closest distance shifts, needle

tranferring cannot be properly
made, causing needle breakage.

−13 −

Standard Adjustment

3) Adjusting the timing of transferring the needle

1

Adjustment nut
Rubber washer

Upper

needle bar

Needle

Lower

needle bar
Rubber washer

1

Locknut

4) Centering the needle bar

Locknut

Pin

Elevating
boss

Support cylinder

Stop pin

Retaining ring

Adjustment nut

Connection groove

Engraved line

Side view

A

Support sleeve

Front view

−14 −

Adjustment Procedures Results of Improper Adjustment

Loosen the upper and lower locknuts 1 to loosen the adjustment
nuts. Turn the handle by hand to bring the needle to the transfer
position.

1) Adjusting the upper needle bar components
1 The needle is tranferred from the upper needle bar to the lower

needle bar.

2 Turn the adjustment nut counterclockwise until the needle

nearly leaves the upper needle bar. (Turning the adjustment
nut counterclockwise will bring the needle to a position where
it will remain in the upper needle bar, or turning the nut
clockwise will bring the needle to a position where it will leave
the upper needle bar. Find a position in between the
aforementioned two positions.)

3 Give the adjustment nut a 1/2 to 3/4 clockwise turn, and fix the

nut with the locknut.

2) Adjusting the lower needle bar components
1 When the needle is transferred from the lower needle bar to

the upper needle bar, bring the needle to the position where it
nearly leaves the lower needle bar as in the case of transferring
the needle from the upper needle bar to the lower needle bar.
Then give the adjustment nut a 1/2 to 3/4 counterclockwise
turn, as viewed from above. Then fix the adjustment nut with

the locknut.
After the adjustment, penetrate the needle into the material to check
that the needle is securely caught.

™ Check that the needle does not

move up or down (from up to down,
from down to up) after transferring
the needle.

™ Check the catching of the needle

when the material used becomes
thick. If the catching is not proper,
causing needle breakage.
To confirm, check whether the
threading needle smoothly enters
the needle eyelet.

After disassembling the needle bar or if stitch wobbling or upper/
lower irregular stitch length occurs, adjust the center of the needle
bar.

1) Adjusting the center of the needle bar using the support cylinder

Change the direction of the groove of the needle bar connection
of the elevating boss by 90˚. At this time, draw out the retaining
ring and stop pin from the support ring, and also change the
direction of the support sleeve by 90˚.

2) Adjusting the center of the needle bar using the support sleeve

If the direction of the needle bar connection is not changed, change
the direction of the support sleeve by 180˚.
Perform adjustment 1) or 2), and align the center of the upper
needle bar with the center of the lower needle bar.
Carefully check the direction of the support sleeve. (The long
groove in section A should look sideways as observed by the
operator.)
An engraved line has been made at the time of delivery. So use it
as reference when disassembling or assembling the needle bar.

™ If the adjustment is not proper,

wobbling and irregular stitch length
will occur.

−15 −

(5) Adjusting the needle guide claw

Standard Adjustment

1) Adjusting the needle and the needle guide claw

Setscrew A

Slide block

Slide case

Needle guide claws

2) Adjusting the thread tension of the needle guide claw

Needle
guide claws

a

Needle

bb

P

Needle guide
claw 1

Slide block

Needle guide
claw 2

Setscrew A

−16 −

Slide block

Slide case

Lever

2

Bracket

1

Adjustment Procedures Results of Improper Adjustment

Close the needle guide claws, move the slide case, and make closer
the clearance “a” between the needle and the needle guide claws as
narrow as possible so that the needle does not come in contact with
the needle guide claws. At this time, tighten setscrew A so that the
clearances of the left and right sides “b” become equal.

™ Position of the needle guide claws

is not proper, the needle guide
claws come in contact with the
needle, or the needle guide claws
do not catch the thread.

Adjust the thread tension of needle guide claws 1 and 2 at the
position where they grasp the thread (reference 86˚ to 166˚).

1) When the needle guide claws grasp the thread, pull the thread in

direction P from between the slide block and the needle guide
claws. At this time, measure the thread tension using a spring
balancer, and adjust so that the thread tension is 500 to 1,200g.

2) When adjusting, loosen setscrews A in the bracket, and move

the bracket in direction “2” to increase the thread retaining force,
or move the bracket in direction “1” to decrease the force.

The thread retaining force greatly changes if greatly moving the
bracket. It is, therefore, necessary to move it by approximately 0.1
mm steps.
Check after the adjustment that the section where the needle guide
claws are completely closed (approx. 86˚ to 166˚).

™ If thread retaining force of the

needle guide claws is weak,
causing loose stitch or thread
breakage. On the other hand, when
the bracket is extremely moved to
the direction “2”, the section where
the needle guide claws are closed
becomes longer, and the claws may
come in contact with the needle bar.
So, be careful.

−17 −

Standard Adjustment

3) Adjusting the timing of opening/closing the tubular cam of the needle guide claw

Lower fixed point

0.5 to 0.8 mm
Position to close the needle guide

(6) Adjusting the thread path guide

Needle guide

Cam follower

Setscrew B (4 pcs.)

Tubular cam of the
needle guide

Standard Adjustment

Support cylinder of
the lower needle bar

0.3 to 1.0 mm

Within 0.5 mm

Within 0.5 mm

−18 −

Setscrew A

Thread

path guide

B

Adjustment Procedures Results of Improper Adjustment

1) Turn the handle until the needle guide claws are brought to the
position where they start closing.

2) Loosen four setscrews B, turn the tubular cam of the needle bar
guide (reference value : 86˚), and adjust so that the needle guide
claws completely close at the position of 0.8 to 0.5 mm before the
lower needle bar reaches its lower fixed position.
* When the needle guide claws are closed, check that the guide

claws have no play by moving the guide claws back and forth
by hand.

™ If the timing shifts, the needle guide

comes in contact with the needle
bar or the needle guide does not
catch the thread.

Adjustment Procedures Results of Improper Adjustment

Loosen setscrew A and adjust so that the edge of the thread path
guide is within 0.5 mm away from the upper position of the center of
needle. Then adjust so that a 0.3 to 1.0 mm clearance is obtained
between the thread path guide and the support cylinder of the lower
needle bar. After making the adjustment, tighten setscrew A.
Check that the thread passes inside of the thread path guide (side
B) when the thread comes off the drum.

™ If the clearance is large :

The thread does not enter the
thread path guide, causing thread
breakage.

™ If the clearance is small :

The thread path guide comes in
contact with the support cylinder of
the lower needle bar, causing
thread path guide breakage.

−19 −

(7) Adjusting the thread haul lever

1) Cam timing

Thread haul lever

Standard Adjustment

Tubular cam A

Tubular cam A Setscrew B

2) Adjusting the thread haul lever

Setscrew A

Thread haul lever

Guide metal fitting

−20 −

Adjustment Procedures Results of Improper Adjustment

1) Turn the handle until the thread haul lever is brought to the position
where it starts moving from the left end to the right.

2) Loosen setscrew B, and turn tubular cam A. Then tighten
setscrew B. Make this position 110˚ to 125˚.
* After the adjustment, check that the thread that the lower looper

scooped enters the drum.

™ If the timing shifts, causing the

thread not to enter the drum.

Loosen setscrew A, and adjust so that the difference in height
between the top end of the thread haul lever and the top end of the
guide metal fitting is set to 1 to –3 mm when the top end of the thread
haul lever reaches its lowest end.
Make the thread approach inside the drum using the thread haul
lever. At this time, if the thread comes off the drum, decrease the
difference in height between the thread haul lever and the guide metal
fitting so that the clearance between them is reduced. This will allow
the needle to smoothly enter the drum.
* After the adjustment, check that the thread haul lever does not

come in contact with the lower looper.

™ If the adjustment is not proper, the

thread does not enter the guide
metal fitting (drum).

−21 −

(8) Adjusting the brush cam

Standard Adjustment

Brush

Setscrew A

(9) Adjusting the hook finger

Standard Adjustment

1) Adjusting the movement amount of the hook finger

Hook finger

A

3 to 6 mm

B

Hook finger

Guide plate

Needle center

Fulcrum shaft

−22 −

Adjustment Procedures Results of Improper Adjustment

Loosen setscrew A in the brush cam, and adjust the brush cam so
that the brush fully closes when the handle is turned until the machine
is brought to the position of 185˚ (reference value).

™ If the timing is too early :

The brush closes before the thread
enters the inside of the drum.

™ If the timing is too late :

The thread comes off the drum.

Adjustment Procedures Results of Improper Adjustment

Loosen the fulcrum shaft of the guide plate so that a 3 to 6 mm
clearance is obtained from the center of the needle to the top end of
the hook finger when the hook finger comes nearest to the operator
in its stroke.
Adjust so that the top end of the hook finger is aligned with the tip of
the needle when the hook finger returns to its home position.
Angle of the timing, when the needle is lowered, is (reference: 88˚).
Keep the rotating shaft in the standard state.
After the adjustment, turn the handle by hand,and check that the
needle does not come in contact with the hook finger.
Check that the top end of hook finger enters between thread A coming
from the drum in the minimum stitch length and thread B entering the
drum, and that the hook finger securely separates threads A and B.

™ If the clearance is too small :

The needle comes in contact with
the hook finger.

−23 −

Standard Adjustment

2) Adjusting the rotating shaft and the tension spring

Eccentric pin

Hook finger

Tension
spring

0.1 to 1.0 mm

Needle

Setscrew A

Lever

3) Adjusting the clearance between the hook finger and the needle

Hook finger

Needle

P

Eccentric
pin

Tension spring

Setscrew B

Rotating shaft

−24 −

Gear

Adjustment Procedures Results of Improper Adjustment

Turn the handle, and turn the eccentric pin to adjust so that a 0.1 to

1.0 mm clearance is obtained between the hook finger and the needle

when the hook finger comes nearest to the needle. Then tighten
setscrew A.
* Simultaneously adjust the item (9)-1) and 2).

1) Loosen setscrew B, and adjust the tension spring so that the
tension in direction P is 10 to 30g or less when the hook finger is
located farthest from the operator side.

−25 −

(10) Adjusting the hook finger to release the thread tension

Standard Adjustment

Needle

Late

Hook finger

Eccentric pin

Rotating shaft

Mark

Mark

Setscrew A

Rotation direction

Early

Thread tension
is reduced.

Late

Thread tension is maximized.

(11) Adjusting the eccentric amount of the eccentric pin

Standard Adjustment

Setscrew

−26 −

A

Adjustment Procedures Results of Improper Adjustment

1) Turn the handle to allow the mark of the rotating shaft and the
marks on the eccentric pin to face toward you.

2) The eccentric pin has two marks on its surface. The position of
the eccentric pin can be adjusted within the range between the
two marks. Loosen setscrew A in the rotating shaft and perform
the adjustment by turning the eccentric pin. After the adjustment,
tighten setscrew A.

(Caution) Do not operate the machine with the mark on the

rotating shaft set out of the range between the two marks on
the eccentric pin.

If the timing to return the hook finger is
excessively retarded, isolated idling
loops may be formed.

Adjustment Procedures Results of Improper Adjustment

1) If the total of upper/lower stitches exceeds 10 mm, loosen screw
A to increase the eccentric amount. (To move to the right.)

2) To release the thread tension, adjust it by shifting the timing of
the hook finger. (Refer to the item (10).)

* When the eccentric amount is shifted, simultaneously perform

the adjustment of item (9) Adjusting the hook finger.

™ If the timing of the hook finger is

retarded, thread tension is reduced,
but isolated idling loops or the like
are likely to be formed.

−27 −

(12) Adjusting the lower feed

Standard Adjustment

1) Adjusting the feed eccentric boss and the lifting cam

Eccentric boss
setscrew A

Setscrew D

Setscrew C

Lever

Lifting cam
setscrew B

180˚

Shaft

0˚

Eccentric
boss

Eccentric boss

2) Adjusting the height of the lower feed dog and the throat plate

Lower feed dog

Nut

Joint

Lifting cam

Throat plate

Lower feed dog

Parallel

0.5 to 0.8 mm

−28 −

Adjustment Procedures Results of Improper Adjustment

1) Turn the handle to bring the machine to its home position (0˚).

2) Loosen setscrew A of the eccentric boss, turn the eccentric boss
by 180˚, and fix it there.

3) Loosen setscrew B of the lifting cam and the lifting cam to the
lowest position of the lower feed dog. Then tighten setscrew B.

™ If the upper feed is not synchronized

with the movement, it will result in
stitch slippage.

1) Loosen the nut of the joint in the previous item 1), and adjust so
that the lower feed dog protrudes from the throat plate by 0.5 to

0.8 mm.

2) Loosen setscrew C and adjust so that the lower feed dog is parallel
to the throat plate, then tighten setscrew C.

™ If the lower feed dog is positioned

lower than the specified amount, the
material to be sewn may not be fed.

−29 −

(13) Adjusting the upper feed dog and the lower feed dog

Standard Adjustment

Setscrew A

Upper feed dog

Lever

Lower feed dog

(14) Adjusting the presser foot

Setscrew A

Center of needle hole

Presser
foot holder

Setscrew D

Presser
foot

Standard Adjustment

Setscrew E

Take-up
plate

Lower feed dog

0.6 mm

Presser foot holder

Presser
foot

Side view

Throat plate
Center of
needle

Throat plate

8.5
mm
(0˚ )

2.6 to 3.0 mm

−30 −

Adjustment Procedures Results of Improper Adjustment

1) Turn ON the power to the machine.

2) Maximize the two stitch length adjusting dials on the control panel.

3) Loosen setscrew A tp set the lever free. Then adjust so that the
upper feed dog meets the lower feed dog by moving the upper
feed dog back and forth. After the adjustment, tighten setscrew
A.
The feed mechanism is controlled by a stepping motor, which
means that the feed components cannot be positioned correctly
unless the power to the machine is turned ON.

™ If the adjustment is not proper, the

stitch length will be unstable.

Adjustment Procedures Results of Improper Adjustment

1) To adjust the center of the needle with respect to the throat plate,
loosen four setscrews A in the take-up plate first. Then position
the throat plate so that the needle enters the center of the needle
hole in the throat plate. Then tighten setscrews A in the take-up
plate.

2) Loosen setscrew E in the presser foot holder, and adjust so that
the needle groove in the throat plate is aligned with the slot in the
presser foot. After the adjustment, tighten setscrew E.

3) Loosen setscrew D, and adjust the relation between the throat
plate and the lower feed dog so that a 0.6 ± 0.1 mm clearance, on
the needle center side, is provided between the throat plate and
the lower feed dog. (Refer to the item (12) Adjusting the lower
feed.)

4) Loosen setscrew D, and you can move the presser foot back and
forth. Now, align the presser foot with the center of the needle by
moving the presser foot so that the groove in the presser foot is
aligned with the center of the needle.

−31 −

(15) Adjusting the upper feed eccentric shaft

Standard Adjustment

(16) Adjusting the left looper

Throat plate

Eccentric
shaft pin

Setscrew A Setscrew B

Eccentric
shaft

Standard Adjustment

Coupling

Shaft

Center of the left
looper shaft

Setscrew B

5 to 6 mm

120 ± 1 mm

3 to 4
mm

Left looper

−32 −

Holder

Setscrew A

Left looper
box nut

0.1 to 0.4 mm

Adjustment Procedures Results of Improper Adjustment

1) Loosen setscrew B. Make the ascending lower feed dog flush
with the throat plate surface by turning the handle.

2) Make the descending upper feed dog engage with the lower feed
dog by turning the coupling to move the eccentric shaft. Then
tighten setscrew B.

(Caution) Never loosen setscrew A.

™ Loosen the screw from underside

of the upper frame.

When the time is too early .....

The material will shift to the left.

™ When the timing is too late :

When the feed completes feeding
the material and the upper feed and
lower feed dogs are moving away
from each other, the presser foot
comes down together with the lower
feed dog.

Adjustment Procedures Results of Improper Adjustment

1) Turn the handle until the left looper is brought to the forward end
position toward you. (250˚ to 255˚)

2) Loosen setscrews B, and adjust so that a distance of 5 to 6 mm
is provided between the center of the needle and the left looper
and that a clearance of 0.1 to 0.4 mm is obtained between the
needle and the left looper. After the adjustment, tighten setscrews
B.

3) Loosen setscrew A, and adjust so that a height difference of 3 to
4 mm is provided between the top end of the left looper and the
needle eyelet when the top end of the looper is aligned with the
center of the needle. After the adjustment, tighten setscrew A.

™ If the timing is too early, the left

looper fails to scoop a loop.

−33 −

(17) Adjusting the right looper cam

Standard Adjustment

Cam follower

(18) Adjusting the right looper

Setscrew A

A

Right looper cam

Lever

Standard Adjustment

1) Adjusting the right looper pin

Holder

Bracket

Pin (2)

1 to 3 mm

Nut

31 to 32 mm

Hexagon nut

Setscrew A

Actuating
lever

Adjusting

screw

Pin (1)

Spring 1

Nut

0.1 to 0.5 mm

Right looper pin

9 ± 0.5 mm

Collar

−34 −

Adjustment Procedures Results of Improper Adjustment

1) Turn the handle until the arrow mark indicates 235˚.

2) Adjust so that the cam is set at position A where the cam follower
starts coming down. Then tighten setscrew A.
The position where the cam follower starts coming down is the
position where the right looper starts scooping a loop from this
side.
* When the right looper returns to this side, check that the right

looper does not come in contact with the support sleeve.

Support sleeve

™ If the timing is too early, the thread

becomes tense. If the timing is too
late, the right looper cam comes in
contact with the support sleeve.

Adjustment Procedures Results of Improper Adjustment

1) Turn the right looper pin and adjust so that a distance of 31 to 32
mm is obtained between the center of pin (1) and the center of pin
(2).
Adjust the timing of the right looper to scoop a loop so that the top
end of the left looper is aligned with the top end of the right looper
at the center of the needle.

2) Loosen hexagon nut, and adjust the installing length of right looper
pin spring 1 so that a distance of 9 mm ± 0.5 mm is provided
between the nut and the collar by turning the nut. After the
adjustment, tighten the hexagon nut.
Give the handle several turns and check that the right looper does
not come in contact with the needle bar. If the looper comes in
contact with the needle bar, re-adjust the position of the right
looper.

−35 −

Standard Adjustment

2) Adjusting the relationship between the right looper and the needle

Setscrew B

Bracket

(19) Adjusting the position of the ellipse gear

Standard Adjustment

Setscrew A

Right looper
fulcrum pin

Setscrew C

Right looper

−36 −

Ellipse gear BN (25166406)
(Long side faces just below.)

Adjustment Procedures Results of Improper Adjustment

1) To adjust the distance from the right looper to the needle, turn the
handle until the left looper is brought to the forward end position
toward the operator. Loosen setscrew A (previous item 1)) in the
holder, and adjust so that a distance of 1 to 3 mm is provided
between the needle and the top end of the right looper. After the
adjustment, tighten setscrew A (previous item 1)).

2) Loosen setscrews B, and adjust so that a clearance of 0.1 to 0.5
mm is provided between the right looper and the needle. After the
adjustment, tighten setscrews B.

3) Assemble the right looper and the bracket to allow the right looper
to smoothly move when pressing the right looper fulcrum pin. Then
tighten setscrew C.

Adjustment Procedures Results of Improper Adjustment

1) Loosen six setscrews A in the power lock connecting the ellipse
gear shaft and the gear.

2) Adjust the scale of handle to 130˚.

3) At this time, turn the gear by hand so that the long diameter side
of ellipse gear BN faces just below as shown in the illustration .

4) When the gear is set to the position in the illustration, tighten six
setscrews A in the power lock with 3.92N.m torque.

5) After completion of the aforementioned adjustment, perform (5 ­(20)) Adjusting the lower looper.

(Caution) Perform checking of feed timing. (Check (12)-1)

Adjusting the feed eccentric boss and the lifting cam.)

−37 −

(20) Adjusting the lower looper

1) Adjusting the lower looper arm

Standard Adjustment

Setscrew A

0 to 10 mm

Claw 1

Center of
needle hole

3 to 5 mm
Claw 2

Lower looper
arm

Setscrew B

Lower looper

0.1 to 0.4
mm

C

Claw 1

Needle

Claw 2

Slide block

About the
center in the
clearance

2) Disassembling and assembling the lower looper

1

2

2

1

−38 −

Adjustment Procedures Results of Improper Adjustment

1) Adjusting the height of the lower looper from the needle, and

the clearance between them

1 Align the top end of the lower looper with the center of the needle.
2 Loosen setscrews B, and by moving the lower looper arm adjust

so that the clearance between the lower looper and the needle is

0.1 to 0.4 mm. After fixing the thrust collar C by pressing it to the
lower looper arm, tighten setscrew B so that there is no clearance
between the thrust collar and the lower looper arm.

3 Loosen two setscrews A, and adjust the height difference between

the top end of the lower looper and the center of the needle hole
to 3 to 5 mm. Then tighten setscrews A. At this time (before
tightening the screws), position the top end of the lower looper at
about the center of the clearance between the slide block and the
top face of the claw end. Turn the handle, give the lower looper
arm one turn, and check that the top end of lower looper does not
touch the periphery of the drum. Then tighten setscrews A.
The position of 83 to 85˚ is the position where the needle guide
claws completely close. Consequently, check that the needle guide
claws are closed when the top end of the lower looper is aligned
with the center of the needle.
Adjust the top end of the lower looper in a state that the play in the
lower looper arm is moved to backward.

2) Adjusting the lower looper and the needle

Turn the handle until the angle board indicates 83 to 85˚.
Loosen arm setscrews B, and adjust so that the distance from the
top end of the lower looper to the center of the needle is 0 to 10 mm.
Then tighten setscrews B.

™ If the adjustment is not proper, a

mistake of lower looper thread
scooping will occur, causing thread
breakage.

Slide case

1) Loosen setscrew 1, and draw out the holder.

2) Before loosening setscrews 2, attach a mark on the holder and
the lower looper. Then disassemble them.

Holder

Lower looper

3) Remove the roller and the bearing mounted on the lower looper,
and remove thread waste, etc. from them.

4) When assembling, follow the aforementioned procedure 1) through

3) for disassembling the lower looper in the reverse order.

Relation of the lower looper and the needle should be the same
as that in the previous item 1).

* After the assembling and adjustment, turn the handle by hand,

and check that the lower looper does not come in contact with
other components.

™ Provide a slightly larger distance

between the looper and the center
of the needle.

™ The distance provided between the

looper and the center of the needle
depends on the position of the
eccentric of the holder.

−39 −

(21) Adjusting the command block and the proximity sensor

Standard Adjustment

Command drum

Command block 1

0.5 ± 0.2mm0.5 ± 0.2

Sensor 1

Setscrew A

Command block 2

mm

Sensor 2

(22) Adjusting the feed, reverse stitching position, and the proximity sensors

Standard Adjustment

Sensor B

Sensor A

Sensor

reflecting

plate

Sensor A

Setscrew

0.5±0.2 mm

Sensor

reflecting

plate

Sensor B

Sensor nut

Sensor

Setscrew

Groove

Sensor B

−40 −

Adjustment Procedures Results of Improper Adjustment

1) Bring the machine to its home position (0˚).

2) Loosen two setscrews A of the command drum.

3) At this time, release sensor 1 from command block 1 and let
sensor 2 enter command block 2. Then tighten setscrews A.

4) The clearance between each sensor and each block should be

0.5 ± 0.2 mm.

Sensor 1 ........Feed change-over timing sensor

When sensor 1 moves away from the command
block, the operative feed changes over between
the top feed and the bottom feed.

Sensor 2 ........Feed start sensor

This is the sensor to detect the stitch length on
the right side or the wrong side of the material.

™ If the clearance is not correct, the

sensor does not detect correctly,
causing defective feed.

Adjustment Procedures Results of Improper Adjustment

1) Adjusting the clearance between the sensor and the sensor
reflecting plate

Adjust with the sensor nut so that a clearance of 0.5 ± 0.2 mm should
be provided between each top end of sensors A and B and the
sensor reflecting plate.

2) Adjusting the position of sensor B (reverse stitching sensor)

Stitch length of the reverse stitching depends on the position of sensor B.
Loosen the sensor nut, move sensor B inside the groove, and fix it
at the position where the stitch length for reverse stitching becomes
1 to 3 mm.
At this time, be careful not to change the clearance between the
sensor and the reflecting plate.

−41 −

(23) Adjusting the needle stopping position

Standard Adjustment

Upper stopping
position

Throat plate

Intermediate
lower stopping
position

From downward
to upward

Intermediate
upper stopping
position

FLS-350N

Detecting plate

C

B

A

Fixing screw of the
detecting plate

Detector

Cover

Cover screw

FLS-350NA • NB
FLS-351NA

A

Detecting plate

B

Fixing screw of the

detecting plate

Cover

−42 −

Adjustment Procedures Results of Improper Adjustment

In case of FLS-350N :

1) Loosen the cover screw and remove the cover.

2) Slightly loosen the fixing screw of the detecting plate.

3) Bring the machine to its home position (0˚), and adjust the upper
needle stopping position by aligning the slit of detecting plate A
with the detector.

4) Adjust the intermediate upper stopping position of the needle by
aligning the slit of detecting plate B with the detector so that the
angle board points 30˚ ± 2˚.

5) When adjusting the intermediate lower stopping position of the
needle, stop the machine at the angle of 210˚ ± 2˚. Then align the
slit of detecting plate C with the detector.

6) Tighten the fixing screw of the detecting plate.

7) Turn ON the power switch and operate the foot pedal to check
the respective stopping positions of the needle.

8) Install the cover.

In case of FLS-350NA • NB and FLS-351NA :

1) Loosen the cover screw and remove the cover.

2) Slightly loosen the fixing screw of the detecting plate.

3) Bring the machine to its home position (0˚), and adjust the upper
needle stopping position by aligning the slit of of detecting plate
B (black color) with the detector.

4) Adjust the intermediate upper stopping position of the needle by
aligning the slit of detecting plate A (red color) with the detector
so that the angle board points 30˚±2˚.

5) Adjustment of the intermediate lower stopping position of the
needle has been set with SC-380 so that the machine stops at
the angle of 210˚.

6) Tighten the fixing screw of the detecting plate.

7) Turn ON the power switch and operate the foot pedal to check
the respective stopping positions of the needle.

8) Install the cover.

™ If the stopping position of the needle

shifts, causing defective stitches or
needle breakage.

−43 −

(24) Adjusting the tension of the timing belt of the feed stepping motor

Standard Adjustment

2 to 3 mm

Stepping
motor pulley

Fulcrum shaft

Setscrew A

P

Timing belt

Stepping
motor

(25) Adjusting the threader needle during replacement

Standard Adjustment

Timing belt

FLS-350N FLS-350NA • NB

FLS-351NA

Threader needle

Threader
needle

ø1.17

Nut B

ø1 hole

Lever

Locknut A

3 to 5 mm

Needle fixing pin

3 to 5 mm

Screw A

−44 −

Adjustment Procedures Results of Improper Adjustment

Loosen setscrews A, and adjust the tension of the timing belt so that
the belt slackens by 2 to 3 mm when 300g of tension are applied on
the belt in direction P.

™ If the timing belt of the stepping

motor is not sufficiently tensed, the
stitch length may be inconsistent.
On the other hand, if the timing belt
is excessively tensed, an excessive
load may occur on the feed shaft
unit. So adjust the tension applied
to the timing belt so that the fulcrum
shaft of the pulley (small) can be
smoothly turned by hand.

Adjustment Procedures Results of Improper Adjustment

In case of FLS-350N :

Loosen locknut A. Remove nut B and pull out the threader needle.
When attaching the threader needle, install it so that it protrudes
from the needle eyelet by 3 to 5 mm when inserted through the needle
eyelet. Then tighten locknuts A and B.

In case of FLS-350NA • NB and FLS-351NA :

Loosen screw A and pull out the threader needle. When attaching
the threader needle, install it so that it protrudes from the needle
eyelet by 3 to 5 mm when inserted through the needle eyelet. Then
tighten screw A.

−45 −

(26) Adjusting the angle of the foot pedal, and the foot pressure of the pedal (FLS-350N only)

Standard Adjustment

Spring 1

A

Knob
Locknut
Spring 2

B

Lever

Rod end

Stay

Pedal

P1

Installation
hole

P2

Check bolt

(27) Servomotor controller box connection diagram

Standard Adjustment

FLS-350N

Synchronizer cable

SC-1

FLS-350NA • NB
FLS-351NA

Synchronizer

Connecter for
synchronizer

−46 −

SC-380

Adjustment Procedures Results of Improper Adjustment

1) Loosen the check bolt, and adjust the angle of the foot pedal by
changing the attaching length of the rod end or installation hole of
the stay to be used.

2) Adjust the foot pressure of the pedal following the procedure
described below.
1 Adjusting the pressure to be applied to the front part of the foot

pedal
Adjust the pressure at position P1 to 2 to 4 kg by changing the
position to which the lever spring of spring 1 at section A is
hooked.

2 Adjusting the pressure to be applied to the rear part of the foot

pedal
Turn the knob to loosen the locknut, and adjust spring 2 at
section B so that a pressure of 7 to 10 kg is applied to position
P2. After the adjustment, be sure to tighten the locknut.

Adjustment Procedures Results of Improper Adjustment

Connect the detector (synchronizer).

−47 −

(28) Disassembling/assembling the needle bar

Standard Adjustment

The period for disassembling and cleaning of the needle bar depends on the operation frequency, however,
be sure to disassemble and clean the needle bar components once a week. If dust accumulates in the
needle bar components, troubles in sewing may result. Be sure to perform disassembling and cleaning
earlier to prevent the troubles from occurring.

1 Locknut

4

8 Support cylinder

2 Needle bar
3 Rubber washer

!0 Stop pin

!5 Steel ball

9 Snap ring

!1 Lock spring

!2 Stop spring

!3 Needle holder pin
!4 Steel ball holder

7 Connecting pin

!6 Support holder

Support sleeve !6

5 Bar spring

6 Support sleeve rod

Setscrew A

Support cylinder 8

Elevating
boss

Snap
ring 9

Spring
check bolt

Stop pin !0

!0

!2

!3

Steel ball !5

Support sleeve rod 6

Connecting
pin 7

−48 −

Lock spring !1

Stop spring !2

Steel ball holder !4

Needle holder
pin !3 Support sleeve !6

Adjustment Procedures Results of Improper Adjustment

Disassemble/assemble the needle bar components following the
procedure described below.
The procedure is common to the upper needle bar and the lower
needle bar.

1) Slightly loosen check bolt 4 of the spring first with the needle bar
attached in place.

2) Turn the handle until the screw in the elevating boss appears before
you. Now, loosen setscrew A, and remove the needle bar from
the main unit of the sewing machine.

3) Completely loosen check bolt 4 of the spring, and remove the
snap ring. (Refer to the item (29) “Removing the snap ring when
disassembling the needle bar”)

4) Draw out stop pin !0 from support cylinder 8.

5) Detach support sleeve !6 from support cylinder 8.

(Caution) At this time, be careful not to lose two steel balls !5.

6) Push connecting pin 7 out from support sleeve !6.

7) Detach lock spring !1 and steel ball holder !4 from support sleeve
!6.

8) Remove needle holder pin !3 and stop spring !2 from steel ball
holder !4.

9) Inspect and clean the components.

(Inspection items)

1 If stop spring !2 has broken or its inside part has been clogged

with dust or has broken, replace stop ring !2 with a new one.

2 If the top end of needle holder pin !3 has broken or inside hole

has been clogged with dust and has been damaged, replace the
pin. If the hole has been clogged with dust, clean the pin.

3 Clean the inside of support sleeve !6 and support cylinder 8.

10) Assemble the needle bar components by reversing the above

procedure from step 8) to step 1).

(Caution) When assembling the needle bar, be careful to position

needle holder pin !3 and stop spring !2 as illustrated when
inserting stop pin !0 in place.

−49 −

(29) Removing the snap ring when disassembling the needle bar

Standard Adjustment

1

3

5

2

2 to 3 mm

4

−50 −

Adjustment Procedures Results of Improper Adjustment

1) Hold the needle bar as shown in 1. At this time, be sure to place
your index finger on the back of the snap ring.

2) Using a needle, slightly take out either end of the snap ring from
the groove. At this time, the lift amount of the end of the snap ring
should be approximately 2 to 3 mm as shown in 2.

3) Press the end (arrow mark section) of the snap ring taken out
from the groove with your thumb, and release your index finger
from the back of the snap ring.

4) Pressing the end of the snap ring with your thumb, slowly turn the
needle bar, and gradually remove the snap ring from the groove
using the tip of a needle.

5) Place the snap ring removed from the groove around the needle
bar as shown in 5.

Provided that the snap ring is removed in accordance with the
above-mentioned procedures, there will be no excessive tension
on the snap ring. There will therefore be no decrease in the spring
of the snap ring.

(Caution) If the snap ring is fitted in the groove in the needle

bar, replace the ring if it comes out of the groove or a play is
excessive.

™ If the snap ring is widened and

protrudes from the needle bar,
machine lock during sewing will
occur.

−51 −

6. ELECTRICAL COMPONENTS

(Caution) 1. When installing or removing a printed circuit board, be sure to turn the power OFF first.

2. Do not touch the connectors of a printed circuit board.

(1) Printed circuit boards in the control box

FLS-350N

FLS-350NA • NB
FLS-351NA

1 Lights up when proximity switch NS-1 (feed start

sensor) is ON...................................................CR 1

2 Lights up when proximity switch NS-2 (feed change-

over timing sensor) is ON. ...............................CR 2

3 Lights up when proximity switch NS-3 (feed origin

retrieval sensor) is ON. ....................................CR 3

4 Lights up when proximity switch NS-4 (reverse stitching

sensor) is ON...................................................CR 4

5 Lights up while reverse stitching command switch PB-

2 is ON.............................................................CR 5

6 Lights up when stitch change-over switch PB-1 is ON.

.........................................................................CR 6

7 Max. stitch length setting variable resistor VR1

The range of the maximum stitch length adjusted by
the max. stitch length setting variable resistor is 8 ±

0.3 mm.
Adjust the variable resistor within the specified range.

8 Min. stitch length setting variable resistor VR2

The range of the minimum stitch length adjusted
by the min. stitch length setting variable resistor is

+0.3

0.6 mm.

–0.1

Adjust the variable resistor within the specified range.

Turn the respective stitch length setting variable
resistors clockwise to maximize the max. or min.

stitch length, or counterclockwise to minimize it.
9 Max. rotating speed setting variable resistor VR3
!0 Min. rotating speed setting variable resistor VR4

Turn the respective rotating speed setting variable

resistors clockwise to minimize the max. or min.

rotating speed, or counterclockwise to maximize it.

(Caution) The variable resistors have already been

factory-adjusted at the time of delivery, so
do not adjust them unless absolutely
necessary.

− 52 −

7. MAINTENANCE AND INSPECTION

™ Be sure to carry out the following maintenance and inspection procedures at regular intervals in order to keep

the machine in best condition at all times.

™ Failure to carry out maintenance and inspection may cause the machine to malfunction.

(1) Electrical components

™ Once a month, check all the connectors for loose contact caused by mechanical vibration or some other

reason.

(2) Mechanical components

™ Lubricate the moving and sliding parts of the machine. (Refer to the next page.)
™ Disassemble the needle bar, wipe away any dust, and grease the needle bar assembly once a week. (Refer to

the item (29).)

™ Grease each gear, cam and cam groove once every six months. (Refer to the next page.)
™ Periodically check the belt tension.

Using the tension roller, adjust the belt tension so that the
center of the belt slackens by about 5 mm when a 1.6 to

2.1 kg load is applied.

5 mm

(Caution) Be careful not to allow any oil to drop or

1.6 to 2.1 kg

splash onto the belt.
If the machine runs with the belt loosened,
excessive slippage may occur resulting in
the machine malfunctioning. To avoid this,
be sure to carry out periodical maintenance
and inspection.

− 53 −

Period

Everyday

Once a week

Once a week

JUKI New Defrix
Oil No. 2

JUKI New Defrix
Oil No. 2

JUKI New Defrix
Oil No. 2

Bearings 1 of upper and lower
needle bars

2

1

Upper feed link 2

Feed drive link A

1

Every six
months

Every six
months

Every six
months

Every six
months

Grease

Grease

Grease

Grease

Ellipse gear
Other gears

Tubular roller cam 4 of the needle
guide claw

Tubular roller cam 5 of the thread
haul lever

Feed eccentric boss 6

2

A

4

2

5

− 54 −

6

Period

Every six
months

Every six
months

Grease

Grease

Slide blocks 7 of elevating bosses
of the upper and lower needle bars

7

(Lower needle bar) (Upper needle bar)

Groove cam wheel 8
Grease the whole surface of the
internal groove.

8

7

8

(3) Consumable parts replacing period table

• The needle bar contains the following consumable parts.
The following table indicates the time to replace these parts. So periodically replace the respective consumable
parts referring to the table below.

Expendable part

1. Stop spring
(25217704)

2. Snap ring
(G5513340000)

3. Needle holder pin
FLS-350N : 25250002
FLS-350NA • NB : 25250010
FLS-351NA : 25234105

4. Rubber washer
(16661704)

5. Thread guide brush
(25240102)

Time for replacement

3 to 6 months

2 to 6 months

0.5 to 1.5 years

0.8 to 1.5 years

0.5 to 1.5 years

Description

In addition to the regular time for replacement, replace them
if it breaks when disassembling the needle bar.

It is recommended to replace the snap ring earlier than the
designated time for replacement. If any gap is found when
fitting the snap ring in the groove on the needle bar support
cylinder or the snap ring is damaged, has burrs or has worn
out, replace the snap ring with a new one.

If the top end of the needle holder pin becomes chipped,
replace it with a new one. If the inside diameter section of
the needle holder pin is clogged with dust, remove the dust
with a drill supplied with the unit.

The rubber washer cracks circularly. Replace the rubber
washer with a new one before it totally breaks. If the rubber
washer has become flat, adjust the timing of the needle
bar.

If the rubber washer is crushed, adjust the needle bar timing.
If the brush bristles have worn out and come off, replace

the brush with a new one.

Trouble

Needle
breakage

Needle bar is
pushed against
the bearing.

Needle bar
shifts out of
position.

Blunt needle tip

Needle
breakage

Needle
breakage

Thread
breakage

− 55 −

8. ERROR CODES

If any error is detected while the machine is in operation, the detector buzzer sounds and the corresponding error
code is given on the display panel. Even when the error code is given, however, there is a case that the error is
simply caused by the disconnection of connector. Be sure to check the error according to the following table.

Error code

E 1

E 2

E 3

E 4

Probable cause

8A fuse in control box broken.

Is the power voltage too low?

Is the power supply capacity too small?

Note : It does this display when power supply is turned OFF,

but this is not an error.

Is the wire to the motor short-circuited?

Is the sewing machine load torque too high?

Is the power voltage too high?

Is the sewing machine inertia too high?

Is the connector to the motor encoder securely inserted?

Are the signals from the motor encoder correct?

Is the sewing machine locked?

Is the motor locked?

Is the motor connector (4-pin) securely inserted ?

Are the signals from the motor connector (4-pin) correct ?

Inspection

Replace the 8A fuse.

Check the power voltage.

Check the power supply capacity.

Check the motor wiring.

Check the sewing machine.

Check the power voltage.

Lengthen the deceleration time.

Check the connector insertion.

Check the encoder signals.

Check the sewing machine.

Check the motor.

Check the motor connector insertion.

Check the motor connector.

E 6

E 8

E 9

Is an extraordinary signal inputted?
(The signal as it repeats ON/OFF at the high frequency.)

Does the noise from outside enter an input signal.

Is the position detector connector securely inserted?

Are the signals from the detector correct?
(UP/DOWN signal interruption)

Is the solenoid connection (thread trimming, presser foot lifter, etc.)
short-circuited ?

Is the solenoid wiring short-circuited ?

Check the input signal.

Removes a noise source.

Check the detector connector insertion.

Check the detector UP/DOWN signals.

Check the solenoid wiring.

Replace the solenoid.

− 56 −

Adjust the thread path guide. [Refer to 5-(6).]

Adjust the thread haul lever.

Check both the outside and inside of the drum, and wipe

away any dust.

Adjust the thread path guide. [Refer to 5-(6).]

Adjust the thread haul lever.

Adjust the lower looper. [Refer to 5-(20).]

Properly finish the guide metal fitting, throat plate, looper,

drum, thread path guide, or other related parts.

Adjust the hook finger. [Refer to 5-(9), -(10), -(11).]

Replace the stop spring. [Refer to 5-(28).]

Replace the needle holder pin. [Refer to 5-(28).]

Clean the needle bar. [Refer to 5-(28).]

The stop spring has broken.

The tip of the needle holder pin is broken.

Dust (thread waste) has accumulated on

the needle bar.

The hole in the needle guard pin is clogged

Replace the rubber washer. [Refer to 5-(28).]

Re-adjust the installation position of the needle holder pin

or stop spring. [Refer to 5-(28).]

with dust.

The rubber washer has broken.

The needle holder pin or stop spring

cannot be installed in the predetermined

position.

Adjust the height of the needle bar. [Refer to 5-(4).]

Faulty catching.

Align the centers of the needle bars.

Replace the needle with a new one.

The lower looper has been threaded

twice.

The thread remains in the drum.

The thread is entangled in the lower

looper shaft and looper roller.

The lower looper fails to catch the

thread.

A scratch has appeared on the thread

path.

The hook finger fails to catch the

thread.

Faulty needle bar

Troubles Cause (1) Cause (2) Corrective measures

9. TROUBLES AND CORRECTIVE MEASURES

(1) Mechanical components

1. Thread breakage

− 57

2. Needle breakage

−

The needle fluctuates to the left or

right when it is delivered between the

upper and the lower needle bars.

The needle is bent.

made.

3. Wobbling or waving stitches are

Adjust the min. stitch length fine adjustment variable resistor

VR2 properly. [Refer to 6. Electrical components.]

Adjust the max. stitch length fine adjustment variable resistor

VR1 properly. [Refer to 6. Electrical components.]

Adjust the left looper.

Adjust the hook finger.

Adjust the needle guide claw.

Adjust the right looper. [Refer to 5-(18)]

Buff the thread path.

The left looper fails to catch the thread.

Faulty timing of the hook finger

Faulty claw chuck of the needle guide

The right looper fails to catch the thread.

Scratch on the thread path

Replace the switch.

Check the cable for breakage.

Adjust the proximity sensor.

Replace the snap ring of the needle bar.

Irregular noise sounds from the underside

Apply grease to the gears and cams.

of the table.

Noise sounds from the inside of the pulley

or inside of the frame.

The feed mechanism fails to feed the

material.

Troubles Cause (1) Cause (2) Corrective measures

be made.

4. Stitch skipping

5. The maximum stitch length cannot

Isolated idle loops are made on the

right side of the material.

Isolated idle loops are made on the

wrong side of the material.

Excessive seam tension

6. Loose stitches

− 58

Defective switch

Damaged power cable

The proximity sensor fails to work.

Check the position where makes the

noise.

7. Reverse stitching is invalid.

8. Abnormal noise sounds.

−

Check the wiring.

Replace fuse F1.

Replace fuse F2.

Fuse F1 has blown.

Fuse F2 has blown.

Replace the cable.

Close the drum cover.

The power cable has been damaged.

The drum cover opens.

Check the cable.

Replace the switch.

Replace fuse F3.

Faulty contact of the limit switch

Fuse F3 has blown.

Check whether the connector has been firmly connected.

Replace the detector.

Turn ON the power switch.

Check the connection of the power cable.

properly.

transformer.

1) The transformer is not connected

2) There is no power to the

Troubles Cause (1) Cause (2) Corrective measures

up even though the power switch

has been turned ON.

(2) Electrical components

1. The machine cannot be powered

cover is actuated.

3) The safety device of the drum

4) Faulty contact of the power switch

work.

5) The electromagnetic switch fails to

1) The connector in the control box is

2. The sewing machine motor fails to

−

− 59

not properly connected.

2) Defective detector

3) The power is not turned ON.

rotate.

disconnected.

4) The power cable has been

Replace the driver.

Replace the control printed circuit board.

Replace the proximity sensor.

Check the connector.

Replace the cable.

Check the power supply.

The connector has been disconnected.

The power cable has been damaged.

Replace the switch.

Adjust the belt tension, and turn OFF the power to the

machine once. Or replace the belt.

Faulty stepping motor driver

Faulty signal output from the control

printed circuit board

Faulty proximity sensor

Troubles Cause (1) Cause (2) Corrective measures

3. The stepping motor fails to run.

Defective power cable

The stepping motor driver cannot be

actuated.

Faulty switch contact

invalid.

4. Change-over of the switch is

The belt between the main shaft and

the intermediate shaft excessively

slacks.

(Synchronizer error)

the pedal, the machine stops

immediately without rotating until

the home position is reached.

5. When moving your foot away from

−

− 60

10. TIME CHART

330

300 360

270

240

210

180

150

255.4˚

252.4˚

2.6 mm

270˚

209.4˚

Needle transfer

222˚

182˚

196˚

166˚

295˚

2.1mm

265˚

255˚

235˚

190˚

180˚

Exreme forward end

345˚

280˚

270˚

Stop near to the needle

255˚

Retreat

250˚

360˚

Neutral

270˚

210˚

Right end stop

170˚

360

345˚

330

320˚

300

Slight opening section

275˚

270

250˚

1.5

Full opening

145˚
140˚

240

210

180

165˚

150

720˚

630˚

540˚

450˚

360˚

270˚

660˚

520˚

300˚

700˚

480˚

340˚

500˚

680˚

320˚

360

Main shaft angle

330

300

270˚

240

210

180˚

150

90 120

60

30

0

-60˚

120

90˚

60

30

0˚

-30˚

Lower looper position

30˚

60˚

210R

90˚

90˚

120˚

180˚

150˚

180˚

210˚

240˚

270˚

2

1

Ratio of angle to speed

120

Thread haul S +2.6 mm

90 ˚

75.4˚

72.4˚

42˚

Most approach section

37˚

(Distance : 23.6 ± 0.1mm)

35˚

29.4˚

2˚

43.9

Height of support cylinder

1.5 mm

10.5

Throat

Needle transfer

-10.5

plate

Thread grasp closing section

86˚

60˚

0

9

-46.5

(Cam lift)

(Slide case St.)

Needle grasping cam

Right looper retreat section

25˚

0˚

0

6.8

Rightlooper cam

2˚

13

(Cam lift)

100˚

Neutral section

72˚

0

6.5

(Cam lift)

Left looper cam

10

110˚

Left end stop

80˚

20˚

0

Thread haul 5

4

(Cam lift)

105˚

0

Brush cam

Lower feed/upper feed

90

180˚

160˚

60

30

1:1 Shaft angle

120˚

90˚

0

1.5

(Cam lift)

Lower feed lifting cam

Double speed shaft angle

140˚

7

0

-7

Lower feed accentric boss

Presser goes up.

Presser comes down

4

0

-4

Upper feed accentric shaft

-90˚

− 61 −

11. CIRCUIT DIAGRAM

(1) Layout drawing of the control box

CN6

Stitch length adjusting variable resistor

1

Stitch length adjusting variable resistor

2

Stitch length adjusting variable resistor

3

Stitch length adjusting selecting switch

4

Stitch length adjusting selecting switch

5
6

Switch regulator

+12 V

GND

CN6

Yellow

1
2
3
4
5

6

White

Black

Red

Brown

Green

White
Black
Black

J2

+12 V

1

1

2

2
3

GND

3

Control printed circuit board

J5

+5 V

1

1

Stitch length adjusting variable resistor input

2

2
3

GND

3

Stitch length adjusting selecting switch input

4

4

5

5

GND

With/without adjusting

6

6

With/without adjusting

7

7

Short : With adjusting
Open : Without adjusting

25209958

J3

+12 V
+12 V

Speed variable resistor
Speed variable resistor

Upper stitch length setting variable resistor
Upper stitch length setting variable resistor
Upper stitch length setting variable resistor
Lower stitch length setting variable resistor
Lower stitch length setting variable resistor
Lower stitch length setting variable resistor

Stitch length selecting switch
Stitch length selecting switch NO

Speed variable resistor

NC

GND
GND

Stitch length selecting switch NC

GND

Stitch length selecting switch NO

Red

J3

11

2

2

3

3

4

4
5

5

6

6
7

7
8

8
9

9

10

10
11

11
12

12
13

13
14

14

15

15

16

16

J3

+12 V
+12 V

VR-1A

Machine rotation speed
setting variable resistor

1K

VR-2A

Machine rotation speed
setting variable resistor

1K

VR-3A

Machine rotation speed
setting variable resistor

1K

NC
NO

Panel printed circuit board

PB-3

Upper/lower
stitch length
selecting
switch

J3

1

Black/White

2
3

Red/White

4
5

Green/white

6

Yellow

7

Yellow/White

8

Brown

9

Brown/White

10
11

Blue/White

12
13

Gray/White

14
15
16

Black

Green

Blue

Gray

1
2

3
4

5

6
7
8
9

10
11
12
13

14
15
16

J6

1

2

3

NS-1

Upper/lower feed sensor

201

CW+

CCW+

CCW-

COM A

COM B

Stepping motor driver

CW-

+CW

-CW

-CCW

J4

Red

1

Green

2

White

3

Black

4

A
A
B

B

Brown

5

Red

6

Yellow

7

Green

8

White

9

Black

10

Yellow

11

+CCW

4321

Black

White

Green

Red

NC

NC

1211 9876 5432

10

Yellow

AC100 V

12

Yellow

13

Brown

Red

Yellow

Green

White
Black

Feed motor power sensor input

GND

Purple

CN9

1

2

3

4
5
6

Feed timing sensor input

+12 V

Reverse stitch switch input

Blue

Upper/lower feed sensor input

Reverse stitch power sensor input

Red

Green

Brown

Orange

GND

Black

White

CN9

Black

A

1

Green

2

A

Yellow

B

3

Red

4

B

Blue

5

COM A
COM B

6

White

Speed command output

J2

1

Black

Stepping

motor

(Feed amount determined)

Red

Brown

Red
Red

Orange

Yellow

Black

Green

Blue

Black

Black

Purple

Black

White

Black

Terminal board

P

(+12V)

201

(Upper/lower feed sensor)

202

(Feed timing sensor)

P

(+12 V)

N

203

(Feed motor origin sensor)

204

(Reverse stitch origin sensor)

N

205

(Reverse stitch switch)

N

301

302

(Speed command)

303

(GND)

Brown
Brown
Black

Black
Brown

Brown
Blue
Blue

Black

Black

Blue
Blue

White

Black

White

Black

Black

White

CN6

1
2
3
4
5

SC-1

CN6

GND

1
2
3
4

Speed command

5

Encoder output

Drive output

7. NC

6. UDET

5. +5 V

4. SG

3. SG

2. X-DET

1. D-DET

CN9

1 to 7

CN3

CN92

CN91

NS-3

NS-4

PB-5

CN3

10

10

P

P

CN92

4

4

P

P

CN91

1

1
2

2

3

3

4

4
5

5

6

6

NS-2

Feed timing sensor

202

Feed motor origin sensor

203

Reverse stitch origin sensor

204

Reverse stitch switch

205

Main motor

Control printed circuit board JA

M8601351JAAA

Brown

200V

Blue

200V

Blue

Green/Yellow

FG

SYNC

− 62 −

(2) Wiring diagram

A

B

F1

(10A)

M1

R2

CN91

R

TE

Operation printed circuit board

Machine rotation speed

T1

PB1

T2

R1

240
230

220
200

0

TR1

(200 VA)

F3

100V

0V 4

12

5

(3A)

M1

PB2

setting variable resistor

Stitch changing variable resistor
J
3

3

Drum
cover
switch

Stitch changing variable resistor

Upper/lower stitch length

selecting switch

VR

CN6

Stitch length adjusting setting
variable resistor

SS1

Stitch length adjusting selecting

M1

(10A)

F2

switch

AVR1

ACL

ACN+V-V

FG

P (+12 V)

N (0V)

J3 J5

J

1

Control printed circuit board

J6

Needle position detecting sensor

NF1

5 A

2

3

4 A

1

4

Flexible light

CN93

Sewing machine

Sewing machine

motor controller

CN92CN3

MTR1

motor

FS-1

Foot pedal

CN6

AC100 VFG

Stepping motor driver

AB

J
4

J2

+

CW

COM A

+

-

COM B

CCW

-

CN9

PM1

Stepping motor

301, 302, 303

TB2

205,N

P,201,N

P,202,N

P,203,N

P,204,N

CN8

NS-1

Feed start

NS-2 Feed timing

NS-3

NS-4

Feed origin

Reverse stitch

PB-5 Reverse stitch command

− 63 −

(3) Cable connection diagram

A

B

P

25210352

J1

+V

N

-V

AVR1

J2

25208518

FG

J5

25208455

16552952

25208554

FG

5A

(L)

AC

AC

Control printed

J6

4A

(N)

circuit board

J3

5A

3

4

4A

25207259

NF1

J4

FG

25207952

5

25207051

2

1

4

25206954

5

T1

135139

R2

M1

25206855

T
R1

4

10 2 4 6 14

25206756

25210857

25210956

25207655

1

T

1

R

2

T

2

R

25206459

25206558

25206657

54321 RTE

25207150

25207457
25207358
25207853

T2

F2

T1

R1

R

F1

25207754

25208356

TB1

To be the twist pair type wire.

25208257

1

2

-

+

CW

Stepping motor driver

3

+

4

-

CCW

5

6

7

A

B

25212507

25208059

8

9

101112

COM A

COM B

4

5

AC100 V

*1 *2

FG

13

2

FG

F3

1

P

TB2

201

202

P

N

203

204N205N301

302

303

25208653

16554156

CN6

J3

25208356

CN9

− 64 −

*1: 25207358

*2: 25207457

12. DRWAING OF THE TABLE

20.5

411.2
385

Working is not

necessary because of

field assembly.

R50

Working is not

R

Z

necessary because
of field assembly.

R50

18

Top

surface

Melamine

decorative

board

X-X (1 : 1)

+0.5
0

21.5

385.5 434.5

68

18

R

R

100

25

R

68

100

Z

2-2 drilled hole,

depth 10

381 40

340

174

Center of
needle

386

30

203

190

45

800

15

Urban white painting (bottom surface)
(Y2)

W-W (1 : 1)

540

520

460

140

235

R50

Y

Y

3-ø45

193

205

256

W

106.5

4

R50

W

226.2 88.8
315

88.8

(620)

R50

R50

266.2

490

1200

R50

520

R50

106.5

540

R50

580

230

235

X

R8

4

R27.5

X

52.5

90

195

2-3.5 drilled
hole, depth 10

R8

R27.5

27.5

R50

310

55

41

10

109˚

45˚

25

R10

Urban white painting (all around end grain)
(Y2)

※R without designation is R10.

5

Z-Z (1 : 1)

Y-Y (1 : 1)

3

Part No. : 25235409

− 65 −

R

Electronic Handstitching Machine

FLS-350N Series

ENGINEER’S MANUAL

29311107

No.01

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 this machine intended for the maintenance personnel and operators at an apparel
factory contains operating instructions in detail. And this manual describes “Standard Adjustment”, Adjustment
Procedures”, “Results of Improper Adjustment”, and other important information which are not covered in the
Instruction Manual.
It is advisable to use the relevant Instruction Manual and Parts List together with this Engineer’s Manual when
carrying out the maintenance service of this machine.
Regarding the motor for the sewing machine with automatic thread trimmer, separately refer to the Instruction
Manual for the motor and Engineer’s Manual. In addition, for the control panel, refer to the Instruction Manual
for the control panel.
This manual gives the “Standard Adjustment” on the former page under which the most basic adjustment value
is described and on the latter page the “Adjustment Procedures” and “Results of Improper Adjustment” under
which the steps of adjusting procedure, and stitching errors and troubles arising from mechanical failures are
described.

CONTENTS

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

2. EXPLANATION OF UNITS......................................................................... 2

(1) Configuration .............................................................................................................2

(2) Operation panel (1 Operation panel) .......................................................................3

3. EXPLANATION OF STITCH LENGTH COMPENSATION FUNCTION..... 5

(1) Function.....................................................................................................................5

1) In case the upper stitch becomes small...........................................................................................5

2) In case the upper stitch becomes large ...........................................................................................5

(2) Operation...................................................................................................................5

4. NEEDLE BAR CURVE AND TIMING ADJUSTMENT CHART ................. 6

5. STANDARD ADJUSTMENT ...................................................................... 8

(1) Before making the adjustments ................................................................................8

(2) Adjusting the home position (adjusting the graduation)............................................8

(3) Adjusting the needle bar groove cam and the left looper cam ...............................10

(4) Adjusting the needle bar.........................................................................................12

1) Adjusting the height of the support cylinder of the upper needle bar.............................................12

2) Adjusting the height of the support cylinder of the lower needle bar .............................................12

3) Adjusting the timing of transferring the needle ..............................................................................14

4) Centering the needle bar ...............................................................................................................14

(5) Adjusting the needle guide claw .............................................................................16

1) Adjusting the needle and the needle guide claw ...........................................................................16

2) Adjusting the thread tension of the needle guide claw ..................................................................16

3) Adjusting the timing of opening/closing the tubular cam of the needle guide claw ........................18

(6) Adjusting the thread path guide..............................................................................18

(7) Adjusting the thread haul lever ...............................................................................20

1) Cam timing.....................................................................................................................................20

2) Adjusting the thread haul lever ......................................................................................................20

(8) Adjusting the brush cam .........................................................................................22

(9) Adjusting the hook finger ........................................................................................22

1) Adjusting the movement amount of the hook finger .......................................................................22

2) Adjusting the rotating shaft and the tension spring........................................................................24

3) Adjusting the clearance between the hook finger and the needle .................................................24

(10) Adjusting the hook finger to release the thread tension .......................................26

(11) Adjusting the eccentric amount of the eccentric pin .............................................26

(12) Adjusting the lower feed .......................................................................................28

1) Adjusting the feed eccentric boss and the lifting cam....................................................................28

2) Adjusting the height of the lower feed dog and the throat plate.....................................................28

(13) Adjusting the upper feed dog and the lower feed dog ..........................................30

(14) Adjusting the presser foot.....................................................................................30

(15) Adjusting the upper feed eccentric shaft ..............................................................32

(16) Adjusting the left looper ........................................................................................32

(17) Adjusting the right looper cam ..............................................................................34

(18) Adjusting the right looper......................................................................................34

1) Adjusting the right looper pin .........................................................................................................34

2) Adjusting the relationship between the right looper and the needle ..............................................36

(19) Adjusting the position of the ellipse gear ..............................................................36

(20) Adjusting the lower looper ....................................................................................38

1) Adjusting the lower looper arm ......................................................................................................38

2) Disassembling and assembling the lower looper...........................................................................38

(21) Adjusting the command block and the proximity sensor ......................................40

(22) Adjusting the feed, reverse stitching position, and the proximity sensors ............40

(23) Adjusting the needle stopping position .................................................................42

(24) Adjusting the tension of the timing belt of the feed stepping motor ......................44

(25) Adjusting the threader needle during replacement...............................................44

(26)

Adjusting the angle of the foot pedal, and the foot pressure of the pedal (FLS-350N only) .....

(27) Servomotor controller box connection diagram ....................................................46

(28) Disassembling/assembling the needle bar ...........................................................48

46

(29) Removing the snap ring when disassembling the needle bar ..............................50

6. ELECTRICAL COMPONENTS ................................................................ 52

(1) Printed circuit boards in the control box..................................................................52

7. MAINTENANCE AND INSPECTION ....................................................... 53

(1) Electrical components.............................................................................................53

(2) Mechanical components.........................................................................................53

(3) Consumable parts replacing period table ...............................................................55

8. ERROR CODES ....................................................................................... 56

9. TROUBLES AND CORRECTIVE MEASURES ....................................... 57

(1) Mechanical components.........................................................................................57

(2) Electrical components.............................................................................................59

10. TIME CHART.......................................................................................... 61

11. CIRCUIT DIAGRAM ............................................................................... 62

(1) Layout drawing of the control box...........................................................................62

(2) Circuit diagram........................................................................................................63

(3) Cable wring diagram...............................................................................................64

12. DRWAING OF THE TABLE ................................................................... 65

R

INTERNATIONAL SALES H.Q.

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

PHONE : [phone] to 4005
FAX : [phone] • 4914 • 4984
TELEX : J22967

Copyright C 1997-2001 JUKI CORPORATION.
All rights reserved throughout the world.

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.

01 · 09 Printed in Japan (E)