JUKI HZL-E70 User manual

SERVICE MANUAL
HZL-E70
COMPUTER SEWING MACHINE

CONTENTS
[1] PRODUCT SPECIFICATIONS FOR HZL-E70 ································ 1
[2] NAMES OF THE RESPECTIVE COMPONENTS ······························ 3
[3] HOW TO REMOVE THE OUTER COMPONENTS ··························· 5
[4] CIRCUIT BOARD CONNECTION DIAGRAM ···································· 9
[5] ADJUSTMENT OF THE RESPECTIVE COMPONENTS ·················· 11
5-1-1 Adjusting the needle bar height ················································· 11
5-1-2 Adjusting the zigzag width needle entry position ···················· 11
5-1-3 Feed dog height ··········································································· 12
5-1-4 Timing belt ···················································································· 12
5-1-5 Feed timing ··················································································· 13
5-1-6 Needle-to-hook timing ···························································· 13,14
5-1-7 Clearance between the needle and the blade point of the hook ····· 15
5-1-8 Position of the bobbin case stopper plate ································· 15
5-1-9 Adjusting the bobbin thread tension ········································· 16
5-1-10 Opening amount of the pre-tension disk ·································· 16
5-1-11 Opening amount of the tension disk ········································· 16
5-1-12 Adjusting the needle thread tension ········································· 17
5-1-13 Tension knob ················································································ 17
5-1-14 Vertical position of the threader hook ······································· 18
5-1-15 Adjusting the position of the presser lifting switch ················· 18
5-1-16 Adjusting the position of the BH switch ···································· 19
5-1-17 Longitudinal feed ········································································· 20
5-1-18 Service mode ··············································································· 20
WARNING :
• When disassembling, assembling or adjusting the sewing machine, remove the
power plug.
• When assembling, be careful about the electrical cord being caught with other
components, damage to the covered parts of the cord or miswiring.
• When replacing the part(s), use the genuine part(s).
To avoid the risk of fire, electric shock, injury to persons or damage to
components, especially keep the following:

[1] PRODUCT SPECIFICATIONS FOR HZL-E70
-1--1-
-1--1-
-1-
• 220-230V AC common to 50/60 Hz
• 120V AC common to 60 Hz
• 100W (Lamp : 240V/15W)
• 1A (Lamp : 120V/15W)
• Dimensions : Main unit : 410 mm (W) X 180 mm (L) X 300 mm (H)
Case set : 440 mm (W) X 215 mm (L) X 305 mm (H)
• Weight : Main unit : 7.3 kg
Case set : 8.4 kg
• Slide speed control
Straight stitching 115 to 900 rpm
Pattern sewing 115 to 750 rpm
Bobbin winding 115 to 900 rpm
Reverse stitching 115±10 rpm (at low speed)
• Controller
The slide speed control is effective even when the controller is used.
It is possible to stop the machine only when the stop button is used.
Number of revolutions is the same as the slide speed control above.
• Safety control
If the sewing machine motor shaft is locked, the power supplied to the
motor is stopped after approximately 0.5 to 0.6 seconds.
If the motor becomes extraordinarily hot, the thermal switch built in the
motor stops the power supplied to the motor. It is possible for the motor to
start again after natural cooling.
The machine stops with its needle down when sewing is completed.
• The machine stops with its needle down except buttonholing.
• The needle moves up when it is in down position and a pattern
is selected.
• The machine stops with its needle up when the reverse
stitching is completed.
• The machine stops with its needle up when the bobbin is to be
wound.
• The machine stops with its needle up when the machine starts
with the presser lifting lever raised.
• Max. 7 mm depending on the patterns.
When zigzag width is changed with the manual lever, buzzer
sounds at the place where zigzag width is changed and zigzag
width amount is displayed on the numeral display LED for 5
seconds.
• Feed amount changes in increments of 0.2 mm by the variable
resistor for manual adjustment.
When feed amount is changed with the manual lever, buzzer
sounds at the place where feed amount is changed over and
feed amount is displayed on the numeral display LED for 5
seconds.
2.4 mm for straight stitching when the feed is set to “Auto”.
[Power source]
[Power consumption]
[Dimensions and weight]
[Speed control]
[Stop position]
[Zigzag width]
[Feed amount]

• Shift selection by the switch mounted on the panel.
• The pattern changes continuously at a period of 0.5 seconds
when the switch is held pressed for 0.5 seconds or more.
• The pattern is changed over to the pattern adjustment sewing
pattern (darning) by operating start button, power switch and
stitch length manual switch for the service personnel.
(For the details, refer to the item “5-1-18 Service mode”.)
• Practical patterns : 50
• 8 kinds : Bartacking on both sides of buttonholes
Straight buttonholes
Round end buttonholes
Eyelet buttonholes (1)
Eyelet buttonholes (2)
Eyelet buttonholes (3)
Stretch buttonholes (A)
Stretch buttonholes (B)
• Press down the threading lever and turn the hook section by
hand, then the lever automatically returns to the home position.
• Sewing speed : 115 rpm (at low speed)
• Straight stitching : 3 stitches forward and 3 stitches backward at
the start of sewing (S/S-SW)
3 stitches backward and 3 stitches forward at
the end of sewing (REV-SW)
• Max. feed amount : 2.6 mm
In case of less than 2.6 mm, the stitch length
is same as that of forward.
• Sewings other than
straight stitching : 3 stitches backward both
at the start of sewing (S/S-SW) and at the end
of sewing (REV-SW)
• Feed amount : Fixed at 0.6 mm (dumpling lock stitching)
[Pattern selection]
[Number of patterns]
[Buttonhole]
[Automatic needle
threading mechanism]
[Automatic lock stitch]
-2--2-
-2--2-
-2-

[2] NAMES OF THE RESPECTIVE COMPONENTS
-3--3-
-3--3-
-3-
Bobbin winder shaft
Spool pin
Bobbin thread guide
Thread tension dial
Bobbin winding regulator
Thread spool cap
Speed controller
Face cover
Auxiliary bed
Stitch width manual button
Stitch width adjusting lever
Stitch length manual button
Stitch length adjusting lever
Automatic lock stitch button
Reverse stitch button
Start/stop button
Drop feed lever
Stitch selection button
Stitch selection panel
Presser foot lever
Light / Power switch
Hand wheel (pulley)
Handle
Pattern adjusting shaft
Speed controller receptacle
Power cord receptacle

-4--4-
-4--4-
-4-
Thread Cutter
Needle clamp
Feed dog
Buttonholing lever
Presser foot release lever
Needle threader
Presser foot shank
Needle
Presser foot
Hook cover release
button
Hook cover
Bobbin
Throat plate
Bobbin case

-5--5-
-5--5-
-5-
[3] HOW TO REMOVE THE OUTER COMPONENTS
1. Face cover
2. Throat plate
3. Base plate and free arm bottom cover
Remove setscrew [1] in the face cover and
remove the face cover.
Remove setscrews [2] and [3] in the throat plate and
remove the throat plate.
Remove setscrews [4] , [5] and [6] in the rubber cushion of
the base plate, setscrew [7] of the base plate, and height
adjusting screw [8] . (Base plate is removed.)
Remove setscrew [9] in the free arm bottom cover.
[1]
[2]
[3]
[6]
[5]
[4]
[7]
[8]
[9]

-6--6-
-6--6-
-6-
4. Front panel and rear panel
5. Thread spool cover
Remove setscrews (bottom) [10] and [11] in the
front panel (Mas. asm.).
Remove setscrews [12] , [13] and [14] in the rear panel (asm.)
and setscrew (rear) [15] in the front panel (Mas. asm.).
(Lift the presser lifting lever when removing screw [15] .)
Remove setscrew (upper) [16] in the thread spool cover and
setscrew (side) [17] in the thread spool cover. (Lower the thread
take-up support and insert a screwdriver from the face cover
side to remove setscrew (side) [17] in the thread spool cover.)
Open the rear panel in the rear and remove the thread spool
cover upward.
Thread take-up support
[10] [11]
[12]
[15]
[13]
[14]
[16]
[17]
[17]

-7--7-
-7--7-
-7-
6. Front panel
7. Remove front panel and rear panel from frame.
Loosen setscrew (front) [18] in the front panel (Mas. asm.),
setscrew (right) [19] in the front panel main unit and
setscrew (bobbin winder) [20] in the front panel main unit after
removing the thread spool cover.
There are hooking sections on the rear sides of both front and rear panel as illustrated in
the figures below. They are “engaging with the frame holes” and “engaging with the
respective covers”.
mark sectionmark section
[18]
[20]
[19]
Rear panel Front panel
Rear panel Front panel
Rear panel
Front panel
Rear panel Front panel

-8--8-
-8--8-
-8-
On condition that the presser lifting lever is lowered, open a little bit the joint section of
the front and rear covers as illustrated in the figure below.
(Rear panel)
• Remove the convex sections of the front panel and the rear panel from the frame so as to move the convex
sections up from the frame as illustrated in the figure below. Then open the respective panels.
• Open the right side (side of presser bar and face plate) of the rear panel and the joint section of the whole
panel is removed.
Note) Remove the rear panel so as to bring the rear panel near the hand wheel side at
the place of the power switch installing plate since there is a convex shape on
the rear panel.
(Front panel)
• Remove the convex sections of the front panel and the rear panel from the frame so as to move the convex
sections up from the frame in the same way as the rear panel above. Then open the panels.
[a] Draw the free arm section toward you. (Lower section of the front panel)
Then remove in the order below.
[b] Thread tension section
[c] Bobbin winder base section
Frame hole
Frame hole
[a]
[b]
[c]
[a]

-9--9-
-9--9-
-9-
[4] CIRCUIT BOARD CONNECTION DIAGRAM
[Power circuit board]
(230V)
(120V)
[Display circuit board] [Microcomputer circuit diagram]
CN52
Lamp (asm.) Fuse 2A/125V
CN55
Power circuit board
connecting wire (asm.)
CN51
Power switch
Fuse 3.15A/250V
CN53
Power transformer
CN54
Motor (asm.)
CN31
Slide Volume
(asm.)
CN32
S/S switch
circuit board
(asm.)
CN 3
CN 5
CN 6
CN 8
CN 1
CN 2
CN 4
CN 7
CN 9 CN10
CN52
Lamp (asm.) Fuse 2A/125V
CN55
Power circuit board
connecting wire (asm.)
CN51
Power switch
Fuse 5A/125V
CN53
Power transformer
CN54
Motor (asm.)

Connector
No.
CN 1
CN 2
CN 3
CN 4
CN 5
Connection
Bobbin winder switch (asm.)
BH switch base (asm.)
MP detecting circuit board (asm.)
One-stitch switch (asm.)
Main shaft detecting circuit board (asm.)
Connector
No.
CN 6
CN 7
CN 8
CN 9
CN 10
Connection
Display circuit board (asm.)
Power circuit board connecting wire (asm.)
Controller receptacle (asm.)
Needle throw STM (asm.)
Feed STM (asm.)
-10--10-
-10--10-
-10-
Table of microcomputer circuit board connectors
Connection diagram
Feed and needle throw STM φ1 RED
φ3 BROWN
YELLOW
φ2
BLUE
φ4

[5] ADJUSTMENT OF THE RESPECTIVE COMPONENTS
5-1-1 Adjusting the needle bar height
Remove the face cover.
• Dimension from the bottom end of the needle bar pin to the top surface of the throat
plate : 19.7 mm
• The needle eyelet inclines to the right by 5° when a needle is attached.
1. Make a gauge needle which has cut a household needle, HA X 1 to dimension A
and attach it to the needle bar.
2. Prepare an appropriate piece of metal as thick as B. (A = 19.7 mm - B)
3. Bring the needle bar to the lowest point of its stroke and slightly loosen setscrew [1]
in the needle bar connection to the extent that the needle bar does not slip down.
4. Place the piece of metal on the throat plate, move the needle bar up or down by hand
so that the cut section of the gauge needle aligns with the top surface of the piece of
metal, and turn the needle bar by 5° as illustrated in the figure.
5. Temporarily tighten setscrew [1] and securely tighten it after re-confirming the
adjustment.
1. Attach a household needle, HA X 1 #14 to the needle bar and adjust the height of
the needle bar in the same way as the adjusting procedure above so that a distance
of 14.83 mm is provided between the top surface of the throat plate and the tip of the
needle when the needle bar is in the highest point of its stroke.
* Setscrew [1] can be loosened at the position where the needle bar is in the lowest
point of its stroke.
Adjustment
How to adjust 1
How to adjust 2
5-1-2 Adjusting the zigzag width needle entry position
Remove the face cover.
1. Select the zigzag pattern (zigzag width 7 mm) after turning the power switch ON.
2. Adjusting the needle entry position
Loosen the hexagonal eccentric screw and turn the hexagonal eccentric shaft to
adjust so that the tip of the needle is located in the position of 0.5 mm on the right
side from the center of the groove of left stitch base line of the throat plate when the
zigzag width is 7 mm as illustrated in the figure below.
3. After the adjustment, tighten the setscrew.
How to adjust
Lowest point
How to adjust 1 How to adjust 2
Hexagonal
eccentric shaft
Needle
(view from the upper part)
0 to 5°
Gauge needle
Lowest point
Piece of metal
Throat plate
Highest point
A19.7 mm
14.83 mm
HAx1 #14
Setscrew
0.5mm
[1]
-11--11-
-11--11-
-11-

-12--12-
-12--12-
-12-
5-1-3 Feed dog height
Remove the needle plate.
1. Set the feed amount to “0”.
2. Turn the hand wheel and bring the feed dog to its highest point.
3. Loosen shaft [ b ] and make a clearance between the cam and the top end of the shaft
as illustrated in the figure.
4. Put the exclusive tool (jig) to the nut and loosen shaft [ a ] on the left-hand side.
5. Turn shaft [ a ] and adjust so that the height of the feed dog is 1±0.1 mm at the
position of the needle entry hole. Then fix the shaft with the nut.
6. Turn shaft [ b ] and adjust so that a clearance of 0.1 mm is provided between the shaft
and the cam. (To such an extent that the shaft slightly comes down when it is
pressed from the upper side.)
How to adjust
Screwdriver
When shaft [b] is loosened,
shaft [a] comes in contact
with the cam and a
clearance is provided
between the cam and the
top end [c] of the shaft.
5-1-4 Timing belt
Remove the outer components. (Front cover, rear cover and face cover)
1. Loosen the setscrew in the idler installing
base and loosen the tension of the timing
belt.
2. Turn the hand wheel and bring the needle
bar to the lowest point of its stroke.
3. Turn the hook driving shaft and bring the
feed dog to the lowest position of its stroke.
4. Be careful that the aforementioned 2. and
3. conditions do not change, and set the
timing belt so that the screw in the main
shaft pulley (asm.) faces toward you
(screw is temporarily tightened.).
How to adjust
Screw No. 1
Jig
Shaft
Cam
Needle entry hole
[b]
[c]
[a]
1 ± 0.1 mm
0.1 mm
45°

5-1-5 Feed timing
After checking the feed dog height and needle bar height, perform this adjustment.
The feed timing will affect the tightness of the needle thread.
1. Attach HA x 1 #14 needle.
2. Loosen two screws in the main shaft pulley.
3. Turn the hand wheel and lower the needle bar to align
the tip of the needle with the top surface of the throat
plate.
4. Turn the hook driving shaft and move the hook driving
shaft in the direction of rotation so that the top end of
the feed dog aligns with the top surface of the throat
plate in the direction where the feed dog comes down
from the highest point.
5. Temporarily tighten the screws in the main shaft pulley
and check again.
6. After performing this adjustment, check also “Needle-to-hook timing”.
How to adjust
* Adjust so that the tip of the needle aligns with the top surface of the throat plate when the feed dog meets with the top
surface of the needle plate. The tolerance is within the range of the tip of the needle to the lower end of the needle hole.
5-1-6 Needle-to-hook timing
Remove the throat plate, base plate, free arm bottom cover and DF installing base.
1. First, make sure that the needle entry position and the height of the needle bar have
been properly adjusted.
2. Select the straight stitch (left needle position).
3. Then turn the hand wheel by hand to bring the needle bar to the lowest point of its
stroke.
4. Further, gradually raise the needle bar by hand and stop it at point C where the center
of the needle aligns with the top end of the blade of the hook.
5. At this time, make sure that dimension D from the top end of the blade of the hook to
the upper end of the needle eyelet is 1.06 to 1.26 mm. When the dimension is not
proper, perform the adjustment below.
How to check
Upper side in the rear
Main shaft pulley
Front side
-13--13-
-13--13-
-13-
Setscrew of DF installing base (2 places)

1. Loosen the setscrew in the hook drive
gear which is hidden as observed from
the bottom side of the sewing machine
when the center of the needle aligns with
the top end of the blade of the hook.
2. Loosen the setscrew in the hook drive
gear and move it in the direction of
rotation so that dimension D from the top
end of the blade of the hook to the upper
end of the needle eyelet is 1.06 to
1.26 mm when raising (3.27 mm) the
needle bar from the lowest point of its
stroke.
At this time, the backlash with the gear
on the hook side changes according to
the position of the hook drive gear in the
direction of the hook driving shaft. Adjust
the hook drive gear by temporarily
tightening the setscrew while taking care
of both directions of rotation and shaft.
Backlash is small. Torque is large,
and rumbling noise occurs.
Backlash is large. Clattering noise
and skipped stitch occurs.
3. After confirming the adjustment, securely
tighten both of the setscrews.
4. Set DF installing base (asm.) while
placing click section (2 places) of DF installing base (asm.)
in the grooves of vertical feed cam and vertical support cam respectively.
5. Temporarily tighten two setscrews of DF installing base.
6. Adjust DF installing base (asm.) to the position where the clearance between the edge
of hook driving shaft metal and the edge of vertical feed cam is 1 to 1.5 mm, and securely
tighten two setscrews of DF installing base.
• DimeAfter adjusting the hook, wipe out the race face of the hook or the bobbin case with
alcohol since there may be a case where dirt, oil, grease, etc. stick on the race face of the
hook or the bobbin case. Otherwise, running noise, noise from the bobbin case, noise of
slip-off of the thread, etc. will happen.
1.06
to
1.26 mm
Outer hook
Screw No.1
Screw No.2
Small
Hook
drive gear
C
D
3.27 mm
Backlash
Large
How to adjust
Caution
-14--14-
-14--14-
-14-
Hook driving shaft metal
Vertical feed cam
Vertical
support
cam
Vertical feed cam
Click section
DF installing base (asm.)
Setscrew of DF installing base
Setscrew of DF
installing base
Click section
1 to 1.5 mm

-15--15-
-15--15-
-15-
5-1-7 Clearance between the needle and the blade point of the hook
Remove the face cover and the needle plate.
1. Set the machine to the zigzag pattern (large) (zigzag width 7 mm). Raise the needle
bar by hand from the lowest point of its stroke and make sure that the clearance
provided between the blade point of the hook and the needle is 0.05 mm to 0.1 mm at
the left and right needle entry points when the blade point of the hook comes to the
rear of the center of the needle. (To such an extent that the needle slightly moves
when it is lightly pressed with a small screwdriver or the like.)
2. Turn drive body stop shaft [2] and adjust the clearance.
Tightening direction Clearance provided between the needle and the hook
becomes larger.
Loosening direction Clearance provided between the needle and the hook
becomes smaller.
* When the clearances at left needle entry point and the right needle entry point are
different from each other, loosen setscrews (left) and (right) in the needle bar lateral
adjusting plate (asm.) and move the needle bar lateral adjusting plate (asm.) to the left
or right to adjust the clearances.
How to adjust
Drive body stop shaft
Blade point
of hook
5-1-8 Position of the bobbin case stopper plate
Remove the throat plate.
1. On condition that the bobbin case is set to the outer hook, loosen setscrew [3] and
determine the longitudinal position of the bobbin case stopper plate so that the rear
end of the projection of the bobbin case aligns with the rear end of the plate spring of
the bobbin case stopper plate.
In addition, for the lateral position, make the turn stopper come in contact with the
right side as much as the occurrence of the play and fix it with setscrew [3] .
* Wipe out the race face of the hook or the bobbin case with alcohol since there may be
a case where dirt, oil, grease, etc. stitck on the race face of the hook or the bobbin
case.
Otherwise, running noise, noise from the bobbin case, noise of slip-off of the thread,
etc. will happen.
How to adjust
Projection of bobbin case
Setscrew [3]
Bobbin case stopper plate
Setscrew
Needle bar lateral
adjusting plate
Setscrew
Needle
0.05 to 0.1 mm
To align
Bobbin case stopper plate
[2]

5-1-9 Adjusting the bobbin thread tension
Remove the throat plate.
1. Position the bobbin case and the tension gauge as illustrated and adjust the adjusting
screw [7] so that the tension is 0.1862±0.0098 [N] (19g±1g) with SHAPPE
#60 thread.
How to adjust
Bobbin case
Bobbin thread should not come
in contact with bobbin case.
Tension gauge
Tension gauge
5-1-10 Opening amount of the pre-tension disk
Remove the face cover and the front panel.
1. Adjust the adjusting screw for releasing the pre-tension disk so that the pre-tension
disk opens approximately 1 mm when the presser lifting lever is raised.
In addition, the tension of the pre-tension is a fixed type and cannot be adjusted.
How to adjust
5-1-11 Opening amount of the tension disk
Remove the face cover and the front panel.
1. Turn the adjusting screw in the thread
tension disk floating plate and adjust
so that the clearance between tension
disk (A) and tension disk (B) is 1 mm
when the thread tension dial is set to
the maximum and the presser lifting
lever is raised.
How to adjust
Adjusting
screw
Disk A
Disk B
-16--16-
-16--16-
-16-
[7]
1 mm
Adjusting screw
for releasing the
pre-tension disk
1 mm
Thread tension
disk floating plate

-17--17-
-17--17-
-17-
1. Remove the tension knob fixing E ring
and remove the thread tension dial
presser, the tension knob and the
tension cam.
2. Prepare SHAPPE SPAN # 60 and the
tension gauge, and pass needle thread
from the base tension to the tension
disk.
3. Lower the presser lifting lever, attach
SHAPPE SPAN # 60 to the tension
gauge, and turn the adjusting nut to
adjust so that the tension is 0.588 [N]
(approx. 60 g).
4. After the adjustment, set the tension
cam to the groove in the adjusting nut
so that the convex of the tension cam
is in the position which is lower by
approximately 7 mm than the crest line
of the thread guide cover B.
5. Fix the tension knob so that the center
of the latch section of the tension knob
meets with the convex of the tension
cam.
6. Fix again the thread tension dial presser
and the tension knob fixing E ring.
7. Fix the tension cam positioning plate.
5-1-12 Adjusting the needle thread tension
Remove the face cover and the front panel.
How to adjust
5-1-13 Tension knob
The tension knob has the structure which can make the correction when the needle thread tension is desired
to be corrected after assembling the front panel and the thread spool cover.
1. In case of increasing the needle thread tension
1) Turn the tension knob in the direction of “a”
until it comes in contact with the stopper.
2) Move (shift) the tension knob to the right side
and the engagement with the tension cam is
disengaged. On this condition, turn the tension
knob in the direction of “a”.
2. In case of decreasing the needle thread tension
1) Turn the tension knob in the direction of “b”
until it comes in contact with the stopper.
2) Move (shift) the tension knob to the right side
and the engagement with the tension cam is
disengaged. In this state, turn the tension
knob in the direction of “b”.
* After performing the adjustment of 5-1-12,
re-adjust so that the thread tightness ratio is
100 to 108 % with cotton broad cloth and
SHAPPE SPAN #60.
Then perform fine adjustment in the 5-1-13 above.
How to adjust
Tension gauge
Thread guide cover B
Adjusting nut
Crest line
Tension cam Tension knob
Latch section
Tension knob
Convex
7mm
a
b