Janome MyLock 744 User manual

SERVICING MANUAL

TO CHANGE THE FACE PLATE UNIT....................................................................................................... 1
TO CHANGE THE BELT COVER ............................................................................................................... 2
TO CHANGE THE TOP COVER UNIT ....................................................................................................... 3
TO CHANGE THE FRONT COVER UNIT ..................................................................................................4
TO CHANGE THE FREE ARM COVER UNIT ............................................................................................ 5
TO CHANGE THE MACHINE BASE .......................................................................................................... 6
TO CHANGE THE MACHINE SOCKET ..................................................................................................... 7
TO ADJUST THE NEEDLE HEIGHT .......................................................................................................... 8
TO ADJUST THE PRESSER BAR HEIGHT ............................................................................................... 9
TO ADJUST THE FEED DOG HEIGHT..................................................................................................... 10
TO ADJUST THE TIMING OF THE NEEDLE AND THE FEED DOG.........................................................11
TO ADJUST THE TIMING OF THE NEEDLE AND THE UPPER KNIFE................................................... 12
TO ADJUST THE CLEARANCE BETWEEN THE NEEDLES AND
THE LOWER LOOPER/NEEDLE GUARDS......................................................................................... 13-15
TO ADJUST THE CLEARANCE BETWEEN THE NEEDLES AND
THE FIXED NEEDLE GUARD................................................................................................................... 16
TO ADJUST THE POSITION OF THE CHAINING FINGER...................................................................... 17
TO ADJUST THE POSITION OF THE UPPER LOOPER ......................................................................... 18
TO ADJUST THE TIMING OF THE NEEDLE AND THE LOWER LOOPER ............................................ 19
TO ADJUST THE TIMING OF THE UPPER AND LOWER LOOPERS ..................................................... 20
TO ADJUST THE CLEARANCE BETWEEN THE LOOPERS................................................................... 21
TO ADJUST THE CLEARANCE BETWEEN THE NEEDLE AND THE UPPER LOOPER....................... 22
TO ADJUST THE POSITION OF THE KNlVES........................................................................................ 23
TO ADJUST THE POSITION OF THE LOOPER THREAD GUlDE ........................................................... 24
TO ADJUST THE STITCH LENGTH.......................................................................................................... 25
TO ADJUST THE THREAD TENSION DIALS ........................................................................................... 26
TABLE OF CONTENTS

1
TO CHANGETHE FACE PLATE UNIT
To remove:
1. Loosen the setscrew A and remove the face plate unit.
To attach:
2. Fit the U-groove of the face plate between the setscrew A and set plate, put the ribs of face plate
into the front cover unit, back cover unit and tighten the setscrew.
Setscrew A
Top cover unit
Front cover unit
Face plate unit
U-groove
Set plate
Back cover unit

2
TO CHANGETHE BELT COVER
To remove:
1. Loosen setscrew A and remove the setscrew B.
2. Remove the belt cover.
To attach:
3. Put the ribs of belt cover into the front cover unit and back cover unit and tighten setscrews A
and B.
Setscrew A
Setscrew B
Belt cover
Front cover unit
Back cover unit

3
To remove:
1. Loosen two setscrews A and remove the top cover unit.
To attach:
2. Put the ribs in the front cover unit.
3. Tighten two setscrews A.
TO CHANGETHE TOP COVER UNIT
Setscrews A
Top cover unit
Front cover unit
Rib

4
To remove:
1. Remove the setscrews A and looper cover unit.
2. Remove the topcover unit.
3. Move the upper looper to its lowest point by turning the handwheel in counter clockwise.
4. Loosen the setscrew B and remove the setscrews C and D and remove the front cover unit.
To attach:
5. Attach the front cover unit, and tighten the setscrews B, C and D.
6. Attach the top cover unit.
7. Attach the looper cover unit and tighten the setscrews A.
TO CHANGETHE FRONT COVER UNlT
Setscrew B
Setscrew C
Setscrew D
Setscrews A
Looper cover unit
Front cover unit

5
To remove:
1. Loosen setscrews A and remove the free arm cover unit.
To attach:
2. Put the ribs of free arm cover into back cover.
3. Tighten the setscrews A.
TO CHANGETHE FREE ARM COVER UNIT
Setscrews A
Free arm cover unit

6
To remove:
1. Remove set screws A, B and four hinge screws C and remove four base cushions D and
washers.
2. Remove the machine base unit.
To attach:
3. Attach the machine base and the four base cushions D, washers, and tighten hinge screws C.
4. Tighten setscrews A and B.
TO CHANGETHE MACHINE BASE
Hinge screw C
Washer
Base cushion D Washer
Setscrew A
Setscrew B

7
To remove:
1. Remove the belt cover.
2. Remove setscrews (A, B) and the machine socket unit from the motor fixing plate.
3. Remove two setscrews C and pull out the cord connectors.
To attach:
4. Insert the cord connectors as shown below.
5. Attach the machine socket and tighten two setscrews C.
6. Attach the machine socket unit on the motor fixing plate and tighten setscrews (A, B).
7. Attach the belt cover.
TO CHANGETHE MACHINE SOCKET
Setscrew C
Setscrew B
Setscrew C
Setscrew A
Machine socket
for 220 ~ 240V
Setscrew A
Motor fixing plate
Setscrew B
Machine socket
for 120V
For 220 - 240V Area
Motor lead cord
(Blue)
(Brown)
Lamp socket lead cord
(Blue)
(Brown)
Lamp sccket lead cord
Lamp socket lead cord
Motor lead cord
For 120V

8
Correct Setting:
The distance between the tip of needle on the right and the surface of needle plate should be 11.6
to 12.2 mm when the needle bar is at the highest position.
To adjust:
1. Remove the looper cover unit, top cover unit and front cover unit.
2. Turn the handwheel toward you with your hand and set the needle bar at the highest position.
3. Loosen the setscrew A to adjust the height and tighten setscrew A after the adjustment is done.
4. Turn the handwheel toward you one cycle and recheck the needle bar height.
5. Attach the front cover unit, looper cover unit and top cover unit.
TO ADJUSTTHE NEEDLE HEIGHT
O. L G05
Setscrew A
Needle bar
Needle #14
Surface of needle plate
11.6 to 12.2 mm 11.6 mm

9
Correct Setting:
The distance between the surface of needle plate and bottom of presser foot should be 4.7 to 5.3
mm when the presser bar lifter is raised.
To adjust:
1. Remove the looper cover unit, top cover unit and front cover unit.
2. Raise the presser bar lifter, and loosen the setscrew A.
Then adjust the presser bar height, the side of presser foot should be parallel with the hole of
needle plate.
3. Tighten the setscrew A.
4. Attach the front cover unit, looper cover unit and top cover unit.
TO ADJUSTTHE PRESSER BAR HElGHT
Presser bar lifter
5 mm
O. L G05
Setscrew A
4.7 ~ 5.3 mm
Top surface of needle plate To be parallel Needles
(Direction of presser foot)

10
Correct Setting:
When the presser foot is lowered and the feed dogs are at their highest position, the distance
between the surface of needle plate and bottom of presser foot should be 0.75 to 0.95 mm.
To adjust:
1. Remove the free arm cover unit and the back cover unit.
2. Set the stitch length dial at Ò 3 Ó and the differential feed dial at Ò 1.0 Ó .
3. Lower the presser foot and raise the feed dogs to their highest position by turning the handwheel.
4. Loosen the screws A, B and C.
5. Insert the screwdriver in the slit of the eccentric pin.
Adjust the main feed dog by turning the pin then tighten the setscrew A.
(The standard setting of the feed dog height is when the slit on the eccentric pin is horizontal and
eccentric position is at the rear side.)
6. Push the sub feed dog upward and adjust the distance between the surface of needle plate and
bottom of presser foot, then tighten the setscrews B and C.
7. Check the clearance between the feed dog and the slot of the needle plate when the stitch length
is set at 5 and differential feed is set at maximum.
(If the direction of the eccentric adjustment is incorrect, the needle plate and feed dog may hit or
rub each other.)
8. Attach the free arm cover unit.
TO ADJUSTTHE FEED DOG HEIGHT
O. L G05 0.85 mm
Setscrew A
Setscrew B
Setscrew C
Eccentric pin

11
Correct Setting:
When the tip of right needle is at 2 to 4 mm above the needle plate in its downward motion and
presser foot lowered, the top of the feed dog teeth should be level with the top surface of needle
plate at their rearmost position.
Before adjustment, check if the needle bar height and the feed dog height are correct.
To adjust:
1. Remove the free arm cover unit.
2. Set the stitch length dial at “ 3 “ and the differential feed dial at “ 1.0 “.
3. Raise the presser foot and move the tip of right needle to 3 mm above the needle plate in its
downward motion by turning the handwheel.
4. Lower the presser foot, and loose two set screws A for feed cam.
# Turn the feed cam to the direction B if the feed dog is lower than the surface of the
needle plate.
# Turn the feed cam to the direction C if the feed dog is higher than the surface of the
needle plate.
5. Tighten two setscrews A.
6. Attach the free arm cover unit.
TO ADJUST THE TIMING OF THE NEEDLE
AND THE FEED DOG
O. L G05 2 mm
2 ~ 4 mm
Setscrews A
B
C

12
Correct Setting:
The upper knife timing is the same as that of the needle bar. In fact, when the needle bar is at
highest position, the upper knife should be also at its highest position.
To adjust:
1. Remove the feed arm cover unit.
2. Loosen two setscrews A and adjust the needle and upper kinfe timing.
3. *Turn the upper knife drive cam to the direction B when the upper knife timing is being delayed.
*Turn the upper knife drive cam to the direction C when the upper knife timing is too soon.
4. Tighten the two setscrews A firmly.
*The cIearance between the upper knife drive cam and upper knife connecting rod shouId be
1 mm.
5. Turn the handwheel toward you one cycle, and recheck the needle and the upper knife timing.
6. Attach the free arm cover unit.
TO ADJUSTTHE TIMING OF THE NEEDLE
AND THE UPPER KNIFE
When the needle bar goes up,
the upper knife goes up. When the needle bar goes down,
the upper knife also goes down.
Setscrews A
C
B

13
Correct setting:
Both right and left needles should have an equal clearance from the front edge of the needlehoIes
on the needle plate.
The standard clearance between the Ieft and right needle and the lower looper is 0 mm to 0.05 mm.
The standard clearance between the needles and the rear needle guard is 0 mm to 0.2 mm.
The above standard clearance allows the needle to slightly touch the front needle guard.
To adjust:
1. Remove the looper cover unit, top cover unit, front cover unit, presser foot, needle plate and
needles.
2. Before loosening set screw C, attach the needle gauge #787-G02 to prevent change of needle
bar height during the adjustment.
Attach two #11 needles on the needle cramp and loosen the setscrew C. Adjust the two needIes,
to make the clearance between both needles and the front edge of the needle hole of the
needle plate equal by turning the needle bar in the D or E direction while pushing up theneedle
bar to prevent change of needle bar height.
Retighten the setscrew C and remove the needle gauge.
TO ADJUSTTHE CLEARANCE BETWEEN (1 of 3)
THE NEEDLES ANDTHE LOWER
LOOPER/NEEDLE GUARDS
Needle clamp
Setscrew C Needle bar lower bushing
No clearance
Needle gauge
(787-G02) (D) (E)
Needle
Lower looper
Needle (L)
Needle (R)
Equal clearance
Needle plate

14
1. Remove the left needle only.
2. Turn the handweel toward you to bring the tip of the lower looper from the left hand to the rear
side of the right needle.
3. Loosen the hexagonal socket screws A on the front needle guard and open a space between
the front needle guard and the needle.
4. Next, loosen the hexagonal bolt B and slide the lower looper unit to the front or to the back to
adjust the clearance between the right needle and the lower looper.The clearance should be
0 mm to 0.05 mm.
Retighten the hexagonal bolt B.
TO ADJUSTTHE CLEARANCE BETWEEN (2 of 3)
THE NEEDLES ANDTHE LOWER
LOOPER/NEEDLE GUARDS
Rear needle guard
Lower looper
Hexagonal bolt B
Front needle gurde
Lower looper bace
Needle #11
Lower looper
0 to 0.05 mm
Front needle
guard
Hexagonal socket
screws A
Rear needle guard

15
TO ADJUSTTHE CLEARANCE BETWEEN (3 of 3)
THE NEEDLES ANDTHE LOWER
LOOPER/NEEDLE GUARDS
1. Change the right needle from #11 to #14.
2. Push the right needle by the front needle guard to adjust the cIearance between the needle
and the lower looper. The cIearance should be 0 mm to 0.05 mm.
3. Attach #14 needle on the left needle position and turn the handwheel toward you to check the
clearance between the left needle and looper.
Make sure the front needle guard is touching the needle slightly and the rear needle guard is
not touching the needle.
4. Check the timing between the needle and the lower looper.
5. Recheck the needle bar height and the clearance between the needle and the lower looper.
Needle #14 0 to 0.05 mm
Lower looper
Rear needle guard
0 to 0.2 mm
Front needle guard
(Rear needle guard is not touching the needle.)
Front needle guard
Hexagonal
socket screws A
Rear needle guard

16
Correct Setting:
The clearance between needles and the fixed needle guard should be 0.1 to 0.4 mm.
To adjust:
1. Remove the free arm cover unit, presser foot and the needle plate and lower the needle to its
lowest position.
2. Loosen the setscrews A and adjust the position of the fixed needle guard.
3. Tighten two setscrews A.
4. Attach the needle plate and set the needle plate setting knob to guide line S.
5. Check the position of the chaining finger.
6. Attach the free arm cover unit and the presser foot.
TO ADJUSTTHE CLEARANCE BETWEEN
THE NEEDLES AND
THE FIXED NEEDLE GUARD
Needle plate setting knob
shouldbesetatÒSÓ
Chaining finger
Fixed needle guard
To be touched
The clearance between the needle
and fixed needle guard
Fixed needle guard
Needle #14
0.1 ~ 0.4 mm
Tip of fixed needle guard
Needle plate
setting knob
Needle plate setting knob should be set at “S”
Setscrews A
Guide line S

17
Correct Setting:
When set the needle plate setting knob to guide line S, chaining finger should touch side of needle
plate, and tip of chaining finger should be same level with the tip of the needle on the needle
plate.
To adjust:
1. Remove the free arm cover unit and the presser foot.
2. Set the needle plate setting knob to guide line S on needle plate.
3. Loosen two setscrews A and move chaining finger unit to correct position.
4. Tighten two setscrews A.
5. Set the needle plate setting knob to guide line S and R, and check the position of chaining
finger.
6. Attach the free arm cover unit and the presser foot.
TO ADJUSTTHE POSITlON OF
THE CHAINING FINGER
Needle plate setting knob is to be “S”
Chaining finger
Fixed needle guard To be touch
Drawing 2
Should be same level
To be touched
Needle plate
setting knob
Setscrews A
Chaining finger unit
Drawing1
Guide line S

18
Correct setting:
When the upper looper is at the leftmost position, the distance between the center of needle on the
right and the center of looper eye should be 4.8 to 5.2 mm.
To adjust:
1. Remove the machine base.
2. Loosen the hexagonal socket screws A, and adjust the distance between upper looper shaft
guide and bottom of upper looper.The distance should be 1.6 to 1.8 mm when the upper looper
is at the lowest position as shown in Drawing 1.
3. Tighten the hexagonal socket screws A.
4. Turn the handwheel and bring the upper looper to the leftmost position.
5. Remove the spreader setscrew B and spreader holding plate C.
6. Loosen the hexagonal socket screw D, and adjust the distance between the center of needle
and center of upper looper eye as shown in Drawing 2.
7. Tighten the hexagonal socket screw D.
8. Set the spreader holding plate C to the upper looper shaft, and tighten the spreader setscrew B.
9. Check the upper and lower loopers timing and clearance between upper and lower loopers.
10. Attach the machine base.
TO ADJUSTTHE POSITION OF
THE UPPER LOOPER
1.7 mm
O.L G05
Needle on the right
5mm
Drawing 2
Spreader
setscrew B
Spreader
holding plate C
Hexagon socket
screw D
Upper looper
shaft
Drawing 3
Upper looper
Hexagonal socket screws A
Drawing 1
Upper looper
1.6 to 1.8 mm Upper looper shaft guide
Upper looper shaft