Janome MC7700 QCP User manual

SERVICE MANUAL
&
PARTS LIST
MC7700 QCP

SERVICE ACCESS
FACE PLATE AND TOP COVER ............................................................................................................1
BELT COVER..........................................................................................................................................2
MACHINE BASE, BASE COVER AND BED COVER .............................................................................3
FREE-ARM COVER................................................................................................................................4
FRONT COVER ......................................................................................................................................5
REAR COVER ........................................................................................................................................6
MECHANICAL ADJUSTMENT
NEEDLE DROP POSITION ....................................................................................................................7
PRESSER BAR HEIGHT AND ALIGNMENT ................................................................................... 8-10
HOOK TIMING ......................................................................................................................................11
NEEDLE BAR HEIGHT.........................................................................................................................12
CLEARANCE BETWEEN NEEDLE AND ROTARY HOOK ................................................................................... 13
BACKLASH OF HOOK AND LOWER SHAFT GEARS ........................................................................14
FEED DOG HEIGHT.............................................................................................................................15
UPPER THREAD TENSION .................................................................................................................16
THREAD TENSION UNIT REPLACEMENT .........................................................................................17
THREAD TENSION MECHANISM .......................................................................................................18
CIRCUIT BOARD “F” REPLACEMENT ................................................................................................19
CIRCUIT BOARD “A” REPLACEMENT ................................................................................................20
CONNECTOR DIAGRAM .....................................................................................................................21
NEEDLE THREADER PLATE REPLACEMENT ...................................................................................22
THREAD TENSION DRAWING LEVER ...............................................................................................23
UPPER FEED DOG ADJUSTMENT (1) ......................................................................................... 24-25
UPPER FEED DOG HEIGHT ...............................................................................................................26
DRIVING MOTOR.................................................................................................................................27
UPPER SHAFT SHIELD PLATE POSITION.........................................................................................28
CENTER NEEDLE POSITION ADJUSTMENT ....................................................................................29
BUTTONHOLE LEVER POSITION.......................................................................................................30
PRESSER BAR LIFTER SWITCH POSITION......................................................................................31
THREAD CUTTER SENSOR POSITION .............................................................................................32
SWITCHING POWER SUPPLY REPLACEMENT ................................................................................33
SOLENOID POSITION .........................................................................................................................34
STRETCH STITCH FEED BALANCE...................................................................................................35
DIAGNOSIS TEST ......................................................................................................... 36-39
INDEXINDEX
INDEXINDEX
INDEX

1
SERVICE ACCESS (1)
FACE PLATE
TOP COVER
[TO REMOVE]
1. OPEN THE FACE PLATE.
REMOVE THE SETSCREWS (B), (C) AND (D).
RAISE THE CARRYING HANDLE AND REMOVE
THE TOP COVER.
[TO ATTACH]
2FOLLOW THE ABOVE PROCEDURE IN
REVERSE.
[TO REMOVE]
1. REMOVE THE SETSCREWS (A) (2 PCS.)TO
REMOVE THE FACE PLATE.
[TO ATTACH]
FOLLOW THE ABOVE PROCEDURE IN REVERSE.
SETSCREWS (A)
SETSCREW (B)
CARRYING
HANDLE
TOP COVER
SETSCREW (C) SETSCREW (D)
FACE PLATE

2
SERVICE ACCESS (2)
BELT COVER
[TO REMOVE]
1. REMOVE THE SETSCREW (A).
LOOSEN THE SETSCREWS (B) AND (C).
REMOVE THE BELT COVER.
[TO ATTACH]
2. FOLLOWTHE ABOVE PROCEDURE IN REVERSE.
SETSCREW (B)
SETSCREW (A)
BELT COVER
SETSCREW (C)

3
MACHINE BASE
[TO REMOVE]
1. REMOVE THE SETSCREWS (A) (4 PCS.).
REMOVE THE MACHINE BASE.
[TO ATTACH]
2. FOLLOW THE ABOVE PROCEDURE IN REVERSE.
BASE COVER
[TO REMOVE]
1. REMOVE THE SETSCREWS (B) (4 PCS.).
REMOVE THE BASE COVER.
[TO ATTACH]
2. FOLLOW THE ABOVE PROCEDURE IN REVERSE.
BED COVER
[TO REMOVE]
1. REMOVE THE SETSCREWS (C) (2 PCS.).
REMOVE THE BED COVER.
[TO ATTACH]
2. FOLLOW THE ABOVE PROCEDURE IN REVERSE.
SETSCREW (A) MACHINE BASE SETSCREW (A)
SETSCREW (A)
SETSCREW (A)
BASE COVER
SETSCREW (B) SETSCREW (B)
SETSCREW (B) SETSCREW (B)
BED COVER
SETSCREW (C)
SERVICE ACCESS (3)

4
FREE-ARM COVER
[TO REMOVE]
1. REMOVE THE MACHINE BASE AND BED COVER
(SEE PAGE 3).
REMOVE THE NEEDLE PLATE.
2. REMOVE THE SETSCREW (A) AND PIN.
UNLOCK THE HOOK (A) AND (B) FROM THE
INSIDE.
REMOVE THE TAB (A) AND (B) FROM THE HOLES.
SLIDE THE FREE-ARM COVER TO THE LEFT TO
REMOVE THE FREE-ARM COVER.
[TO ATTACH]
3. FOLLOWTHE ABOVE PROCEDURE IN REVERSE.
THE HOOK (B) SHOULD HOLD THETHREAD
CUTTER PLATE.
FREE-ARM COVER
TAB (B)
TAB (A)
PIN
NEEDLE PLATE
SETSCREW (A)
HOOK (B)
HOOK (A)
THREAD
CUTTER
PLATE
SERVICE ACCESS (4)

5
[TO REMOVE]
1. REMOVE THE TOP COVER, MACHINE BASE, BASE
COVER AND FREE-ARM COVER (SEE PAGES 1, 3
AND 4).
2. LOOSEN THE SETSCREWS (A), (B), (C), AND (D).
UNLOCK THE REAR COVER HOOKS (E) FROM
THE FRONT COVER.
REMOVE THE CONNECTORS FROMTHE CIRCUIT
BOARD A (SEE PAGE 20).
REMOVE THE FRONT COVER.
[TO ATTACH]
3. FOLLOW THE ABOVE PROCEDURE IN REVERSE.
FRONT COVER
SETSCREW (A)
HOOK (E)
SETSCREW (B)
SETSCREW (C)
SETSCREW (D)
HOOK (E)
HOOK (E) HOOK (E)
SERVICE ACCESS (5)

6
[TO REMOVE]
1. REMOVE THETOP COVER, MACHINE BASE, BASE
COVER AND FREE-ARM COVER (SEE PAGES 1, 3
AND 4).
2. REMOVE THE SETSCREWS (A) (6 PCS.).
UNLOCK THE REAR COVER HOOK FROMTHE
FRONT COVER.
REMOVE THE REAR COVER.
[TO ATTACH]
3. FOLLOWTHE ABOVE PROCEDURE IN REVERSE.
REAR COVER
SETSCREWS (A)
SETSCREWS (A)
SETSCREWS (A)
REAR COVER
SERVICE ACCESS (6)

7
MECHANICAL ADJUSTMENT
NEEDLE DROP POSITION
WHEN THE STRAIGHT STITCH IS SELECTED,THE NEEDLE SHOULD BE AT THE CENTER OF THE HOLE OF
THE NEEDLE PLATE.WHEN THE MAXIMUM ZIGZAG WIDTH (7.0) IS SELECTED, THE DISTANCE BETWEEN THE
NEEDLE AND THE EDGE OFTHE HOLE OF THE NEEDLE PLATE AT THE RIGHT AND LEFT NEEDLE
POSITIONS SHOULD BE 0.2 mmOR MORE AS SHOWN IN FIG. 2.
HEXAGONAL
SOCKET SCREW (A)
ECCENTRIC PIN (B)
THREADER
LEVER
FIG. 1.
1. OPEN THE FACE PLATE.
CHECK THE NEEDLE DROP POSITION ON THE
STITCH PATTERN ( ) AND ZIGZAG STITCH ( )
WITH MAXIMUM WIDTH.
2. LOOSEN THE HEXAGONAL SOCKET SCREW (A)
JUST ENOUGH TO TURNTHE ECCENTRIC PIN (B).
ADJUST THE NEEDLE DROP POSITION BY
TURNING THE ECCENTRIC PIN.THE DIRECTION
OF THE ECCENTRIC PIN (B) SHOULD BE AS
SHOWN IN FIG. 1.
3. TIGHTEN THE HEXAGONAL SOCKET SCREW (A).
CHECK THE CENTER NEEDLE POSITION SENSOR.
(SEE PAGE 29)
4. CLOSE THE FACE PLATE.
HOLE OF NEEDLE PLATE
0.2 mm OR
MORE
0.2 mm OR
MORE
A=B
FIG. 2

8
SETSCREW E SETSCREW B
PRESSER BAR HEIGHT AND ALIGNMENT (1)
WHEN THE PRESSER FOOT IS LIFTED, THE DISTANCE BETWEEN THE SURFACE OF THE NEEDLE PLATE AND
THE BOTTOM OF THE ZIGZAG FOOT SHOULD BE 6 MM.
SETSCREW (A)
LED LAMP
NEEDLE BAR
SUPPORTER
SPRING
1. ATTACHTHE ZIGZAG FOOT A.
ADJUST THE PRESSER FOOT PRESSURE DIAL
TO “7”.
REMOVE THE TOP COVER.
(SEE PAGE 1)
2. RAISE THE PRESSER FOOT LIFTER.
3. LOWERTHE FEED DOG.
4. REMOVE THE NEEDLE BAR SUPPORTER
SPRING.
5. REMOVE THE SETSCREW (A) AND REMOVE THE
LED LAMP.
6. REMOVE THE SETSCREWS (B), (C) AND (D).
REMOVE THE CARRYING HANDLE
SUPPORTER.
7. REMOVE THE SETSCREWS (E), (F) AND (G).
REMOVE THE FRONT BRACKET.
SETSCREW (D)
SETSCREW (C)
SETSCREW (G) SETSCREW (F)
CARRYING
HANDLE
SUPPORTER
FRONT
BRACKET
MECHANICAL ADJUSTMENT

9
WITH THE BLOCK (A)
REMOVED, THE
PRESSER FOOT WILL
BE LOWERED
NEEDLE PLATE 6.6 mm 6.0 mm
WASHER
NO GAP GAP
BLOCK (A)
PRESSER FOOT
LIFTER
SETSCREW (H)
PRESSER BAR
SUPPORTER PRESSER BAR HEIGHT AND ALIGNMENT (2)
8 PLACE THE BLOCK (A) (6.6 mm) BETWEEN THE
PRESSER FOOT AND NEEDLE PLATE.
(THE PRESSER FOOT LIFTER SHOULD BE AT
THE NORMAL UP POSITION)
9 LOOSEN THE SETSCREW (H) ON THE PRESSER
BAR SUPPORTER WHILE THE PRESSER FOOT
HOLDING THE BLOCK (A).
MAKE SURE THERE SHOULD BE NO GAP
BETWEEN THE WASHER ANDTHE PRESSER BAR.
TIGHTEN THE SETSCREW (H).
WHEN REMOVING THE BLOCK (A), THE DISTANCE
BETWEEN THE SURFACE OF THE NEEDLE PLATE
AND THE BOTTOM OF THE ZIGZAG FOOT SHOULD
BE 6 mm.
NORMAL UP
POSITION
MECHANICAL ADJUSTMENT

10
1. LOOSEN THE SETSCREW ON THE ROTATION
STOPPER WHILE THE PRESSER FOOT HOLDING
THE BLOCK (A) (SEE PAGE 9 FOR THE BLOCK
(A)).
ADJUST THE DIRECTION OFTHE PRESSER BAR.
THE GAP BETWEEN THE BLOCK ANDTHE
ROTATION STOPPER MUST BE 0.3 mm.
2. REMOVE THE BLOCK (A).LOWER THE PRESSER
FOOT TO CHECK THE DIRECTION OF THE
PRESSER FOOT.THE SLOTS FOR FEED DOG AND
THE PRESSER FOOT MUST BE PARALLEL.
3. RAISE THE PRESSER FOOT. PUSH UP THE
PRESSER FOOT WITHYOUR FINGER. CHECK IF
THE BLOCK MOVES SMOOTHLY.
BLOCK
SETSCREW (A)
GAP
ROTATION STOPPER
PRESSER
BAR
VIEWY
MECHANICAL ADJUSTMENT
ROTATION STOPPER SETSCREW
GAP
0.3 mm
WRONG CORRECT
SETSCREW (A) THE BLOCK
MOVES
SMOOTHLY.
VIEWY
PRESSER BAR HEIGHT AND ALIGNMENT (3)
WHEN THE PRESSER BAR IS LOWERED, THE PRESSER FOOT SHOULD BE PARALLEL WITH THE SLOTS FOR
THE FEED DOGS.
4. IF THE BLOCK DOES NOT MOVE SMOOTHLY:
LOOSEN THE SETSCREW (A) AND ADJUST THE
ROTATION STOPPER SO THAT THE BLOCK SHOULD
BE PARAELL TO THE ROTATION STOPPER.
SETSCREW (A) SHOULD NOT INTERFERE WITH
NEITHER ROTATION STOPPER NOR PRESSER
BAR AS ILLUSTRATED.
5. ATTACHTHE FRONT BRACKET (UNIT).
MAKE SURE THE PRESSER FOOT LIFTER SWITCH
PLATE IS ABOVE THE SWITCH LEVERS, NOT UNDER
THE LEVERS.
6. ATTCH THE CARRYING HANDLE SUPPORTER AND
LED LAMP.
7. ATTACHTHE NEEDLE BAR SUPPORTER SPRING.
8. ATTACHTHE FACE COVER AND TOP COVER.
SLOTS FOR FEED DOGS
TO BE PARALLEL
WITH SLOTS FOR
FEED DOGS

11
1. REMOVE THE MACHINE BASE (SEE PAGE 3).
2. TURN THE POWER SWITCH ON AND SELECT
STITCH PATTERN ( ) .
3. SET THE ZIGZAG WIDTH AT “0.0” AND TURN THE
POWER SWITCH OFF.
4. REMOVE THE PRESSER FOOT, NEEDLE PLATE
AND BOBBIN HOLDER.
5. TURN THE HANDWHEEL TOWARDYOU TO LOWER
THE NEEDLE BAR AT ITS LOWEST POSITION.
6. LOOSEN THE HEXAGONAL SOCKET SCREWS (A)
AND (B) ON THE LOWER SHAFT GEAR (C).
7. MOVE THE NEEDLE BAR 3.5 MM – 3.75 MM FROM
THE LOWEST POSITION.
8. TURN THE LOWER SHAFT GEAR (C) UNTIL THE
TIP OF THE HOOK MEETS THE RIGHT SIDE OF
THE NEEDLE WHILE HOLDING THE HANDWHEEL.
9. TIGHTEN THE HEXAGONAL SOCKET SCREW (A)
AND (B).
10.ATTACH THE BOBBIN HOLDER, NEEDLE PLATE
AND PRESSER FOOT.
11 ATTACH THE MACHINE BASE.
HOOKTIMING
THE AMOUNT OF ASCENDING TRAVEL OF THE NEEDLE BAR FROM ITS LOWEST POSITION TO THE
POSITION WHERE THE TIP OFTHE ROTARY HOOK EXACTLY MEETS THE RIGHT SIDE OF THE NEEDLE
SHOULD BE 3.50 TO 3.75 mm.
HEXAGONAL SOCKET SCREW (A)
LOWER SHAFT
GEAR (C)
3.50 – 3.75mm
LOWEST
POINT
NEEDLE SIZE 14 TIP OF HOOK
NEEDLE
PLATE
BOBBIN
HOLDER
HEXAGONAL SOCKET
SCREW (B)
MECHANICAL ADJUSTMENT

12
1. TURN THE POWER SWITCH ON AND SELECT
STITCH PATTERN ( ).
2. SET THE ZIGZAG WIDTH AT “0.0” ANDTURN THE
POWER SWITCH OFF.
REMOVE THE TOP COVER (SEE PAGE 1).
3. OPEN THE FACE PLATE.
REMOVE THE PRESSER FOOT, NEEDLE PLATE,
AND BOBBIN HOLDER.
4. TURN THE HANDWHEEL TOWARDYOU UNTIL
THE TIP OF THE HOOK MEETS THE RIGHT SIDE
OF THE NEEDLE.
5. LOOSEN THE HEXAGONAL SOCKET SCREW (C).
6. MOVE THE NEEDLE BARTO ADJUST THE
NEEDLE BAR HEIGHT, AND TIGHTENTHE
HEXAGONAL SOCKET SCREW (C). BE CAREFUL
NOT TO TURN THE NEEDLE BAR.
7. ATTACHTHE BOBBIN HOLDER, NEEDLE PLATE
AND TOP COVER.
8. CLOSE THE FACE PLATE.
NEEDLE
PLATE
BOBBIN
HOLDER
TIP OF HOOK
HOOK RACE
NEEDLE SIZE 14
1.4–1.75 mm
UPPER EDGE OF
NEEDLE EYE
HEXAGONAL SOCKET
SCREW (C)
NEEDLE BAR HEIGHT
BEFORE PROCEEDING WITH THIS ADJUSTMENT, CHECK THE HOOK TIMING (SEE PAGE 11).THE DISTANCE
BETWEEN THE UPPER EDGE OFTHE NEEDLE EYE AND THE TIP OFTHE HOOK SHOULD BE IN THE RANGE
OF 1.4 –1.75 mm WHEN THE TIP OFTHE HOOK MEETS RIGHT SIDE OF THE NEEDLE IN THE LEFT NEEDLE
POSITION ( ) AS THE NEEDLE ASCENDS FROM ITS LOWEST POSITION.
MECHANICAL ADJUSTMENT

13
MECHANICAL ADJUSTMENT
CLEARANCE BETWEEN NEEDLE AND ROTARY HOOK
THE CLEARANCE BETWEEN NEEDLE AND THE TIP OF THE ROTARY HOOK (J) SHOULD BE BETWEEN –0.1
AND +0.05 MM
[ADJUSTMENT II]
1. REMOVE THE BASE COVER AND BED COVER
(SEE PAGE 3).
2. TURN THE POWER SWITCH ON, AND SELECT
THE STITCH PATTERN . ADJUST THE ZIGZAG
WIDTH AT “7.0”,
3. REMOVE THE PRESSER FOOT, NEEDLE PLATE
AND BOBBIN HOLDER.
4. LOOSEN THE SETSCREWS (E) AND (F).
LOOSEN THE SETSCREW (G) JUST ENOUGH
TO MOVE THE HOOK BASE PLATE (H).
5. TURN THE HANDWHEEL TOWARD YOU UNTIL
THE TIP OF HOOK COMES JUST BEHINDTHE
MASTER NEEDLE.
ADJUST THE CLEARANCE BETWEEN THE
NEEDLE AND THE TIP OF THE ROTARY HOOK
BY MOVING THE HOOK BASE PLATE UP OR
DOWN, TO WITHIN –0.1TO +0.05 MM AT THE
LEFT AND RIGHT NEEDLE POSITIONS.
6. TIGHTEN THE SETSCREWS (E), (F) AND (G)
FIRMLY.
7. CHECK THE BACKLASH BETWEEN THE HOOK
DRIVE AND LOWER SHAFT GEARS.
SEE PAGE 14 FORTHE ADJUSTMENT.
8. ATTACH THE BASE COVER, BED COVER,
BOBBIN HOLDER, NEEDLE PLATE AND
PRESSER FOOT.
SETSCREW (G)
SETSCREW(F)
SETSCREW(E)
HOOK BASE
PLATE (H)
MASTER
NEEDLE (I)
TIP OF HOOK (J)
–0.10 TO +0.05 mm
[ADJUSTMENT I]
1. REMOVE THE TOP COVER (SEE PAGE 1) AND
PRESSER FOOT PRESSURE DIAL.
ATTACH MASTER NEEDLE (I).
2. TURN THE POWER SWITCH ON.
3. SELECT THE STITCH PATTERN AND ADJUST
THE ZIGZAG WIDTH AT “7.0”.
4. REMOVE THE PRESSER FOOT, NEEDLE PLATE
AND BOBBIN HOLDER.
5. LOOSEN THE HEXAGONAL SOCKET SCREW (A)
AND ADJUST THE CLEARANCE BETWEEN THE
NEEDLE AND TIP OF ROTARY HOOK (J) BY
MOVING THE NEEDLE BAR SUPPORTER.
CHECK THE CLEARANCE (D) BETWEEN THE
NEEDLE AND THE EDGE OF NEEDLE PLATE
HOLE. IF THE CLEARANCES (D) ARE NOT EVEN,
FOLLOW THE PROCEDURE BELOW
[ADJUSTMENT II].
HEXAGONAL
SOCKET
SCREW (A)
NEEDLE BAR
SUPPORTER (B)
HOLE OF NEEDLE PLATE (C)
CLEARANCES (D)
MUST BE EVEN
D
D

14
AA
AA
A
BB
BB
B
MECHANICAL ADJUSTMENT
1. REMOVE THE BASE COVER (REFER TO PAGE 3)
2. REMOVE THE NEEDLE, NEEDLE PLATE AND
BOBBIN HOLDER.
3. LOOSEN THE HEXAGONAL SOCKET SCREW (D).
4. IF THE BACKLASH IS TOO MUCH, TURN THE
LOWER SHAFT BUSHING IN DIRECTION A.
IF THE BACKLASH IS TOO LITTLE, TURN THE
LOWER SHAFT BUSHING IN DIRECTION B.
5. TIGHTEN THE HEXAGONAL SOCKET SCREW (D).
6. ATTACHTHE NEEDLE, NEEDLE PLATE AND
BOBBIN HOLDER.
7. ATTACHTHE BASE COVER.
BACKLASH OF HOOK DRIVE AND LOWER SHAFT GEARS
THE GEARS TURNS SMOOTHLY AND ROTARY PLAY OF THE HOOK SHOULD BE 0.8 mm OR LESS WHENTHE
TIP OF HOOK (E) IS WITHIN THE WIDTH OF THE FEED DOG (C) AS SHOWN BELOW.
LOWER SHAFT BUSHING
HEXAGONAL SOCKET SCREW (D)
WIDTH OF THE FEED DOG (C)
TIP OF HOOK (E)
0.8 mm OR LESS

15
NUT
SETSCREW (A) ADJUSTING SCREW (B)
PRESSER FOOT
0.80 – 0.90mm
SURFACE OF
NEEDLE PLATE
FEED DOG
HEXAGONAL SOCKET SCREW (I)
LEFT-HANDED
SETSCREW (D)
THREADED HOLE (C)
[ADJUSTMENT I]
1. TURN THE POWER SWITCH ON. ADJUST THE
STITCH LENGTH AT MAXIMUM LENGTH.
TURN THE POWER SWITCH OFF.
2. REMOVE THE BED COVER AND BASE COVER.
3. SET THE PRESSURE ADJUSTING DIAL AT “7”
WITH THE PRESSER FOOT LOWERED.
4. TURN THE HANDWHEEL TOWARDYOU TO
RAISE THE FEED DOG AT ITS HIGHEST POSITION.
4. LOOSEN THE SETSCREW (A).
5. LOOSEN THE NUT.
ADJUST THE FEED DOG HEIGHTTO 0.85 mm BY
TURNING THE ADJUSTING SCREW (B).
7. TIGHTEN THE NUT AND SETSCREW (A).
8. ATTACH THE BED COVER.
[ADJUSTMENT II]
IF THE FEED DOG IS NOT PARALLEL TO THE
SURFACE OF THE NEEDLE PLATE AT ITS HIGHEST
POSITION, MAKE THE ADJUSTMENT AS FOLLOWS:
*FOR THIS ADJUSTMENT, A HEXAGONAL SOCKET
SCREW 4 x 6 (I), PART NO.000111108 IS
REQUIRED.
1. INSERT A HEXAGONAL SOCKET SCREW (I),
PART NO. 000111108 INTO THE THREADED
HOLE (C) UNTIL IT STOPS.
2. TURN THE SETSCREW (D) CLOCKWISETO
LOOSEN IT.
3. TURN THE HEXAGONAL SOCKET SCREW (I)
UNTIL THE FEED DOG IS PARALLEL WITH THE
SURFACE OF THE NEEDLE PLATE.
4. TIGHTEN THE LEFT-HANDED SETSCREW (D).
5. REMOVE THE HEXAGONAL SOCKET SCREW (I).
6. ATTACH THE BED COVER AND BASE COVER.
FEED DOG HEIGHT
WHEN THE PRESSURE ADJUSTING DIAL IS AT “7” ANDTHE PRESSER FOOT (A) IS LOWERED,THE HIGHEST
POSITION OF THE FEED DOG SHOULD BE 0.80 TO 0.90 mm FROM THE SURFACE OFTHE NEEDLE PLATE.
SETSCREW (B) HEXAGONAL
SOCKET
SCREW (I)
SETSCREW (A) SETSCREW (D)
MECHANICAL ADJUSTMENT

16
1. SET THE THREAD TENSION DIAL (A) TO “AUTO”.
2. OPEN THE FACE PLATE.
ADJUST THE TENSION BY TURNING THE THREAD
TENSION ADJUSTING SCREW.
TO LOOSEN THETENSION, TURN IT CLOCKWISE.
(IN THE DIRECTION OF “–”)
TO TIGHTEN THETENSION, TURN IT COUNTER
CLOCKWISE (IN THE DIRECTION OF “+”).
THREAD TENSION DIAL
THREAD TENSION
ADJUSTING SCREW
WHITE POLYESTER THREAD SIZE 50
UPPERTHREADTENSION
THE UPPER THREADTENSION SHOULD BE 75–90 GRAMS WHEN PULLINGTHE THREAD (WHILE POLYESTER
THREAD SIZE 50) AT THE SPEED OF 110 MM/SEC WITH THETENSION DIAL AT “AUTO” (MAKE SURETHE
FOOT IS LOWERED.)
MECHANICAL ADJUSTMENT

17
THREADTENSION UNIT REPLACEMENT
[TO REMOVE]
1. OPEN THE FACE COVER.
REMOVE THE TOP COVER.
2. REMOVE SETSCREW (A) AND (B).
REMOVE THE THREAD TENSION UNIT.
[TO ATTACH]
3. REVERSE THE PROCEDURE ABOVE.
CHECK THE THREAD TENSION (SEE PAGE 16).
ADJUST THE THREAD TENSION MECHANISM
(SEE PAGE 18).
SETSCREW (A)
SETSCREW (B)
MECHANICAL ADJUSTMENT
SETSCREW (A)
SETSCREW (B)

18
1. OPEN THE FACE PLATE.
REMOVE THE TOP COVER (SEE PAGE 2).
2. LOWERTHE PRESSER LIFTER.
3. ADJUST THE THREAD TENSION DIAL AT “9”.
LOOSEN THE SETSCREW (A).
4. PRESS THE TENSION RELEASE PLATE TO
THE DISK HOLDER.
5. TIGHTEN THE SETSCREW (A).
RAISE THE PRESSER FOOT LIFTER.
MAKE SURE THETENSION DISKS SHOULD OPEN
AT “9” SETTING.
6. LOWERTHE PRESSER FOOT LIFTER.
TURN THE THREAD TENSION DIAL “9” TO “0”.
MAKE SURE THETENSION DISKS DOES NOT
MOVE.
7. ATTACH THE TOP COVER.
CLOSE THE FACE PLATE.
AFTER THIS ADJUSTMENT, CHECK THE THREAD
TENSION (SEE PAGE 16).
MECHANICAL ADJUSTMENT
THREADTENSION MECHANISM ADJUSTMENT
WHEN THE PRESSER FOOT LIFTER IS RAISED, THE TENSION DISKS SHOULD OPEN APPROXIMATELY 1.0 MM.
WHEN THE PRESSER FOOT IS LOWERED,THE TENSION DISKS SHOULD CLOSE AND THE TENSION RELEASE
PLATE (2) SHOULD BE FREE FROMTENSION.
SETSCREW (A)
99
99
9
THREAD TENSION DIAL
TENSION RELEASE PLATE
DISK HOLDER
TENSHON DISKS