Janome DC3050 Service Manual

SERVICING MANUAL

DC3018 & DC3050

CONTENTS

WHA T TO DO WHEN....................................................................................................................... 1 - 3

FACE COVER ........................................................................................................................................ 4

BED COVER .......................................................................................................................................... 5

FRONT COVER ................................................................................................................................ 6 - 7

REAR COVER ....................................................................................................................................... 8

PRESSER BAR HEIGHT AND ALIGNMENT......................................................................................... 9

NEEDLE DROP POSITION ................................................................................................................. 10

NEEDLE BAR HEIGHT........................................................................................................................ 11

NEEDLE TO HOOK TIMING................................................................................................................ 12

NEEDLE CLEARANCE TO SHUTTLE ................................................................................................ 13

BACKLASH (BETWEEN LOWER SHAFT GEAR AND SHUTTLE HOOK GEAR).............................. 14

FEED DOG HEIGHT............................................................................................................................ 15

ZIGZAG SYNCHRONIZATION ............................................................................................................ 16

NEEDLE THREAD TENSION .............................................................................................................. 17

STRETCH STITCH FEED BALANCE.................................................................................................. 18

REPLACEMENT AND ADJUSTMENT OF NEEDLE THREADER PLATE........................................... 19

CONNECTOR CONNECTION DIAGRAM........................................................................................... 20

REPLACING THE PRINTED CIRCUIT BOARD “A” ............................................................................ 21

REPLACING THE SLIDE VOLUME AND PRINTED CIRCUIT BOARD “F” ........................................ 22

REPLACING THE DC MOTOR AND ADJUSTING THE MOTOR BELT TENSION ............................. 23

REPLACING THE FUSE...................................................................................................................... 24

REPLACING THE MACHINE SOCKET................................................................................................25

REPLACING THE TRANSFORMER ....................................................................................................26

REPLACDING THE ZIGZAG MOTOR.................................................................................................27

REPLACING THE FEED MOTOR .......................................................................................................28

ADJUSTING THE BUTTONHOLE LEVER ...........................................................................................29

ADJUSTING THE BOBBIN WINDER SWITCH ....................................................................................30

OILING ..................................................................................................................................................31

WHAT TO DO WHEN

CONDITION CAUSE HOW TO FIX REFERENCE

1. SKIPPING STITCHES

1. NEEDLE IS NOT INSERTED PROPERLY.

2. NEEDLE IS BENT OR WORN.

3. INCORRECTLY THREADED.

4. NEEDLE OR THREAD ARE INAPPROPRIATE FOR FABRIC BEING SEWN.

5. SEWING ON STRETCH FABRIC.

6. PRESSER FOOT PRESSURE IS TOO WEAK.

7. INAPPROPRIATE NEEDLE BAR HEIGHT.

8. INAPPPROPRIATE NEEDLE TO SHUTTLE TIMING.

INSERT THE NEEDLE PROPERLY.

CHANGE THE NEEDLE.

RETHREAD.

USE THE RECOMMENDED SEWING NEEDLE AND THREAD.

USE A #11 BLUE TIP NEEDLE.

ADJUST THE PRESSER BAR LEVEL TO MAKE THE PRESSURE STRONGER.

SEE MECHANICAL ADJUSTMENT “NEEDLE BAR HEIGHT”.

SEE MECHANICAL ADJUSTMENT “NEEDLE TO SHUTTLE TIMING”.

P. 11

P. 1 2

2. FABRIC NOT MOVING

9. INAPPROPRIATE NEEDLE TO SHUTTLE CLEARANCE.

1. PRESSER FOOT PRESSURE IS TOO WEAK.

2. INCORRECT F.D. HEIGHT.

3.F.D. IS IN DOWN POSITION.

4.THREAD ON BOTTOM SIDE OF FABRIC IS JAMMED UP.

5. FEED DOG TEETH ARE WORN.

SEE MECHANICAL ADJUSTMENT “CLEARANCE BETWEEN NEEDLE AND HOOK”.

ADJUST THE PRESSER BAR LEVEL TO MAKE THE PRESSURE STRONGER.

SEE MECHANICAL ADJUSTMENT “FEED DOG HEIGHT”.

RAISE THE F.D. LEVEL.

MAKE SURE TO BRING BOTH NEEDLE AND BOBBIN THREAD UNDER THE FOOT WHEN STARTING SEWING.

CHANGE THE FEED DOG.

P. 1 3

P. 1 5

CONDITION CAUSE HOW TO FIX REFERENCE

3. BREAKING UPPER THREAD

4. BREAKING BOBBIN THREAD

1. INITIAL SEWING SPEED IS TOO FAST.

2. THREAD PATH IS INCORRECT.

3. NEEDLE IS BENT OR DULL.

4. UPPER THREAD TENSION IS TOO STRONG.

5. NEEDLE SIZE IS INAPPROPRIATE FOR FABRIC.

6. NEEDLE EYE IS WORN.

7. NEEDLE HOLE IN NEEDLE PLATE IS WORN OR BURRED.

1. INCORRECITLY THREADED BOBBIN.

2. TOO MUCH THREAD IS AROUND ON THE BOBBIN.

START WITH MEDIUM SPEED.

USE THE PROPER THREAD PATH.

REPLACE WITH A NEW NEEDLE.

ADJUST NEEDLE THREAD TENSION CORRECTLY.

USE APPROPRIATE NEEDLE FOR FABRIC AND THREAD IN USE.

CHANGE THE NEEDLE.

REPAIR THE HOLE OR REPLACE THE NEEDLE PLATE.

THREAD BOBBIN CORRECTLY.

ADJUST THE POSITION OF STOPPER.

P. 1 7

5. NEEDLE BREAKS

3. LINT IS STUCK INSIDE THE BOBBIN HOLDER.

4. THREAD QUALITY IS TOO LOW.

5. THREAD IS JAMMING AROUND THE BOBBIN.

1. NEEDLE IS HITTING THE NEEDLE PLATE.

2. NEEDLE IS BENT OR WORN.

3. NEEDLE IS HITTING THE SHUTTLE.

4. THE FABRIC MOVES WHILE THE NEEDLE IS PIERCING IT, OR THE NEEDLE ZIGZAGS WHILE IN FABRIC.

CLEAN THE SHUTTLE.

CHANGE TO A HIGH QUALITY SEWING THREAD.

CLEAR OUT THE JAMMING THREAD.

SEE MECHANICAL ADJUSTMENT “NEEDLE DROP POSITION”. CHANGE THE NEEDLE.

SEE MECHANICAL ADJUSTMENT “CLEARANCE BETWEEN NEEDLE AND HOOK”.

SEE MECHANICAL ADJUSTMENT “ZIGZAG SYNCHRONIZATION”.

P. 1 0

P. 1 3

P. 1 6

5. FABIRIC IS BEING PULLED TOO STRONGLY WHILE SEWING.

GUIDE THE FABRIC GENTLY WHILE SEWING.

CONDITION CAUSE HOW TO FIX REFERENCE

6. NOISY OPERATION

7. DEFORMATION PATTERN

1. BACKLASH BETWEEN SHTTLE HOOK GEAR AND LOWER SHAFT GEAR IS TOO GREAT.

2. LOWER SHAFT GEAR IS LOOSE.

3. INAPPROPRIATTE BELT TENSION.

4. NOT ENOUGH OIL.

1. INAPPROPRIATE FEED BALANCE.

2. INAPPROPRIATE ZIGZAG SYNCHRONIZATION.

3. UPPER THREAD TENSION IS TOO STRONG.

SEE MECHANICAL ADJUSTMENT “BACKLASH (LOWER SHAFT GEAR)”.

ELIMINATE THE LOOSENESS.

SEE PART REMOVAL AND REPLACEMENT “DRIVING MOT OR (DC MOTOR)”.

OIL ALL MOVING PARTS.

SEE MECHANICAL ADJUSTMENT “STRETCH STITCH FEED BALANCE”.

SEE MECHANICAL ADJUSTMENT “ZIGZAG SYNCHRONIZATION”.

SEE MECHANICAL ADJUSTMENT “NEEDLE THREAD TENSION”.

P. 1 4

P. 2 6

P. 3 4

P. 1 8

P. 1 6

P. 1 7

SERVICE ACCESS (1)

FACE COVER

TO REMOVE:

1. REMOVE THE CAP (A).

2. REMOVE THE SETSCREW (B) AND REMOVE THE FACE COVER (C).

TO INSTALL:

3. INSERT THE HOOK (D) AND RIBS (E) OF THE FACE COVER INTO THE REAR COVER AND TIGHTEN THE SETSCREW, THEN ATTACH THE CAP.

Setscrew (B)

Cap (A)

Face cover

Ribs (E)

Hook (D)

SERVICE ACCESS (2)

BED COVER

TO REMOVE:

1. SET THE DROP LEVER (A) TO THE LEFT AND REMOVE THE 3 SETSCREWS (B). REMOVE THE BED COVER (C).

TO INSTALL:

2. SET THE DROP LEVER (A) TO THE LEFT AND INSTALL THE BED COVER (C). SECURE IT IN PLACE WITH THE 3 SETSCREWS (B).

SETSCREW (B)

DROP LEVER (A)

2 SETSCREWS (B)

BED COVER (C)

SERVICE ACCESS (3-1)

FRONT COVER

TO REMOVE:

1. REMOVE THE FACE COVER AND BED COVER (SEE PAGES 7 AND 8).

2. LOOSEN THE SETSCREWS (A), THEN REMOVE THE SETSCREWS (B), (C), (D), (E), (F), (G) AND (H).

3. REMOVE THE FRONT COVER (SEE PAGE 10) AND DISCONNECT EACH SWITCH CONNECTORS.

NOTES TO DISCONNECT THE CONNECTORS:

1. GRASP THE CONNECTOR DIRECTLY WITH YOUR FINGERS AND PULL. DO NOT PULL ON THE LEAD WIRE, AS THIS MAY DAMAGE THE CONTACT SLEEVE INSIDE THE CONNECTOR.

2. WHEN DISCONNECTING THE MACHINE SOCKET AND POWER TRANSFORMER CONNECTORS, PULL THEM WHILE PUSHING THEM TOWARD THE PRINTED CIRCUIT BOARD A TO UNLOCK THEM.

TO INSTALL:

TO INSTALL THE FRONT COVER, FOLLOW THE ABOVE PROCEDURE IN REVERSE. NOTES: TO CONNECT THE CONNECTORS:

1. BE SURE THAT THE COLOR OF EACH CONNECTOR CORRESPONDS TO THE COLOR OF THE CONNECTOR POST ON THE PRINTED CIRCUIT BOARD (PCB) TO WHICH IT IS CONNECTED.

2. INSERT THE CONNECTOR AT THE RIGHT ANGLE. THEN PUSH IT STRAIGHT DOWN UNTIL IT LOCKS IN PLACE.

SETSCREW (H)

SETSCREW (C)

SETSCREW (B)

SETSCREW (D)

SETSCREW (A)

SETSCREW (E)

SETSCREW (F)

SETSCREW (G)

MACHINE SOCKET (CONNECTOR ON THE PCB)

POWER TRANSFORMER (CONNECTOR ON THE PCB)

SERVICE ACCESS (3-2)

FRONT COVER

1. UNFASTEN THE FRONT AND REAR COVER HOOKS AND THE BOTTOM SIDE HOOK AS SHOWN.

2. PULL THE FRONT COVER TO CLEAR OF THE FEED BALANCING KNOB.

3. PULL THE FRONT COVER TO CLEAR OF THE MACHINE SOCKET AND REMOVE THE FRONT COVER.

* REMOVE THE SETSCREWS (F) AND (G) ON THE REAR COVER TO FACILITATE CLEARANCE OF THE

FRONT COVER FROM THE MACHINE SOCKET.

SETSCREW (F)

FEED BALANCE DIAL KNOB

Hook

MACHINE PLUG

SETSCREW (G)

SERVICE ACCESS (4)

REAR COVER

TO REMOVE:

1. REMOVE THE FRONT COVER (SEE PAGE 6 AND 7).

2. REMOVE SETSCREWS (A), (B) AND (C), THEN REMOVE THE REAR COVER. * TO REMOVE THE COVER, DETACH THE PRESSER FOOT LIFTER SECTION FIRST, WITH THE PRESSER FOOT LIFTER IN THE DOWN POSITION.

TO INSTALL:

3. FOLLOW THE ABOVE PROCEDURE IN REVERSE.

SETSCREW (B)

SETSCREW (A)

SETSCREW (C)

PRESSER FOOT LIFTER

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