Janome DC3050 Service Manual

SERVICING MANUAL

DC3018 & DC3050

CONTENTS
WHAT 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	1. NEEDLE IS NOT INSERTED	INSERT THE NEEDLE PROPERLY.
STITCHES	PROPERLY.
	2. NEEDLE IS BENT OR WORN.	CHANGE THE NEEDLE.
	3. INCORRECTLY THREADED.	RETHREAD.
	4. NEEDLE OR THREAD ARE	USE THE RECOMMENDED
	INAPPROPRIATE FOR	SEWING NEEDLE AND THREAD.
	FABRIC BEING SEWN.
	5. SEWING ON STRETCH	USE A #11 BLUE TIP NEEDLE.
	FABRIC.
	6. PRESSER FOOT PRESSURE	ADJUST THE PRESSER BAR
	IS TOO WEAK.	LEVEL TO MAKE THE
		PRESSURE STRONGER.
	7. INAPPROPRIATE NEEDLE	SEE MECHANICAL ADJUSTMENT	P. 11
	BAR HEIGHT.	“NEEDLE BAR HEIGHT”.
	8. INAPPPROPRIATE NEEDLE	SEE MECHANICAL ADJUSTMENT	P. 12
	TO SHUTTLE TIMING.	“NEEDLE TO SHUTTLE TIMING”.
	9. INAPPROPRIATE NEEDLE	SEE MECHANICAL ADJUSTMENT	P. 13
	TO SHUTTLE CLEARANCE.	“CLEARANCE BETWEEN NEEDLE
		AND HOOK”.
2. FABRIC NOT	1. PRESSER FOOT PRESSURE	ADJUST THE PRESSER BAR
MOVING	IS TOO WEAK.	LEVEL TO MAKE THE
		PRESSURE STRONGER.
	2. INCORRECT F.D. HEIGHT.	SEE MECHANICAL	P. 15
		ADJUSTMENT “FEED DOG HEIGHT”.
	3.F.D. IS IN DOWN POSITION.	RAISE THE F.D. LEVEL.
	4.THREAD ON BOTTOM SIDE	MAKE SURE TO BRING BOTH
	OF FABRIC IS JAMMED UP.	NEEDLE AND BOBBIN THREAD UNDER
		THE FOOT WHEN STARTING SEWING.
	5. FEED DOG TEETH ARE WORN.	CHANGE THE FEED DOG.

1

CONDITION	CAUSE	HOW TO FIX	REFERENCE
3. BREAKING	1. INITIAL SEWING SPEED IS	START WITH MEDIUM SPEED.
UPPER	TOO FAST.
THREAD
	2. THREAD PATH IS INCORRECT.	USE THE PROPER THREAD PATH.
	3. NEEDLE IS BENT OR DULL.	REPLACE WITH A NEW NEEDLE.
	4. UPPER THREAD TENSION IS	ADJUST NEEDLE THREAD TENSION	P. 17
	TOO STRONG.	CORRECTLY.
	5. NEEDLE SIZE IS	USE APPROPRIATE NEEDLE FOR
	INAPPROPRIATE FOR FABRIC.	FABRIC AND THREAD IN USE.
	6. NEEDLE EYE IS WORN.	CHANGE THE NEEDLE.
	7. NEEDLE HOLE IN NEEDLE	REPAIR THE HOLE OR REPLACE
	PLATE IS WORN OR BURRED.	THE NEEDLE PLATE.
4. BREAKING	1. INCORRECITLY THREADED	THREAD BOBBIN CORRECTLY.
BOBBIN	BOBBIN.
THREAD
	2. TOO MUCH THREAD IS	ADJUST THE POSITION OF STOPPER.
	AROUND ON THE BOBBIN.
	3. LINT IS STUCK INSIDE THE	CLEAN THE SHUTTLE.
	BOBBIN HOLDER.
	4. THREAD QUALITY IS	CHANGE TO A HIGH QUALITY
	TOO LOW.	SEWING THREAD.
	5. THREAD IS JAMMING	CLEAR OUT THE JAMMING THREAD.
	AROUND THE BOBBIN.
5. NEEDLE	1. NEEDLE IS HITTING THE	SEE MECHANICAL	P. 10
BREAKS	NEEDLE PLATE.	ADJUSTMENT “NEEDLE DROP
		POSITION”.
	2. NEEDLE IS BENT OR WORN.	CHANGE THE NEEDLE.
	3. NEEDLE IS HITTING THE	SEE MECHANICAL ADJUSTMENT	P. 13
	SHUTTLE.	“CLEARANCE BETWEEN NEEDLE
		AND HOOK”.
	4. THE FABRIC MOVES WHILE	SEE MECHANICAL ADJUSTMENT	P. 16
	THE NEEDLE IS PIERCING	“ZIGZAG SYNCHRONIZATION”.
	IT, OR THE NEEDLE ZIGZAGS
	WHILE IN FABRIC.
	5. FABIRIC IS BEING PULLED TOO	GUIDE THE FABRIC GENTLY
	STRONGLY WHILE SEWING.	WHILE SEWING.

2

CONDITION	CAUSE	HOW TO FIX	REFERENCE
6. NOISY	1. BACKLASH BETWEEN SHTTLE	SEE MECHANICAL ADJUSTMENT	P. 14
OPERATION	HOOK GEAR AND LOWER	“BACKLASH (LOWER SHAFT GEAR)”.
	SHAFT GEAR IS TOO GREAT.
	2. LOWER SHAFT GEAR IS	ELIMINATE THE LOOSENESS.
	LOOSE.
	3. INAPPROPRIATTE BELT	SEE PART REMOVAL AND	P. 26
	TENSION.	REPLACEMENT “DRIVING MOTOR
		(DC MOTOR)”.
	4. NOT ENOUGH OIL.	OIL ALL MOVING PARTS.	P. 34
7. DEFORMATION	1. INAPPROPRIATE FEED	SEE MECHANICAL ADJUSTMENT	P. 18
PATTERN	BALANCE.	“STRETCH STITCH FEED BALANCE”.
	2. INAPPROPRIATE ZIGZAG	SEE MECHANICAL ADJUSTMENT	P. 16
	SYNCHRONIZATION.	“ZIGZAG SYNCHRONIZATION”.
	3. UPPER THREAD TENSION	SEE MECHANICAL ADJUSTMENT	P. 17
	IS TOO STRONG.	“NEEDLE THREAD TENSION”.

3

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.

Face cover

Setscrew (B)

Cap (A)

Ribs (E)

Hook (D)

4

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)

5

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 (C)

SETSCREW (B)

SETSCREW (D)

SETSCREW (A)

SETSCREW (E)

SETSCREW (H)

SETSCREW (F) SETSCREW (G)	MACHINE SOCKET	POWER
	(CONNECTOR ON	T R A N S F O R M E R
	THE PCB)	(CONNECTOR ON
		THE PCB)

6

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.

FEED BALANCE DIAL KNOB

Hook

MACHINE PLUG

SETSCREW (F)

SETSCREW (G)

7

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 (A)

SETSCREW (C)

SETSCREW (B)

PRESSER

FOOT LIFTER

8