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New Home NH7 Service Manual

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SERVICE MANUAL
MODEL: NH7

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Summary of Contents for New Home NH7

  • Page 1 SERVICE MANUAL MODEL: NH7...

  • Page 2: Table Of Contents

    CONTENTS WHAT TO DO WHEN ................. 1-3 SERVICE ACCESS FACE PLATE .................. 4 REAR COVER ................5 FRONT COVER ................6 MECHANICAL ADJUSTMENT TOP TENSION ................7 BOBBIN TENSION ................. 8 PRESSER BAR HEIGHT AND ALIGNMENT ........ 9 NEEDLE SWING ................10 NEEDLE DROP ................

  • Page 3: What To Do When

    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.
  • Page 4 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 USE THE PROPER THREAD INCORRECT. PATH. 3. NEEDLE IS BENT OR DULL. REPLACE WITH A NEW NEEDLE. 　P.7 4.
  • Page 5 CONDITION CAUSE HOW TO FIX REFERENCE 6. NOISY 1. BACKLASH BETWEEN SEE MECHANICAL P.13 OPERATION SHUTTLE HOOK GEAR AND ADJUSTMENT “CLEARANCE LOWER SHAFT GEAR IS TOO BETWEEN NEEDLE AND HOOK GREAT. (NO.2)”. 2. LOWER SHAFT GEAR IS ELIMINATE THE LOOSENESS. LOOSE.

  • Page 6: Service Access

    SERVICE ACCESS FACE PLATE FACE PLATE SETSCREW TO REMOVE: 1. REMOVE THE CAP AND SETSCREW. REMOVE THE FACE PLATE. TO ATTACH: 2. FOLLOW THE ABOVE PROCEDURE IN REVERSE.

  • Page 7: Rear Cover

    SERVICE ACCESS REAR COVER REAR COVER TO REMOVE: REMOVE THE FACE COVER (SEE PAGE 4). OPEN THE SHUTTLE COVER AND REMOVE THE SETSCREWS (A). REMOVE THE SETSCREWS (B), (C), (D) AND RUBBER CUSHION (E) (2 PCS.), AND THEN REMOVE THE REAR COVER. TO ATTACH: MOUNT THE REAR COVER IN REVERSE PROCEDURE OF THE REMOVING.

  • Page 8: Front Cover

    SERVICE ACCESS FRONT COVER PATTERN SELECTOR DIAL FRONT COVER TO REMOVE: REMOVE THE FACE COVER AND REAR COVER (SEE PAGE 4-5). PULL OUT THE PATTERN SELECTOR DIAL. LOOSEN THE SETSCREWS (A), (B) AND REMOVE THE SETSCREWS (C), (D), (E), (F) AND RUBBER CUSHION (G), THEN REMOVE THE FRONT COVER.

  • Page 9: Mechanical Adjustment

    MECHANICAL ADJUSTMENT TOP TENSION TO CHECK: THE STANDARD UPPER THREAD TENSION SHOULD BE 65 - 95g WHEN PULLING THE THREAD (COTTON THREAD #50) IN THE DIRECTION OF (B) WITH SETTING THE TENSION DIAL AT “3”. (MAKE SURE THE FOOT SHOULD BE LOWERED.) IF THE TENSION IS OUT OF THE STANDARD RANGE, ADJUST IT AS FOLLOWS: ADJUSTMENT PROCEDURE: REMOVE THE FRONT COVER UNIT (SEE PAGE 6).

  • Page 10: Bobbin Tension

    MECHANICAL ADJUSTMENT BOBBIN TENSION TO CHECK: SET THE BOBBIN IN THE BOBBIN CASE AND PASS THE THREAD (COTTON #50) THROUGH THE TENSION SPRING. THE BOBBIN THREAD TENSION SHOULD BE 45 - 55g WHEN PULLING THE THREAD IN THE DIRECTION OF (B). IF THE TENSION IS OUT OF THE RANGE, ADJUST IT AS FOLLOWS: ADJUSTMENT PROCEDURE: TURN THE ADJUSTING SCREW (C) IN THE DIRECTION OF (D) WHEN THE...

  • Page 11: Presser Bar Height And Alignment

    MECHANICAL ADJUSTMENT PRESSER BAR HEIGHT AND ALIGNMENT TO CHECK: RAISE THE PRESSER FOOT LEVER. THE DISTANCE BETWEEN THE PRESSER FOOT (C) AND THE NEEDLE PLATE (D) SHOULD BE 6.0MM (0.24"). ADJUSTMENT PROCEDURE: REMOVE THE FACE PLATE (SEE PAGE 4). REMOVE THE SCREWS (A) AND TAKE THE LAMP SOCKET OFF. RAISE THE PRESSER FOOT LEVER AND LOOSEN THE SCREW (B) ON THE PRESSER BAR HOLDER.

  • Page 12: Needle Swing

    MECHANICAL ADJUSTMENT NEEDLE SWING TO CHECK: ADJUST THE NEEDLE SWING ACCORDING TO THE FOLLOWING PROCEDURE, IF THE NEEDLE BAR STARTS MOVING SIDEWAYS WHILE THE NEEDLE IS IN THE FABRIC AT SEWING THE ZIGZAG PATTERN (WITH MAXIMUM ZIGZAG WIDTH). ADJUSTMENT PROCEDURE: SET THE PATTERN SELECTOR DIAL WITH MAXIMUM ZIGZAG WIDTH, AND REMOVE THE FRONT COVER (SEE PAGE 6).

  • Page 13: Needle Drop

    MECHANICAL ADJUSTMENT NEEDLE DROP TO CHECK: WHEN THE NEEDLE SWINGS IN MAXIMUM ZIGZAG WIDTH, THE DISTANCE BETWEEN THE BOTH ENDS OF NEEDLE HOLE ON THE NEEDLE PLATE AND THE NEEDLE DROP POSITIONS SHOULD BE EQUAL. IF NOT, MAKE AN ADJUSTMENT AS FOLLOWS: ADJUSTMENT PROCEDURE: REMOVE THE FACE PLATE (SEE PAGE 4).

  • Page 14: Clearance Between Needle And Hook (No.1)

    MECHANICAL ADJUSTMENT CLEARANCE BETWEEN NEEDLE AND HOOK (NO.1) TO CHECK: THE CLEARANCE BETWEEN NEEDLE AND SHUTTLE RACE SHOULD BE –0.05 - 0.10MM. IF NOT, MAKE AN ADJUSTMENT AS FOLLOWS: ADJUSTMENT PROCEDURE: REMOVE THE FACE PLATE (SEE PAGE 4). SET THE PATTERN SELECTOR DIAL AT MAXIMUM ZIGZAG WIDTH, AND TURN THE HANDWHEEL TOWARD YOU TO BRING THE NEEDLE AT LEFT NEEDLE POSITION.

  • Page 15: Clearance Between Needle And Hook (No.2)

    MECHANICAL ADJUSTMENT CLEARANCE BETWEEN NEEDLE AND HOOK (NO.2) TO CHECK: USE THIS ADJUSTMENT NO.2 WHEN ADJUSTMENT NO.1 CAN NOT BE USED. THE CLEARANCE BETWEEN NEEDLE AND SHUTTLE RACE SHOULD BE –0.05-0.10MM. ADJUSTMENT PROCEDURE: SET THE PATTERN SELECTOR DIAL AT MAXIMUM SIGZAG WIDTH, AND TURN THE HANDWHEEL TOWARD YOU TO ERING THE NEEDLE TO THE LEFT NEEDLE POSITION.

  • Page 16: Feed Dog Height

    MECHANICAL ADJUSTMENT FEED DOG HEIGHT TO CHECK: LOWER THE PRESSER FOOT. TURN THE HANDWHEEL TOWARD YOU TO BRING THE FEED DOG TO ITS HIGHEST POSITION. THE HEIGHT OF THE FEED DOG FROM THE NEEDLE PLATE SHOULD BE 0.75 – 0.90MM. IF IT IS NOT IN THE RANGE, ADJUST AS FOLLOWS.

  • Page 17: Needle Bar Height

    MECHANICAL ADJUSTMENT NEEDLE BAR HEIGHT TO CHECK: WHEN THE TIP OF SHUTTLE HOOK MEETS THE LEFT SIDE OF THE NEEDLE IN ASCENDING TRAVEL OF THE NEEDLE FROM ITS LEFT AND LOWEST POSITION, THE DISTANCE BETWEEN THE TOP OF THE NEEDLE EYE AND THE TIP OF THE SHUTTLE HOOK SHOULD BE IN THE RANGE OF 2.9 –...

  • Page 18: Needle Timing To Shuttle

    MECHANICAL ADJUSTMENT NEEDLE TIMING TO SHUTTLE TO CHECK: THE HEIGHT OF THE NEEDLE POINT FROM ITS LOWEST POINT OF TRAVEL SHOULD BE IN THE RANGE OF 1.4-2.0 MM WHEN THE TIP OF THE SHUTTLE HOOK JUST MEETS THE LEFT SIDE OF THE NEEDLE AT THE LEFT NEEDLE POSITION.

  • Page 19: Buttonhole Feed Balance

    MECHANICAL ADJUSTMENT BUTTONHOLE FEED BALANCE TO CHECK: WHEN SEWING BUTTONHOLE, THE STITCHES ON EACH SIDE OF BUTTONHOLE SHOULD BE THE SAME STITCH DENSITY. THE RANGE OF 9-11 STITCHES IN THE RIGHT SIDE ROW “BACKWARD FEEDING” AGAINST 10 STITCHES IN THE LEFT SIDE ROW “FORWARD FEEDING” IS CONSIDERED ACCEPTABLE.

  • Page 20: Adjustment Of Right Hand Line Tack Width And Cam Follower Release Amount

    MECHANICAL ADJUSTMENT ADJUSTMENT OF RIGHT HAND LINE TACK WIDTH AND CAM FOLLOWER RELEASE AMOUNT * THE WIDTH OF THE LEFT AND RIGHT SIDE LINE TACK OF BUTTONHOLE SHOULD BE EQUAL. IF THERE IS LARGE DIFFERENCE BETWEEN LEFT AND RIGHT LINE TACK WIDTH, THE CAM FOLLOWER MAY BE HINDERED WITH THE ZIGZAG CAM BLOCK WHEN YOU TURN THE PATTERN SELECTOR DIAL.

  • Page 21: Motor Belt Tension

    MECHANICAL ADJUSTMENT MOTOR BELT TENSION TO CHECK: TOO TIGHT OR TOO LOOSE MOTOR BELT TENSION MAY CREATE BELT NOISE AND ALSO TOO TIGHT MOTOR BELT TENSION CAN CAUSE THE MACHINE TO RUN SLOW AND WILL OVERLOAD THE MOTOR. TOO LOOSE MOTOR BELT TENSION MAY CAUSE JUMPING OF THE BELT TEETH ON THE MOTOR PULLEY.

  • Page 22: Wiring

    WIRING WIRING FOR MACHINE SOCKET UNIT LAMP (BLUE) (BROWN) (BROWN) (BLUE) MOTOR...

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