Janome MC9900 Service Manual
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Janome MC9900 Service Manual

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SERVICE MANUAL
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PARTS LIST
MC9900

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Summary of Contents for Janome MC9900

  • Page 1 SERVICE MANUAL & PARTS LIST MC9900...

  • Page 2: Table Of Contents

    INDEX CHANGING EXTERNAL PARTS Face cover ............................1 Belt cover ............................1 Top cover .............................2 Base plate ............................3 Base cover ............................3 Bed cover ............................4 Free arm cover ..........................4-5 Front cover ............................6 Rear cover ............................7 REPLACING ELECTRONIC COMPONENTS Printed circuit board A .........................8 Printed circuit board F .........................9 Printed circuit board B (USB board) ....................9 Switching power supply unit ......................10...

  • Page 3: Changing External Parts

    Changing External Parts (1) 　 Face cover Face cover To remove: Setscrews 1. Remove the setscrews (2 pcs.). Remove the face cover. To attach: 1. Follow the above procedure in reverse. Belt cover Belt cover To remove: Setscrew A 1. Remove the cap and setscrew A. 2.

  • Page 4: Top Cover

    Changing External Parts (2) 　 Top cover Fig. 1 Setscrew A Top cover To remove: Carrying 1. Raise the carrying handle and remove the setscrew A. handle 2. Open the top cover. Pull out the flange plate from the bobbin winder spindle (see fig. 2). 3.

  • Page 5: Base Plate

    Changing External Parts (3) 　 Base plate Base plate To remove: 1. Remove the setscrews (x 4). 2. Remove the base plate. To attach: 1. Follow the above procedure in reverse. Setscrews Fig. 1 Base cover To remove: Rail cover 1.

  • Page 6: Bed Cover

    Changing External Parts (4) 　 Bed cover To remove: 1. Remove the setscrews (x 2). 2. Remove the bed cover. To attach: 1. Follow the above procedure in reverse. Bed cover Setscrew Free arm cover Fig. 1 To remove: Needle plate Free arm cover 1.
  • Page 7 Changing External Parts (5) 　 Fig. 3 5. Loosen the setscrew (see fig. 3). Free arm cover Setscrew Free arm cover Fig. 4 6. Slide the free arm cover in the direction of arrow until there is no clearance between the free arm cover and the free arm (see fig.

  • Page 8: Front Cover

    Changing External Parts (6) 　 Front cover Fig. 1 To remove: 1. Remove the belt cover, top cover and base plate (see pages 1, 2 and 3). 2. Loosen the setscrews A, B, C, D and E (see fig. 1-5). Setscrew A 3.

  • Page 9: Rear Cover

    Changing External Parts (7) 　 Rear cover Fig. 1 Setscrew A Rear cover To remove: 1. Lower the presser foot. 2. Remove the belt cover, top cover and base cover (see pages 1, 2 and 3). 3. Loosen the setscrews A and B (see fig. 1). Remove the setscrews C (see fig.

  • Page 10: Replacing Electronic Components

    Replacing electronic components Printed circuit board A To remove: 1. Remove the front cover (see page 6). 2. Grasp the connector directly with your fingers and pull. Do not pull the lead wire, as this may damage the Setscrew contact sleeve inside the connector. Remove the setscrews.

  • Page 11: Printed Circuit Board F

    Replacing electronic components Printed circuit board F o remove: 1. Remove the front cover (see page 6). Printed circuit board F CS ring 2. Disconnect the connector from the circuit board A (see page 8). 3. Remove the CS rings. 4.

  • Page 12: Switching Power Supply Unit

    Replacing electronic components Switching power supply unit Switching power supply unit To remove: 1. Remove the belt cover (see page 1). 2. Loosen the setscrew A. Remove the cord guide plate. (see fig. 1) 3. Disconnect the relay connector between the printed circuit board A and the switching power supply unit (see fig.

  • Page 13: Driving Motor

    Replacing electronic components Fig. 1 Driving motor To remove: 1. Remove the belt cover and the base plate (see pages Setscrew A 1 and 3). 2. Loosen the setscrew A and remove the cord guide plate (see fig. 1). 3. Disconnect the DC motor connector from the printed circuit board A (see page 8).

  • Page 14: Thread Tension Unit

    Replacing electronic components Thread tension unit Thread tension unit To remove: 1. Remove the belt cover, top cover, base plate and front cover (see pages 1, 2, 3 and 6). 2. Disconnect the printed circuit board G3 (thread tension motor) connector and printed circuit board G1 (thread cut detecting sensor) connector (see page 8).

  • Page 15: Mechanical Adjustment

    Mechanical adjustment Feed dog height When the foot pressure dial is at “5” and the presser foot A is lowered, the highest position of the feed dog should be 0.80 to 0.90 mm from the surface of the needle plate. Presser foot Adjustment 1: 0.85±0.05 mm...

  • Page 16: Clearance Between Needle And Tip Of The Rotary Hook

    Mechanical adjustment Clearance between needle and tip of the rotary hook The clearance between the needle and the point of hook should be -0.1 to +0.05 mm. Adjustment 1 Fig. 1 Fig. 2 1. Remove the top cover (see page 2). Needle plate hole 2.
  • Page 17 Adjustment 2 1. Remove the base cover and bed cover (see page 3 and 4). 2. Loosen the setscrews A and B. Loosen the setscrew C just enough to move the hook base plate (see fig. 5). Fig. 5 Hook base plate 3.

  • Page 18: Backlash Between Hook Drive Gear And Lower Shaft Gear

    Mechanical adjustment Backlash between hook drive gear and lower shaft gear The rotary play of the hook should be 0.8 mm or less when the tip of rotary hook is within the width of feed dog. 1. Remove the presser foot, the needle plate and the bobbin holder.

  • Page 19: Needle Drop Position

    Mechanical adjustment Needle drop position When the straight stitch is selected, the needle should be positioned in the center of the needle plate hole. When the needle drop position is set at "0.0" and "9.0", the clearance between the side of the needle and the needle hole should be 0.2 mm or more.

  • Page 20: Hook Timing

    Mechanical adjustment Hook timing The amount of ascending travel of the needle bar from its lowest position to the position (Needle drop position 0.0) where the tip of the rotary hook exactly meets the right side of the needle should be 3.70 to 4.00 mm To adjust: (Needle drop position 0.0) 1.

  • Page 21: Needle Bar Height

    Mechanical adjustment Needle bar height The distance between the upper edge of the needle eye and the hook race should be in the range of 1.6 to 2.0 mm when the tip of the hook meets right side of the needle in the needle drop position "0.0" as the needle ascends from its lowest position.

  • Page 22: Upper Shaft Shield Plate Position

    Mechanical adjustment Upper shaft shield plate position When the machine is set for zigzag stitch, the needle should start to swing 7.2 to 8.2 mm above the surface of the needle plate. To check: Fig. 1 1. Attach the needle #14. Needle #14 2.

  • Page 23: Upper Thread Tension

    Mechanical adjustment Upper thread tension The standard upper thread tension should be 59 to 67 grams when pulling the thread (white polyester thread size 50) at the speed of 110 mm/sec with the tension at "3.4" (Be sure the presser foot is lowered). 1.

  • Page 24: Tension Release Mechanism

    Mechanical adjustment Tension release mechanism When the presser foot is lowered, the thread tension discs will be closed and pull the thread. When the thread tension will be released, the tension disc will be opened and release the thread correctly. 1 Remove the belt cover, top cover, front cover and base cover (see page 1, 2, 3 and 6).

  • Page 25: Needle Threader Plate

    Mechanical adjustment Needle threader plate If the hook of the threader plate is damaged, change or adjust the part as follows: To remove: 1 Push down the needle threader knob and pull the needle threader plate (A) down to remove it (see Fig. 1). Pin (B) To attach: 1.

  • Page 26: Thread Drawing Lever

    Mechanical adjustment Thread drawing lever The standard height of the thread drawing lever from the surface of bobbin holder should be in the range of 5.5 to 6.0 1. Remove the presser foot, the needle plate and the bobbin holder. (see page 4-5) Thread drawing lever * You may use a fabric to prevent damaging the needle Hook race...

  • Page 27: Buttonhole Lever Adjustment

    Mechanical adjustment Buttonhole lever adjustment 1 Turn the power switch ON while pressing the Start/Stop button and the Reverse stitch button to enter the factory setting mode. Press "BH Sensor" key. 2. Attach the automatic buttonhole foot (R). Open the face cover. Lower the Buttonhole lever. Lower the drop feed dog.

  • Page 28: Presser Bar Lifter Switch Position

    Mechanical adjustment Presser bar lifter position The clearance between the presser foot and the surface of the needle plate should be 5.7 to 6.3 mm when the presser foot is raised. The presser foot (zigzag foot A) should be pararell to the slot of the feed dog teeth when attached. To adjust: 1.

  • Page 29: Embroidery Foot Height

    Mechanical adjustment Embroidery foot height The distance between the embroidery foot and the surface of the needle plate should be in the range of 0.9 to 1.5 mm when the presser bar is at its lowest position. Fig. 1 To adjust: Presser bar link Setscrew 1.

  • Page 30: Embroidery Foot Detecting Sensor Adjustment

    Mechanical adjustment Embroidery foot detecting sensor adjustment To adjust: Adjust the presser foot height and embroidery foot height before this adjustment (see page 26 and 27). 1. Remove the top cover (see page 2). Remove the setscrews (see fig. 1). Remove the carrying handle with the carrying handle base plate.

  • Page 31: Presser Foot Lifter Switch Adjustment

    Mechanical adjustment Presser foot lifter detecting switch adjustment To adjust: 1. Remove the top cover (see page 2). 2. Turn the power switch ON while pressing the Start/ Stop button and the Reverse stitch button to enter the factory setting mode. Press "Foot Sen/Feed Dog"...

  • Page 32: Knee Lifter

    Mechanical adjustment Knee lifter To adjust: 1. Remove the top cover (see page 2) 2. Remove the presser foot holder. 3. Lower the presser foot lifter. 4. Turn the handwheel toward you to lower the presser Reverse foot bar at its lowest position. stitch button 5.

  • Page 33: Thread Cutter

    Mechanical adjustment Thread cutter The distance between the end of thread cutter plate slit and the edge of moving cutter should be in the range of 0.8 to 1.6 To check: 1. Remove the bed cover and free arm cover (see page 4 and 5).

  • Page 34: Remaining Bobbin Threader Sensor

    Mechanical adjustment Remaining bobbin thread sensor 1. Prepare the empty bobbin (diameter: 8.4 mm) and the gauge bobbins (diameter: 12.5 mm and diameter: 18.9 mm). 2. Remove the presser foot and needle plate. (see page 4 and 5) * You may use a fabric to prevent damaging the needle plate.

  • Page 35: Needle Plate Sensor

    Mechanical adjustment Needle plate sensor To remove: Fig. 1 1. Remove the belt cover, top cover, base cover, bed cover, free-arm cover and the front cover (see pages Needle plate sensor 1 to 4 and 6). 2. Disconnect the connector from the needle plate sensor switch from the printed circuit board A (see page 8).
  • Page 36 4. Turn the power switch ON while pressing the Start/ Stop button and the Reverse stitch button to enter the factory setting mode. Press "Other sensor" key. 5. Be sure that "Straight" indicates "L", and "ZigZag" indicates "H" when the needle plate is attached. Reverse stitch button 6.

  • Page 37: Bobbin Winder

    Mechanical adjustment Bobbin winder The amount of thread wound on the bobbin should be 16.5 to 19.5 mm in diameter. To adjust bobboin thread amount: 1. Loosen the setscrew A. Adjust the stopper position to determine the thread amount of bobbin. 16.5 to 19.5 mm Fig.

  • Page 38: Stretch Stitch Feed Balance

    Mechanical adjustment Stretch stitch feed balance When the stretch pattern "8" is sewn 8 times with the stretch stitch balancing dial at the standard setting mark, the length of five of stretch patterns should be in the range of 33 to 39 mm. To check: Fig.

  • Page 39: Y-Carriage Play Adjustment

    Mechanical adjustment Y-carriage play adjustment There should be no play in the direction of arrow A (see fig. 1). 1. Push down the lever to open the Y-carriage. X-carriage 2. Remove the cap under the embroidery unit (see fig. 2). 3.

  • Page 40: Adjusting X And Y Sensors (Simple Adjustment)

    Mechanical adjustment Adjusting X and Y sensors (simple adjustment) To adjust: 1. Remove the foot holder. 2. Turn the power switch OFF. Attach the embroidery unit. Extend the carriage arm. 3. Attach the embroidery hoop and the template. Reverse 4. Turn the power switch ON while pressing the Start/Stop stitch button button and the Reverse stitch button to enter the factory Start/Stop button...

  • Page 41: Cloth Guide Start Position

    Mechanical adjustment Cloth guide start position The distance between the cloth guide and center needle position should be 15 mm when the cloth guide is at the start position. 1. Turn the power switch off. Attach the embroidery hoop. (Do not open the Y-carriage.) 2.

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