Singer 9920 Service Manual
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Singer 9920 Service Manual

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SERVICE MANUAL
9940/20/10
9/20/2003

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Summary of Contents for Singer 9920

  • Page 1 SERVICE MANUAL 9940/20/10 9/20/2003...

  • Page 2: Table Of Contents

    LOCATING THE DEFFECTED ELECTRICAL PART ........29 1. To turn off the audible beep ..............29 2. The self-diagnostic program ..............29 3. Messages on LCD (9940/9920) .............. 33 4. Electrical Parts Connection ..............34 SINGER® is a registered Trademark of The Singer Company Ltd.

  • Page 3: Removing The Exterior Parts

    SERVICE MANUAL REMOVING THE EXTERIOR PARTS The exterior parts should be removed in sequence as followings. CAUTION: Always disconnect the main lead plug from electcrial outlet when removing the exterior parts. A. Light Cover 1. Loosen the light cover set screw (a). 2.

  • Page 4: Top Cover (Flap)

    SERVICE MANUAL C. Top Cover (Flap) 1. Open the top cover. 2. Push the right side of top cover backward and remove the hinge (a). 3. Slide the top cover to the right and remove the hinge (b). D. Hinge Cover 1.

  • Page 5: Side Enclosure

    SERVICE MANUAL F. Side Enclosure 1. Remove the screw (a). 2. Push the side enclosure slightly backward to come off the 2 hooks (b, c). 3. Pull the side enclosure to the right and remove it. G. Handle and Unit Cover 1.

  • Page 6: Needle Plate

    SERVICE MANUAL 4. Next, push the left side of unit cover backward and pull up it to come off from the thread guide cover. 5. Slide the handle and unit cover to the left and remove them. 6. Carefully disconnect the connector which connects to the contrast control board.

  • Page 7: Front Enclosure

    SERVICE MANUAL I. Front Enclosure 1. Loosen the screw (a). 2. Push the left side of rear enclosure (b) and pull the front enclosure (hook-c will come off). 3. Pull up the front enclosure and come off the hook-d. 4. Pull the enclosure to the left and come off the hook-e. 5.

  • Page 8: Rear Enclosure

    SERVICE MANUAL J. Rear Enclosure 1. Lower the presser foot lifter. 2. Remove the 3 screws (a, b, c). (screw-c is longer than others.) 3. Pull the rear enclosure backward and remove it. K. Front panel (from Front Enclosure) 1. Disconnect the 2 connectors from the front panel (a: Reverse switch board) (b: Controller jack assy.) TYPE A (Secured by 4 screws) 2.

  • Page 9: Replacing The Exterior Parts

    SERVICE MANUAL REPLACING THE EXTERIOR PARTS The exterior parts should be replaced in reverse se- quence when removing. (K. to A.) K. Front panel (to Front Enclosure) 1. Pass the cords through the openings of front enclo- sure. 2. Ride the 3 hooks of front panel on the front enclosure. TYPE A (Secured by 4 screws) 3.

  • Page 10: Front Enclosure

    SERVICE MANUAL I. Front Enclosure 1. Connect the 2 connectors (g, h) to the machine. 2. Replace the front enclosure so that the 4 hooks will fit in place. 3. Push lower end of front enclosure arm backward and retighten the screw (a). H.

  • Page 11: Handle And Unit Cover

    SERVICE MANUAL G. Handle and Unit Cover 1. Set the handle to the unit cover and insert the handle hinge pin into the left side hole of handle from left side. 2. Place the handle and unit cover onto the top of machine.

  • Page 12: Side Enclosure

    SERVICE MANUAL F. Side Enclosure 1. Replace the side enclosure so that the each hook fit into place. 2. Retighten the screw (a). E. Thread Tension Cover 1. Replace the thread tension cover so that the each hook fit into place. 2.

  • Page 13: Top Cover (Flap)

    SERVICE MANUAL C. Top Cover (Flap) 1. Slide the top cover to the left so that the hook (b) will fit onto the pin of unit cover. 2. Pull the right side of top cover and snap on the hook (a) onto the pin of unit cover.

  • Page 14: Light Cover

    SERVICE MANUAL A. Light Cover 1. Loosen the light cover set screw (a). 2. Replace the ligth cover so so that the hook (b) will fit into place. 3. Retighten the screw (a).

  • Page 15: Check And Adjustment

    SERVICE MANUAL CHECK AND ADJUSTMENT 1. HEIGHT OF NEEDLE BAR Height of needle bar could be the cause for stitches to skip. Check as the following procedures. 1. Set the pattern to [Utility stitch No.1] which is straight stitch on center needle position. 2.

  • Page 16: Gap Between Needle And Hook

    SERVICE MANUAL 2. GAP BETWEEN NEEDLE AND HOOK If the needle hits against the hook, it may be the cause of needle and thread breakages. If the gap between needle and hook is too big, it will cause to skip stitches. Check and adjust as follows: Prior to make this adjustment, check that the needle is not bent and the needle is inserted correctly.

  • Page 17: Timing Of The Hook

    SERVICE MANUAL 3. TIMING OF THE HOOK Prior to making this adjustment, be sure that the needle bar is set at the correct height. (Sec. 1) Check the timing of hook as follows: 1. Remove the needle plate and bobbin holder. 2.

  • Page 18: Height Of The Feed Dog

    SERVICE MANUAL 4. HEIGHT OF THE FEED DOG If the feed dog does not come up over the needle plate enough, it will result in insufficient and/or uneven feed of fabrics. 1. The feed dog should come up over the needle plate (1.0-1.1 mm) when its highest position.

  • Page 19: Needle Plate And Needle Position

    SERVICE MANUAL 5. NEEDLE PLATE AND NEEDLE POSITION 1. When the straight stitches is set at center needle position (Utility No.1), the needle should fall into the center of needle plate hole (the distance needle and edge of hole at each side). If it is not so, adjust as follows: 2.

  • Page 20: Timing Of The Upper And Lower Shaft

    SERVICE MANUAL 6. TIMING OF THE UPPER AND LOWER SHAFT The upper and lower shaft must be positioned correctly as follows. 1. Remove the front enclosure. 2. Turn the handwheel toward you until the needle is its lowest point. At this time, the mark (a - very small molded line on edge) on the lower shaft timing pulley must be facing toward you.

  • Page 21: Adjusting The Forward Reverse Stitch

    Check and adjust as follows. • We recommend checking “Height of the Feed-dog (Sec. 4)” before you make this adjustment. 9920 1. Turn on the power switch with pressing the buttons as Feed Adjust shown. LCD wiil indicate the message “Feed Adjust”.

  • Page 22: Bobbin Winder

    SERVICE MANUAL 8. BOBBIN WINDER If bobbin winds unevenly, adjust as follows: 1. If bobbin winds as shown, turn the adjusting screw (a) to the left. 2. If bobbin winds as shown, turn the adjusting screw (a) to the right. 3.

  • Page 23: Height And Direction Of Presser Foot

    SERVICE MANUAL 9. HEIGHT AND DIRECTION OF PRESSER FOOT 1. The height of the presser foot from the needle plate should be 6.5 mm when it is lifted up. The presser foot should be facing frontward (the edge of foot is parallel with the feed dog slot on needle plate).

  • Page 24: Height Of Needle Threader

    SERVICE MANUAL 10. HEIGHT OF NEEDLE THREADER If the height of needle threader is not correct, the hook on threader will not enter the needle eye. Adjust as follows: 1. Remove the light cover. 2. Remove the 2 screws (a, b) and remove the take up lever cover and bracket (c) by sliding it upward.

  • Page 25: Adjustments For Buttonhole Lever Position

    2. Turn on the power switch with pressing the buttons as 9920 shown. The self-diagnostic program will run. 3. Attach the buttonhole foot. 4. Lower the presser foot and the buttonhole lever.

  • Page 26: Motor Belt Tension

    SERVICE MANUAL 12. MOTOR BELT TENSION If the motor belt tension is too tight or too loose, machine will not run smoothly. Adjust as follows: 1. Remove the front enclosure. 2. Loosen the 2 screws (a, b) 3. Move the motor up or downward and tentatively tighten the screws.

  • Page 27: Backlash Of Hook Gear

    SERVICE MANUAL 14. BACKLASH OF HOOK GEAR If there is too much play on the hook gear on the turning direction, it may be the cause for machine not to sew 0-0.5 mm properly and/or making excessive sewing noise. 1. Free play at the tip of hook may be 0-0.5 mm. If it is not so, adjust as follows.

  • Page 28: Upper Thread Tension Unit

    SERVICE MANUAL 15. UPPER THREAD TENSION UNIT The upper thread tension regulator unit has been adjusted to the best sewing conditions at the position [AUTO]. However, if you wish to change this, do it as follows: 1. Remove the thread tension cover. 2.

  • Page 29: Locating The Deffected Electrical Part

    1. Turn off the power switch. 2. Turn on the power switch with pressing the buttons indicated in the right chart. 3. To return the normal mode, turn off the power switch 9920 and turn on without pressing any button. 9910 2. The self-diagnostic program...
  • Page 30 SERVICE MANUAL Condition of switches and sensors The condition of each switch and sensor is indicated as follows. b: Buttonhole lever switch -Rear 1=Neutral 0=Lever is pulled. f: Buttonhole lever switch -Front 1=Neutral 0=Lever is pushed. Lower the buttonhole lever and check these switch by pulling or pushing this lever.
  • Page 31 SERVICE MANUAL K: Response of each button 9920 By pressing each button, number will be indicated as below. 8 9 10 11 12 9910 9940 13 14 12 13 14 15 16 10 11 20 21 8 9 10 11 12...
  • Page 32 Checking Starting point of Z and F pulse 9940 motors 1. When self-diagnositic program is running; 9920 • By pressing the button (a), Z pulse motor will move to starting point. • By pressing the button (b), F pulse motor will move to 9910 starting point.

  • Page 33: Messages On Lcd (9940/9920)

    SERVICE MANUAL 3. Messages on LCD (9940/9920) 1. Winding the bobbin. 2. Lower the buttonhole lever. 3. Raise the presser foot lifter and set the buttonhole foot to correct position. 4. Release the foot controller pedal. 5. Lower the presser foot.

  • Page 34: Electrical Parts Connection

    SERVICE MANUAL 4. Electrical Parts Connection a. CPU Board b. Power Circuit Board c. Power Switch Assy. d. Terminal Box Assy. e. Motor f. F Pulse Motor g. Z Pulse Motor h. LED Board Assy. i. BH Switch Assy. j. Presser Foot Switch Assy. k.

This manual is also suitable for:

99409910

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