ELNA Elinita EF72 Service Manual
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ELNA Elinita EF72 Service Manual

ELNA Elinita EF72 Service Manual

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First Edition: 09 April 2020
SERVICE MANUAL
MODEL: ef72

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Summary of Contents for ELNA Elinita EF72

  • Page 1 First Edition: 09 April 2020 SERVICE MANUAL MODEL: ef72...

  • Page 2: Table Of Contents

    INDEX Changing external parts Face plate ................................. 1 Top cover ................................1 Belt cover ................................. 2 Base ................................. 2 Power supply cover ............................3 Thread cutter cover ............................3 Front cover ............................... 4 Thread guide coverr ............................5 Arm thread guide unit ............................6 Replacing Electronic Components Changing the printed circuit board A ........................

  • Page 3: Changing External Parts

    Changing external parts (1) Face plate To remove: 1. Remove the setscrew A to remove the face plate. To attach: 2. Attach the face plate with the setscrew A. Setscrew A Face plate Top cover To remove: 1. Remove the setscrews B (2 pcs.). Setscrew B Setscrew B Top Cover...

  • Page 4: Belt Cover

    Changing external parts (2) Hook Belt cover Belt cover To remove: 1. Remove the top cover (refer to page 1). Remove the caps (2 pcs.) and setscrews A (2 pcs.). 2. Loosen the setscrew B and remove the belt cover. Setscrew A To attach: 3.

  • Page 5: Power Supply Cover

    Changing external parts (3) Power supply cover To remove: 1. Remove the setscrews A (3 pcs.) and remove the power supply cover. Setscrew A To attach: 1. Attach the power supply cover with setscrews A (3 pcs.). Power supply cover Setscrew A Thread cutter cover Hook...

  • Page 6: Front Cover

    Changing external parts (4) Front cover To remove: 1. Remove the face plate, top cover and belt cover (refer to pages 1 and 2). 2. Loosen the setscrews A, B, C, D and E (6 pcs.). 3. Disconnect the LCD connector and printed circuit Setscrew A board K connector from the printed circuit board A.

  • Page 7: Thread Guide Coverr

    Changing external parts (5) Thread guide cover To remove: 1. Remove the face plate and the top cover (refer to Thread guide cover Setscrew A page 1). 2. Loosen the setscrews A and B, and remove the thread guide cover. To attach: 1.

  • Page 8: Arm Thread Guide Unit

    Changing external parts (6) Arm thread guide unit To remove: 1. Remove the face plate, top cover and thread guide cover (refer to pages 1 and 5). Setscrew A 2. Remove the setscrew A. Loosen the setscrew B, and remove the arm thread guide (unit).

  • Page 9: Changing The Printed Circuit Board A

    Changing the printed circuit board A To remove: Printed circuit board A 1. Remove the front cover (refer to page 4). Setscrew A Setscrew A 2. Remove the setscrews A (4 pcs.) and disconnect all the connectors from the printed circuit board A. Remove the printed circuit board A.

  • Page 10: Changing The Printed Circuit Board K

    Changing the printed circuit board K To remove: 1. Remove the front cover (refer to page 4). Connector for printed circuit board F 2. Disconnect the connector for printed circuit board F. 3. Remove the setscrews A (6 pcs.) and printed circuit board K.

  • Page 11: Changing The Printed Circuit Board F And Slide Volume

    Changing the printed circuit board F and slide volume Printed circuit board F To remove: Connector for printed 1. Remove the front cover (refer to page 4). circuit board F 2. Disconnect the connector for printed circuit board F and slide volume connector. Setscrew A 3.

  • Page 12: Changing Lcd

    Changing LCD To remove: Setscrew A 1. Remove the front cover (refer to page 4). 2. Remove the setscrews A (4 pcs.) and remove the LCD. To attach: 1. Follow the steps of removal procedure in reverse. Setscrew A...

  • Page 13: Wiring Diagram

    Wiring diagram Refer to this wiring diagram for locating the connectors on the printed circuit board A. ErP connector (green 2P) Foot control (white 2P) LED (arm) (blue 2P) (Switching power supply) LED (arm) (red 2P) Bobbin winder motor (black 4P) LED (face plate) (white 2P) (Programming) LCD (white 16P)

  • Page 14: Needle Drop Position

    Needle drop position When the straight stitch is selected, the needle should be positioned in the center of the needle plate hole. When the zigzag stitch is selected with the maximum stitch width of 9.0, the clearance between the side of the needle and needle hole should be 0.2 mm or more. 1. Remove the face plate. Select straight stitch #1 ( in mode 1 and check the needle drop position.

  • Page 15: Backlash Between Hook Drive Gear And Lower Shaft Gear

    Backlash between hook drive gear and lower shaft gear The gears turn smoothly and rotary play of the hook should be 0.8 mm or less when the tip of hook is within the width of the feed dog as shown below. 1.

  • Page 16: Hook Timing

    Hook timing The amount of ascending travel of the needle bar from its lowest position to the position where the tip of the rotary hook exactly meets the right side of the needle in the left needle position (“0.0”) should be 3.70 to 4.00 mm. 1. Attach the #14 needle. 2. Turn the power switch on and select the straight stitch The tip of the rotary hook #1 ( ).

  • Page 17: Adjustment Of Needle Bar Height

    Adjustment of needle bar height Before proceeding with this adjustment, check the hook timing. The distance between the upper edge of the needle eye and the tip of the hook should be in the range of 1.6 to 2.0mm when the tip of the hook meets right side of the needle in the left needle position (“0.0”) as the needle ascends from its lowest position.

  • Page 18: Clearance Between Needle And Tip Of The Rotary Hook (1)

    Clearance between needle and tip of the rotary hook (1) The clearance between the needle and the tip of the rotary hook should be between -0.10 to +0.05 mm. Clearance adjustment 1 1. Remove the top cover and face plate (refer to page 1 ). 2.

  • Page 19: Clearance Between Needle And Tip Of The Rotary Hook (2)

    Clearance between needle and tip of the rotary hook (2) The clearance between the needle and the tip of the rotary hook should be between -0.10 to +0.05 mm. Clearance adjustment 2 1. Remove the base. (Refer to page 2) 2.

  • Page 20: Adjustment Of Height And Direction Of Presser Bar

    Adjustment of height and direction of presser bar The clearance between the presser foot and the surface of the needle plate should be 6.0 mm when the presser foot is raised. The presser foot should be parallel to the slot of the feed dog teeth when attached. 1.

  • Page 21: To Adjust The Feed Dog Height

    To adjust the feed dog height When the pressure adjusting dial is at “3” and the presser foot is lowered, the highest position of the feed dog should be 0.80 to 0.90 mm from the surface of the needle plate. To adjust: 1.

  • Page 22: To Replace Needle Thread Tension Unit

    To replace needle thread tension unit To remove: 1. Remove the face plate, top cover, thread guide cover Thread and arm thread guide (refer to pages 1, 5 and 6). tension release arm 2. Lower the presser foot lifter. 3. Loosen the hexagonal socket screw. Thread tension 4.

  • Page 23: To Adjust The Upper Thread Tension Release (1)

    To adjust the upper thread tension release (1) The clearance of upper thread tension disks should be 0.8 mm when the presser foot is raised. 1. Remove the face plate, top cover, thread guide cover and arm thread guide (refer to pages 1, 5 and 6) Thread tension disk 2.

  • Page 24: To Adjust The Upper Thread Tension Release (2)

    To adjust the upper thread tension release (2) Upper thread tension disks should open 0.8 mm when the tension thread release motor operates. If not, adjust follows. (Fig. 1) 1. Remove the face plate, top cover and thread guide Base Setscrew C cover (refer to pages 1 and 5).

  • Page 25: Adjusting The Needle Thread Tension

    Adjusting the needle thread tension The upper thread tension should be 75 to 90 grams-force when pulling the thread (white polyester thread size 50) at the speed of 110 mm/sec. with the tension dial at “4”. 1. Set the thread tension dial at “4”. Tension dial 2.

  • Page 26: To Adjust The Bobbin Winder Stopper

    To adjust the bobbin winder stopper The diameter of thread wound on a bobbin should be 16.5 to 19.5 mm. 1. To adjust the thread amount for bobbin, loosen the setscrew and turn the bobbin winder stopper. Turn the bobbin winder stopper in the direction of (A) when the thread amount for bobbin is too large.

  • Page 27: Needle Threader Hook Position

    Needle threader hook position The threader hook comes out through the needle eye from behind when the needle threader lever is lowered. 1. Push down the threader lever and hold it just before the threader hook enters the needle eye. 2.

  • Page 28: To Adjust Thread Cutter Switch

    To adjust thread cutter switch The distance between the left end of thread cutter plate slit and the left end of moving cutter should be in the range of 0.7 to 1.5 mm. 1. Turn the poewr switch off. End of thread End of moving cutter Remove the needle plate, base and thread cutter cutter plate slit...

  • Page 29: To Adjust Thread Drawing Lever

    To adjust thread drawing lever The maximum height of the thread drawing lever should be between 5.5 to 5.7 mm from the hook race. 1. Remove the needle plate. 2. Loosen the hexagonal socket screw. Thread drawing lever When the thread drawing lever is at the highest position, adjust the drawing lever so that the distance between the hook race and the drawing lever is 5.5 to 5.7 mm.

  • Page 30: Replacing The Thread Take-Up Lever

    Replacing the thread take-up lever When you replace the thread take-up lever, insert the needle bar crank pin into the take-up lever crank as illustrated. The hexagonal socket screw (long) must hold the needle bar crank pin cut surface. Thread take-up lever Hexagonal socket scerw (long) Take-up lever crank Needle bar crank pin cut surface...

  • Page 31: To Attach Lower Shaft

    To attach lower shaft When you replace the lower shaft or the lower shaft parts, adjust the phases as shown below. The phases of the thread drowing lever cam (A) and the feed cam (B) are the same as that of the spring pin (C).

  • Page 32: Synchro Belt

    Synchro belt Alignment mark (A) When you replace the synchro belt, set the alignment mark (A) on the belt wheel at upper left (10 degrees), the 10 degrees alignment mark (B) on the lower shaft gear at upper right as shown. Belt wheel Synchro belt Alignment mark (B)

  • Page 33: To Replace Driving Motor And Adjust Belt Tension

    To replace driving motor and adjust belt tension To remove: 1. Remove the face plate, top cover, belt cover and front cover (refer to pages 1, 2 and 4). Motor belt 2. Remove the motor belt. 3. Disconnect the motor connector from the printed circuit board A.

  • Page 34: Upper Shaft Shield Plate Position

    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. 1. Attach the #14 needle. 2 Turn the power switch on while pressing the auto- lock key and needle up/down key to enter the factory Needle #14 setting mode.

  • Page 35: Adjusting Buttonhole Lever Position

    Adjusting buttonhole lever position Auto-lock key 1. Turn the power switch on while pressing the auto- (Factory setting mode) Needle up/down key lock key and needle up/doun key to enter the factory setting mode. 2. Press the numeral key “4” to select the upper shaft positioning sensor adjusting mode.

  • Page 36: Stretch Stitch Feed Balance

    Stretch stitch feed balance When the stretch pattern 8 is sewn 8 times with the stretch stitch balancing dial at the neutral position, the length of five of stretch patterns should be in the range of 33 to 39 mm. Auto-lock key (Factory setting mode) 1. Attach the satin stitch foot F. Needle up/down key 2. Set the stretch stitch balance dial to the neutral position.

  • Page 37: Adjustment Of Presser Bar Lifter Switch Position

    Adjustment of presser bar lifter switch position To check: Auto-lock key (Factory setting mode) 1. Attach the zigzag foot A. Needle up/down key 2. Lower the presser foot lifter. 3. Turn the power switch on while pressing the auto- lock key and needle up/doun key to enter the factory setting mode.

  • Page 38: To Adjust And Replace Needle Plate Sensor Switch

    To adjust and replace needle plate sensor switch To replace: To remove: 1. Remove the base. (Refer to page 2) 2. Remove the front cover. (Refer to page 4) Rear side 3. Disconnect the needle plate sensor switch connector from the printed circuit board A. 4.

  • Page 39: To Replace Switching Power Supply

    To replace switching power supply To remove: 1. Remove the power supply cover and belt cover. 2. Disconnect the connector for power supply from the switching power supply. Connector for power supply 3. Disconnect the connector for foot control (connected to the switching power supply) from the printed circuit board A.

  • Page 40: To Replace And Adjust Drop Feed Micro Switch

    To replace and adjust drop feed micro switch To replace: To remove: 1. Remove the base and front cover (refer to pages 1 (View from the belt cover side) and 4). Drop feed micro switch 2. Disconnect the connector for drop feed micro switch from the printed circuit board A.

  • Page 41: Feed Dog Troubleshooting

    Feed dog troubleshooting When the feed dog does not return to “Up” position and the machine do not feed a fabric, check and adjust the feed lifting cam. Projection of feed lifting cam 1. Check the drop feed lever 1) Remove the base. 2) Bring the needle bar at the lowest position.

  • Page 42: Self Diagnosis

    Self diagnosis NOTE: 1. The power switch must be turned off when replacing parts. 2. The language on the LCD is English only. Preparation: 1.Shift the bobbin winder stopper to the right. 2. Slide the drop feed lever to the left to raise the feed dog. 3.
  • Page 43 1. Function of buzzer, LCD and LED Correct condition Faulty condition 1. Buzzer sounds Buzzer does not sound.   2. LCD and LED blink at 1 second The step 1 screen does not appear. interval. LED of the start/stop key does not 3.
  • Page 44 3. Detecting switch Correct condition Faulty condition 1. Bobbin winder switch (Spool) Buzzer does not sound. Move the bobbin winder stopper The display does not change or is to the left and right. reversed. Left: “H” To adjust or replace a part: Right: “L”...
  • Page 45 4. Foot control/speed control slider 1. Foot control Correct condition Faulty condition When the foot control is not The number is less than 240. connected: 240 or more The screen does not change. The number changes when the foot To replace: control is connected/pressed and released.
  • Page 46 7. Thread cutter motor Correct condition Faulty condition Turn the handwheel to move the The thread cutter motor is not needle bar to the zigzag phase (up initialized. position). When pressing the needle “E4” is indicated. up/down key, the thread cutter motor The caution buzzer sounds when is initialized and the buzzer sounds.

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