background image

21

SELF DIAGNOSTIC TESTS

Preparation:

 

1. Turn the power switch off.

 

2. Move the bobbin winder spindle to the left.

 

3. Remove the presser foot and raise the presser foot lifter.

 

4. Turn the hand wheel toward you to raise the needle to its highest position.

Notes:

 

• Be careful: the sewing machine may start running in its own while in test mode.

 

• Turn off the power switch before replacing any parts.

 

• Repeat the diagnostic test until the problem has been resolved.

 

• You can skip steps in the diagnostic procedure and go directly to the test you want to perform.

 

    (Enter self-diagnostic mode, then select the step number of the diagnostic test you require by 

 

    pressing the reverse button)

To begin:

    Turn on the switch, if any of the following problems occur, take the recommended actions in the order 
    they are shown.
     
   1. The machine does not respond when the power switch is turned on:

 

 • Check each connector connection

 

 • Replace the machine socket

 

 • Replace the Switching regulator.

 

 • Replace the A-board

   2. The sewing machine lamp does not light up:

 

 • Replace the light bulb

 

 • Replace the A-board

To enter self-diagnostic mode:

Turn the power switch on while 
pressing the Reverse button.

Press the Ring button     (left) mark.
The LCD display indicates "01".

Press the Ring button     (right) 
mark to enter the self-diagnostic 
mode.

No.1

No.2

No.3

If you do not press the next button within 1.5 sec, the machine will revert to normal sewing mode.
Should this occur, start over again from step No.1.

Содержание NH40

Страница 1: ...SERVICE MANUAL MODEL NH40...

Страница 2: ...12 Clearance between Needle and Hook Point 13 Backlash Lower Shaft Gear 14 Feed Dog Height 15 Needle Swing Timing 16 Needle Thread Tension 17 Stretch Stitch Feed Balance 18 Adjust the Buttonhole Lever...

Страница 3: ...HA x 11 blue tip needle Adjust the presser bar level to make the pressure stronger See mechanical adjustment Needle bar height See mechanical adjustment Needle to hook timing See mechanical adjustment...

Страница 4: ...ch thread is wound on the bobbin 3 Lint is stuck inside the bobbin holder 4 Thread quality is too low 5 Thread is jamming around the bobbin holder Set the bobbin thread correctly Adjust the position o...

Страница 5: ...backlash lower shaft gear Eliminate the looseness See part removal and replacement driving motor DC motor Oil all moving parts P 14 P 27 P 31 7 Deformation pattern 1 Inappropriate feed balance 2 Inapp...

Страница 6: ...the cap and setscrew A and remove the face cover while pushing the rib B up TO INSTALL 2 Attach the face cover engaging the hook C and the rib B with the rear cover and tighten screw A 3 Attach the c...

Страница 7: ...5 BED COVER TO REMOVE 1 Remove the 4 setscrews A remove the bed cover TO INSTALL 2 Follow the above procedures in reverse SERVICE ACCESS 2 Setscrew A Setscrew A Setscrew A Bed cover Setscrew A...

Страница 8: ...O REMOVE 1 Remove the needle plate 2 Remove the bed cover see page 5 3 Loosen the setscrew A and B TO INSTALL 4 Follow the above procedures in reverse SERVICE ACCESS 3 Setscrew A Setscrew B Free arm c...

Страница 9: ...d loosen setscrew C 4 Disconnect all the connectors from the circuit board A see page 20 NOTE Do not disconnect the connectors by pulling on cord To disconnect grasp the connector not the cord Remove...

Страница 10: ...E 1 Remove the front cover see pages 7 2 Loosen setscrews A 3 Remove the setscrews B C D and E then remove the rear cover TO INSTALL 4 Follow the above procedure in reverse Setscrew B Setscrew A Setsc...

Страница 11: ...the foot and the feed dog window on the needle plate should be parallel 1 Remove the face cover see page 4 and raise the presser foot Loosen the setscrew to adjust the presser foot height 6 0 mm and t...

Страница 12: ...s 1 Remove the face cover see page 4 2 Turn the power switch on and check the needle drop position 3 If the needle drop is out of position adjust it to proper position by turning the adjusting screw s...

Страница 13: ...the pattern simple zigzag maximum zigzag width 3 Remove the bed cover see page 5 4 Turn the handwheel toward you and set the needle bar at the lowest position 5 Loosen the 2 setscrews on the lower sh...

Страница 14: ...attern simple zigzag maximum zigzag width 4 Turn the handwheel toward you until the tip of hook meets the right side of the needle 5 Loosen the setscrew 6 Adjust the height of the needle bar by moving...

Страница 15: ...B C then slightly tighten the hinge screw C 2 Turn the handwheel toward you to bring the hook point behind the needle Adjust the clearance between the test pin and the point of the hook in the left a...

Страница 16: ...0 8 mm If there is more than 0 8 mm play adjust as follows ADJUSTMENT PROCEDURE 1 Remove the bed cover see page 5 and loosen the setscrew 2 Turn the lower shaft bushing eccentric in the direction A w...

Страница 17: ...urn the power switch on 3 Select the straight stitch pattern with maximum length 4 Turn the handwheel toward you to set the feed dog at the highest position 5 Loosen the setscrew and nut 6 Adjust the...

Страница 18: ...y with your hand until the needle start to swing Loosen the setscrew and turn the upper shaft shield plate in the direction of A If the swing point is higher than 8 7 mm B If the swing point is lower...

Страница 19: ...ot within the above limit adjust as follows 1 Set the tension dial at 4 2 Lower the presser foot 3 Remove the front cover see page 7 4 Pull the spring D away from the lead screw If the top tension is...

Страница 20: ...e Sew the stitch pattern 8 until the machine stop automatically and check the stitch length Standard length of five 8 characters 32 mm to 40 mm 4 Remove the base cap 5 If the length is too short turn...

Страница 21: ...osition and open a 1 6 mm gap between the slider and the buttonhole foot 6 Turn the adjusting screw to the left until the LCD display BH symbol 7 Next turn the adjusting screw right until the BH symbo...

Страница 22: ...ing on the cord To disconnect grasp the connector not the cord Connect the connector to the connector post of the same color on the circuit board Bobbin winder switch Upper shaft sensor Buttonhole sen...

Страница 23: ...test you require by pressing the reverse button To begin Turn on the switch if any of the following problems occur take the recommended actions in the order they are shown 1 The machine does not respo...

Страница 24: ...lever is pulled buzzer sounds and LCD displays BH symbol When the buttonhole lever is pushed buzzer sounds and LCD displays BH symbol LCD displays SC 04 When the bobbin winder spindle is moved to the...

Страница 25: ...ce the circuit board A 06 Upper shaft positioning sensor 07 Zigzag motor Step motor Feed motor Turn the handwheel toward you Lower the needle bar from its highest to its lowest position Press the ring...

Страница 26: ...board A 09 Not applicable for this model Press the ring button up mark If the result is correct condition press the reverse button to proceed the next step If the result is defective condition press t...

Страница 27: ...determined Correct Buzzer sounds and LCD displays 00 Defective Caution buzzer sounds and LCD displays the defective part number Refer to page 22 24 and fix the defective part The defective part number...

Страница 28: ...ot disconnect the connectors by pulling on cord To disconnect grasp the connector not the cord REPLACING PRINTED CIRCUIT BOARD A Setscrew Setscrew Setscrew Setscrew Setscrew Setscrew Circuit board A B...

Страница 29: ...lt with 2 setscrews 4 Loosen the setscrews slightly and move the motor up or down to adjust the motor belt tension The belt should deflect 7 9 mm when applying 300 grams of load to the middle of the b...

Страница 30: ...2 setscrews A and a setscrew B then remove the switching regulator TO INSTALL 3 Follow the above procedures in reverse NOTE Cords should not contact the lower shaft motor belt etc REPLACING SWITCHING...

Страница 31: ...Remove 2 setscrews A 3 Remove E ring 4 Remove stepping motor zigzag TO INSTALL 5 Follow the above procedures in reverse NOTE Check the needle drop position after replacing the stepping motor REPLACING...

Страница 32: ...setscrews A 3 Remove E ring 4 Remove stepping motor feed TO INSTALL 5 Follow the above procedures in reverse NOTE Check the stretch stitch balance after replacing the stepping motor REPLACING STEPPING...

Страница 33: ...y parts need to be lubricated OIL Use good quality sewing machine oil at the points A B C D E F G H J K indicated by black arrows GREASE White grease is recommended for use on gears and cam surfaces I...

Отзывы: