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23

Threader plate supporter (A)

Pin (B)

Hook

Groove

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).

2.  To install the needle threader plate, line the groove up  
  with the pin (B) and push it up to snap it.

To adjust:
3.  If the hook on the threader plate touches the left or    
  right side of the needle eye, loosen setscrew (C) and   
  adjust the hook position (Fig. 2).

4.  If the hook on the threader plate touches the top or
  bottom side of the needle eye, loosen setscrew (D)    
  and adjust the hook position (Fig. 3).

View A

View A

Hook

Setscrew

Threader plate

Needle bar

Threader position set plate

Setscrew (D)

Needle threader

Fig. 1

Fig. 2

Fig. 3

Summary of Contents for Horizon MC8900 QCP Special Edition

Page 1: ...SERVICE MANUAL PARTS LIST MC8900 QCP...

Page 2: ...op position 13 Presser bar height 14 Hook timing 15 Needle bar height 16 Clearance between needle and tip of the rotary hook 17 18 Presser bar lifter switch position 19 Backlash between hook drive gea...

Page 3: ...reverse Setscrew A Face cover Top cover To remove 1 Raise the carrying handle Remove the setscrew B Close the carrying handle Setscrew B Top cover Setscrew C Setscrew D 2 Open the top cover Remove the...

Page 4: ...al Parts 2 Belt cover To remove 1 Remove the setscrews A Setscrew A 2 Loosen the setscrews B and C 3 Remove the belt cover To attach 1 Follow the above procedure in reverse Setscrew B Setscrew C Setsc...

Page 5: ...crew A Setscrew A Setscrew A Machine base Base cover To remove 1 Remove the setscrews B 2 Remove the base cover To attach 1 Follow the above procedure in reverse Setscrew B Setscrew B Setscrew B Setsc...

Page 6: ...e plate Needle plate release lever Needle plate Changing External Parts 4 2 Remove the setscrew and pin 3 Unlock the hook A inside of the machine base and B edge of the free arm 4 Slide the free arm c...

Page 7: ...machine base Setscrew B Setscrew C Setscrew D 3 Loosen the setscrew B inside of the top cover 4 Loosen the setscrew C inside of the face cover 5 Loosen the setscrew D inside of the belt cover 6 Unlock...

Page 8: ...crew A Changing External Parts 6 Setscrews A Setscrews B Setscrews C Setscrews C Rear cover D E 3 Remove the setscrew B 4 Remove the setscrews C Unlock the rear cover hook from the front cover 5 Push...

Page 9: ...crews and printed circuit board A To attach 1 Follow the above procedure in reverse Be sure that the connector post on the printed circuit board to which it is connected Position the connector correct...

Page 10: ...ont cover see page 5 2 Disconnect the connectors from the circuit board A see page 7 3 Remove the CS rings 4 Remove the setscrews and the circuit board F To attach 1 Follow the above procedure in reve...

Page 11: ...t the power supply connector from the switching power supply unit 4 Remove the foot control connector from the printed circuit board A 5 Remove the setscrews B and switching power supply To attach 1 F...

Page 12: ...etscrews 2 pcs and the driving motor Replacing electronic components To attach 1 Attach the driving motor Tighten the setscrews temporarily 2 Adjust the motor belt deflection to about 5 mm by pressing...

Page 13: ...over see pagesf 1 and 2 2 Remove the front cover see page 5 3 Disconnect the Solenoid 1 thread tension release connector from the printed circuit board A see page 7 4 Remove the setscrews A and B Remo...

Page 14: ...ot lowered 4 Turn the handwheel toward you to raise the feed dog at its highest position 5 Loosen the setscrew A 6 Loosen the nut Adjust the feed dog height to 0 85 mm by turning the adjusting screw B...

Page 15: ...he needle drop position The direction of eccentric pin should be as shown as fig 2 4 Tighten the hexagonal socket screw Check the hook timing and the needle bar height after this adjustment see page 1...

Page 16: ...oot A Slot Setscrew To adjust 1 Attach the zigzag foot A 2 Drop the feed dogs 3 Raise the presser foot with the presser foot lifter 4 Open the face cover Loosen the setscrew on the presser bar suporte...

Page 17: ...n the power switch ON Select straight stitch Set the needle drop position at 0 0 Do not turn the switch OFF 4 Remove the presser foot the needle plate and the bobbin holder see page 4 Cover the needle...

Page 18: ...just the the needle bar height Tighten the hexagonal socket screw Be careful not to turn the needle bar 7 Attach the bobbin holder needle plate Hexagonal socket screw Needle setting groove Tip of hook...

Page 19: ...eedle plate when removing 3 Attach the master needle 4 Turn the power switch ON Select the zigzag stitch pattern 9 Adjust the stitch width at its maximum 9 0 Needle plate hole Setscrew Needle bar supp...

Page 20: ...ve the hook base plate 5 Turn the handwheel toward you Adjust the clearance between the needle and the tip of the rotary hook by moving the hook base plate up or down between 0 1and 0 05 mm at the bot...

Page 21: ...e presser bar is at normal up position the Foot Lift shows UP When the presser bar is at lowered position the foot lifter shows DOWN When the presser bar is at the extra lifted position the Assist lif...

Page 22: ...see page 4 Cover the needle plate with the fabric to prevent damaging the needle plate when removing 3 Turn the handwheel toward you so the the tip of the rotary hook is within the width of feed dog a...

Page 23: ...u until Phase state changes from q to BM w 4 The needle height should be 7 2 to 8 2 mm above from the surface of the needle plate If not adjust the upper shaft shield position To adjust 1 Remove the m...

Page 24: ...50 at the speed of 110 mm sec with the tension at AUTO Be sure the presser foot is lowered 1 Set the thread tension dial to AUTO 2 Open the face cover Adjust the tension by turning the thread tension...

Page 25: ...the needle threader plate line the groove up with the pin B and push it up to snap it To adjust 3 If the hook on the threader plate touches the left or right side of the needle eye loosen setscrew C a...

Page 26: ...page 4 You may use a fabric to prevent damaging the needle or the presser foot holder when removing the needle plate 2 Loosen the hexagonal bolt Adjust the distance between the lower part of thread d...

Page 27: ...sition is set at raised position 5 Check if the clearance between the upper feed link shaft and upper feed lower shaft is 2 5 mm If not follow the procedure on page 27 View from the base cover side 2...

Page 28: ...rn the power switch off 6 The clearance between the dual feed foot and upper feed dog should be 4 mm If not follow the procedure below To adjust 1 Remove the top cover see page 2 2 Loosen the hexagona...

Page 29: ...raised position 6 Lower the presser foot Turn the power switch off 7 Raise the toe of the dual feed foot in the direction of arrow as Fig 3 Keep the toe of the dual feed dog raised Mechanical adjustme...

Page 30: ...sser foot Turn the power switch off Turn the handwheel toward you to raise the needle 2 Open the face cover Loosen the setscrew You can lower the buttonhole lever half way if necessary You may insert...

Page 31: ...the buttonhole lever guide left or right so the Buttonhole lever slightly touches to the Buttonhole foot Tighten the setscrew To check 1 While pressing the needle up down and lock stitch buttons turn...

Page 32: ...page 3 4 2 Turn the power switch off Slide the moving cutter to the right with your finger 3 Turn the power switch on The moving cutter motor is initialized and moving cutter moves to its home positio...

Page 33: ...Factory adjust then adjusting screen will appear Turn the jog dial to select 09 Solenoid Press the confirm button Enter key 2 Press the confirm button to release the thread tension The LCD will displ...

Page 34: ...dial to select 08 88888888 Press the confirm button Enter key 2 Set the stretch stitch balance dial C at the setting mark D 3 Sew test patterns and check the measurement of five of them The range of p...

Page 35: ...ve the base plate up or down to adjust it Tighten the setscrews TP firmly after the adjustment The actuator of the micro switch should be alighed with the needle plate sensor knob as shown in fig 3 To...

Page 36: ...hed Bobbin Remote Cut ZZ Plate Needle plate switch Bobbin Remote Cut Straight Plate Needle plate switch 2 Be sure that Needle plate indicates ZZ Plate when the needle plate is attached 3 Replace the n...

Page 37: ...re starting the diagnosis test Check or replace the following part s if nothing happens when the power switch is turned on 1 The connectors are connected properly refer to page 7 2 Replace the circuit...

Page 38: ...ion DOWN 3 Extra bar lifter switch Assist lift Presser foot is extra lifted position UP Presser foot is up position DOWN Presser foot is down position DOWN 4 Remote cutter Remote cut Remote cutter is...

Page 39: ...ext step CORRECT CONDITION Thread the machine needle thread Lower the presser foot Adjust the thread tension dial to 9 Press the confirm button to release the thread tension The LCD will display ON Ma...

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