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Janome 4120QDC Service Manual And Parts List

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SERVICE MANUAL
PARTS LIST
4120QDC

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Summary of Contents for Janome 4120QDC

  • Page 1 SERVICE MANUAL PARTS LIST 4120QDC...

  • Page 2: Table Of Contents

    INDEX What to do when..........................1 - 3 Changing External Parts Face Cover ..............................4 Free-arm Cover ............................5 Front Cover............................6 - 7 Rear Cover ..............................8 Mechanical Adjustment Presser Bar Height ..........................9 Needle Drop Position..........................10 Adjustment of Hook Timing........................11 Adjustment of Needle Bar Height ......................12 Clearance between Needle and Tip of Rotary Hook ................13 Feed Dog Height ...........................14 Top Tension ............................15...

  • Page 3: What To Do When

    wHat to do wHen Condition Cause How to fix RefeRenCe 1. Skipping 1. needle iS not inSerted inSert the needle properly. StitcheS properly. 2. needle iS bent or worn. change the needle. 3. incorrectly threaded. rethread. 4. needle or thread are USe the recommended Sewing inappropriate for the needle and thread.
  • Page 4 condition caUSe how to fix reference 3. breaking 1. initial Sewing Speed iS Start with mediUm Speed. Upper too faSt. thread. 2. thread path iS incorrect. USe the proper thread path. 3. needle iS bent or dUll. replace with a new needle. 4.
  • Page 5 condition caUSe how to fix reference 6. noiSy 1. backlaSh between hook eliminate the backlaSh. operation gear and lower Shaft gear iS too great. 2. lower Shaft gear iS eliminate the looSeneSS. looSe. 3. inappropriate belt See part removal and p.

  • Page 6: Changing External Parts

    CHanging exteRnal PaRts faCe CoveR to Remove: 1. looSen the SetScrew q and lift the face cover to diSengage the rib on the inSide. remove the face cover w. to attaCH: 2. follow the above procedUreS in reverSe.

  • Page 7: Free-Arm Cover

    CHanging exteRnal PaRts fRee-aRm CoveR to Remove: 1. looSen the SetScrew q and w. move the free-arm cover e to the left. remove the free-arm cover. to attaCH: follow the above procedUreS in reverSe.

  • Page 8: Front Cover

    CHanging exteRnal PaRts fRont CoveR (1) to Remove: 1. remove the face cover and free-arm cover (See page 8 and 9). 2. remove the SetScrewS (a) q (2 pcS.). 3. remove the SetScrewS (b) w (6 pcS.), back cover e. 4.
  • Page 9 CHanging exteRnal PaRts fRont CoveR (2) 1. diSengage the front cover and rear cover hookS. 2. remove the front cover. to attaCH: follow the above procedUreS in reverSe.

  • Page 10: Rear Cover

    CHanging exteRnal PaRts ReaR CoveR to Remove: 1. remove the face cover and free-arm cover (See page 4 and 5). 2. remove the SetScrewS (a) q (5 pcS.). 3. remove the SetScrewS (b) w (6 pcS.) and back cover. 4. remove the SetScrewS (c) e (2 pcS.). remove the rear cover. to attaCH: 5.

  • Page 11: Mechanical Adjustment

    meCHaniCal adjustment PResseR baR HeigHt the diStance between the bottom of the preSSer foot in Up poSition and the needle plate ShoUld be 6.0 mm. 1. remove the face plate and needle. 2. lower the feed dog below the needle plate. place a block 6 mm thick Under the preSSer foot and lower the preSSer foot lifter w.

  • Page 12: Needle Drop Position

    meCHaniCal adjustment needle dRoP Position Set the Stitch pattern to “ ”. the Standard needle drop poSition ShoUld be at cen- ter of the needle plate hole q. Select zigzag Stitch “ ”, and Set the Stitch width at “5.0”. the clearance between the needle and the edge of the needle hole ShoUld be at leaSt 0.2 mm on either Side.

  • Page 13: Adjustment Of Hook Timing

    meCHaniCal adjustment adjustment of 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 ShoUld be 3.25 to 3.55 mm. 1.

  • Page 14: Adjustment Of Needle Bar Height

    meCHaniCal adjustment adjustment of needle baR HeigHt before proceeding with thiS adjUStment, check the hook timing (refer to page 11). 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 2.0 mm when the tip of the hook timing meetS right Side of the needle in the left needle poSition ( ) aS the needle aScendS from itS loweSt poSition.

  • Page 15: Clearance Between Needle And Tip Of 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 PRoCeduRe: 1. remove the needle plate and bobbin holder. attach the maSter needle. tUrn the power Switch on and Set the zigzag width at maximUm.

  • Page 16: Feed Dog Height

    meCHaniCal adjustment feed dog HeigHt the higheSt poSition of the feed dog ShoUld be between 0.80 and 0.90 mm from the SUrface of the needle plate. 1. lower the preSSer foot and tUrn the power Switch on. 2. tUrn the handwheel toward yoU to Set the feed dog at the higheSt poSition. 3.

  • Page 17: Top Tension

    meCHaniCal adjustment toP tension the top tenSion ShoUld be between 65 and 80g when pUlling the thread Up in the direction of arrow. * USe polyeSter Sewing thread #50 (white). * if it iS not within the above limit, adjUSt aS followS. 1.

  • Page 18: Replacing The Electronic Components

    RePlaCing tHe eleCtRoniC ComPonents CiRCuit boaRd-a ConneCtion note: do not diSconnect the connectorS by pUlling on cord. to diSconnect, graSp the connector, not the cord. q printed circUit board f y toUch panel (white) !4 micro Switch (white) u feed motor (white) (preSSer foot w printed circUit board l2 i printed circUit board p (black)

  • Page 19: Self-Diagnostic Test

    self-diagnostiC test PRePaRation: 1. tUrn the power Switch off. 2. move the bobbin winder Spindle to the left. 3. raiSe the feed dog. 4. Set the Speed control lever to the left. 5. remove the preSSer foot and raiSe the preSSer foot lifter. 6.
  • Page 20 self-diagnostiC test Step and procedUre correct condition defective condition itemS to check tUrn on the power Switch Sewing lamp and lcd backlight lit. Sewing lamp doeS not lit. while SimUltaneoUSly preSS- lcd diSplayS “----”. lcd backlight doeS not lit. fUnction of ing the needle Up/down lcd doeS not diSplay.

  • Page 21: Stitch Length

    self-diagnostiC test Step and procedUre correct condition defective condition itemS to check bUzzer doeS not SoUnd. lcd diSplayS “05”. move the preSSer foot lifter preSSer foot Symbol doeS Up and down. preSSer when the preSSer foot lifer iS not appear. foot lifter lowered, bUzzer SoUndS and lcd if the reSUlt iS correct condi-...

  • Page 22: Foot Control

    self-diagnostiC test Step and procedUre correct condition defective condition itemS to check attach the foot control to the lcd diSplayS “08”. the foot control Sym- machine. bol doeS not appear. foot depreSS the foot control aS far aS bUzzer doeS not control it goeS, then releaSe it.
  • Page 23 self-diagnostiC test Step and procedUre defective condition correct condition itemS to check tUrn the handwheel toward yoU to lcd diSplayS “12”. thread cUtter motor raiSe the needle bar at itS higheSt doeS not work. the thread cUtter Symbol will thread poSition.
  • Page 24 self-diagnostiC test bUzzer SoUndS after few SecondS when the Self-diagnoStic teSt haS been finiShed. the teSt reSUlt haS been determined. CoRReCt: bUzzer SoUndS and lcd diSplayS “00” defeCtive: caUtion bUzzer SoUndS and lcd diSplayS the defective part nUmber. refer to page 19-21 and fix the defective part.

  • Page 25: Circuit Board-A

    RePlaCing tHe eleCtRoniC ComPonents CiRCuit boaRd-a (1) to Remove: 1. remove the front cover. (See pageS 6 – 7) 2. pUll oUt connectorS from the circUit board-a. 3. remove the ScrewS (4pcS.) and the circUit board-a. to attaCH: 1. follow the above procedUreS in reverSe. note: do not diSconnect the connectorS by pUlling on cord.

  • Page 26: Driving Motor

    RePlaCing tHe eleCtRoniC ComPonents dRiving motoR to Remove: 1. remove the front cover. 2. remove the SetScrewS (2pcS.) and the driving motor and the belt. to attaCH: 1. inStall the driving motor and the motor belt. tighten them with SetScrewS (2pcS.) lightly.

  • Page 27: Switching Regulator Unit

    RePlaCing tHe eleCtRoniC ComPonents switCHing RegulatoR unit to Remove: 1. remove the front cover and the rear cover. 2. remove the SetScrewS a (3 pcS.) and the Switching regUlator. 3. remove the SetScrewS b (4 pcS.). to attaCH: 4. follow the above procedUreS in reverSe. Switching regUlator SetScrew a...

  • Page 28: Adjusting Buttonhole Lever Position

    meCHaniCal adjustment adjusting buttonHole leveR Position to adjust tHe buttonHole leveR guide: 1. enter the diagnoStic teSt of bUttonhole SenSor mode. (See page 18 and 19. the lcd ShoUld diSplay 03 and bh Symbol.) 2. remove the face cover (See page 4) and looSen the SetScrew q. 3.

  • Page 29: Parts List

    4120QDC PARTS LIST PARTS DESCRIPTION PARTS LIST MODEL : 4120QDC...
  • Page 30 4120QDC PARTS LIST...
  • Page 31 4120QDC PARTS LIST PARTS DESCRIPTION 808601005 Upper shaft (unit) 000111201 Hexagonal socket screw 4x4 000112800 Hexagonal socket screw 4x6 000036201 Washer FT80 508054008 Shaft fixing metal 820166001 Lower shaft ring 808003001 Upper shaft shielding plate 000004200 Spring pin 3x18 508021006...
  • Page 32 4120QDC PARTS LIST...
  • Page 33 4120QDC PARTS LIST PARTS DESCRIPTION 808640202 Presser bar base plate (unit) 808006107 Presser bar base plate 808007005 Thread tension release lever 503041007 Thread tension release spring 502024001 Presser foot lifter 000001609 Snap ring E-5 808076005 Presser bar spring adjusting plate...
  • Page 34 4120QDC PARTS LIST...
  • Page 35 4120QDC PARTS LIST PARTS DESCRIPTION 809603000 Hook race (whole unit) 809601008 Hook race (unit) 650623008 Hook body (unit) 846632003 Bobbin holder stopper (unit) 000164405 Setscrew 4x16 825515004 Feed base plate (unit) 825237009 Setscrew 808610100 Thread cutter (unit) 000063104 Nut 3-2-5.5...
  • Page 36 4120QDC PARTS LIST...
  • Page 37 4120QDC PARTS LIST PARTS DESCRIPTION 809608005 Presser foot pressure adjustment (unit) 809018002 Presser foot pressure adjusting set plate 808078203 Presser foot pressure dial 808079008 Adjusting arm 1 808080002 Adjusting arm 2 000002105 Snap ring E-3 000081005 Setscrew 4x8 860544300 Needle plate (unit)
  • Page 38 4120QDC PARTS LIST...
  • Page 39 4120QDC PARTS LIST PARTS DESCRIPTION 809604104 Rear cover (unit) 809025105 Rear cover 827503108 Top cover thread guide (unit) 000162001 Setscrew 2.6x5 650503403 Thread guide (unit) 000014409 Snap ring CS-8 809027004 Spool pin 809028005 Arm leg rear 000198604 Setscrew 4x14 (B)
  • Page 40 4120QDC PARTS LIST...
  • Page 41 4120QDC PARTS LIST PARTS DESCRIPTION Front cover (unit) 809605105 Front cover 809030206 808103002 Front cover lid 809031218 Panel 1 809033117 Button 1 Panel 2 809032208 Slide volume 809036202 Touch panel (unit) 809501007 Touch Panel seat 809043109 Printed circuit board A (unit)
  • Page 42 4120QDC PARTS LIST...
  • Page 43 4120QDC PARTS LIST PARTS DESCRIPTION 809870103 Standard accessories (unit) 809870309 Standard accessories (unit) (Canada) 822804118 Satin foot (F) 829801002 Zipper foot (E) 825817009 Blind hem foot (G) 822801001 Overedge foot (C) 102261103 Bobbin 820827007 Assorted needle set 820832005 Screwdriver 802424004...

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