- DL manuals
- Janome
- Sewing Machine
- 4120QDC
- Service Manual And Parts List
Janome 4120QDC Service Manual And Parts List
Summary of 4120QDC
Page 1
Service manual parts list 4120qdc.
Page 2
Index what to do when................................................................................................................................ 1 - 3 changing external parts face cover ................................................................................................................
Page 3: What to Do When
1 condition cause how to fix reference 1. Skipping stitches 1. Needle is not inserted properly. 2. Needle is bent or worn. 3. Incorrectly threaded. 4. Needle or thread are inappropriate for the fabric being sewn. 5. Sewing on stretch fabric. 6. Inappropriate needle bar height. 7. Inappropriate needl...
Page 4
2 condition cause how to fix reference 3. Breaking upper thread. 1. Initial sewing speed is too fast. 2. Thread path is incorrect. 3. Needle is bent or dull. 4. Top tension is too strong. 5. Needle size is inappropriate for fabric. 6. Needle eye is worn. 7. Needle hole in needle plate is worn or bur...
Page 5
3 condition cause how to fix reference 6. Noisy operation 1. Backlash between hook gear and lower shaft gear is too great. 2. Lower shaft gear is loose. 3. Inappropriate belt tension. 4. Not enough oil. 5. Upper shaft gear is loose. Eliminate the backlash. Eliminate the looseness. See part removal a...
Page 6: Changing External Parts
4 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. Q w.
Page 7: Changing External Parts
5 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. Changing external parts q w e.
Page 8: Changing External Parts
6 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. Remove the setscrews (c) r (2 pcs.). 5. Loosen the setscrew t. 6. Disconnect all the c...
Page 9: Changing External Parts
7 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: Changing External Parts
8 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. Follow the above...
Page 11: Mechanical Adjustment
9 6.0 mm 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...
Page 12: Mechanical Adjustment
10 0.2 mm or more 0.2 mm or more a = b 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 e...
Page 13: Mechanical Adjustment
11 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. Remove the needle plate and bobbin holder. 2. Turn the power switch on. 3. Select the pattern (le...
Page 14: Mechanical Adjustment
12 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...
Page 15: Mechanical Adjustment
13 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. 2. Remove the face cover. 3. Loosen the setscrew a (2 pcs.). 4. Turn the handwheel toward you. Adjust the clearance between the needle and th...
Page 16: Mechanical Adjustment
14 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. Remove the free-arm cover. 4. Loosen the setscrew ...
Page 17: Mechanical Adjustment
15 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. Set the tension dial “4”. 2. Remove the cover. 3. Lower the ...
Page 18
16 circuit board-a connection note: do not disconnect the connectors by pulling on cord. To disconnect, grasp the connector, not the cord. Replacing the electronic components printed circuit board a printed circuit board f printed circuit board l2 q printed circuit board f (white) w printed circuit ...
Page 19: Self-Diagnostic Test
17 to enter self-diagnostic mode: 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. Turn the hand wheel toward you to raise the ...
Page 20: Self-Diagnostic Test
18 lcd displays “04”. When the bobbin winder spindle is moved to the right, buzzer sounds and lcd displays the bobbin symbol. When the bobbin winder spindle is moved to the left, buzzer sounds and lcd displays “04”. Correct condition sewing lamp and lcd backlight lit. Lcd displays “----”. 01) functi...
Page 21: Self-Diagnostic Test
19 correct condition step and items to check 05) presser foot lifter switch procedure defective condition turn the handwheel toward you. Lower the needle bar from its highest to its lowest position. Raise the needle bar from its lowest position to its highest position. If the result is correct condi...
Page 22: Self-Diagnostic Test
20 correct condition lcd displays “08”. Step and items to check 08) foot control procedure attach the foot control to the machine. Depress the foot control as far as it goes, then release it. If the result is correct condition, press the start/stop button to proceed the next step. If the result is d...
Page 23: Self-Diagnostic Test
21 thread cutter symbol correct condition lcd displays “12”. The thread cutter symbol will blink, and thread cutter motor will be initialized. Step and items to check 12) thread cutter motror, thread cutter solenoid procedure turn the handwheel toward you to raise the needle bar at its highest posit...
Page 24: Self-Diagnostic Test
22 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 defe...
Page 25
23 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. To di...
Page 26
24 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. 2. Move the motor up or down to adjust the motor belt tension. The belt ...
Page 27
25 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. Replacing the electronic components switching regulator setsc...
Page 28: Mechanical Adjustment
26 bh sensor 1.6 mm gap to enter adjusting mode 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)...
Page 29: Parts List
27 4120qdc parts list key parts no. No. Description parts list model : 4120qdc.
Page 30: Parts List
28 4120qdc parts list 1 2 3 4 4 5 5 6 7 8 8 9 10 10 11 12 13 14 15 16 16 18 19 20 17 21 22 16 27 16 26 25 23 24 28 29 29 2 30 31.
Page 31: Parts List
29 4120qdc parts list key parts no. No. Description 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 808601005 000111201 000112800 000036201 508054008 820166001 808003001 000004200 508021006 000024206 502064003 661024007 508055009 000002806 731312005 000081005 5080...
Page 32: Parts List
30 4120qdc parts list 1 2 3 4 5 6 7 8 9 12 13 14 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 15 33 34 35 36 37 38 39 40 41 42 44 44 45 46 48 47 49 50 43 51 52 53 54 54 56 55 57 9 10 58 9 44 11 59 60 60 61 62 65 9 64 63 66 56 67 56.
Page 33: Parts List
31 4120qdc parts list key parts no. No. Description 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 808640202 808006107 808007005 503041007 502024001 000001...
Page 34: Parts List
32 4120qdc parts list 1 27 2 3 4 5 26 28 29 31 32 33 30 41 34 35 36 37 38 39 42 43 6 7 18 12 17 13 9 8 10 21 19 22 23 24 25 14 16 15 20 11 9 9 9 15 27 38 38 40 44 45 46 47 48 47 49 50 51 52.
Page 35: Parts List
33 4120qdc parts list key parts no. No. Description 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 809603000 809601008 650623008 846632003 000164405 825515004 825237009 808610100 000063104 809013007 8...
Page 36: Parts List
34 4120qdc parts list 6 6 6 7 2 3 5 4 7 1 8 9 10 9 11 15 12 13 14 16 17 19 20 21 22 23 24 25 18 7 26 28 29 30 27 7 33 32 34 7 35 7 31 31.
Page 37: Parts List
35 4120qdc parts list key parts no. No. Description 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 809608005 809018002 808078203 808079008 808080002 000002105 000081005 860544300 681009101 846271103 808614001 808038005 625217100 000002806 000115607 80...
Page 38: Parts List
36 4120qdc parts list 1 5 2 3 4 6 7 8 9 10 11 13 12 12 18 22 12 19 14 15 16 17 10 12 12 17 22 21 23 12 20 24 25 26.
Page 39: Parts List
37 4120qdc parts list key parts no. No. Description 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 809604104 809025105 827503108 000162001 650503403 000014409 809027004 809028005 000198604 735003002 809026003 000081005 822020503 809606106 809606302 809606209 809040209 840602006...
Page 40: Parts List
38 4120qdc parts list 1 2 4 5 7 8 9 10 11 6 11 11 12 13 14 15 16 17 22 23 24 21 18 20 19 25 26 27 28 31 28 32 28 29 30 30 30 3 33 34 35 36.
Page 41: Parts List
39 4120qdc parts list key parts no. No. Description 809605105 809030206 808103002 809031218 809033117 809032208 809036202 809501007 809043109 809503102 000120203 809035119 809034118 809502008 000140007 858511105 808118000 735016307 000101828 000071013 000061205 639005003 000114802 000160102 73500300...
Page 42: Parts List
40 4120qdc parts list 1 2 3 4 5 6 7 8 9 10 11 12 15 16 19 13 14 20 17 21 18 22 23.
Page 43: Parts List
41 4120qdc parts list key parts no. No. Description 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 809870103 809870309 822804118 829801002 825817009 822801001 102261103 820827007 820832005 802424004 647808009 822019509 822020503 809041004 753801004 856519004 830314018 830335004 c-1036 8...