TN-840B, 870B
TL-840B
CONTENTS
1. NAMES OF MAJOR PARTS................................. 1
2. MACHINE SPECIFICATIONS................................. 3
3. OPTIONAL PARTS .................................................. 8
4. WORK TABLE AND MOTOR................................ 11
5. INSTALLATION ........................................................ 13
5-1. Installing the oil pan ........................................... 14
5-2. Installing the machine head ............................... 15
5-3. Installing the knee lifter assembly ..................... 16
5-4. Installing the belt................................................. 18
5-5. Installing the bobbin winder .............................. 18
5-6. Installing the belt cover ...................................... 19
5-7. Installing the cotton stand .................................. 21
5-8. Ground Wire Connections .................................. 21
5-9. Installing the electromagnetic presser bar liter
assembly (–900, option) ...................................... 22
5-10. Installing the air equipment (–700) .................. 26
5-11. Installing the knee switch
(–700, –900, option) ........................................... 28
5-12. Selecting the presser bar lifter function
(–700, –900, option) ........................................... 29
5-13. Connection of Wires
(–700, –900, Option parts) ................................. 30
5-14. When not using the knee switch
(–900, option) ..................................................... 31
5-15. Lubrication .......................................................... 33
5-16. Checking the machine pulley rotating
direction .............................................................. 35
6. PREPARATION BEFORE SEWING ...................... 36
6-1. Installing the needle ............................................ 36
6-2. Removing the bobbin or cap ............................. 37
6-3. Winding the lower thread................................... 38
6-4. Installing the bobbin or cap ............................... 40
6-4-1. Installing the bobbin
[842B, 847B, 872B]....................................... 41
6-4-2. Installing the cap [845B, 848B, 875B] ........ 42
6-5. Threading the upper thread ............................... 43
6-6. Adjusting the stitch length ................................. 45
6-7. Thread Wiper ....................................................... 46
6-8. Corner sewing method [845B, 848B, 875B] ...... 47
6-8-1. To stop the needle bars (right and left).... 47
6-8-2. Number of stitches: quick-reference
guide ............................................................. 48
7. SEWING..................................................................... 49
7-1. Sewing.................................................................. 50
7-2. Backtacking........................................................... 50
8. THREAD TENSION.................................................. 51
8-1. Adjusting the thread tension.............................. 51
8-2. Adjusting the presser foot pressure .................. 52
8-3. Adjusting the trailing length after thread
trimming ............................................................... 52
9. SWITCHING BETWEEN UPPER FEED AND
LOWER FEED [842B-C0F, 845B-C01]
................. 55
10. CLEANING ................................................................ 59
11. STANDARD ADJUSTMENTS ............................... 62
11-1. Adjusting of the feed dog height ...................... 63
11-2. Adjusting the presser foot height ...................... 64
11-3. Adjusting the thread tension spring .................. 65
11-4. Adjusting the needle and rotary hook timing .. 67
11-4-1. Needle to rotary hook point gap ............... 67
11-4-2. Clearances between rotary hooks
and needle plate .......................................... 68
11-4-3. Clearance between rotary hook and
opener........................................................... 69
11-4-4. Needle bar height and lift amount ............ 70
11-5. Thread Wiper Adjustment .................................. 75
11-6. Movable and Fixed Knife Adjustment ............... 78
11-7. Tension Release................................................... 81
11-8. Synchronizer Adjustment ................................... 83
11-9. Upper and Lower Shaft Timing Adjustment .... 85
11-10. Adjusting the rotary hook lubrication
amount ............................................................... 87
12. REPLACING GAUGE PARTS (CHANGING THE
NEEDLE WIDTH)
..................................................... 89
13. INSTALLING OPTIONAL PARTS ......................... 96
13-1. Replacing the rotary hook.................................. 97
13-2. Replacing the upper thread tension
assembly ............................................................ 101
14. TROUBLESHOOTING GUIDE .............................. 102