DB2-B727, B728 (English)
CONTENTS
1. NAMES OF MAJOR PARTS...................... 01
2. MACHINE SPECIFICATIONS ..................... 02
3. WORK TABLE AND MOTOR .................... 03
3-1. Work Table ............................................ 3
3-2. Motor (B727) ......................................... 4
4. OPTIONAL PARTS ....................................... 05
5. INSTALLATION............................................. 06
5-1. Installing the oil pan ............................ 7
5-2. Installing the machine head ............... 7
5-3. Installing the knee lifter assembly ..... 8
5-4. Adjusting the knee lifter ...................... 9
5-5. Installing the belt ................................. 10
5-6. Installing the bobbin winder ............... 10
5-7. Installing the belt cover ....................... 11
5-8. Installing the cotton stand .................. 14
5-9. Ground Wire Connections (B727) ...... 14
5-10. Lubrication ............................................ 15
5-11. Checking the machine pulley
rotating direction.................................. 16
5-12. Test operation ....................................... 17
6. PREPARATION BEFORE SEWING ........... 18
6-1. Installing the needle ............................ 18
6-2. Removing the bobbin case ................. 19
6-3. Winding the lower thread ................... 20
6-4. Threading the lower thread ................ 22
6-5. Threading the upper thread ................ 23
6-6. Adjusting the stitch length .................. 24
7. SEWING ......................................................... 25
7-1. Sewing .................................................. 26
7-2. Backtacking ........................................... 26
8. THREAD TENSION ...................................... 27
8-1. Adjusting the thread tension .............. 27
8-2. Adjusting the presser foot pressure .. 29
8-3. Adjusting the trailing length
after thread trimming (B728) .............. 30
9. STANDARD ADJUSTMENTS ................... 31
9-1. Adjusting the presser foot height ...... 32
9-2.
Adjusting the feed dog height and angle
33
9-3. Adjusting the needle bar height......... 35
9-4. Adjusting the needle and feed
mechanism timing ............................... 36
9-5. Adjusting the needle and rotary
hook timing........................................... 38
9-6. Adjusting the thread tension spring .. 39
9-7. Adjusting arm thread guide R ............ 41
9-8.
Adjusting the difference between the
forward and backtack stitch lengths ........
42
9-9.
Adjusting the tension release timing .......
43
9-10. Adjusting the walking foot
and presser foot ................................... 44
9-11. Adjusting the rotary hook
lubrication amount............................... 47
9-12. Adjusting the oil pump ....................... 47
9-13. Adjusting the synchronizer (B728) ..... 48
10. REPLACING THE FIXED KNIFE
AND MOVABLE KNIFE (B728) ................ 50
10-1. Replacing the fixed knife ..................... 50
10-2. Replacing the movable knife ............... 51
11. CLEANING ................................................... 52
12. TROUBLESHOOTING ................................ 56
13. GAUGE PARTS ........................................... 72