Brother Db2-b714-3 Instruction Manual

							11] Thread tension  release lever 
mechanism 
(8707 /8716/8747) 
* When trim signal is input.  the trimmer solenoid 0 
functions.  the tension  release plate 8 pushes the 
tension  release 
bar 8 via the  tension  release lever 
8 and the tension  release wire 0 and opens the 
tension  disc. 
When the needle upper stop signal is input, current 
no longer flows to the thread trimmer solenoid, and 
the tension disc closes. 
[!] Quick-back  mechanism 
0 
• 
• 
* When the quick-back  switch is pressed, the reverse 
solenoid 
0 functions.  the solenoid  lever plate 8 is 
pulled  via the  solenoid  lever 8 and the connecting 
link 
0. and the  reverse  lever 8 is pulled 
downward. 
While the quick-back  switch remains  pressed,  the 
machine does  reverse stitching.  When 
the switch is 
released, it is returned to its original  position by a 
return spring and the machine  resumes forward 
stitching. 
[I] Thread wiper mechanism 
(8707 /8716/8747) 
* When the needle upper stop signal is input, there is 
a delay of 85 ms, and then the solenoid 0 
functions. the thread wiper  lever 8 moves the 
thread wiper 8 via the grooved  link 0. and the · 
neelde thread is wiped on top of the material after 
thread trimming. 
When 
the current stops flowing to the solenoid, the 
thread wiper is returned to its  original  position  by a 
spring. 
[!] Automatic  presser lifter mecha­
nism 
* When  the power switch is turned on, the presser 
lifter  solenoid 
0 functions (ON) and the knee lifter 
presser 
bar 8 is pressed upward via the presser 
lifter  link 
8. 
* When the upper part of the foot pedal is depressed 
lightly, 
the presser  lifter solenoid 0 becomes OFF, 
the presser  lifter link 8 returns, and the presser 
drops back down. 
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From  the library  of: Superior  Sewing Machine  & Supply  LLC  
						

							CDISASSEMBLY -~ 
I. Loosen the set screw 8 and remove  the needle G. (Loosen  the set and remove  the thread  wiper.) 
2. Remove  the three  screws 0. and then remove  the face  plate 8 and the packing 0. 
3. Remove  the five  screws 0 and then  remove  the side  cover 0. 
4. Remove  the two  screws 0. and then  remove  the oil stopper plate 0. 
5. Remove  the oil cap Gi) and the oil cap CD. 
6. Loosen  the set screw CB and remove  the tension  regulator  assembly •. 
7. Remove  the slide  plate e. 
8. Remove  the two  screws 6. and then  remove  the needle  plate 48. 
II) Presser 
I. Loosen  the two  set screws 8 and  remove  the feed dog G. (Use  the presser  lifter lever to raise the presser 
assembly.) 
2.  Loosen  the set screws 
0 and remove  the presser  foot 8. (Remove  the screw, and then  remove  the thread  wiper 
holder.) 
3.  Remove  the screw 
8. and then  remove  the presser  spring bar O. the presser  spring 8. and the washer 0. 
4. Loosen  the set screw 0 and remove  the presser bar clamp fl). 
5. Remove  the presser bar CD by extracting  it from  the top of the arm. 
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From  the library  of: Superior  Sewing Machine  & Supply  LLC  
						

							!., 
[I) Rotary hook 
f) 
~~~"L,..~~-· 
r---"\:'~· 
l. Tilt  the machine. 
2. Remove  the bobbin  case 0. 
3. Remove  the screw f). and then  remove  the rotary hook position  bracket. 
4.  Loosen  the three  set screws 
G and remove  the rotary hook 0. 
[I] Thread trimmer 
I. 
2. 
3. 
4. 
5. 
6. 
7. 
8. 
9. 
10. 
II. 
12. 
13 . 
0 
f) 
Remove  the screw 0. and then  remove  the fixed  knife f). 
Push the thread trimmer connecting  rod 0 in the  direction  indicated  by the arrow, and then  position  the two 
screws 
G where  they can be seen. 
Remove  the screws 
0. and then  remove  the movable  knife 0. 
Remove the screw 8. and then  remove  the lower thread finger 0. 
Remove  the screw 0 on the  thread trimmer lever 0 side. 
Remove  the bolt 
41). and then  remove  the knife  holder  assembly 0. the movable  knife holder fl, and the 
trimmer connecting  rod 0. 
Remove the trimmer lever spring G). 
Remove  the screw e. and then  remove  the thread  tension  lever fl. 
Remove  the screw ~. and then remove  the trimmer solenoid CD. 
Move the trimmer cam lever assembly Gil in the  direction  indicated  by the  arrow, and then  remove  the stop ring 
41. Loosen the set screw G), and then  remove the trimmer cam lever shaft f) toward the right  side (the trimmer 
solenoid  side). 
Remove  the collar 
fi, the cam lever return spring fJ, the trimmer cam lever  assembly e. the washer f), and 
the  cushion fJ. 
Remove  the screw f), and  then  remove  the trimmer lever 0. the trimmer leverspringfl), and the forked shaft 
•• 
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From  the library  of: Superior  Sewing Machine  & Supply  LLC  
						

							[I] Feed mechanism (8706/8707) 
I. Remove  the wick 0. 
2. Loosen  the two  set screws 0 on the  right  side of the feed  lifting  rock shaft 8, and then  remove  the collar 8. 
3. Loosen  the two  set screws 8 on the  feed  lifting  rock shaft arm 8 and the three  set screws 0 on the  feed  lifting 
arm 8. 
4. Tap wedges into the notches oft he feed  lifting  rock shaft arm 8 and the feed  lifting arm 8, and then  remove  the 
feed  lifting  rock shaft 
8 toward the left side. (The oil rejector 8 and  the feed  lifting arm 8 will also  come  off.) 
5. Loosen  the two  set screws CD on the  right  side of the feed  rock  shaft G), and then  remove  the collar •. 
6. Remove  the wick fD from  the feed bar arm G). 
7. Loosen  the set screw e on the  feed  rock  shaft arm • and the two  set screWS·· on the feed bar arm G). 
8. Tap wedges  into the notches  in the  feed  rock shaft arm Cl and the feed bar arm G), and then  remove  the feed 
rocker  shaft j toward  the left.  (The  oil rejector 
fD and the  feed bar arm G) will  also  come  off.) 
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From  the library  of: Superior  Sewing Machine  & Supply  LLC  
						

							[II Feed mechanism (8714/8716/8747) 
I. Loosen  the nut 0. and remove  the screw 8. 
2. Remove  the two  set screws 8. and remove  the oil stopper G. 
3. Loosen  the set screw 8, rotate  the taper pin 8. and remove  the feed  lifting  rock shaft 8 and feed lifting arm 0. 
4. Loosen  the set screw 8. and remove  the feed arm pin GD. 
5. Remove  the two  set screws G), and remove  the oil stopper 48. 
6. Loosen  the set screw 8. disconnect  the taper pin fD, and remove the feed  rock  shaft fl, feed rock  shaft arm tD. 
and feed bar 8. 
[!] Needle bar mechanism 
Needle  bar 
bushing  U 
I. Tilt  the machine. 
• 
• 
• 
• 
2. Remove  the needle bar thread  guide G. 
3. Remove  the wick 8 from  the top of the needle bar bushing U. 
4. Loosen  the set screw 8. and remove  the needle bar 8. and needle bar clamp 8. (Remove  the slide  block.) 
5.  Remove  the oil cap 
8. loosen  the set screw 8 and remove  the thread  take-up support pin 0. 
6. Remove  the oil cap and loosen  the two  set screws 8. Now  remove  the thread  take-up  rocking arm GD. needle bar 
crank G), needle bar connecting  rod CJ, and wahser e. 
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From  the library  of: Superior  Sewing Machine  & Supply  LLC  
						

							~ ASSEMBLY ) 
[I] Needle bar 
•• 
Reference 
J~t 
lines ~~ /·-= 
Line 
Screw flat 
B706 
DA x 1 DB X 1 B707 DA X 1 DB X 1 
B714  DA X 1 DB X 1 
B716  DA X 1 DB X 1 
B747 DB X 1 
----
I. Install  the thread  take-up arm assembly 0. the needle bar crank f), the needle bar connecting  rod 0. and the ~ 
washer 8 with the set screw 8. -___/ 
* Refer  to the  above  illustration  for the  position of the  needle bar crank f) screw  flat. 
2. 
Thread the  wick  through  the thread take-up lever support shaft 8. (Refer to the illustration.) 
3.  Fit  the  thread  take-up  lever 
support shaft 8 through the thread take-up arm assembly 0. and then secure  it 
with  the set screw 
8. 
4. Fit  the  block 0 into  the groove, and then  fit the  needle bar clamp 8 through the neelde bar connecting  rod 0 
and the block 0. 
(Fit the block  into the groove  with the chamfered  side toward  the inside.) 
5.  Fit  the  needle 
bar 0 into  needle bar bushing U fD from  the top. and then pass it through  the needle bar clamp 
•• 6. Pass the  wick through from  needle bar bushing U fD. (Refer to the illustration.) 
7. Turn the pulley and set the  needle bar to the  lowermost  position. 
8.  Align  the second  reference  line from  the 
bottom on the  needle bar fD with  the bottom end of needle bar bushing 
oe. 
@Threading  the wicks 
( l) Thread  the wick through the thread  take-up arm 
assembly 8. 
(2) Thread the wick  into the machine  while installing 
the  thread  take-up 
arm assembly 8. 
(3) Insert  a length of piano  wire into the oil hole and 
pull out the  wick  as shown in the  illustration. 
(4)  Align  the end 
of the wick  with the edge of the 
thread  take-up 
arm assembly 8 and insert the rest 
of the  wick  into the oil hole. 
Piano wire 
Wick 
(I) Thread the  wick  through  the upper end of the 
needle 
bar bushing. 
(2)  Manually 
turn the pulley and set the  thread  take­
up to the uppermost position. 
(3)  As shown  in the  illustration,  insert the wick  until 
it 
contacts  the top of the thread  take-up arm 
assembly 0. 
(4) Insert  the end of the  wick  into the oil hole. 
-14-
From  the library  of: Superior  Sewing Machine  & Supply  LLC  
						

							II] Feed mechanism (8706/8707) 
• 
~ I 
I 
I 
I• 
Feed  dog 
I. Install  the needle  plate 0 with the screws 8. 
2. Tilt  the machine. 
• 
• 
• 
3. Mount the  feed  lifting  rock shaft 8 (from the left  side),  the feed  lifting arm 8. the oil rejector 8. and the  feed 
lifting  rock shaft 
arm 8. 
4. Mount the set collar 0 onto the  feed  lifting  rock shaft 8. and then secure  it with  the screw 8 so that it moves 
easily  with no play. 
5. 
Connect the  wick 8 to feed  lifting  rock shaft 8. (Refer to the  illustration  below.) 
6. Fit the  forked part of the feed bar f1 onto the  roller on the end of the feed  lifting arm 8. 
7. Mount the feed  rock  shaft e (from  the left side), the feed bar arm$. the  oil rejector G), and the  horizontal  feed 
rock  shaft 
arm 41. 
8. Fit the feed  rock  shaft 4D into the set collar 0. and then  secure  it with  the screw 8 so that it moves  easily with no 
play. 
* Secure  the feed  rock shaft·arm 4D with the screw 41 in a  position  where the level  feed arm link assembly  moves 
easily. 
* Secure  the feed  lifting arm 8 and the feed bar arm $ with  the screws fD in a position  where the feed dog G) 
divides  the groove  in the  needle  plate 0 front to back and left to right. In addition,  tighten the  screw CD so that 
the feed dog G) projects  I mm out of the  needle  plate 0. 
9. Connect the wick 8 to the  feed  lifting  rock shaft 8. (Refer to the diagram  below.) 
* Secure the feed  lifting  rock shaft arm 8 with the screws G) in a position  where the vertical  feed connecting  rod 
fJ) moves easily. 
Ql)--
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From  the library  of: Superior  Sewing Machine  & Supply  LLC  
						

							II] Feed mechanism (8714/8716/8747) 
~ 1 I I I• 
• 
Feed dog 
I. Install  the needle  plate 0 with the screws 8. 
2. Tilt  the mac}line. 
3. Mount the taper pin 8 onto the arm bed. 
4. 
Mount the  feed dog 8 onto the feed bar 8 with  the screws 8. 
1/ 1/ 
• 
• 
G 
5. Secure  the feed  rock  shaft 8. the feed  rock  shaft arm O. and the feed bar 8. with  the set screw f) so that they 
move  easily  with no play 
on the taper pin 8. (At this  time,  adjust  the feed dog 8 so that it divides  the groove  in 
the 
throat plate  into left and right.) 
6. Fit the  forked  shaft 0 into the forked part of the feed  rock  shaft arm 0. and then secure  the feed  rock  shaft 
arm pin 4D with  the set screw Q). 
7. Mount the  oil stopper fl with  the screws CJ). 
8. Mount the taper pin $ onto the arm bed. 
9. 
Mount the  feed  lifting  rock shaft 8 and the feed  lifting arm Cl with  the set screw G) so that they  move  easily 
with  not play 
on the taper pin $. 
10. Fit the side  block G) of the feed  lifting arm C1 into the forked part of the feed bar 8. and then  confirm that it 
slides  easily. 
II. Fit the  screw fJ) into  the crank  rod fD and the feed  lifting  rock shaft fl, and then secure  it with  the nut 8. 
12. Install  the oil stopper fl with  the screws fl. 
13. Turn the pulley and loosen  the screw fa to adjust  the feed dog 8 so that it extends I mm out of the top ofthe 
needle  plate. 
14. Set the length  control  dial to the highest  setting and turn the pulley. 
15. Loosen  the screw fa and adjust  the feed  rock  shaft 8 so that the feed dog 8 divides  the groove  in the  needle 
plate  in 
half front  to back. 
-16-
From  the library  of: Superior  Sewing Machine  & Supply  LLC  
						

							fl] Thread trimmer 
I. Fit the  forked  shaft 0 into the arm bed. 
2. Mount the collar 8. the cam lever  return  spring 8. the trimmer cam lever assembly G. the washer8 and the 
cushion 8 onto the arm bed, and then mount the trimmer cam lever  shaft 8 (after fitting the slide block 8 of 
the trimmer cam lever  assembly 8 into the fork of the forked shaft 0). 
3. Fit  the stop ring 0 onto the trimmer cam lever shaft 8. 
4. Tighten the  set screw ~. 
5. Mount the thread trimmer solenoid 4D to the arm bed  with  the screw $. 
Mount the solenoid  so that the gap  between  the trimmer cam lever shaft 8 and the solenoid  lever G) on the 
trimmer solenoid CD is as small as possible. 
6. 
Mount the  tension  releasing  lever CD with the screw 48. (Refer to p.23  for instructions on adjusting the  tension 
releasing  lever.) 
7. 
Mount the  movable  knife holder 4D onto the arm bed, and then mount the knife  holder  assembly 41 (and then 
trimmer connecting  rod 8> with the bolt Cl). 
8. Mount the trimmer lever spring~ and the trimmer lever fJ onto the forked shaft 0 and secure  them with the 
screw 
fl. 
9. Mount the thread trimmer connecting rod 8 to the thread trimmer lever fJ with the screw tl. 
10. Mount the  lower  thread  finger fJ to the arm bed with  the screw fi. 
II. Mount the  fixed  knife f) to the arm bed with  the screws fi. 
12. Mount the  movable  knife f1 to the movable  knife holder 4D with the screws 1). 
13. Hook the trimmer lever spring~ onto the trimmer lever fl. 
14. Confirm that the position of the trimmer cam is correct. 
* Move  the lower  thread  finger fJ towards the movable  knife in order to maintain  the space  between  it and the 
rotary hook. 
-17-
From  the library  of: Superior  Sewing Machine  & Supply  LLC  
						

							~ Thread trimmer  timing adjustment 
I. Thread trimmer cam position adjustment 
* Turn the pulley, and then  when  the needle bar rises  5 mm 
above the  lowermost  position, press the thread trimmer 
solenoid CD and adjust  the thread trimmer cam G) so that 
the  roller  shaft contacts  the cut out part of the thread 
trimmer cam G) and the end of the cam and the end of the 
roller  shaft 
is 0.6 to 0.8 mm when the thread trimmer cam 
lever  assembly  returns. 
2. Fixed knife and moving  knife position adjustments 
* The end of the fixed  knife e and the blade of the movable 
knife 
e must  be in the  position  shown in Fig.  A when the 
roller  shaft of the thread trimmer cam lever  assembly 0 
moves up the thread trimmer cam G). (The mating mark on 
the movable  knife holder fD must be in alignment  with the 
mating mark on the kpife holder assembly $). 
If the positions do not agree  with those  in Fig.  A. move  the 
thread 
trimmer lever fJ) and tighten  the screw f) so that the 
end 
of the  fixed  knife e and the blade of the movable  knife 
e agree with the position in Fig.  A when  the roller  shaft 
moves 
up the  thread trimmer cam G). 
[!] Rotary hook 
Bottom  of the needle  bar bushing 
• 41 
~ em] 
 -..... 
Reference -lines --: ---
~j 
~·[; 
Lower  shaft fJ 
-
B706 DA X 1 DB X 1 B707 DA X 1 DB X 1 
~~;~re 
·,~>'o ~ • B714  DA X 1 DB x  1 
B716  DA 
X 1 DB X 1 
B747 DB X 1 ~ 
• 
I. Mount the  needle  plate. 
2. Mount the rotary hook 0 onto the lower  shaft 0 and secure  it with  the screw 8. 
3. Mount the rotary hook position  bracket 0 with the screws 8. 
1-1.5 mm 
• 
4. Mount the needle bar thread  guard 8 onto the needle  bar, and then secure the needle 8 with  the set screw 8. 
5. Turn the  pulley  so that the needle bar rises  from  the lowermost position and align  the needle bar reference  line 
with  the 
bottom of the needle bar bushing  as shown in the  illustration. 
6.  Align  the 
rotary hook point with the center of the  needle 8. 
At this  time, adjust so that the distance  between the rotary hook point and the upper edge of the eye of the needle 
is 0 to 0.5 mm and the  distance  between the needle 8 and the rotary hook tip is 0.05 to 0.1 mm. 
7. Mount the needle  plate. 
8. 
Mount the  slide  plate C). 
9. Adjust  the feed  timing. 
Turn the pulley  forward and adjust so that the tip of the  needle is aligned  with the upper surface of the needle 
plate  when  the feed 
dog finishes  the feed and begins to retract and the  tip of the  feed dog is aligned  with the upper 
surface of the needle  plate. (Refer to the timing adjustment on p.21.) 
* Confirm that the gap between  the rotary hook position  bracket 0 and the rotary hook 0 is just enough for the 
thread being  used to pass through easily. 
-18-
From  the library  of: Superior  Sewing Machine  & Supply  LLC