Brother Db2-b714-3 Instruction Manual

							.~ 
[I] Presser mech~r:'_ism 
• 
--Approx. 6 mm 
f 
I. Insert the presser bar 0 from  the top of the arm. 
2. 
Mount the  presser bar guide  bracket 8 onto the groove  in the arm, and then  pass the presser bar 0 through  the 
presser 
bar guide  bracket G. 
3. Mount the washer 8, the  presser  bar spring 8, and the presser bar spring  guide 8, and then  tighten  the presser 
foot  adjustment  screw 
8. 
(Mount the thread  wiper holder  onto the presser bar 0 and  secure  it with  the screw.) 
4. Mount the presser  foot 8 onto the presser bar 8 with  the screw 8. 
5. Adjust  the height of the presser  foot 8 to approximately  6 mm. 
[]]Cover 
l'l~ Screw_./ · 
Thread wi~er . _ 
I. Mount the  tension  regulator  assembly 0 with the screw G. 
(The  thread  take-up  spring operating  range is 8 mm and the  tension is 20 to 30 kg.) 
2. Mount the oil stopper plate 8 with  the screws 8. 
3. Mount the oil cap 8 and  the oil cap 8. 
4. Mount the  rear  cover 8 and the packing 8 with  the screws C). 
5. Mount the face  plate f) and the packing CD with  the screws CB. 
(Mount the thread  wiper with the screw.) 
-19-
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							[I] Needle and rotary  hook timing  adjustments 
In order for the  tip of the rotary  hook to catch the loop in the  needle thread  when the needle  rises from  the lowest 
point.  the needle 
and rotary  hook must be correct. 
1 . Needle  bar height 
• 
Reference line 
* Turn the pulley  slowly. and lower the needle  bar 8 to the needle down position.  Confirm that the second  from 
bottom reference  line on the  needle bar 8 is aligned  with the bottom of the needle bar bushing. 
• Loosen  set screw 8 and  align  this second  reference  line with  the bottom of the needle bar bushing 8. After 
adjusting.  firmly tighten  set screw 
8. 
2. Rotary  hook position 
0 
Reference line 
* Turn the pulley  slowly. and align the bottom reference  line on the  needle bar 8 with  the bottom of the needle bar 
bushing 8. With  the needle bar in this  position.  check that the rotary  hook pointe is aligned  with the needle 
center 
0 and that the  needle 0 to rotary  hook point 8 gap is between 0.05 -0.1 mm. 
• Loosen  set screw 8 and after aligning  the rotary hook point 8 with  the needle  center 0. adjust the needle 0 
to rotary hook point 8 gap  to between 0.05  -0.1 mm.  Firmly  tighten  set screw 8. 
* Always  perform  the steps  for rotary  hook lubrication  adjustment  after replacing  the rotary  hook. 
-20-
From  the library  of: Superior  Sewing Machine  & Supply  LLC  
						

							I~ 
II] Feed dog height  adjustment 
•• A 
~
. 
~ j B •• 
A 
F1 
B 
~ 
Feed dog height 
,---Rises in the forward  direction ===::l ~ t=:= __.., 
r-_ Descends  in the  forward  direction 
==:::::1 ~ c::::::::= _./ 
I. The standard  height of the feed dog for sewing  thin materials is 0.8 mm.  for medium  materials 1.0 mm, and for 
thick  materials 
1.2 mm (when  the stitch  length is set to the maximum). 
2. Adjust  the feed dog height  by loosening  the screw 8 when  the feed  dog 8 is at its height  position  from the 
needle  plate surface,  and move  the feed  lifting 
arm 0 up and  down. 
Feed  dog angle 
I. The standard  angle of the feed dog 8 (horizontal to the needle  plate surface  when the feed dog is at its highest 
position) 
is obtained  by matching  the 0 mark of the feed  plate  shaft 8 with the notch on the feed bar arm 8. 
• In order to  prevent  packering.  raise the feed dog 8 in the  forward  direction. 
• In order to  prevent  the material  from slipping.  slant the feed dog 8 in the  forward  direction. 
2. 
In order to  adjust  the feed dog angle,  loosen  the screws 8 and  then turn the feed  plate  shaft 8 90° in the 
directions  indicated by the  arrows. 
* When  the feed dog angle  has been  adjusted,  check to confirm that its height  has not changed. 
[I) Feed  timing  adjustment 
Feed dog~ 
~ 
I. Turn the pulley  manually;  the area of the  needle  between  the tip and the  lower  edge of the eye  should  be in 
alignment  with the top surface of the needle  plate when  the feed dog completes  the feed  and retracts  so that the 
tip 
of the  feed dog is level  with the top surface of the needle  plate. 
2. If the feed timing is not correct,  loosen the set screw 8 of the  feed  cam 8 and adjust. 
If the feed dog retracts too early,  turn the feed  cam slightly  in the  opposite  direction  from which  the machine 
turns;  if the  feed 
dog retracts too late, turn the feed cam slightly  in the  same  direction  as that in which  the 
machine  turns. 
3. After adjusting  the timing,  tighten the screw  securely. 
[I] Presser  height adjustment 
* The amount of presser foot rise should  be 6 mm 
when  the presser  foot 
8 is raised  by the  presser 
bar lifter  lever 8. 
Turn the presser  regulating  screw 0 and lower 
the  presser 
bar lifter  lever 8. 
Remove  the cap 8 from the front  cover.  loosen 
the  screw 
8. and move  the presser bar 8 up and 
down 
to adjust  it. 
-21-
6mm 
From  the library  of: Superior  Sewing Machine  & Supply  LLC  
						

							IT] Synchronizer adjustment 
1 . Position adjustment of the thread trimmer signal 
18-22 mm 
Synchronizer Adjustment (8707 /8716) 
1. Turn off the  power of the machine. 
(If the  hole  ICs are to be  adjusted. it is important that the  power  first be turned  off.) 
2. Remove  the synchronizer cover. 
3.  Rotate  the pulley  towards  you 
and stop the needle  5 mm  above  its lowest  point. The lower end oft he magnet 0 
must  be aligned at this  time  with the upper  edge of the thread-trimmer  hole IC 8. 
· If the  lower  end of the magnet 0 and the upper  edge oft he thread-trimmer hole·IC8 are not  aligned,  adjust by 
loosening  the screw 
8 and moving  the thread-trimmer hole IC. 
4. 
Turn on the  power and stop the  machine at the needle-down  positidh. At this  time  the needle bar must stop 18-
22 mm  above  the surface of the  needle  plate. 
If  the  needle 
bar does  not stop at this position,  adjust by loosening  the screw 8 and moving  the needle-down 
hole  IC 
8. 
5. Stop the machine at the needle-up  position. The point of the needle  must stop 9 -II mm above  the needle  plate 
for  thin 
and medium  thickness  materials.  and 10 -12 mm above the needle  plate for thick  materials. 
If the point of the needle  does not stop at this position,  adjust by loosening  the screw 8 and moving  the needle­
up hole IC f). 
* The  needle bar will lower  when hole IC 8 and hole  IC 8 are moved in the direction of machine  rotation. and 
rise when  they are moved  in the  opposite  direction. 
Synchronizer  Adjustment (8747) 
I. Turn off the  power of the  machine. 
(If the  hole  ICs are to be  adjusted,  it is important that the power  first be turned  off.) 
2.  Remove  the synchronizer  cover. 
3.  Rotate  the pulley  towards  you 
and stop the needle  7 mm  above  its lowest  point. The lower end of the magnet 0 
must  be aligned at this  time  with the upper edge of the thread-trimmer  hole IC 8. 
If the lower  end of the magnet 0 and the  upper  edge ofthe thread-trimmer hole IC8 are not aligned.  adjust by 
loosening  the screw 
8 and moving  the thread-trimmer hole IC. 
4. 
Turn on the power and stop the  machine at the  needle-down  position. At this  time  the needle bar must stop 18-
22 mm  above  the surface of the needle  plate. 
If  the  needle 
bar does  not stop at this position.  adjust by loosening  the screw 8 and moving  the needle-down 
hole  IC 
0. 
5. Stop the machine at the needle-up  position. The point of the needle  must stop 9 -II mm above  the needle  plate 
for  thin 
and medium  thickness  materials,  and 10--12 mm above  the needle  plate for thick  materials. 
If  the  point 
of the needle  does not stop at this position,  adjust by loosening  the screw 8 and moving  the needle­
up hole  IC f). 
* The needle bar will lower  when hole IC 8 and hole  IC 8 are moved in the direction of machine  rotation, and 
rise when  they are moved  in the  opposite  direction. 
-22-
From  the library  of: Superior  Sewing Machine  & Supply  LLC  
						

							11] Thread trimmer  adjustment 
1 . Replacement  of the  fixed  knife and movable knife 
* Turn off the power. 
ilstone 
Removal of the fixed  knife 
(I) Tip the machine of its side. 
(2.) Remove  the screw 0 and the  rotary hook position  bracket 8. 
(3) Remove  the screw 8 and the  fixed  knife 8. 
@ If the  thread trimmer should  need sharpening,  sharpen the fixed  knife 8 as shown  in Fig.  A. 
Removal 
of the  movable  knife 
(I) Use the presser  foot lifter  lever to lift the  presser  foot. 
(2)  Remove  the screw 
8 and the  needle  plate 8. 
(3) Turn the pulley  until the needle bar is at its highest  position. 
(4) 
Press the  thread  trimmer  connecting bar 8 in the  direction of the arrow and stop in at the  point  where  the 
screw 
8 can  be seen. 
(5)  Remove  the screw 
8 and  the movable  knife 8. 
* Remove the needle  plate 8 and the movable  knife 8 only after  the needle  has been  removed. 
* Assemble  in the  reverse order of disassembly. 
2. Adjustment of the  fixed  knife, movable knife,  and lower thread  finger 
1-1.5 mm Fig. 8 
~ 
~~ 
• 
(I) After attaching  the movable  knife 8 and the fixed  knife 8, depress  the thread  trimmer  connecting  rod 8, and 
match up the  marking on the  movable  knife holder Cl) with the marking  on the  knife  holder  assembly CD. 
At this  time  the relationship  between the end of the  fixed  knife 8 and the blade of the  movable  knife 0 must 
be  as shown  in Fig. 
B. 
If it is not,  loosen  the screw 8 and  adjust  the thread  trimmer  lever G). 
* If the  above  adjustment cannot be performed,  refer to thread trimmer timing adjustment on p.l6. 
* In order to maintain  the distance  between the lower  thread  finger and the rotary  hook, move the lower  thread 
finger  towards  the movable  knife 
8. 
-23-
From  the library  of: Superior  Sewing Machine  & Supply  LLC  
						

							(I] Tension release lever adjustment 
* Adjust the nut f) so that the thread trimmer 
solenoid 
0 moves  easily for the  first 0 -2  mm 
(tension  release lever does 
not operate) and resists 
moving  for the  next  2 
-5 mm. 
Confirm 
that the  tension  disc 8 opens 0.5-I mm 
at this  time. 
Also,  when the solenoid 
is not operating,  confirm 
that the disc is firmly  closed. 
[!]Thread wiper adjustment 
I. Attach the thread  wiper bearing 0 so that when the 
presser  foot 
is lifted with the knee  lifter,  it does  not 
come  in contact  with the presser  bar. 
2. Loosen  the thread  wiper lever screw and position 
the  thread  wiper lever 
f) so that the groove of the 
grooved  link 
8 is vertical to the bed  surface. 
3. Attach  the thread  wiper 8 so that the end of it does 
not come in contact with  the presser  foot when  the 
presser  foot 
is raised. 
[!] Automatic  presser foot lifter adjustment  ( -900; electromagnetic  type) 
oo 
=?:mmm Tighten fully 
,..,~ .. ~ 
_£dog 
~Knee lifter 
o.a--O.s mm \~complying bar f) 
Presser foot lifter link  Adjustable 
range 
• 
I. 
Adjustment of the  solenoid and plunger 
Adjust  so 
that the noise  (impact  noise) made by the  presser  foot when  it is lifted is small. 
Turn the adjustment  nut 0 so that the space  between  the solenoid and the  plunger f) is 0.6 -0.8 mm. 
2. Damper support joint adjustment 
Adjust  so 
that the noise  (impact  noise) made by the  presser  foot when  it comes down is small. 
Se  the  feed 
dog in its lowest  position. 
Loosen  the screw 
8. and after adjusting  the space  between  the knee  lifter  push bar and the presser  foot lifter  link 
to 0.3-0.5 mm,  match  up the damper support joint 8 with  the rubber cushion 8. 
3. Damper adjustment 
Adjust  the speed  the  presser foot comes  down with the 
adjustment screw 8 of the damper 8. Adjust  the 
adjustment  screw 
8 to approximately 30° from the fully  tightened  position. 
* When the adjustment  screw 8 is to tight. the presser  foot will not come  down  (will not press against  the 
material). 
If this  screw is too loose,  the presser  foot will come  down too fast, thus making an impact  noise and possibly 
damaging  the material  being sewn. 
* The above  procedure (I --3) is the standard adjustment; however,  there may be subsequent  variations due to 
changes in presser  foot pressure and power  supply  voltage. 
-24-
From  the library  of: Superior  Sewing Machine  & Supply  LLC  
						

							~==T=R=O=U=B=L=E=SH====O=O=TI=N=G=G=U=I=D=E=. :::::::::~ 
[I] Machine head 
I Trouble I L...-..-.-1 _cause -------~~ 1~...-----c_heck _I IL--_Solution_____._____....l Page I 
r--Improper  needle installation 1--Needle  bias. height -Reinstall  properly 
/ 
-Bent needle,  blunt 
needle tip, blocked  needle hole 1--Needle ......____ Replace  needle 
/ 
-Improper  feed timing 1--Is material fed when  needle f---Adjust  timing 21 is in material? 
Needle  breaks 
r-
Refer to .. Needle  and Rotary -Needle bar lift stroke -Hook  Timing  Adjustment 20 
....._ Improper needle 
hook  timing  to 
rotary r-r-Needle bar height r--Refer  to .. Needle  and Rotary 20 Hook  Timing Adjustment 
---Needle  to rotary  hook gap r--Refer  to .. Needle  and Rotary 
Hook  Timing Adjustment 20 
.---Improper  threading f--Threading 1-Rethread properly 
/ 
-Bent needle,  blunt needle f--Needle f---Replace  needle 
/ tip, blocked needle hole 
-Improper  needle installation 1--Needle bias, height r--Reinstall  properly 
/ 
Thread breaks i-
/ 
-Exc~ssive upper thread f--Upper  thread  tension -Adjust  tension tens10n 
r-Excessive  lower thread 1--Lower  thread  tension -Adjust  tension 
/ tension 
....._ Loose upper thread r--Thread  take-up  spring -Adjust take-up  spring 
/ stroke 
.---Burr in thread  path  Remove 
with sandpaper 
/ 
Thread  frays r-
....._ Blunt needle  tip 
Replace needle 
/ 
-25-
From  the library  of: Superior  Sewing Machine  & Supply  LLC  
						

							..._____T_rouble-------,J.II L....---_cause -------~~~ L....---_Check -------~~ IL..,_____Solutio_n ....~....----..1 Page I 
-Improper needle installation -Needle  bias. height -Reinstall  properly 
/ 
-Bent needle or blunt  needle -Needle  bias, height -Replace  needle 
v tip 
-Improper threading -Threading ,....--Rethread  properly 
/ 
r--Needle bar lift stroke 1-Refer to Needle  and Rotary 20 Hook Timing Adjustment 
Skipped stitches I-I-Improper needle to rotary f-f--Needle lift length 1--Refer  to .. Needle and Rotary 20 hook timing  Hook Timing· Adjustment 
....__ Needle to rotary hook gap f----Referto Needle and Rotary 20 Hook Timing Adjustment 
Upper  thread  left at needle is too Adjust  pretension 
/ 
-short and doesnt  remain in material 
Bobbin  idles and bobbin  thread 
Bobbin case idler  prevention  Replace 
idler prevention 
/ 
-is too short 
to rise during thread -1--trimming screw  spring 
--Thread take-up 
spring is too -Thread take-up spring -Adjust thread take-up 
/ weak to lift  bobbin  thread 
tension  spring 
Upper  thread  tension 
too Increase upper thread 
/ 
-weak  tension 
Upper thred does not -tighten 
/ 
-Exc~ssive upper thread 
Decrease 
bobbin thread tensiOn tension 
r--Excessive  upper thread  Decrease upper thread 
/ tension  tension 
Lower 
thread does not t-tighten 
1/ 
Lower  thread 
tension too Increase bobbin thread --weak 
tension 
-26-
From  the library  of: Superior  Sewing Machine  & Supply  LLC  
						

							..__T_rouble______.l~ ~_cause ______.II----_check ______,II~ _solution~~ Page I 
Thread trimmer  misses  Movable and fixed 
knives Check 
alignment of thread  trimmer Align movable  and 
fixed 23 r--do not  meet 1--holder and thread  trimmer  holder -knives presser i ndcx marks 
a. neither upper or low-Movable and fixed knife blades Movable  and 
fixed  knife 
Replace movable  and fixed 23 er thread is cut r--are burred or abraded t---blades -knives · 
Movable and fixed  knife Is thread 
trimmer 
signal f---Check electrical  circuitry 
v 
-does not move t---output? 
-Improper  needle installation f---Needle  bias -Reinstall  properly 
/ 
b. upper thread is not Stitch skips at last  stitch and Thread  take-up  spring  Adjust thread take-up 
v 
r--upper thread  trimmer  does not f----cut catch  upper  thread stroke  spring 
Movable 
and fixed  knives Check  alignment of thread  trimmer .Align  movable  and 
fixed 23 r--do not meet t---holder  and thread  trimmer  holder -knives presser index marks 
Poor cutting by movable  Movable 
and fixed 
knife 
Replace movable and fixed 23 r--and fixed  knives -blades -knives 
c. lower thread is not ..... cut 
Movable and fixed  knives Check alignment of thread 
trimmer Align movable  and 
fixed 23 --do 
not  meet -holder  and thread  trimmer  holder r--knives presser index marks 
-Insufficient  tension disc -Tension  disc ,opening f---Adjust tension  release lever 24 opening 
Upper 
thread casts off at -r--~xcessive pretension  Adjust 
pulley tension / sewing  start 
Thread too thick  for needle 
Needle size 
/ i--hole 
Needle upper stop position is too Thread  take-up  height when Delay needle  up stop 22 --high and thread  left by thread f---machine is in needle  upper stop -take-up  position 
-27-
From  the library  of: Superior  Sewing Machine  & Supply  LLC  
						

							.._T_rouble______.JI L..----1 _cause _____,II L..---_check ______,II L.---_solution--------------1 Page I 
Thread cutter 
does not -Thread trimmer  signal not 
Check circuits 
v move output 
r--Upper thread too long  Check and adjust 
pretension 
v 
1--Excessive  material and Replace with presser  foot 
v presser foot resistance  with rear gap 
Thread  wiper does not 
pull  upper  thread  up I-from 
material 
v 
1--Early timing~ pulls off Adjust operating time 
before  tension  disc closes 
---Thread  wiper operating time 
Adjust operating time [7 too short 
....--Thread wiper operating time  Adjust operating time [7 too long 
Thread wiper strikes 
needle  and 
does  not 1-return 
v 
.__ Automatic presser 
foot rises 
Adjust operating  time of too 4uickly presser foot 
-28-
From  the library  of: Superior  Sewing Machine  & Supply  LLC