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....

[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...

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...

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...

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)...

(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...

~==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...

..._____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 .....

..__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...

.._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...