Brother 431C Sewing Machine User Manual


 
6. TROUBLESHOOTING
. TROUBLESHOOTING
CAUTION
Turn off the power switch and disconnect the power cord before carrying out troubleshooting, otherwise
the machine will operate if the foot switch is depressed by mistake, which could result in injury.
Problem Cause Remedy Ref.
<430, 431, 433, 434, 435, 436, 484>
Work clamp operation is sluggish.
Grease the sliding part of the work
clamp.
P.104
P.105
Work clamp (Button clamp) lift
amount is too great.
Adjust the work clamp (button
clamp) lift amount.
P.104
P.105
P.106
Too much friction between work
clamp plate and work clamp arm
lever plate. (430, 431, 433, 434
solenoid specifications)
Grease the work clamp plate and
work clamp arm lever plate.
P.104
P.105
Work clamp does not
rise.
Button clamp does
not rise. (438)
Work clamp is contacting thread
wiper.
Adjust the position of the thread
wiper.
P. 111
-
P.113
Work clamp is not
lowered.
Button clamp is not
lowered. (438)
Presser lifter link is not moving
back.
Check if the link return spring is
unhooked.
P.65
-
P.68
Work clamp lift
amount is incorrect.
Button clamp lift
amount is incorrect.
(438)
<Solenoid specifications>
Incorrect position of work clamp arm
lever plate (button clamp holder
hook assembly).
<Pneumatic specifications>
Incorrect position of work clamp arm
lever.
Adjust the work clamp (button
clamp) lift amount.
P.104
P.105
P.106
Work clamp does not
close. (432)
Incorrect position of presser closing
roller.
Check whether stop lever is
engaged with stop position
adjusting plate or not, and adjust
the position of presser closing roller.
P.108
Adjust the height of the thread
wiper.
P. 111
-
P.113
The thread wiper is obstructing the
needle.
Adjust the operating distance of the
thread wiper.
P. 111
-
P.113
Thread wiper does
not operate correctly.
Thread wiper position is incorrect.
Adjust the operating distance of the
thread wiper.
P. 111
-
P.113
Lower thread winds
to one side.
Tension stud height is incorrect.
Adjust the height of the tension
stud.
Instruction
manual
Lower thread winding
amount is incorrect.
Bobbin presser position is incorrect.
Adjust the position of the bobbin
presser.
Instruction
manual
Stitches being skipped at the
sewing start.
Refer to “Skipped stitches occur” P.134
Uneven needle thread. Adjust the sub-tension.
Instruction
manual
Thread comes
unthreaded.
Needle thread is too short.
Adjust the thread take-up lever
stroke.
P.114
P.115
KE-430B, 430C series
133