Troubleshooting; Machine Head - Brother BAS-705 Instruction Manual

10. TROUBLESHOOTING

10. TROUBLESHOOTING

10-1. Machine Head

Problem
Presser does not rise.
Thread wiper does not
operate correctly.
Lower thread winds to
one side.
Lower thread winding
amount is incorrect.
Threads comes
unthreaded.
Lower thread breaks.
Cause
Presser lifter air tube is
bent or damaged.
Presser lifter air tube is
bent or damaged.
Presser is contacting
thread wiper.
The thread wiper is
obstructing the needle.
Thread wiper position is
incorrect.
Bobbin winder thread
tension stud height is
incorrect.
Bobbin presser position
is incorrect.
Stitches being skipped
at the sewing start.
Uneven upper thread
length.
Needle is too thick for
the thread.
Incorrect height or tension
of thread take-up spring.
Lower thread tension is
too strong.
Damaged or burred needle hole
plate, bobbin case corner, shuttle
race thread guide or shuttle race.
Tension of bobbin
presser spring in bobbin
case is too strong.
Lower thread winding
method is incorrect.
Check
Presser lifter air tube
Presser lifter air tube
Thread wiper standby
position
Clearance between
thread wiper and needle
tip
Thread wiper position
Bobbin winder thread
tension stud height
Thread winding amount
Refer to "Skipped
stitches occur".
Upper thread length
Thread and needle
Tension and height of
thread take-up spring
Lower thread tension
Damage
Bending amount of
bobbin presser spring
Lower thread tension
74
Remedy
Page
Straighten the bend in the
tube or replace the tube.
Straighten the bend in the
tube or replace the tube.
Adjust the position of the
thread wiper.
Adjust the height of the
thread wiper.
Adjust the operating
distance of the thread
wiper.
Adjust the height of the
thread tension stud.
Adjust the position of the
bobbin presser.
Refer to "Skipped
stitches occur".
Adjust the sub-tension.
Select a needle that matches the thread.
Check that the thread path. gives the
correct amount of resistance to the thread.
Increase the tension or
lower the height of the
thread take-up pring.
Adjust the lower thread
tension.
File smooth or replace
the affected part.
Reduce the tension of
the bobbin presser spring.
Adjust the lower thread
26.28
tension.
7
7
45
45
45
26
26
28
28
29
28
28
BAS-705