S-7300A
11. TROUBLESHOOTING
176
Problem
Possible cause
Page
7 Uneven seam
・
Is the presser foot pressure too weak?
Adjust the presser foot pressure.
・
Is the feed dog too low?
Adjust the feed dog height.
・
Is the bobbin scratched?
If the bobbin is damaged, smooth it with an oiled grindstone or
replace it.
Alternatively, replace the bobbin.
Instruction
manual
122*
8 Large degree of puckering
(Thread is too tight)
・
Is the upper thread tension too strong?
Make the upper thread tension as weak as possible.
・
Is the lower thread tension too strong?
Make the lower thread tension as weak as possible.
・
Is the needle tip blunt?
Replace the needle if it is blunt.
・
Is the needle too thick?
Replace with as thin a needle as possible.
・
Is the thread take-up spring tension too strong?
Make the thread take-up spring tension as weak as possible.
・
Is the thread take-up spring operating range too large?
Lower the position of the thread take-up spring to as low a
position as possible.
・
Is the presser foot pressure too strong?
Adjust the presser foot pressure.
・
Is the sewing speed too fast?
Gradually reduce the sewing speed.
・
Is the angle of the feed dog correct?
Tilt the front of the feed dog down slightly.
Instruction
manual
Instruction
manual
114*
114*
Instruction
manual
Instruction
manual
120*
9 Lower thread is tangled at
the sewing start.
Bobbin is spinning during
thread trimming.
・
Is the bobbin spinning direction correct when the lower thread is
being pulled?
Set the bobbin so that it turns in the opposite direction to the
rotary hook.
・
Is there too much thread wound
onto the bobbin?
The bobbin winding
amount should not be
more that 80 %.
・
Is the anti-spin spring attached?
Attach the anti-spin spring.
・
Is the bobbin turning smoothly?
If the bobbin is not turning smoothly, replace the bobbin.
・
Is a bobbin other that the light-alloy bobbins specified by Brother
being used?
Use only bobbins which are specified by Brother.
Instruction
manual
Instruction
manual
Instruction
manual
Instruction
manual
Lower
thread
0751M
2124M
0978M
0473M