8. TROUBLESHOOTING

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Problem

 

 

 

Possible cause

 

Page

 

 

8

Material slippage

Is the presser foot pressure too strong?

 

 

 

 

 

 

Adjust the presser foot pressure.

 

 

 

 

 

0750M

 

 

 

 

 

 

 

 

 

 

 

 

 

 

9

Lower thread is tangled at

Is the bobbin spinning direction correct when the lower thread is

 

 

 

 

the sewing start.

being pulled?

 

 

 

 

 

 

 

Spinning of bobbin during

Set the bobbin so that it turns in the opposite direction to the

 

 

 

 

thread trimming

rotary hook.

 

 

 

 

 

 

Lower

Is there

too

much

thread

 

 

 

 

 

wound onto the bobbin?

 

 

 

 

 

thread

 

 

 

 

 

The

bobbin

winding

 

 

 

 

 

 

 

 

 

 

 

 

amount

should

not be

 

 

 

 

 

 

more than 80 %.

 

2124M

 

 

 

 

 

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.

 

 

 

 

 

0751M

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

10

Upper and lower threads

Is the needle bent or is the needle tip broken?

 

 

 

 

 

are breaking.

Replace the needle if it is bent or broken.

 

 

 

 

 

 

Is the needle properly installed?

 

 

 

 

 

 

If it is incorrect, install the needle correctly.

 

 

 

 

 

 

Is the machine properly threaded?

 

 

 

 

 

 

If it is incorrect, thread the thread correctly.

 

26

 

 

 

 

Is the upper or lower thread tension too weak or too strong?

 

 

 

 

 

 

Adjust the upper thread or lower thread tension.

 

 

 

 

 

 

Is the upper thread may be loose because the thread take-up spring

 

 

 

 

 

operating range is too small?

 

 

 

 

 

 

Adjust the position of the thread take-up spring.

 

26*

 

 

 

 

Is the rotary hook, feed dog or other part damaged?

 

 

 

 

 

 

If they are damaged, smooth them with an oiled grindstone or

 

 

 

 

 

replace the damaged parts.

 

*

 

 

 

 

Is the thread path damaged?

 

 

 

 

 

 

If the thread path is damaged, smooth it with sandpaper or

 

 

 

 

 

replace the damaged part.

 

*

 

 

 

0471M

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11

Incorrect thread trimming

Is the fixed knife or movable knife damaged or worn?

 

 

 

 

 

(Upper and lower threads

Replace the fixed knife or the movable knife.

 

27*

 

 

 

are both not being

 

 

 

 

 

 

 

 

 

trimmed)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

12

Incorrect thread trimming

Is the needle properly installed?

 

 

 

 

 

(Upper thread or lower

If it is incorrect, install the needle correctly.

 

 

 

 

 

thread is not being

Is the fixed knife or movable knife blunt?

 

 

 

 

 

trimmed)

Replace the fixed knife or the movable knife.

 

27*

 

 

 

 

 

 

 

 

 

 

 

S-7000DD

36