12. TROUBLESHOOTING

Problem

Cause

Remedy

Reference

 

 

 

 

 

Thread is too thick for the needle.

Select a thread which is suitable for the

P. 26

 

needle.

 

 

 

 

Needle is not installed correctly.

Install the needle so that it faces

P. 22

 

correctly.

 

 

 

 

Thread is not threaded correctly.

Thread the thread correctly.

P. 22

 

 

 

 

 

Damage or burring in parts such as the

Repair the respective part by buffing it.

 

 

rotary hook, needle hole plate, needle

 

Upper thread is

Alternatively, replace the part.

 

or thread path.

 

 

 

breaking.

 

 

 

Needle and rotary hook timing is

Adjust the timing.

P. 59

 

 

incorrect.

 

 

 

 

 

 

 

 

Upper thread tension is too strong.

Reduce the upper thread tension.

P. 26

 

 

 

 

 

Thread take-up spring tension is too

Reduce the tension of the thread

P. 58

 

strong.

take-up spring.

 

 

 

Thread breaks due to heat.

Use a needle cooler unit (optional).

P. 22

 

Reduce the sewing speed.

P. 31

 

 

 

Damage to the needle hole plate or

Repair the respective part by buffing it.

 

Lower thread is

bobbin case.

Alternatively, replace the part.

 

breaking.

Lower thread tension is too strong.

Reduce the lower thread tension.

P. 26

 

 

 

 

 

 

Needle is bent.

Replace the needle.

P. 22

 

 

 

 

 

Needle is too thin.

Select a needle that is suitable for the

P. 26

 

sewing conditions.

 

 

 

 

Needle and rotary hook tip are

Adjust the driver needle guard.

P. 59

Needle breaks.

 

 

touching.

Adjust the needle clearance.

P. 60

 

 

 

 

 

 

 

 

Needle and rotary hook timing is

Adjust the timing.

P. 59

 

incorrect.

 

 

 

 

Feed timing is too slow.

Advance the feed timing.

 

 

 

 

 

 

Movable knife is blunt.

Replace the movable knife with a new

P. 61

 

one.

P. 63

 

 

 

Fixed knife is blunt.

Sharpen the fixed knife or replace it

P. 63

 

with a new one.

 

 

 

Upper thread is not cut.

Movable knife is not picking up the

Adjust the timing.

P. 59

 

 

 

 

 

 

upper thread.

Adjust the standby position of the

P. 61

 

 

movable knife.

 

 

 

 

Movable knife is not picking up the

 

 

 

needle thread because the last stitch is

Refer to "Skipped stitches occur".

P. 78

 

being skipped.

 

 

Lower thread is not cut.

Lower thread tension is too weak.

Increase the lower thread tension.

P. 26

 

 

 

 

(Continued on next page)

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BAS-311H