11. TROUBLESHOOTING￿

 

Problem

 

 

 

Cause

 

 

Remedy

 

Ref.

 

 

 

 

 

 

 

 

 

 

 

Upper

thread is

not

Movable knife is blunt.

 

 

Replace the movable knife.

 

P. 68

trimmed.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fixed knife is blunt.

 

 

Sharpen or replace the fixed knife.

P. 68

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Adjust the position of the shuttle race

P. 67

 

 

 

 

Movable knife does not pick up the

thread guide.

 

 

 

 

 

 

 

 

 

 

 

thread.

 

 

 

 

Adjust the needle bar lift amount.

P. 66

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The movable knife does not pick up the

Refer to “Skipped stitches occur”.

P. 77

 

 

 

 

thread because of skipped stitches at

 

 

 

 

the sewing end.

 

 

 

 

 

 

 

 

 

 

Movable knife position is incorrect.

 

Adjust the position of the movable

P. 68

 

 

 

 

 

knife.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Sub-tension is too weak.

 

 

Turn the sub-tension nut to adjust the

P. 30

 

 

 

 

 

 

tension.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Thread jamming.

 

Thread

take-up

spring

tension

and

Adjust the tension and height

of the

P. 64

 

 

 

 

height are incorrect.

 

 

thread take-up spring.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Incorrect needle and rotary hook timing.

Adjust the needle bar lift amount.

P. 66

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Shuttle

race thread

guide is

not

Adjust the position of the shuttle race

P. 67

 

 

 

 

separating the threads.

 

 

thread guide.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Poor

seam

finish

on

Shuttle race thread guide is separating

Adjust the position of the shuttle race

P. 67

reverse

side

of

the threads insufficiently.

 

 

thread guide.

 

material.

 

 

 

 

 

 

 

 

 

 

 

 

Upper thread is not properly tight.

 

Adjust the upper thread tension.

 

P. 63

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Uneven needle thread.

 

 

Adjust the sub-tension.

 

P. 30

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Adjust the sub-tension.

 

 

 

 

 

 

Needle thread is too long.

 

<When using the thread nipper

P. 30

 

 

 

 

 

 

 

 

 

device>

 

 

 

 

 

 

 

 

 

 

 

Turn the tension nut to adjust the upper

 

 

 

 

 

 

 

 

 

 

thread trailing length to 35 – 38 mm.

 

 

 

 

 

Needle is striking the button. (BE-438F)

Refer to “5-5. Checking the

sewing

P. 42

 

 

 

 

pattern”.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Incorrect thread

 

Upper thread tension is too weak.

 

Adjust the upper thread tension.

 

P. 63

tightness.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Lower thread tension is too weak.

 

Adjust the lower thread tension.

 

P. 63

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Thread

take-up

spring

tension

and

Adjust the tension and height

of the

P. 64

 

 

 

 

height are incorrect.

 

 

thread take-up spring.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Machine does not

 

 

 

 

 

 

Check if the machine head switch cord

P. 17

operate when power is

 

 

 

 

 

is disconnected.

 

turned on and foot

 

 

 

 

 

 

 

 

 

switch is depressed.

 

Machine head switch does not work.

 

Adjust the position of the switching

P. 25

 

 

 

 

 

plate.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Replace the machine head switch if it is

 

 

 

 

 

 

 

 

 

 

broken.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

KE-430F, BE-438F

78