207
ZE-855A,856A
16. TROUBLESHOOTING
16. FEHLERSUCHE
16. RESOLUTION DES PROBLEMES
16. LOCALIZACION DE AVERIAS
130
130
–
–
145
144
132
84
148
50
48
47
–
–
–
46
51
130
144
151
153
–
–
80%
Problem
Possible cause
Page
8. Large degree of puckering
(excess tension)
• 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 point of the needle broken?
If the point of the needle is broken, replace the needle.
• Is the needle too thick?
Replace with as thin a needle as possible.
• Are the thread take-up spring tensions too strong?
Make the thread take-up spring tension as weak as possible.
• Is the thread tension spring operating range too large?
Lower the position of the thread tension spring to as low a posi-
tion as possible.
• Is the presser foot pressure too strong?
Adjust the presser foot pressure.
• Is the sewing speed too fast?
Reduce the sewing speed slightly.
• Is the angle of the feed dog incorrect?
Tilt the front of the feed dog down slightly.
9. Lower thread is tangled at
the sewing start.
Lower
thread
• 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 than 80%.
• Is the bobbin tension spring attached? (856A)
Attach the bobbin tension spring.
• Is the bobbin turning smoothly?
If the bobbin is not turning smoothly, replace the bobbin.
• Is a bobbin other than the light-alloy bobbins specified by Brother
being used? (856A)
Use only bobbins which are specified by Brother.
Sprinning of bobbin during
thread trimming (856A)
10. Upper and lower threads
are breaking.
• Is the needle bent or is the needle tip broken?
Replace the needle if it is bent or broken.
• Is the needle properly installed?
If it is incorrect, install the needle correctly.
• Is the needle properly threaded?
If it is incorrect, thread the needle correctly.
• 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 tension
spring operating range is too small?
Adjust the position of the thread tension spring.
• Is the needle and rotary hock timing incorrect?
Adjust the height of the needle bar.
Adjust the clearance between the needle and the rotary hock.
• Is the thread too thick for the needle?
Use the correct needle or the correct thread.
• Is the rotary hook, bobbin case, thread take-up lever or some
other part in the thread path damaged?
Repair the damage, or replace the part with a new one.
0627M
0628M
0629M
0471M
