Troubleshooting; Machine Head - Brother ZE-855A Instruction Manual

16. TROUBLESHOOTING

16. FEHLERSUCHE
16. RESOLUTION DES PROBLEMES
16. LOCALIZACION DE AVERIAS
16. TROUBLESHOOTING
• Please check the following points before calling for repairs or service.
• If the following suggestions do not solve the problem, turn off the machine power supply and contact your nearest
Brother service center.

16-1. Machine head

Wait at least 5 minutes after turning off the power switch and disconnecting the power cord from the wall
outlet before opening the face plate of the control box. Touching areas where high voltages are present can
result in severe injury.
Turn off the power switch and disconnect the power cord before carrying out troubleshooting, otherwise the
machine will operate if the treadle is pressed by mistake, which could result in injury.
Problem
1. Upper thread is not tight.
2. Lower thread is not tight.
3. Skipped stitches occur
while sewing
4. Flattened zigzags appear
in the stitch during inter-
mittent sewing (855A)
205
DANGER
CAUTION
• Is the upper thread tension too weak, or is the lower thread ten-
sion too strong?
Adjust the upper thread tension or lower thread tension.
0573M
• Is the lower thread tension too weak, or is the upper thread ten-
sion too strong?
Adjust the lower thread tension or upper thread tension.
0574M
• Is the needle tip bent? Is the needle tip blunt?
If the needle tip is bent or broken, replace the needle.
• 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.
• Is the presser foot pressure too weak?
Adjust the presser foot pressure.
• Is the needle too thin?
Replace the needle with a needle that is one rank thicker.
• Is the presser foot too high?
Adjust the height of the presser foot.
• Is the needle and rotary hook timing incorrect?
Adjust the height of the needle bar.
Adjust the clearance between the needle and the rotary hook.
• Is the thread tension spring too weak?
Adjust the tension of the thread tension spring.
0621M
• Has the treadle been depressed backward?
Do not press the treadle backward when the sewing machine is
stopped.
(When DIP switch 2-4 is set to ON, needle zigzagging also oc-
curs when the treadle is depressed backward, in order to pre-
vent a flattened zigzag from being sewn if the treadle is depressed
backward by mistake.)
• Does the treadle move too easily when it is depressed back-
ward?
Adjust the force required to depress the treadle backward so
1406M that it is a bit heavier.
Possible cause
ZE-855A,856A
Page
130
130
–
46
51
132
–
146
151
153
145
–
40
44