Brother SU-877A Bedienungsanleitung Seite 121

Problem
7. Upper thread trimming
errors (877B/878B)
8. Lower thread trimming
errors (877B/878B)
9. Lower thread is tangled at
the sewing start.
Spinning of bobbin
during thread
trimming
(877B/878B)
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Is the timing correct during thread trimming?
Adjust the timing for thread trimming.
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Are the tips of the movable knives damaged or bent?
Replace the movable knife which is damaged.
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Is there too much clearance between the tips of the movable knives
and the rotary hook stoppers?
Adjust so that the clearance is 0.05 - 0.2 mm.
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Is the tension release mechanism working correctly?
Adjust the tension release mechanism.
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Are the tips of the movable knives in the correct positions?
Adjust the positions of the movable knives.
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Are the tips of the movable knives too low?
Are the tips of the movable knives damaged or bent?
Replace the movable knife which is damaged.
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Are the rotary hooks too high?
Push the rotary hooks down to install them correctly.
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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.
Lower
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Is there too much thread wound onto the bobbin?
thread
The bobbin winding amount should not be more than 80%.
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Is the anti-racing spring attached?
Attach the anti-racing spring.
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Is the bobbin turning smoothly?
If the bobbin is not turning smoothly, replace the bobbin.
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Is a bobbin other than the light-alloy bobbins specified by Brother
being used?
80%
Use only bobbins which are specified by Brother.
manuals search engine
15. TROUBLESHOOTING GUIDE
15. FEHLERSUCHE
15. RECHERCHES DE PANNES
15. GUIA PARA LA LOCALIZACION DE FALLAS
Where to check
SU-877A/B, TU-878A/B (English)
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