Brother International T-8422A Instruction Manual - English - Page 52

TROUBLESHOOTING, Problem, Possible cause

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11. TROUBLESHOOTING Problem 5 Uneven seam 2948M 6 Large degree of puckering (excess tension) 7 Material slippage 2949M Possible cause Is the presser foot pressure too weak? Adjust the presser foot pressure. Is the feed dog too low? Adjust the feed dog height. Is the bobbin scratched? If the bobbin is damaged, smooth it with an oiled grindstone or replace it. 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. Are the thread take-up spring tensions too strong? Make the thread take-up spring tension as weak as possible. Is the thread take-up spring operating range too large? Move the stopper to as high a position as possible. Is the presser foot pressure too strong? Adjust the presser foot pressure. Is the sewing speed too fast? Use the sewing speed control keys to gradually reduce the sewing speed. Is the thread take-up amount too small? Adjust the thread take-up amount. Is the presser foot pressure too strong? Adjust the presser foot pressure. Page 36 * 35 35 * * 36 26 37 36 2950M 8 Lower thread is tangled at the sewing start. Spinning of bobbin during thread trimming Lower thread 2951M 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 that 80 %. Is the anti-spin spring attached? (Models with thread trimmer) Attach the anti-spin spring. Is the bobbin turning smoothly? If the bobbin is not turning smoothly, replace the bobbin. Is a bobbin other that the light-alloy bobbins specified by Brother being used? Use only bobbins which are specified by Brother. 2124M 19 18 19-20 19-20 T-8421A, 8422A, 8452A, 8722A, 8752A 46

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T-8421A, 8422A, 8452A, 8722A, 8752A
11. TROUBLESHOOTING
46
Problem
Possible cause
Page
5
Uneven seam
y
Is the presser foot pressure too weak?
Adjust the presser foot pressure.
y
Is the feed dog too low?
Adjust the feed dog height.
y
Is the bobbin scratched?
If the bobbin is damaged, smooth it with an oiled grindstone or
replace it.
36
*
6
Large degree of puckering
(excess tension)
y
Is the upper thread tension too strong?
Make the upper thread tension as weak as possible.
y
Is the lower thread tension too strong?
Make the lower thread tension as weak as possible.
y
Are the thread take-up spring tensions too strong?
Make the thread take-up spring tension as weak as possible.
y
Is the thread take-up spring operating range too large?
Move the stopper to as high a position as possible.
y
Is the presser foot pressure too strong?
Adjust the presser foot pressure.
y
Is the sewing speed too fast?
Use the sewing speed control keys to gradually reduce the
sewing speed.
y
Is the thread take-up amount too small?
Adjust the thread take-up amount.
35
35
*
*
36
26
37
7
Material slippage
y
Is the presser foot pressure too strong?
Adjust the presser foot pressure.
36
8
Lower thread is tangled at
the sewing start.
Spinning of bobbin during
thread trimming
y
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.
y
Is there too much thread
wound onto the bobbin?
The
bobbin
winding
amount should not be
more that 80 %.
y
Is
the
anti-spin spring attached? (Models with thread trimmer)
Attach the anti-spin spring.
y
Is the bobbin turning smoothly?
If the bobbin is not turning smoothly, replace the bobbin.
y
Is a bobbin other that the light-alloy bobbins specified by Brother
being used?
Use only bobbins which are specified by Brother.
19
18
19-20
19-20
2948M
2949M
2950M
2951M
2124M
Lower
thread