S-7300A
11. TROUBLESHOOTING
175
Problem
Possible cause
Page
5 Skipped stitches at sewing
start
Thread unraveling at
sewing start.
・
Is the thread take-up spring tension too strong?
Reduce the tension of the thread take-up spring.
・
Is the thread take-up spring operating range too large?
Lower the position of the thread take-up spring.
・
Is the trailing length of the upper thread too short after thread
trimming?
Adjust the pretension.
・
Are the threads not being trimmed cleanly?
Replace the upper knife and the lower knife.
・
Is the needle too thick?
Replace the needle with a needle that is one rank thinner.
・
Is the length of thread trailing out from the bobbin case after thread
trimming too short
If the bobbin is spinning loosely, replace the anti-spin spring in
the bobbin case.
・
Is the sewing speed too fast at the sewing start?
Use the slow start key.
・
Is the needle up stop position too high?
Adjust the needle up stop position.
・
Is the upper thread trailing length too short after thread trimming?
Turn on the thread pull-out prevention function.
・
If the thread is pulling out at the sewing start, try the following
remedies.
1. Check the upper thread trailing length.
2. Set the slow start number to "3" or less.
3. Re-adjust the upper thread trailing length to make it longer.
4. Keep pressing the best PFM mode key (3), and then select
"Prev. thread away PARA" from "Best PFM mode setting".
(1) Set the 2nd stitch pitch
to "3".
(2) Increase the current
stitch pitch settings for
the 1st and 2nd stitches
by about 0.5 to 1.
・
Is the needle hole in the needle plate too large for the needle being
used?
Replace the needle place with one with a needle hole that is
one rank thinner.
・
Is the presser foot groove too wide?
Replace the presser foot with one that has a narrower groove
so that it presses the material at the needle drop position.
・
Is the sewing machine starting to sew before the presser foot has
dropped?
Lower the presser foot before starting sewing.
・
Is the presser foot being raised before the sewing machine has
stopped sewing?
Raise the presser foot after the sewing machine has stopped
sewing.
114*
114*
135
・
136
147*
Instruction
manual
Instruction
manual
Instruction
manual
Instruction
manual
Instruction
manual
Instruction
manual
Instruction
manual
6 Large bird's nests are
forming at the sewing
start.
・
Is the upper thread trailing length too long after thread trimming?
Increase the tension of the pre-tension.
135
・
136
0749M