14. TROUBLESHOOTING
Problem
Possible cause
Page
10 Upper and lower threads
are breaking.
・
Is the needle tip bent? Is the needle tip blunt?
If the needle tip is bent or blunt, 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 rotary hook sufficiently lubricated?
If the oil gauge is down to the lower reference line in the oil
gauge window, add more oil.
・
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 take-up spring
operating range is too small?
Adjust the position of the thread take-up spring.
・
Is the rotary hook, feed dog or other part damaged?
If the thread path is damaged, smooth it with sandpaper or
similar.
Alternatively, replace the damaged part.
・
Is the thread path damaged?
If the thread path is damaged, smooth it with sandpaper.
Alternatively, replace the damaged part.
16
18
7
67
73*
*
*
11 Thread breaks during
backtack sewing.
・
Is the backtack sewing speed too fast?
Use the panel to reduce the backtack sewing speed.
28
・
30
12 Backtack sewing pitch
varies depending on the
sewing direction.
Backtack edge is not
aligned.
Adjust using MSW-201.
51*
13 Thread tightening around
X-over seam areas.
・
Is the height of the feed dog correct?
Increase the feed dog height.
76*
14 Upper thread is pulling out
of the needle after thread
trimming.
・
Is the upper thread trailing length after thread trimming appropriate?
Decrease the tension of the pre-tension.
・
Is the thread path not smooth enough?
Use a file with a fine grain or sandpaper to polish smooth the
thread path.
・
Does the thread being used slip easily?
Turn the needle bar bush thread guide D sideways to increase
the resistance.
・
If the upper thread is pulling out of the needle after thread trimming,
check using the method given below.
1. Check the upper thread trailing length.
2. Re-adjust the upper thread trailing length to make it longer.
3. Keep pressing the best PFM mode key, and then select "T/T
short parameter".
(1) Delete the stitch pitch for the previous stitch.
(2) Decrease the sewing speed for the final stitch and the
stitch before it.
68
68
35*
Stitch pitch for 1st stitch
Stitch pitch for 2nd stitch
0471M
S-7300A
93