10
Troubleshooting
3.Thread breakage
[Example of phenomenon] [Check item before adjustment]
Is home-use sewing machine needle (HA × 1)used?
Is the needle installed correctly?
Is the needle bent or deformed?
Is the combination of needle and thread adequate for the
fabric?
Is the upper thread tension set correctly?
Are upper and lower threads threaded properly?
Step Item Diagnosing Method Standard
Reference
Page
1. Upper thread
tension dial
Upper
thread
tension
<Condition>
Upper thread tension dial: "5"
Thread: Cotton yarn # 60
<Diagnosis>
Pass the upper thread from the spool of
thread to the thread guide, pull the
thread vertically and measure the ten-
sion (A) when the value has stabilized.
(Using a measuring instrument)
A = 0.85 to 1.15
N
[Adjustment]
page.33
2. Needle plate
Flaw on
needle
plate
<Diagnosis>
Check the needle plate by touching
around the needle plate hole.
Flaw not
allowed.
Repair with
sand paper
(#800).
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