Atlanta 4500A, Technical Manual & Parts Lists, Page: 94 / 166

Technical Manual & Parts Lists
86
3.4.2. Sewing Troubleshooting
No Malfunctions Causes Corrective Measures
1 Thread breakage
1. Quality of thread is bad.
2. Thread is thick compared to
needle.
3. Thread breakage due to heat of
needle.
4. Thread tension is too strong.
5. The thread path of needle,
looper, throat plate, needle
guard, looper guide and all
other thread paths are bruised.
6. Due to twice passing of thread.
1. Use a better quality thread
2. Change the needle or thread to
proper size.
3. This occurs on synthetic thread.
Use silicon oil lubricant. Lower
r.p.m.
4. Weaken the thread tension.
5. Sharpen with oil whetstone or by
buffing.
6. Activate the thread take-up
tension lever.
2 Skip-stitch Skip stitching of needle thread.
2 stitches collapse
*(This occurs when looper does not
scoop needle thread).
Loopers thread skip-stitches.
* One stitch collapse.
*(This occurs when the needle
drops into the triangle of thread).
Inadequate linking of loop.
(This occurs when the needle thread
is too much on left side)
1. Verify the scooping amount of
looper.
2. Verify the clearance between the
looper and needle.
3. Verify the timing of the looper &
needle.
4. Depending on the thread, activate
the thread take-up tension lever.
5. Verify the correct installation of
the needle.
6. Verify the timing of the needle
guard.
7. Refer to the passing of the
thread.
1. Verify above (1) & (3).
2. Verify the timing of the looper
thread cam.
3. Adjust the position of the thread
spreader hook.
4. Make the tension of the looper
thread stronger.
5. Refer to passing of the thread
1. Refer 1.3 of skipping of needle
thread
2. Verify the timing of the thread
spreader and position of hook of
the looper