Troubleshooting - Alfa 4900 Manuel D'instructions

Troubleshooting

Condition
The needle thread
breaks.
The bobbin thread
breaks.
The needle breaks.
Skipped stitches
Seam puckering
The cloth is not
feeding smoothly.
Stitches form loops
below the fabric.
The machine does not
work.
Buttonhole is not sewn
properly.
The machine does not
run smoothly and is
noisy.
1. The needle thread is not threaded properly.
2. The needle thread tension is too tight.
3. The needle is bent or blunt.
4. The needle is incorrectly inserted.
5. The needle thread and the bobbin thread are not set under the
presser foot when starting sewing.
6. The thread is either too heavy or too fine for the needle.
1. The bobbin thread is not threaded properly in the bobbin holder.
2. Lint has collected in the bobbin holder.
3. The bobbin is damaged and doesn't turn smoothly.
1. The needle is incorrectly inserted.
2. The needle clamp screw is loose.
3. The threads are not drawn to the rear after sewing.
4. The needle is too fine for the fabric being used.
1. The needle is bent, blunt or incorrectly inserted.
2. The needle and/or fabrics are not suitable for the work being
sewn.
3. A Blue Tip needle is not being used when sewing stretch, very
fine fabrics or synthetics.
4. The needle thread is not threaded properly.
5. A poor quality needle is being used.
1. The needle thread tension is too tight.
2. The needle thread is not threaded properly.
3. The needle is too heavy for the fabric being sewn.
4. The stitch length is too long for the fabric.
1. The feed dog is packed with lint.
2. The stitches are too fine.
3. The feed dog is not raised after "drop feed" sewing.
1. The needle thread tension is too loose.
2. The needle is either too heavy or too fine for the thread.
1. The machine is not plugged in.
2. Thread has been caught in the hook race.
3. The bobbin winder spindle is not returned to the left after bobbin
winding.
1. The stitch density is not suitable for the fabric being sewn.
2. A suitable interface material has not been used for stretch or
synthetic fabric.
1. Thread has been caught in the hook race.
2. Lint has built up in the hook race or bobbin holder.
Cause
176
Reference
See page 44
See page 50
See page 34
See page 34
See page 52
See page 36
See page 42
See page 166
Exchange bobbin.
See page 34
See page 34
See page 52
See page 36
See pages 34, 36
See page 36
See page 36
See page 44
Change the needle.
See page 50
See page 44
See page 36
Make the stitch coarser
See page 166
Make the stitch coarser.
See page 30
See page 50
See page 36
See page 14
See page 166
See page 40
See page 88
See page 80
See page 166
See page 166