MODEL REFERENCE

Brother 2340CV

11 troubleshooting topics · 1 guide

Brother 2340CV

The checks and guides below come from the official manuals for this model.

Troubleshooting

Find the problem you are experiencing
Needle thread is too loose3 steps
  1. For the selected coverstitch or chain stitch, raise the needle-thread tension dial.
  2. Alternatively, lower the looper-tension dial to loosen the looper thread.
  3. Sew a test seam and adjust again if needed.
Needle thread is too tightView
Lower the needle-thread tension dial, or raise the looper-tension dial to tighten the looper thread. Test on a scrap of the same fabric before sewing the garment.
Fabric puckers or stretches while feeding4 steps
  1. Adjust the differential feed for the fabric and test a seam.
  2. A setting below 1 stretches lightweight fabric to prevent puckering; above 1 gathers stretchy fabric to reduce waves.
  3. Start at 1, test a scrap, and avoid differential feed on thick non-stretch fabric such as denim.
  4. The manual allows a differential ratio of 0.7–2.0.
Replace or refit the needles4 steps
  1. Turn off the power.
  2. Use the handwheel to raise the needle fully, loosen the correct set screw and remove the needle.
  3. Insert a straight compatible needle with its flat side toward the back, push it fully up and tighten the screw.
  4. Use the proper needle positions for the stitch; lightly tighten unused-position screws.
Thread the needles and looper6 steps
  1. Turn off the machine before threading.
  2. Raise the presser foot and needles, then follow each color-coded path shown in the guide.
  3. Hold the tension-release button right while seating thread in the tension discs.
  4. For the looper, follow the blue path, pull the release lever at the indicated step, thread the eye and return the looper until it locks.
  5. Close the front cover.
  6. Thick decorative looper thread uses the alternate route shown on manual page 10.
Prepare a three-needle coverstitch3 steps
  1. Install left, center and right needles and thread them plus the looper for a 6 mm coverstitch.
  2. Start with each needle-tension dial at 4 and looper tension at 4, seat the threads in the tension discs and sew a test seam.
  3. Adjust for balanced top stitches and underside loops.
Prepare a two-needle coverstitch3 steps
  1. For a 6 mm coverstitch, use the left and right needles; for 3 mm, use left and center.
  2. Thread both needles and the looper, tighten unused needle-position screws and start each active tension dial at 4.
  3. Test and adjust before hemming.
Prepare a chain stitch2 steps
  1. Use the center needle and looper only.
  2. Tighten screws at unused needle positions, thread the illustrated paths, set the starting tension shown in the guide and sew a test seam before adjusting.
Remove the fabric without pulling the seam4 steps
  1. Turn the handwheel toward you until the needles are highest, raise the presser foot and hold the fabric.
  2. Push the appropriate needle tension-release buttons right, then slowly draw the fabric toward the back.
  3. Cut the needle threads above the fabric, pull gently again to bring their ends to the back, cut the looper thread and tie the ends together.
  4. Keep clear of the hot bulb.
Hem a garment with coverstitch2 steps
  1. Fold and press the hem, measure and mark the folded edge position from the top, and align the left needle just to the left of that mark.
  2. Sew along the mark, then remove the fabric using the tension-release procedure.
Finish a tubular garment seam2 steps
  1. Raise the foot, position the garment, lower the foot and sew.
  2. Overlap the beginning and end by about 4 cm, then remove the garment with the documented thread-release procedure and secure the ends.

Guides

Changing the light bulb

Instructions from the manual
Replace the light bulb3 steps
  1. Unplug the machine and let the bulb cool.
  2. Loosen the cover screw, remove the cover, remove the old bulb and fit a replacement of the original type.
  3. Refit the cover and tighten its screw; follow the original bulb rating.

Model details

Model and compatibility

Needles
The guide specifies SCHMETZ 130/705H, size 90/14. It also recommends the SUK ball-point variant for reducing material breakage. [1]
Stitches
Use three needles and four threads for 6 mm coverstitch, two needles and three threads for 6 or 3 mm coverstitch, or the center needle and looper for chain stitch. [1]
Stitch length
The documented stitch length is 2–4 mm. Differential feed and presser-foot pressure can be adjusted for the fabric. [1]

Manuals and sources

  1. Brother operation manual
  2. Brother model support and details
  3. Brother manual download listing
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