MODEL REFERENCE

Brother LS-2125/2125i/2129

11 troubleshooting topics

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

Find a code or problem on this model

Troubleshooting

Find the problem you are experiencing

Upper thread breaks6 checks

The upper thread is not installed correctly.: Rethread the upper thread through the guides and tension discs.
The upper thread is tangled.: Remove the tangle and rethread the machine.
Upper thread tension is too high.: Turn the upper tension dial to a lower number.
The spool is not seated correctly.: Position the spool correctly on its pin before threading.
The needle is bent or dull.: Replace the needle.
The needle, thread, and fabric do not match.: Choose a needle and thread size suited to the fabric using the manual chart.

Lower thread breaks4 checks

The bobbin thread is tangled.: Remove the tangle and install the bobbin with thread unwinding in the correct direction.
The bobbin thread is not routed through the shuttle hook correctly.: Rethread the bobbin case slot and delivery eye.
Lower thread tension is too high.: Check thread tension as described in the manual; the bobbin tension is factory set for general use.
The lower threading path is incorrect.: Remove and reinstall the bobbin so the thread unwinds in the correct direction.

Skipped stitches5 checks

The needle is not fully or correctly inserted.: Insert the needle with its flat side facing back and tighten the clamp.
The needle is damaged or worn.: Replace the damaged or worn needle.
The needle and thread are not matched to the fabric.: Select the needle and thread sizes listed for the fabric.
Lint has built up beneath the needle plate.: Remove the needle plate and brush out accumulated lint.
The threading path is incorrect.: Rethread the upper thread through the guides and tension discs.

Thread loops in seam1 check

The thread tension is set incorrectly.: Adjust thread tension and test the stitch on scrap fabric.

Fabric puckers4 checks

Upper thread tension is too high.: Turn the upper tension dial to a lower number.
The machine is threaded incorrectly.: Rethread the machine through its guides and tension discs.
The selected needle is unsuitable for the fabric or thread.: Use the manual chart to select the correct needle.
The needle, thread, and fabric are mismatched.: Select compatible needle and thread sizes for the fabric.

Fabric does not feed properly4 checks

The needle/thread/fabric combination is unsuitable.: Choose compatible needle and thread sizes for the fabric.
The needle is damaged or worn.: Replace the damaged or worn needle.
Thread is tangled.: Clear the tangle and rethread the machine.
The darning plate is still installed.: Remove the darning plate before normal feeding.

Needle breaks4 checks

The needle is not inserted correctly.: Insert the needle fully with its flat side to the back, then tighten the clamp.
The needle is damaged or worn.: Replace the damaged or worn needle.
The needle, thread, and fabric are mismatched.: Use the manual chart to choose the correct needle and thread.
The fabric is being pulled too hard.: Let the feed dogs move the fabric and avoid pulling it.

Machine is noisy or slow2 checks

Lint is collecting under the needle plate.: Unplug the machine, remove the needle plate, and brush away lint.
The moving parts need oil.: Unplug the machine and oil the indicated points as the manual directs.

Machine does not start4 checks

The power plug is disconnected.: Connect the machine power plug to a wall outlet.
The main power switch is off.: Move the switch toward the I mark.
The foot controller is not being operated correctly.: Press the foot controller to start sewing, with more pressure for higher speed.
The bobbin winding shaft is still in its winding position.: Slide the bobbin winding shaft back to the left.

Thread loops on fabric surface2 checks

Upper thread tension is too high.: Turn the upper tension dial to a lower number.
Bobbin thread tension is too low.: First lower the upper tension dial setting; if that does not help, follow the manual’s bobbin adjustment procedure.

Thread loops on reverse of fabric1 check

Upper thread tension is too low.: Turn the upper tension dial to a higher number.