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Mechanical Failures
False Thread Breaks
False thread breaks on the machine are usually caused when the upper tension is too loose, such that the
thread sensor fails to detect the thread moving against the thread sensor bar.
Step Symptom/Procedure Condition Solution/Step
1 Check upper thread tension Too loose Adjust thread feed parameters
in the software
Correct Tension Go to Step 2
2 Tighten the thread feed pa-
rameters (reduce the amount
of thread feed in and see if
problem goes away)
Problem goes away Tension was too loose
Problem still occurs Go to Step 3
3 Inspect condition of thread
feeder rollers. They may be
damaged or worn.
Damaged or worn Replace rollers
Rollers all good Go to Step 4
4 Replace thread break sensor
assembly
Problem goes away Sensor is bad
Problem still occurs Contact Technical Support
Loose/Looping Stitches
Possible Causes Solutions
Thread feed settings too low Troubleshoot the thread feeder assembly. Check
the adjustment of the tread feed parameters in the
Bravo OS software. Contact Technical Support if
necessary.
Bobbin tension too low Adjust the bobbin tension by tightening the screw
on the bobbin case. Refer to the Operator Manual
for instructions.
Uneven thread size Replace with quality thread
Rotary hook timing is incorrect Adjust hook timing
Inadequate rotary hook lubrication Lubricate the rotary hook
Thread feeder roller worn or damaged Replace thread feeder roller
Design density too tight Decrease density (refer to Bravo OS manual for
design editing)
Needle Breaks
Possible Causes Solution
Needle is bent Replace needle
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