Jumping Jupiter

[Big Dog]

What is going on here?
I'm using a design that I digitzed and I've run over 50 times with no issues and all of a sudden the machine with give a bobbin break error, the bobbin thread is not broken, but the machine has jumped backward in the design around 10-15 stitches.
I've tried a new bobbin, cleaned the bobbin case, the machine is clean and oiled as normal.
Sometimes the jump is in the walk stitch underlay, other times in the column stitch lettering, other times in the fill stitch portion of the design.
It hasn't done this in the previous runs with the same design file.
What in the world could be causing this?

[Greenwing]

This is nothing new, just the basics, sorry

You did not say if this was starting the project again (after doing others) or if you were on sew out of # 51 in a run of 100 for example.

Try a shut down and a restart of OS Machine & computer if the below fails.

Is the presser foot adjusted for what your sewing?

did you check the bobbin tension? (drop test)

is the thread feed set to what it should be for your project?

Is the material thickness set properly?

Is it threaded properly? I have had an operator some how miss the thread break bar before.

The backing up 10 stitches is the norm for a bobbin break. no problem there.

Hope this helps.

[gcannon]

Have you changed any of the parameters in the locks & trims?

[Kathy Shaw]

This has happened to me and all I do i shut off the bobbin detection and poff it's gone.

[signman]

sometimes it can be the bobbin thread itself...I keep magnetic bobbins handy to throw in when things just don't go right. Even cleaning out under the tension bar on the bobbin with the corner of a card helps-but sometimes, rare but it happens-you just have a spool of bobbin thread that won't play well with others. Also, carefully roll the silver 'bar' behind the thread on the needle case. This can 'reset' the detection. Don't know if it builds up static electricity or what it does, but just rotating it carefully a half turn or so will sometimes fix the problem when nothing else works. Don't spin it around and around-just a quarter turn or so once and see what happens.

[Big Dog]

No changes in any of the parameters at all.
The problem occurred when stitching the design as a new project. I stitched several of these in the past with no trouble, about two weeks ago.
Garment is an Ultra Club Whisper Pique polo, using one layer of No Show Mesh backing, same as the others I've stitched in the past, thread feed set to Auto, fabric thickness 5, presser foot one click up from the lowest position(again the same), bobbin is full and case is clean, tension normal on a drop test, machine threaded properly, error occurs on two of the three colors, the cones have not been moved since the previous runs.
Odd that the bobbin break detector is seeing a break that it never saw in the past.
Next time I'll try shutting off the bobbin detection and see how that works. I get periodic reorders for this design on a pretty regular basis.
Any ideas why it's suddenly detecting a non-existant break?

[gcannon]

I believe Signman might be right- sensor bar?

[Big Dog]

Signman, I forgot about gently rolling the thread detection bar a quarter turn or so, I'll have to remember that for the next order.
The card trick didn't seem to matter, I do that each time I put in a new bobbin which I just did, last night.
Thanks everyone!

[Juli in Kona]

Is the Bobbin in backwards? That could cause problems.

Juli

[Steve I]

When you listed your parameters you said you had auto feed and thickness of 5. Did that mean your lower limit is 5? If so reduce it to 2 and give it another try. Is it only happening on one needle? If it's only on one needle try moving that color to another needle. If you have tried all of the suggestions given and are still having trouble, clean and gread the thread rollers (red and yellow) on that needle and see if that fixes it. I know it sounds strange but I have been having that same problem on occasion and cleaning greasing the rollers cures the problem.

Steve Ingram
Trinity Embroidery