Question about Bernina Activa 140

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Tension on bernina 140

It sews well until the loose tension allows the top thread to slip off the thread take up arm which is a lot. How do I know if something is missing and how to fix it? I took the top off and the tension plates inside are very loose even when the spring is at full tension.

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Take the top off again. Behind the tension disks (on top) you will see a torx head screw that goes through a knurled nut that has a flat side on it. Loosen that screw and turn that flat sided nut a bit. Then tighten the screw. This works like an eccentric that opens the discs either narrower or wider (depending on your needs) when you lift the presser foot bar. You may have to try this several times until you can see its good.

Posted on Jul 24, 2008


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Posted on Jan 02, 2017


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My bottom tention of Bernina Deco 340 is to loose. How to I correct is. The top treat shows to much at the bottom

Um, the top thread is showing on the bottom of the fabric? The top tension is too loose. The two threads create a tension battle, one pulling against the other. To pull the bobbin thread up, tighten the top tension. The tension is accurate when the two threads meet "in the middle" of the fabric. On thinner fabric, you might see a tiny spot of bobbin thread on the top and a tiny spot of top thread on the bottom.

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Bernina 440 QE thread sensor shows thread is broken when it is not

Try enterng this in the google search block; "bernina 440 qe maintenance" it comes up with a lot of informaton and even videos.

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Bernina 1008 thread bunching on bottom

"Nesting or Rat's Nesting" on the bottom side of Bernina sewing machines (CB hook type) is generally the result of very loose top tension. If the problem is found in newer sewing machines such as machines made after 1986 (serial numbers beginning with 26xx xxxx), may have an older Bernina bobbin case in the machine. The problem with the older bobbin cases is that the rounded projection of the latch on the left side of the casing will catch thread, preventing easy thread escapement during the take-up lever cycling resulting in loops on the bottom side and or thread breakage, etc..
Note:....Timings and modified latch geometry's were applied to later models to allow for good thread escapement. Older Bernina cases cannot be used on newer machines but newer cases can be used on all CB hook Bernina machines.
Additionally, Chinese copies of the Bernina/Cerliani OEM bobbin are rampant and can cause sewing issues. Always ask for OEM Bernina cases.

Note the following trouble shooting logic:
1. The center tension disk that is visible through the thread slot in the top cover of most machines must be positioned exactly in the middle of the top cover slot. By loosening the fixing screws on the top tension mechanism, one can adjust the disk position to center.
2. It would be a very rare situation for the top tension to change whatsoever from the (red center marking) factory setting. The most likely cause of loose top tension under the normal center mark position, would be accumulated lint, thread, or a sticky substance between the disks. This would prevent the tension compression disks from applying an even tension on the sewing yarn (thread). Often this can be blown out with compressed air when the presser foot lever is lifted in the up position. In some cases, soft drinks and other sticky or corrosive liquids can find their way between the disks. In this case, the tension assembly must be removed, disassembled, and the disks cleaned and polished.
3. Check the facial surfaces of the bobbin case for corrosion, and sticky substances that prevents the thread from easily sliding over the bobbin case.
4. Check that the spindle of the hook body is not bent or warped, causing the bobbin case to wobble, thus creating an intermittent pressure on the hook race cover at the moment that the thread is trying to escape over the bobbin case finger. (Replace the hook body)
5. Inspect the undercut on the hook body spindle for thread wrappings and knots. This condition can cause the bobbin case to press hard against the hook race cover, hence hindered thread escapement .
6. Exceedingly tight bottom tension can cause some problems as well. ( If you don't know how to adjust Bernina bobbin cases to factory settings, please ask).
7. Hook timing, (loop lift) can be out enough to affect thread escapement. This is typical of newer machines made after 1986 since Bernina no longer made fixed timed machines like the earlier Swiss made models. The later made models have timing components that can slip under stressed machine mechanics.
SewTechnical Home ">

Feb 13, 2014 | Bernina 1008

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My Bernina Bernette 65 has a problem with the thread bunching up every 10-15 stiches on the bottom. Some of the thread stitches on the bottom of the fabric are in a straight line, and then the thread will...

try a new needle--one that is for the fabric being sewed
then try to adjust the top thread tension again, if the stitches remain loose and the tension won't adjust then the tension knob needs to be checked to see if there is something wrong with it.
also check to make sure the bobbin is inserted correctly into the bobbin case, if the bobbin is not turned the right way in the bobbin case the sewing machine will not stitch correctly.

Aug 05, 2013 | Bernina BERNETTE 65 Mechanical Sewing...

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My bernina activa 130 wont sew

Fit a new needle, clean and oil the hook race, whether-or-not your manual says it doesn't need it and check that you have some tension on the thread coming out of the bobbin case and top tension unit. Are you threading the top thread with the foot up or down ? You should always thread the machine with the foot up to ensure the thread goes through the tension unit properly.

Mar 02, 2012 | Bernina Activa 140

2 Answers

I have tried several steps to correct my Bernina 160's bottom thread tension; too loose. I did occur after I cleaned out bobbin case & hook race,

Buy to loose do you mean big loops on the botom? If so fallow these steps.
Usaly big loops on the botom of the fabric means that the top is not threaded coreccty. I would sugest threading the top thread again all the way to the needle. After you have done that pull on the thread and lift and lower the presser foot. There should be tension when it is down and no tensoin when it is up. I allway do this before I sew on a machine. If you do not have tension on it when the presser foot is down you did not get ithe thread in the tension unit. If you have tension when it is up then your machine needs a upper tension release adjustement.
Hope this helps friend.
Other problems could be a small peace of broke needle it the race area(inspect this close).
If you adjusted your bobbin tension this may need to be reset.

Mar 17, 2011 | Bernina Virtuosa 160

1 Answer

The bottom thread on my Bernina 140 jams

Try pulling more thread out before you begin the seam - about 6". If you can hold the threads while you take the first few stitches that helps too.

Apr 02, 2010 | Bernina Activa 140

1 Answer

Singer 301a...sews on top of fabric nicely...bottom is just loose loops of's like the bobbin is not sewing...I put 2 different colors in to is perfect...on bottom of fabric I see the...

This is a tension adjustment problem. It's good to use two different colors of thread, like you did. From your description, the top thread (needle thread) tension needs to be tighter. As you tighten the tension of the top thread, you'll see that the top thread pulls the bobbin thread up into the fabric so it's no longer laying loose on the bottom of the fabric.

You'll need to have the pressure foot down when you tighten the tension. Tighten it a little, sew a practice seam, check to see what the stitch looks like. Tighten it a little more, sew, check, etc etc--until both top and bottom look the same--you shouldn't see much (if any) of the bobbin thread color on top of the fabric or the top thread color on the underside.

Let me know how this works for you, ok?


Jan 25, 2010 | Singer Sewing Machines

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