I have model 8280 and the bobbin thread keeps bunching up on the bottom. I have tried to rethread it but it keeps happening.

Hi Bettyme2.
just found this on the web.
Try rethreading the top. A sewing machine repairman told me one time that if the top messes up rethread the bottom and if the bottom messes up rethread the top. Check for lent in the bobbin area too. Don't use canned air but a soft clean brush. Hope this helps.

or try this link out.
https://www.google.com/search?q=Thread+bunching+on+Activa+230&rlz=1C1AVFC_enGB797GB798&oq=Thread+bunching+on++Activa+230&aqs=chrome..69i57.9137j0j4&sourceid=chrome&ie=UTF-8

what you have is called bird nesting and is from the needle thread tension being not tight enough

not sure if this will help you...Check Your Tension Settings. Looping underneath the fabric usually occurs when there is not enough tension in the needle thread to pull the bobbin thread. Sometimesthread buching can be caused by something as simple as the tension dial being inadvertently turned.

WHY IS THREAD BUNCHING UNDERNEATH MY FABRIC ? ' eBay

www.ebay.co.uk/gds/WHY-IS-THREAD-BUNCHING-UNDERNEATH-MY.../g.html..
or you could go to this link and see if it helps you out.. thread keeps looping Google Search

Is it really the bobbin thread that is bunching? Generally, thread messes under the fabric are the fault of the top thread, and thread messes on top of the fabric are a bobbin problem.

Top thread bunching under the fabric is called "thread nesting" or "bird nesting" but I prefer to call it thread "barfs." Most often, it occurs because the top thread has not been seated completely in the tension disk.

Install a brand new needle.
Remove the top thread from the machine.
RAISE the presser foot and rethread the top thread.
(Verify the thread path is correct.)
Set the top tension disk at the midway point.

Retest your machine. Tweak the top tension if required.

Try these suggestions
1. Change needle
2. Rethread the machine--top --make sure to use every thread guide
3. Take the bobbin out --make sure it is inserted correctly into the bobbin
Case, & make sure the bobbin is turned the correct way
4. make sure the thread has not come off the thread take up lever
5. Clean under the needle plate & in the bobbin area for lint or threads

Put the tension back up to about 5. Rethread the machine entirely, and make sure you have the pressure foot in the up position when you rethread. If your getting bunching on the bottom, it's probably your top thread that's bunching up. After you rethread, put a small piece of fabric under the pressure foot, lower the pressure foot, and turn the handwheel in the forward direction and watch the thread as it comes around the bobbin case. If it goes around smoothly, try it with the foot control. If it hangs up as it goes around the bobbin case, you might have a burr on the black plastic bobbin case. Take it out, check for any burrs, sand them down, and try again.

It is in your top threading, try this test, rethread, now with the presser foot up, pull the top thread, it should feed smoothly, now lower the presser foot, it should barely move. Sometimes this seats the thread in the tension discs. Also, make sure that your needle is fresh.

change the needle
clean under the needle plate where the feed dogs are for lint
make sure the thread has not come off the thread take up lever
rethread the machine

When I have run into similar problems with my older Singer, it's because there is a bit of thread caught somewhere in the bobbin mechanism that doesn't allow the shuttle to run freely. Take the bobbin assembly apart and use a bright light to see if you see any bits of thread in there.

Good luck and let me know if this works!

I had the same problem and I tried everything including removing the bobin case, cleaning out lint, changing the needle, adjusting the tension but it did not work. Then I finally tried reloading the bobin thread, making sure to load the bobin according the manual directions....and the problem was solved...no more tangles... just a nice even stitch...yeah!