Try holding onto the thread tails as you begin to sew, this happens on most machines. If you remember to hold onto the thread tails as you start sewing, they won't get all blobbed up underneath, nor will the thread pull out of the needle (which happens when the thread take-up lever is not at it's highest position). After a while, it will become 2nd nature to you.
Linda in NJ

I have a Janome 6600 which I love, but.......... when I'm piecing and using the thread cutter on the machine, the thread underneath ALWAYS blobs up at the beginning of a new line of stitching. I have tried pushing the fabric thru past the place where I should begin stitching to hopefully straighten out this thread, but to no avail. In fact sometimes that makes it tighten up and it pops out of my needle and I need to then re-thread the needle.

Any suggestions?

I absolutely love my 6600 too! I have all the extra feet and use it almost daily. I don't know why I settled before. I had it in for cleaning and I about died without it. Anyone who is interested in this machine should check it out. My favorite online quilt group is the Janome Jedi's 6500/6600 quilt group. I learn so much from everyone.

I just bought one and am going to my 'learning to use it' class tomorrow. Thanks for sharing your experiences!

After using one of these machines at a quilting retreat I went to last fall, I was hooked. This is the best quilting machine, it's got some embrodery stitches and the thread cutter button. But the best thing about this machine is the accu-feed that has interchangable feet to help you in what ever you are doing at that time. I have the stitch in the ditch accu-feed foot, the 1/4 foot (which I use to do my bindings, and it works like a dream!) I also have the open toe so I can do decorative stitches and not have puckers on the quilt back. I'm still learning the many things it can do, and as the motto of my favorite quilt shop says, "I have more fun with a sewing machine than I should have" And that's just not whistling dixie!!!!
If you have a dealer in your area, you really should try one.