Are you bringing up the bobbin thread (through the top) when you begin stitching?
Someone stated above they would only get the Janome Horizon 7700 for regular sewing - it was built more for quilting and has the 11" throat space, FMQs beautifully, and also has a free arm and great "regular" sewing features, so I don't get that...OH, NEVER MIND! I realize now you were wanting embroidery, too. Sorry!
Anyhow, I agree you need to figure out the problem first (but STILL go for the new machine!).